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Sample records for broadleaf deciduous forest

  1. Leaf-on canopy closure in broadleaf deciduous forests predicted during winter

    USGS Publications Warehouse

    Twedt, Daniel J.; Ayala, Andrea J.; Shickel, Madeline R.

    2015-01-01

    Forest canopy influences light transmittance, which in turn affects tree regeneration and survival, thereby having an impact on forest composition and habitat conditions for wildlife. Because leaf area is the primary impediment to light penetration, quantitative estimates of canopy closure are normally made during summer. Studies of forest structure and wildlife habitat that occur during winter, when deciduous trees have shed their leaves, may inaccurately estimate canopy closure. We estimated percent canopy closure during both summer (leaf-on) and winter (leaf-off) in broadleaf deciduous forests in Mississippi and Louisiana using gap light analysis of hemispherical photographs that were obtained during repeat visits to the same locations within bottomland and mesic upland hardwood forests and hardwood plantation forests. We used mixed-model linear regression to predict leaf-on canopy closure from measurements of leaf-off canopy closure, basal area, stem density, and tree height. Competing predictive models all included leaf-off canopy closure (relative importance = 0.93), whereas basal area and stem density, more traditional predictors of canopy closure, had relative model importance of ≤ 0.51.

  2. Multidisciplinary Research on Canopy Photosynthetic Productivity in a Cool-Temperate Deciduous Broadleaf Forest in Japan

    NASA Astrophysics Data System (ADS)

    Muraoka, H.; Noda, H. M.; Saitoh, T. M.; Nagai, S.

    2014-12-01

    Forest canopy has crucial roles in regulating energy and material exchange between the atmosphere and terrestrial ecosystems and in ecological processes with respect to carbon cycle and growth in the ecosystems. Challenges to the canopy of tall forests for such research involve the access to the leaves for ecophysiological observations, responses of leaves to the changing environments from seconds to years, and up-scaling the leaf-level phenomena to canopy and landscape-levels. A long-term, multidisciplinary approach has been conducted in a cool-temperate deciduous broadleaf forest in Takayama site (ca. 1400m a.s.l.) in central Japan. This forest canopy is dominated by Quercus crispula and Betula ermanii. We have been focusing on the phenology of photosynthetic productivity from a single leaf to canopy, and to landscape level, by combining leaf ecophysiological research, optical observations by spectroradiometers and time-laps cameras with the aid of "Phenological Eyes Network (PEN)", and process-based modellings. The canopy-level photosynthesis is then compared with the micrometeorolgical observation of CO2 flux at the site. So far we have been clarifying that (1) inter-annual variations in seasonal growth rate and senescence rate of leaf photosynthetic capacity and canopy leaf area are largely responsible for the inter-annual change in forest photosynthesis, and (2) spectral vegetation indices such as enhanced vegetation index (EVI) and chlorophyll index (CCI) can be the indicator to observe the phenology of forest canopy photosynthesis. In addition to these efforts since 2003, we established an open-field warming experiment on the branches of the canopy trees, to investigate the possible influence of temperature increase on leaf photosynthetic and optical properties and then to examine whether the optical satellite remote sensing can detect the changes in photosynthetic capacity and phenology by ongoing global warming.

  3. Estimating soil respiration using spatial data products: A case study in a deciduous broadleaf forest in the Midwest USA

    NASA Astrophysics Data System (ADS)

    Huang, Ni; Gu, Lianhong; Niu, Zheng

    2014-06-01

    This study aimed to investigate the potential of spatially distributed data products in estimating soil respiration (Rs), including land surface temperature (LST) and spectral vegetation index from the Moderate Resolution Imaging Spectroradiometer (MODIS) and root zone soil moisture derived from the assimilation of the NASA Advanced Microwave Scanning Radiometer-EOS and a land surface model, at a deciduous broadleaf forest site in the Midwest USA. Several statistical models were used to examine the dependencies of Rs on these spatial data products, and accuracy of these models was compared to the models based on in situ measurements. The models based on mean LST (i.e., averaging nighttime and daytime LST from MODIS) and root zone soil moisture explained 82% and 72% of seasonal variations in Rs for spring and winter dormant periods, respectively. In the growing season, the models depending on mean LST, root zone soil moisture, and photosynthesis-related enhanced vegetation index showed comparable accuracy with the models entirely based on in situ measured data, except for the midgrowing period. Drought stress led to a relatively low explanation capacity for the Rs model based on spatial data products during the midgrowing period. However, this model still explained 76% of temporal dynamics of Rs over the midgrowing period. Our results suggested that simple models based entirely on spatial data products have the potential to estimate Rs at the temperate deciduous forest site. The conclusions drawn from the present study provided valuable information for large-scale estimates of Rs in temperate deciduous forest ecosystems.

  4. Tree species composition influences dependence of climate forcing on spring phenology across temperate deciduous broadleaf forests in Eastern United States

    NASA Astrophysics Data System (ADS)

    Melaas, E. K.; Friedl, M. A.; Richardson, A. D.

    2014-12-01

    Phenological events in temperate deciduous forests, such as bud burst and senescence, exert strong control over seasonal fluxes of water, energy and carbon. The timing of these transitions is influenced primarily by air temperature, which makes them robust indicators of biological responses to climate change. However, the exact nature and magnitude of these controls is currently poorly understood. In this paper, we used a combination of surface meteorological data, species composition maps, remote sensing, and ground-based observations, including camera-based time series of canopy greenness from PhenoCams and citizen science data from the USA-National Phenology Network, to develop and test models that predict the timing of spring leaf emergence across several different deciduous broadleaf forest types in the eastern contiguous United States (68°W-95°W, 30°N-50°N). As part of this analysis, we analyzed two existing land surface model phenology subroutines and specifically examined predictions for two years with anomalously warm temperatures during dormancy to investigate the role of chilling. The results indicate significant differences in cumulative heating requirements and photoperiod cues among forest types. Moreover, we found that regional patterns of species composition explain spatial variation in prediction errors from existing models. In addition, we identified a marginal, but statistically significant decrease in model bias when chilling requirements were included during an anomalously warm winter with average spring temperatures, but no significant improvement when both winter and springtime temperatures were more representative of future climate.

  5. Post-clearcut dynamics of carbon, water and energy exchanges in a midlatitude temperate, deciduous broadleaf forest environment.

    PubMed

    Williams, Christopher A; Vanderhoof, Melanie K; Khomik, Myroslava; Ghimire, Bardan

    2014-03-01

    Clearcutting and other forest disturbances perturb carbon, water, and energy balances in significant ways, with corresponding influences on Earth's climate system through biogeochemical and biogeophysical effects. Observations are needed to quantify the precise changes in these balances as they vary across diverse disturbances of different types, severities, and in various climate and ecosystem type settings. This study combines eddy covariance and micrometeorological measurements of surface-atmosphere exchanges with vegetation inventories and chamber-based estimates of soil respiration to quantify how carbon, water, and energy fluxes changed during the first 3 years following forest clearing in a temperate forest environment of the northeastern US. We observed rapid recovery with sustained increases in gross ecosystem productivity (GEP) over the first three growing seasons post-clearing, coincident with large and relatively stable net emission of CO2 because of overwhelmingly large ecosystem respiration. The rise in GEP was attributed to vegetation changes not environmental conditions (e.g., weather), but attribution to the expansion of leaf area vs. changes in vegetation composition remains unclear. Soil respiration was estimated to contribute 44% of total ecosystem respiration during summer months and coarse woody debris accounted for another 18%. Evapotranspiration also recovered rapidly and continued to rise across years with a corresponding decrease in sensible heat flux. Gross short-wave and long-wave radiative fluxes were stable across years except for strong wintertime dependence on snow covered conditions and corresponding variation in albedo. Overall, these findings underscore the highly dynamic nature of carbon and water exchanges and vegetation composition during the regrowth following a severe forest disturbance, and sheds light on both the magnitude of such changes and the underlying mechanisms with a unique example from a temperate, deciduous

  6. Effects of a windthrow disturbance on the carbon balance of a broadleaf deciduous forest in Hokkaido, Japan

    NASA Astrophysics Data System (ADS)

    Yamanoi, K.; Mizoguchi, Y.; Utsugi, H.

    2015-12-01

    Forests play an important role in the terrestrial carbon balance, with most being in a carbon sequestration stage. The net carbon releases that occur result from forest disturbance, and windthrow is a typical disturbance event affecting the forest carbon balance in eastern Asia. The CO2 flux has been measured using the eddy covariance method in a deciduous broadleaf forest (Japanese white birch, Japanese oak, and castor aralia) in Hokkaido, where incidental damage by the strong Typhoon Songda in 2004 occurred. We also used the biometrical method to demonstrate the CO2 flux within the forest in detail. Damaged trees amounted to 40 % of all trees, and they remained on site where they were not extracted by forest management. Gross primary production (GPP), ecosystem respiration (Re), and net ecosystem production were 1350, 975, and 375 g C m-2 yr-1 before the disturbance and 1262, 1359, and -97 g C m-2 yr-1 2 years after the disturbance, respectively. Before the disturbance, the forest was an evident carbon sink, and it subsequently transformed into a net carbon source. Because of increased light intensity at the forest floor, the leaf area index and biomass of the undergrowth (Sasa kurilensis and S. senanensis) increased by factors of 2.4 and 1.7, respectively, in 3 years subsequent to the disturbance. The photosynthesis of Sasa increased rapidly and contributed to the total GPP after the disturbance. The annual GPP only decreased by 6 % just after the disturbance. On the other hand, the annual Re increased by 39 % mainly because of the decomposition of residual coarse-wood debris. The carbon balance after the disturbance was controlled by the new growth and the decomposition of residues. The forest management, which resulted in the dead trees remaining at the study site, strongly affected the carbon balance over the years. When comparing the carbon uptake efficiency at the study site with that at others, including those with various kinds of disturbances, we

  7. Effects of a windthrow disturbance on the carbon balance of a broadleaf deciduous forest in Hokkaido, Japan

    NASA Astrophysics Data System (ADS)

    Yamanoi, K.; Mizoguchi, Y.; Utsugi, H.

    2015-07-01

    Forests play an important role in the terrestrial carbon budget, with most being in a carbon sequestration stage. The net carbon releases that occur result from forest disturbance, and windthrow is a typical disturbance event affecting the forest carbon balance in eastern Asia. The carbon budget has been measured using the eddy covariance method in a deciduous broadleaf forest (Japanese white birch, Japanese oak, and castor aralia) in Hokkaido, where accidental damage by the strong typhoon, Songda, in 2004 occurred. We also used the biometrical method to demonstrate the carbon flow within the forest in detail. Damaged trees amounted to 40 % of all trees, and they remained on site where they were not extracted by forest management. Gross primary production (GPP), ecosystem respiration (Re), and net ecosystem production were 1350, 975, and 375 g C m-2 yr-1 before the disturbance and 1262, 1359, and -97 g C m-2 yr-1 2 years after the disturbance, respectively. Before the disturbance, the forest was an evident carbon sink, and it subsequently transformed to net a carbon source. Because of light enrichment at the forest floor, the leaf area index and biomass of the undergrowth (Sasa kurilensis and S. senanensis) increased by factors of 2.4 and 1.7, respectively, in 3 years subsequent to the disturbance. The photosynthesis of Sasa increased rapidly and contributed to the total GPP after the disturbance. The annual GPP only decreased by 6 % just after the disturbance. On the other hand, the annual Re increased by 39 % mainly because of the decomposition of residual coarse-wood debris. The carbon balance after the disturbance was controlled by the new growth and the decomposition of residues. The forest management, which resulted in the dead stands remaining at the study site, strongly affected the carbon budget over the years. When comparing the carbon uptake efficiency at the study site with that at others, including those with various kinds of disturbances, we

  8. Year-long carbon dioxide exchange above a broadleaf deciduous forest in Sapporo, Northern Japan

    NASA Astrophysics Data System (ADS)

    Nakai, Y.; Kitamura, K.; Suzuki, S.; Abe, S.

    2003-04-01

    This paper reports the results of a full year (2000) of measurements of CO2 flux at a successional forest of mature birch and growing oak with Sasa-bamboo in Sapporo, Japan. Eddy covariance fluxes of CO2 were obtained using a closed-path infrared gas analyzer. Changes in CO2 storage under the eddy-flux measurement level were quantified using vertical profiles of the CO2 concentration. Seasonal variations in net CO2 exchange between the forest and the atmosphere are discussed in terms of both phenological developments of the forest canopy and micrometeorological variables. To estimate the annual exchange of CO2, the net CO2 exchange data both during periods of poor turbulence and during periods of missing data were replaced by simple parametric models based on measurements of soil temperatures and photosynthetically active radiation. The corrected annual carbon sequestration estimate was 260 g C m-2. The estimates of annual gross carbon gain and loss at the forest were 1120 and 860 g C m-2.

  9. Effects of drought on leaf gas exchange in an eastern broadleaf deciduous forest

    NASA Astrophysics Data System (ADS)

    Roman, D. T.; Brzostek, E. R.; Dragoni, D.; Rahman, A. F.; Novick, K. A.; Phillips, R.

    2013-12-01

    Understanding plant physiological adaptations to drought is critical for predicting changes in ecosystem productivity that result from climate variability and future climate change. From 2011-2013, southern Indiana experienced a late growing season drought in 2011, a severe early season drought in 2012, and a wet growing season in 2013 characterized by an absence of water stress with frequent precipitation and milder temperatures. The 2012 drought was unique due to the severity and early onset drought conditions (compared to the more frequent late season drought) and was characterized by a Palmer Drought severity index below -4 and precipitation totals from May - July that were 70% less than the long-term (2000 - 2010) mean. During the 2012 drought, an 11% decline in net ecosystem productivity relative to the long-term mean was observed at the AmeriFlux tower in Morgan Monroe State Forest despite a growing season that started ~25 days earlier. Thus, the objective of this study is to evaluate species-specific contributions to the canopy-scale response to inter-annual variability in water stress. We investigated differences between tree species in their response to climate variability using weekly leaf gas exchange and leaf water potential measurements during the growing seasons of 2011-2013. We used this unique dataset, collected at the top of the canopy with a 25 m boom lift, to evaluate changes in leaf water status and maximum assimilation capacity in the drought versus non-drought years. The leaf-level physiology of oak (Quercus) species appears to be less sensitive to drought than other species (tulip poplar [Liriodendron tulipifera], sassafras [Sassafras albidum] and sugar maple [Acer saccharum]). Preliminary data shows mean canopy leaf water potential for oaks was 30.5% more negative in May-July 2012 versus the same time period in 2013. During these same periods the rate of C assimilation in oaks was reduced by only 3%, whereas other species were reduced by

  10. Comparison of MODIS-Data With Selected Model Parameters and Measured Flux-Data for two Biome Types (Broadleaf-Deciduous and Needle-Leaf Forest)

    NASA Astrophysics Data System (ADS)

    Vetter, M.; Knohl, A.; Zhao, M.; Churkina, G.; Gloor, M.

    2002-12-01

    MODIS-data were available for 2001 for the following cites: Hainich (broadleaf deciduous; beechforest) and Tharandt (needleleaf; spruceforest) both Germany, Sor\\o (broadleaf decidious; beechforest) Denmark and Hyytiälä (needleleaf; pineforest) Finland. The extracted MODIS-data were 5 x 5 km2 cutoffs with center at the fluxtower cites. For modelling of LAI and NPP we used the mechanistic model Biome-BGC (Running and Coughlan, 1988, Running and Gower,1991, Running 1994) with general ecophysiological parameterization schemes (White et al, 2000). Long term climate records were generated by MT-CLIM (Thornton et al, 2000). The modeled and measured NEE were in good agreement (R2 between 0.71 - 0.89). The modeled annual variation of LAI was close to the measured LAI for Hainich, for the other cites maximum LAI were close to modeled maximum. We will investigate how the MODIS parameters LAI, GPP and PSN cover measured and modeled parameters for the selected cites and biome types. This will give valuable information on how the parameters may be used for model evaluation (fluxes) or as model initialisation (LAI). References:\\Running, S.W. and Coughlan, J.C.,1988, A general model of forest processes for regional applications. Ecological Modeling, 42, pp. 125 - 124.\\Running, S.W. and Gower, S.T., 1991, FOREST BGC, A general model of forest ecosystem processes for regional applications. II Dynamic carbon allocation and nitrogen budgets. Tree Physiol., 9, pp. 147 - 160.\\Running, S.W., 1994, Testing forest BGC ecosystem process simulations across a climatic gradient in Oregon. Ecol. Appl., 4, pp. 238 - 247.\\Thornton et al.,2000,Simultaneous estimation of daily solar radiation and humidity from observed temperature and precipitation: an application over complex terrain in Austria. Agricultural and Forest Meteorology, 4, pp. 255 - 271.

  11. Species and stand traits of broadleaf deciduous and evergreen trees and its role on hydrologic processes in a semiarid forest

    NASA Astrophysics Data System (ADS)

    Arredondo, T.; Perez Suarez, M.; Rodriguez Robles, U.

    2013-05-01

    Empirical and modelling studies have pointed out to the importance of morphologic, physiologic and chemical traits of plant species on the control of functional aspects of ecosystems. Land use change exerts a pervasive effect on ecosystems through its effects on plant cover, species composition and the arrangement of vegetation. Species footprint influence on ecosystem processes occurs through their functional plant traits, understanding their role might be possible to predict alterations in ecosystem functioning. Using the concept of functional matrix we examined how traits of two dominant forest species, one broadleaf (Quercus potosina) and one evergreen (Pinus cembroides) observed as mixed and monospecific stands, exerted an influence on ecohydrological processes. Thus, differences in plant height, canopy structure, litter production and quality, root system distribution, etc. determined differences in vertical and horizontal rain fluxes. Oak monospecif stands showed 20% higher throughfall compared to mixex and pure pine stands as a consequence of exhibiting a monolayered canopy. On the other hand, runoff was 67 and 33 % in pine compared to oak and mixed stands a result that arosing from observed differences in litter decomposition stage as well as its proportion. Differences between root systems accounted for less negative plant water potentials in oak in contrast to pine. These differences together with leaf phenology allowed oak trees to reduce the plant water potential during the drought period. Similar pattern observed for pine is attributed to foraging capabilities of an extensive root system.

  12. Seasonal cycles of water-soluble organic nitrogen aerosols in a deciduous broadleaf forest in northern Japan

    NASA Astrophysics Data System (ADS)

    Miyazaki, Yuzo; Fu, PingQing; Ono, Kaori; Tachibana, Eri; Kawamura, Kimitaka

    2014-02-01

    The seasonal variations in aerosol water-soluble organic nitrogen (WSON) concentrations measured in a deciduous forest canopy over an approximately 30 month period were investigated for possible sources in the forest. The WSON concentrations (average 157 ± 127 ng N m-3) and WSON/water-soluble total nitrogen mass fractions (average 20 ± 11%) in the total suspended particulate matter exhibited a clear seasonal cycle with maxima in early summer. The WSON mass was found to reside mostly in the fine-mode size range (Dp < 1.9 µm) during the summer months. WSON was positively correlated with oxidation products of α-pinene and isoprene with similar size distributions, suggesting that secondary formation from biogenic hydrocarbon precursors is a plausible source for WSON in summer. In contrast, the majority of WSON in autumn was associated with coarse fraction (Dp > 1.9 µm), which was similar to the size distributions of sugar compounds, indicating that the major WSON sources in autumn are associated with primary biological emissions. The vertical differences in WSON concentrations suggest that the water-soluble organic aerosol is enriched with nitrogen below the canopy level relative to the forest floor. The WSON concentration increased with enhanced hydrogen ion concentrations in aerosol in the early summer, indicating that aerosol acidity associated with anthropogenic sources outside the forest likely plays an important role in the formation of WSON in that season. The study suggests that multiple sources of WSON within the forest canopy may dominate over others in specific seasons, providing insights into WSON formation processes in forest environments.

  13. Endocarp thickness affects seed removal speed by small rodents in a warm-temperate broad-leafed deciduous forest, China

    NASA Astrophysics Data System (ADS)

    Zhang, Hongmao; Zhang, Zhibin

    2008-11-01

    Seed traits are important factors affecting seed predation by rodents and thereby the success of recruitment. Seeds of many tree species have hard hulls. These are thought to confer mechanical protection, but the effect of endocarp thickness on seed predation by rodents has not been well investigated. Wild apricot ( Prunus armeniaca), wild peach ( Amygdalus davidiana), cultivated walnut ( Juglans regia), wild walnut ( Juglans mandshurica Maxim) and Liaodong oak ( Quercus liaotungensis) are very common tree species in northwestern Beijing city, China. Their seeds vary greatly in size, endocarp thickness, caloric value and tannin content. This paper aims to study the effects of seed traits on seed removal speed of these five tree species by small rodents in a temperate deciduous forest, with emphasis on the effect of endocarp thickness. The results indicated that speed of removal of seeds released at stations in the field decreased significantly with increasing endocarp thickness. We found no significant correlations between seed removal speed and other seed traits such as seed size, caloric value and tannin content. In seed selection experiments in small cages, Père David's rock squirrel ( Sciurotamias davidianus), a large-bodied, strong-jawed rodent, selected all of the five seed species, and the selection order among the five seed species was determined by endocarp thickness and the ratio of endocarp mass/seed mass. In contrast, the Korean field mouse ( Apodemus peninsulae) and Chinese white-bellied rat ( Niviventer confucianus), with relatively small bodies and weak jaws, preferred to select small seeds like acorns of Q. liaotungensis and seeds of P. armeniaca, indicating that rodent body size is also an important factor affecting food selection based on seed size. These results suggest endocarp thickness significantly reduces seed removal speed by rodents and then negatively affects dispersal fitness of seeds before seed removal of tree species in the study

  14. Estimation of Leaf Area Index Using Downward and Upward Looking Digital Cameras in a Deciduous Broadleaf Forest

    NASA Astrophysics Data System (ADS)

    Choi, J.; Kang, S.; Lim, J.; Nasahara, K. N.

    2010-12-01

    Monitoring the distribution and changes of leaf area index (LAI) is important for assessing growth of a forest ecosystem. However, it is difficult and time consuming to directly measure LAI. In this study, we suggest an indirect method to calculate the LAI based on the analyses of digital spectral image from the Phenological Eyes Network (PEN) system which consists of Automatic-capturing Digital Fisheye Camera (ADFC) and Hemi-Spherical Spectroradiometer (HSSR). Our main purpose is to develop indirect methods for estimating LAI using either upward or downward ADFC without other ancillary field observation. In developing stage, we used field measured LAI by LAI-2000 plant canopy analyzer (PCA, LI-Cor.), two ADFCs and Hemiview software. The ADFC is a set of Nikon coolpix 4500 camera and FC-E8 fisheye lens and it automatically capture downward and upward canopy in hourly interval. The downward ADFC was used to calculate various vegetation indices through RGB analysis. Meanwhile, the upward ADFC was used to estimate LAI using the Hemiview software. Threshold value of the Hemiview is important to separate the leaves and background such as sky, wood, edge on digital image. In other to decide accurate threshold value of the Hemiview, we performed that comparison of field measured LAI measured and the Hemiview LAI using upward ADFC digital image. Based on the determined threshold value, an objective method to recognize peculiar patterns of RGB histogram around the threshold was developed and applied to estimate LAI from upward ADFC images only. As well, two spectral indices (i.e. G/R ratio and 2G-RB) were calculated from the downward ADFC images. The relations between the spectral indices and LAI time series from the upward ADFC images were investigated and regression models were developed. The regression models were utilized to reconstruct seasonal LAI variation from the downward ADFC images only. Both field-measured and upward ADFC-derived LAIs showed good agreement (R2

  15. Inversely Estimating the Vertical Profile of the Soil CO2 Production Rate in a Deciduous Broadleaf Forest Using a Particle Filtering Method

    PubMed Central

    Sakurai, Gen; Yonemura, Seiichiro; Kishimoto-Mo, Ayaka W.; Murayama, Shohei; Ohtsuka, Toshiyuki; Yokozawa, Masayuki

    2015-01-01

    Carbon dioxide (CO2) efflux from the soil surface, which is a major source of CO2 from terrestrial ecosystems, represents the total CO2 production at all soil depths. Although many studies have estimated the vertical profile of the CO2 production rate, one of the difficulties in estimating the vertical profile is measuring diffusion coefficients of CO2 at all soil depths in a nondestructive manner. In this study, we estimated the temporal variation in the vertical profile of the CO2 production rate using a data assimilation method, the particle filtering method, in which the diffusion coefficients of CO2 were simultaneously estimated. The CO2 concentrations at several soil depths and CO2 efflux from the soil surface (only during the snow-free period) were measured at two points in a broadleaf forest in Japan, and the data were assimilated into a simple model including a diffusion equation. We found that there were large variations in the pattern of the vertical profile of the CO2 production rate between experiment sites: the peak CO2 production rate was at soil depths around 10 cm during the snow-free period at one site, but the peak was at the soil surface at the other site. Using this method to estimate the CO2 production rate during snow-cover periods allowed us to estimate CO2 efflux during that period as well. We estimated that the CO2 efflux during the snow-cover period (about half the year) accounted for around 13% of the annual CO2 efflux at this site. Although the method proposed in this study does not ensure the validity of the estimated diffusion coefficients and CO2 production rates, the method enables us to more closely approach the “actual” values by decreasing the variance of the posterior distribution of the values. PMID:25793387

  16. High sensitivity of northeastern broadleaf forest trees to water availability

    NASA Astrophysics Data System (ADS)

    Levesque, M.; Pederson, N.; Andreu-Hayles, L.

    2015-12-01

    Temperate deciduous forests of eastern US provide goods and services to millions of people and play a vital role in the terrestrial carbon and hydrological cycles. However, ongoing climate change and increased in CO2 concentration in the atmosphere (ca) are expected to alter growth and gas exchange of trees, and ultimately forest productivity. Still, the magnitude of these effects is unclear. A better comprehension of the species-specific responses to environmental changes will better inform models and managers on the vulnerability and resiliency of these forests. Tree-ring analysis was combined with δ¹³C and δ18O measurements to investigate growth and physiological responses of red oak (Quercus rubra L.) and tulip poplar (Liriodendron tulipifera L.) in northeastern US to changes in water availability and ca for the period 1950-2014. We found very strong correlations between summer climatic water balance (June-August) and isotopic tree-ring series for δ¹³C (r = -0.65 and -0.73), and δ18O (r = -0.59 and -0.70), for red oak and tulip poplar, respectively. In contrast, tree-ring width was less sensitive to summer water availability (r = 0.33-0.39). Prior to the mid 1980s, low water availability resulted in low stomatal conductance, photosynthesis, and growth. Since that period, pluvial conditions occurring in northeastern US have increased stomatal conductance, carbon uptake, and growth of both species. These findings demonstrate that broadleaf trees in this region could be more sensitive to drought than expected. This appears especially true since much of the calibration period looks wet in a multi-centennial perspective. Further, stronger spatial correlations were found between climate data with tree-ring isotopes than with tree-ring width and the geographical area of the observed δ18O-precipitation response (i.e. the area over which correlations are > 0.5) covers most of the northeastern US. Given the good fit between the isotopic time series and water

  17. Seasonal and vertical changes in leaf angle distribution for selected deciduous broadleaf tree species common to Europe

    NASA Astrophysics Data System (ADS)

    Raabe, Kairi; Pisek, Jan; Sonnentag, Oliver; Annuk, Kalju

    2014-05-01

    Leaf inclination angle distribution is a key parameter in determining the transmission and reflection of radiation by vegetation canopies. It has been previously observed that leaf inclination angle might change gradually from more vertical in the upper canopy and in high light habitats to more horizontal in the lower canopy and in low light habitats [1]. Despite its importance, relatively few measurements on actual leaf angle distributions have been reported for different tree species. Even smaller number of studies have dealt with the possible seasonal changes in leaf angle distribution [2]. In this study the variation of leaf inclination angle distributions was examined both temporally throughout the growing season and vertically at different heights of trees. We report on leaf inclination angle distributions for five deciduous broadleaf species found commonly in several parts of Europe: grey alder (Alnus incana), Silver birch (Betula pendula Roth), chestnut (Castanea), Norway maple (Acer platanoides), and aspen (Populus tremula). The angles were measured using the leveled camera method [3], with the data collected at several separate heights and four times during the period of May-September 2013. The results generally indicate the greatest change in leaf inclination angles for spring, with the changes usually being the most pronounced at the top of the canopy. It should also be noted, however, that whereas the temporal variation proved to be rather consistent for different species, the vertical variation differed more between species. The leveled camera method was additionally tested in terms of sensitivity to different users. Ten people were asked to measure the leaf angles for four different species. The results indicate the method is quite robust in providing coinciding distributions irrespective of the user and level of previous experience with the method. However, certain caution must be exercised when measuring long narrow leaves. References [1] G.G. Mc

  18. Multiscale modeling of spring phenology across Deciduous Forests in the Eastern United States.

    PubMed

    Melaas, Eli K; Friedl, Mark A; Richardson, Andrew D

    2016-02-01

    Phenological events, such as bud burst, are strongly linked to ecosystem processes in temperate deciduous forests. However, the exact nature and magnitude of how seasonal and interannual variation in air temperatures influence phenology is poorly understood, and model-based phenology representations fail to capture local- to regional-scale variability arising from differences in species composition. In this paper, we use a combination of surface meteorological data, species composition maps, remote sensing, and ground-based observations to estimate models that better represent how community-level species composition affects the phenological response of deciduous broadleaf forests to climate forcing at spatial scales that are typically used in ecosystem models. Using time series of canopy greenness from repeat digital photography, citizen science data from the USA National Phenology Network, and satellite remote sensing-based observations of phenology, we estimated and tested models that predict the timing of spring leaf emergence across five different deciduous broadleaf forest types in the eastern United States. Specifically, we evaluated two different approaches: (i) using species-specific models in combination with species composition information to 'upscale' model predictions and (ii) using repeat digital photography of forest canopies that observe and integrate the phenological behavior of multiple representative species at each camera site to calibrate a single model for all deciduous broadleaf forests. Our results demonstrate variability in cumulative forcing requirements and photoperiod cues across species and forest types, and show how community composition influences phenological dynamics over large areas. At the same time, the response of different species to spatial and interannual variation in weather is, under the current climate regime, sufficiently similar that the generic deciduous forest model based on repeat digital photography performed

  19. Thresholds in forest bird occurrence as a function of the amount of early-seral broadleaf forest at landscape scales

    USGS Publications Warehouse

    Betts, M.G.; Hagar, J.C.; Rivers, J.W.; Alexander, J.D.; McGarigal, K.; McComb, B.C.

    2010-01-01

    Recent declines in broadleaf-dominated, early-seral forest globally as a function of intensive forest management and/or fire suppression have raised concern about the viability of populations dependent on such forest types. However, quantitative information about the strength and direction of species associations with broadleaf cover at landscape scales are rare. Uncovering such habitat relationships is essential for understanding the demography of species and in developing sound conservation strategies. It is particularly important to detect points in habitat reduction where rates of population decline may accelerate or the likelihood of species occurrence drops rapidly (i.e., thresholds). Here, we use a large avian point-count data set (N = 4375) from southwestern and northwestern Oregon along with segmented logistic regression to test for thresholds in forest bird occurrence as a function of broadleaf forest and early-seral broadleaf forest at local (150-m radius) and landscape (500–2000-m radius) scales. All 12 bird species examined showed positive responses to either broadleaf forest in general, and/or early-seral broadleaf forest. However, regional variation in species response to these conditions was high. We found considerable evidence for landscape thresholds in bird species occurrence as a function of broadleaf cover; threshold models received substantially greater support than linear models for eight of 12 species. Landscape thresholds in broadleaf forest ranged broadly from 1.35% to 24.55% mean canopy cover. Early-seral broadleaf thresholds tended to be much lower (0.22–1.87%). We found a strong negative relationship between the strength of species association with early-seral broadleaf forest and 42-year bird population trends; species most associated with this forest type have declined at the greatest rates. Taken together, these results provide the first support for the hypothesis that reductions in broadleaf-dominated early-seral forest due to

  20. Satellite-based phenology detection in broadleaf forests in South-Western Germany

    NASA Astrophysics Data System (ADS)

    Misra, Gourav; Buras, Allan; Menzel, Annette

    2016-04-01

    results and suggest that different satellite SOS extraction techniques work well for specific phases of ground phenology information. More than half of the broadleaf pixels show an earliness in SOS which matches with the trend in ground phenology. References 1. F.-W. Badeck, A. Bondeau, K. Bottcher, D. Doktor, W. Lucht, J. Schaber, and S. Sitch, 2004, "Responses of spring phenology to climate change," New Phytologist, vol. 162, no. 2, pp. 295-309. 2. E. Hamunyela, J. Verbesselt, G. Roerink, and M. Herold, 2013, "Trends in Spring Phenology of Western European Deciduous Forests," Remote Sensing, vol. 5, no. 12, pp. 6159-6179. 3. V. F. Rodriguez-Galiano, J. Dash, and P. M. Atkinson, 2015, "Intercomparison of satellite sensor land surface phenology and ground phenology in Europe: Inter-annual comparison and modelling," Geophysical Research Letters, vol. 42, no. 7, pp. 2253-2260. 4. J. Fisher, J. Mustard, and M. Vadeboncoeur, 2006, "Green leaf phenology at Landsat resolution: Scaling from the field to the satellite," Remote Sensing of Environment, vol. 100, no. 2, pp. 265-279. 5. K. White, J. Pontius, and P. Schaberg, 2014, "Remote sensing of spring phenology in northeastern forests: A comparison of methods, field metrics and sources of uncertainty," Remote Sensing of Environment, vol. 148, pp. 97-107.

  1. Winning and Losing Tree Species of Reassembly in Minnesota’s Mixed and Broadleaf Forests

    PubMed Central

    Hanberry, Brice B.; Palik, Brian J.; He, Hong S.

    2013-01-01

    We examined reassembly of winning and losing tree species, species traits including shade and fire tolerance, and associated disturbance filters and forest ecosystem types due to rapid forest change in the Great Lakes region since 1850. We identified winning and losing species by changes in composition, distribution, and site factors between historical and current surveys in Minnesota’s mixed and broadleaf forests. In the Laurentian Mixed Forest, shade-intolerant aspen replaced shade-intolerant tamarack as the most dominant tree species. Fire-tolerant white pine and jack pine decreased, whereas shade-tolerant ashes, maples, and white cedar increased. In the Eastern Broadleaf Forest, fire-tolerant white oaks and red oaks decreased, while shade-tolerant ashes, American basswood, and maples increased. Tamarack, pines, and oaks have become restricted to sites with either wetter or sandier and drier soils due to increases in aspen and shade-tolerant, fire-sensitive species on mesic sites. The proportion of shade-tolerant species increased in both regions, but selective harvest reduced the applicability of functional groups alone to specify winners and losers. Harvest and existing forestry practices supported aspen dominance in mixed forests, although without aspen forestry and with fire suppression, mixed forests will transition to a greater composition of shade-tolerant species, converging to forests similar to broadleaf forests. A functional group framework provided a perspective of winning and losing species and traits, selective filters, and forest ecosystems that can be generalized to other regions, regardless of species identity. PMID:23613911

  2. Permian polar forests: deciduousness and environmental variation.

    PubMed

    Gulbranson, E L; Isbell, J L; Taylor, E L; Ryberg, P E; Taylor, T N; Flaig, P P

    2012-11-01

    Forests are expected to expand into northern polar latitudes in the next century. However, the impact of forests at high latitudes on climate and terrestrial biogeochemical cycling is poorly understood because such forests cannot be studied in the modern. This study presents forestry and geochemical analyses of three in situ fossil forests from Late Permian strata of Antarctica, which grew at polar latitudes. Stem size measurements and stump spacing measurements indicate significant differences in forest density and canopy structure that are related to the local depositional setting. For forests closest to fluvial systems, tree density appears to decrease as the forests mature, which is the opposite trend of self-thinning observed in modern forests. We speculate that a combination of tree mortality and high disturbance created low-density mature forests without understory vegetation near Late Permian river systems. Stable carbon isotopes measured from permineralized wood in these forests demonstrate two important points: (i) recently developed techniques of high-resolution carbon isotope studies of wood and mummified wood can be applied to permineralized wood, for which much of the original organic matter has been lost and (ii) that the fossil trees maintained a deciduous habit at polar latitudes during the Late Permian. The combination of paleobotanical, sedimentologic, and paleoforestry techniques provides an unrivaled examination of the function of polar forests in deep time; and the carbon isotope geochemistry supplements this work with subannual records of carbon fixation that allows for the quantitative analysis of deciduous versus evergreen habits and environmental parameters, for example, relative humidity. PMID:22845834

  3. Lidar Altimeter Measurements of Canopy Structure: Methods and Validation for Closed Canopy, Broadleaf Forests

    NASA Technical Reports Server (NTRS)

    Harding, D. J.; Lefsky, M. A.; Parker, G. G.; Blair, J. B.

    1999-01-01

    Lidar altimeter observations of vegetated landscapes provide a time-resolved measure of laser pulse backscatter energy from canopy surfaces and the underlying ground. Airborne lidar altimeter data was acquired using the Scanning Lidar Imager of Canopies by Echo Recovery (SLICER) for a successional sequence of four, closed-canopy, deciduous forest stands in eastern Maryland. The four stands were selected so as to include a range of canopy structures of importance to forest ecosystem function, including variation in the height and roughness of the outer-most canopy surface and the vertical organization of canopy stories and gaps. The character of the SLICER backscatter signal is described and a method is developed that accounts for occlusion of the laser energy by canopy surfaces, transforming the backscatter signal to a canopy height profile (CHP) that quantitatively represents the relative vertical distribution of canopy surface area. The transformation applies an increased weighting to the backscatter amplitude as a function of closure through the canopy and assumes a horizontally random distribution of the canopy components. SLICER CHPs, averaged over areas of overlap where lidar ground tracks intersect, are shown to be highly reproducible. CHP transects across the four stands reveal spatial variations in vegetation, at the scale of the individual 10 m diameter laser footprints, within and between stands. Averaged SLICER CHPs are compared to analogous height profile results derived from ground-based sightings to plant intercepts measured on plots within the four stands. Tbe plots were located on the segments of the lidar ground tracks from which averaged SLICER CHPs were derived, and the ground observations were acquired within two weeks of the SLICER data acquisition to minimize temporal change. The differences in canopy structure between the four stands is similarly described by the SLICER and ground-based CHP results, however a Chi-square test of similarity

  4. [Effects of Phyllostachys edulis invasion of native broadleaf forest on soil fungal community].

    PubMed

    Li, Yong-chun; Liang, Xue; Li, Yong-fu; Wang, Qi; Chen, Jun-hui; Xu, Qiu-fang

    2016-02-01

    To investigate variation of soil fungal community in response to invasion of Phyllostachys edulis into native broadleaf forest, we characterized the community structure and the abundance of fungi in soil under bamboo (BB), mixture forest of bamboo and broadleaf (MF) and broadleaf forest (BL) using terminal restriction fragment length polymorphism (T-RFLP) and real-time quantitative PCR. The results showed that the most obvious difference in the soil fungal community structure was observed between the BB and BF stands, followed by that between the MF and BL. Shannon index and evenness index of soil fungi were higher in the MF than in the BB and BL. pH and NH4+-N content were the most important environmental gradients on the distribution of fungal community under BB, while NO3(-)-N content significantly affected the distribution of the fungal community under BL. The abundance of fungi in BL was significantly higher than that in BB and MF, and the fungi abundance showed a negative correlation with soil pH but a positive correlation with NO3(-)-N content. These results implied that heterotrophic nitrification driven by fungi could occur in soil of BL, and this process might be changed by the bamboo invasion. PMID:27396134

  5. Growing up with stress - carbon sequestration and allocation dynamics of a broadleaf evergreen forest

    NASA Astrophysics Data System (ADS)

    Griebel, Anne; Bennett, Lauren T.; Arndt, Stefan K.

    2016-04-01

    Evergreen forests have the potential to sequester carbon year-round due to the presence of leaves with a multi-year lifespan. Eucalypt forests occur in warmer climates where temperature and radiation are not imposing a strong seasonality. Thus, unlike deciduous or many coniferous trees, many eucalypts grow opportunistically as conditions allow. As such, many eucalypts do not produce distinct growth rings, which present challenges to the implementation of standard methods and data interpretation approaches for monitoring and explaining carbon allocation dynamics in response to climatic stress. As a consequence, there is a lack of detailed understanding of seasonal growth dynamics of evergreen forests as a whole, and, in particular, of the influence of climatic drivers on carbon allocation to the various biomass pools. We used a multi-instrument approach in a mixed species eucalypt forest to investigate the influence of climatic drivers on the seasonal growth dynamics of a predominantly temperate and moisture-regulated environment in south-eastern Australia. Ecosystem scale observations of net ecosystem exchange (NEE) from a flux tower in the Wombat forest near Melbourne indicated that the ecosystem is a year-round carbon sink, but that intra-annual variations in temperature and moisture along with prolonged heat waves and dry spells resulted in a wide range of annual sums over the past three years (NEE ranging from ~4 to 12 t C ha-1 yr-1). Dendrometers were used to monitor stem increments of the three dominant eucalypt species. Stem expansion was generally opportunistic with the greatest increments under warm but moist conditions (often in spring and autumn), and the strongest indicators of stem growth dynamics being radiation, vapour pressure deficit and a combined heat-moisture index. Differences in the seasonality of stem increments between species were largely due to differences in the canopy position of sampled individuals. The greatest stem increments were

  6. Spatial pattern of 137Cs in soils in a mixed deciduous forest in Fukushima, Japan

    NASA Astrophysics Data System (ADS)

    Takada, M.; Yamada, T.; Takahara, T.; Okuda, T.

    2015-12-01

    Spatial heterogeneity of 137Cs contamination was studied in a forest floor of Fukushima region, c.a. 40 km NW of Fukushima Daiichi Nuclear Power Plant (FDNPP) focusing on downwards flow from forest canopy via stemflow and throughfall which play major role in determining spatial contamination of 137Cs after the FNDP accident. Setting a study plot (400 m2) in a secondary mixed deciduous forest, dominated by Quercus crispula and Abies firma in canopy layer in August and November 2014, we sampled the souk from surface to 5 cm in depth of soils and measured 137Cs in every 2 m grids and at tree stem bases. The total estimated activity of 137Cs in soil within the study plot was approximately 210 kBq/m2, but showed large spatial heterogeneity showing 30 times of difference between the lowest and highest activities. The activity decreased with increasing distances from tree stem bases. High activity around tree stem bases was presumably due to the stemflow containing 137Cs seeped into soil only around tree stem bases that raised radioactivity in soil locally in the areas. Relatively low activity away from trees (outside canopies) may be due to small effects of stemflow and throughfall. Activity of 137Cs around bases of deciduous broadleaf trees increased with increasing the tree size. Because larger trees have higher potentials to capture larger amount of 137Cs on the tree surface, cumulative activity of 137Cs included in stemflow may increase with increasing the tree size. However evergreen coniferous tree species (Abies firma) did not show such a pattern relating to the tree size. The difference is assumed to be affected by phenological characteristics as the accident happened in winter and deciduous broadleaf trees did not have leaves and 137Cs deposited on tree bodies, while evergreen coniferous tree had leaves and 137Cs was intercepted by the canopies.

  7. Comparing the effects of Different Remote Sensing Techniques for Extracting Deciduous Broadleaf Phenology

    NASA Astrophysics Data System (ADS)

    Ilushin, D.; Richardson, A. D.; Toomey, M. P.; Pless, R.; Shapiro, A.

    2013-12-01

    patterns and trends among different land classifications. This information will help better our understanding of how growth patterns are affecting net uptake of carbon and how trees and forests respond to changing climate on a more regional level as well as giving a basis of comparison for satellite imagery to surface-level phenology.

  8. Precipitation controls on vegetation phenology in a temperate broadleaf forest estimated from MODIS vegetation index

    NASA Astrophysics Data System (ADS)

    Hwang, T.; Song, C.; Bolstad, P.; Band, L. E.

    2010-12-01

    Forest canopy phenology is an important control of annual water and carbon budgets, and has been shown to respond to regional interannual climate variation. In steep terrain, there are complex spatial variations in phenology in response to well expressed topographic influences on microclimate, community composition, and available soil moisture. We investigate interannual variation in topography-mediated controls on vegetation phenology in a humid temperate broadleaf forest. Moderate-resolution imaging spectro-radiometer (MODIS) vegetation indices are used to derive local patterns of topography-mediated vegetation phenology using a simple post-processing analysis and a non-linear model fitting. Extracted phenological signals show reasonable correlations in terms of both inter-annual variation and inter-site differences with two continuous FPAR measurements from walk-up towers. Combined effects of temperature and orographic precipitation show distinct quadratic responses of senescence timing along elevation gradient, also associated with forest community types. Interannual variation of these quadratic responses is quite related to the amount of precipitation and available soil water (precipitation - potential evapotranspiration) from late summer to fall, which clearly shows precipitation controls on senescence phenology even in a humid temperate broadleaf forest. Normalized plant water stress from continuous soil moisture measurements with TDR sensors also directly supports water stress related controls on senescence phenology. This study also suggests that temperature increases may have less uniform effect on senescence especially in low elevation regions where water availability is also a critical factor for senescence timing. Temperature increases instead may exacerbate plant water stress due to potential evapotranspiration increases, which may increase the degree of dependence of senescence phenology on water availability within the study site. The earlier

  9. Chronic water stress reduces tree growth and the carbon sink of deciduous hardwood forests.

    PubMed

    Brzostek, Edward R; Dragoni, Danilo; Schmid, Hans Peter; Rahman, Abdullah F; Sims, Daniel; Wayson, Craig A; Johnson, Daniel J; Phillips, Richard P

    2014-08-01

    Predicted decreases in water availability across the temperate forest biome have the potential to offset gains in carbon (C) uptake from phenology trends, rising atmospheric CO2 , and nitrogen deposition. While it is well established that severe droughts reduce the C sink of forests by inducing tree mortality, the impacts of mild but chronic water stress on forest phenology and physiology are largely unknown. We quantified the C consequences of chronic water stress using a 13-year record of tree growth (n = 200 trees), soil moisture, and ecosystem C balance at the Morgan-Monroe State Forest (MMSF) in Indiana, and a regional 11-year record of tree growth (n > 300 000 trees) and water availability for the 20 most dominant deciduous broadleaf tree species across the eastern and midwestern USA. We show that despite ~26 more days of C assimilation by trees at the MMSF, increasing water stress decreased the number of days of wood production by ~42 days over the same period, reducing the annual accrual of C in woody biomass by 41%. Across the deciduous forest region, water stress induced similar declines in tree growth, particularly for water-demanding 'mesophytic' tree species. Given the current replacement of water-stress adapted 'xerophytic' tree species by mesophytic tree species, we estimate that chronic water stress has the potential to decrease the C sink of deciduous forests by up to 17% (0.04 Pg C yr(-1) ) in the coming decades. This reduction in the C sink due to mesophication and chronic water stress is equivalent to an additional 1-3 days of global C emissions from fossil fuel burning each year. Collectively, our results indicate that regional declines in water availability may offset the growth-enhancing effects of other global changes and reduce the extent to which forests ameliorate climate warming. PMID:24421179

  10. [Effects of Phyllostachys edulis expansion on soil nitrogen mineralization and its availability in evergreen broadleaf forest].

    PubMed

    Song, Qing-Ni; Yang, Qing-Pei; Liu, Jun; Yu, Ding-Kun; Fang, Kai; Xu, Pei; He, Yu-juan

    2013-02-01

    By the methods of space-time substitution and PVC tube closed-top in situ incubation, this paper studied the soil mineralized-N content, N mineralization rate, and N uptake rate in Phyllostachys edulis-broadleaf mixed forest (PBMF) formed by P. edulis expansion and its adjacent evergreen broadleaf forest (EBF) in Dagangshan Mountain of Jiangxi Province, China. There existed the same spatiotemporal variation trend of soil total mineralized-N (TMN) content between the two forests. The annual average N mineralization rate was slightly lower in PBMF than in EBF. In PBMF, soil N mineralization was dominated by ammonification; while in EBF, soil ammonification and nitrification were well-matched in rate, and soil nitrification was dominated in growth season (from April to October). The N uptake by the plants in PBMF and EBF in a year was mainly in the form of NH4+-N, but that in EBF in growth season was mainly in the form of NO3- -N. These findings indicated that the expansion of P. edulis into EBF could promote the ammonification of soil N, weakened soil nitrification and total N mineralization, and also, increased the NH4+-N uptake but decreased the NO3- -N and TMN uptake by the plants. PMID:23705376

  11. The Legacy of Episodic Climatic Events in Shaping Temperate, Broadleaf Forests

    NASA Technical Reports Server (NTRS)

    Pederson, Neil; Dyer, James M.; McEwan, Ryan W.; Hessl, Amy E.; Mock, Cary J.; Orwig, David A.; Rieder, Harald E.; Cook, Benjamin I.

    2015-01-01

    In humid, broadleaf-dominated forests where gap dynamics and partial canopy mortality appears to dominate the disturbance regime at local scales, paleoecological evidence shows alteration at regional-scales associated with climatic change. Yet, little evidence of these broad-scale events exists in extant forests. To evaluate the potential for the occurrence of large-scale disturbance, we used 76 tree-ring collections spanning approx. 840 000 sq km and 5327 tree recruitment dates spanning approx. 1.4 million sq km across the humid eastern United States. Rotated principal component analysis indicated a common growth pattern of a simultaneous reduction in competition in 22 populations across 61 000 km2. Growth-release analysis of these populations reveals an intense and coherent canopy disturbance from 1775 to 1780, peaking in 1776. The resulting time series of canopy disturbance is so poorly described by a Gaussian distribution that it can be described as ''heavy tailed,'' with most of the years from 1775 to 1780 comprising the heavy-tail portion of the distribution. Historical documents provide no evidence that hurricanes or ice storms triggered the 1775-1780 event. Instead, we identify a significant relationship between prior drought and years with elevated rates of disturbance with an intense drought occurring from 1772 to 1775. We further find that years with high rates of canopy disturbance have a propensity to create larger canopy gaps indicating repeated opportunities for rapid change in species composition beyond the landscape scale. Evidence of elevated, regional-scale disturbance reveals how rare events can potentially alter system trajectory: a substantial portion of old-growth forests examined here originated or were substantially altered more than two centuries ago following events lasting just a few years. Our recruitment data, comprised of at least 21 species and several shade-intolerant species, document a pulse of tree recruitment at the

  12. [Dynamic Characteristics of Base Cations During Wet Deposition in Evergreen Broad-leaf Forest Ecosystem].

    PubMed

    An, Si-wei; Sun, Tao; Ma, Ming; Wang, Ding-yong

    2015-12-01

    Based on field tests and laboratory experiments, effects of precipitation, throughfall, litterfall, and groundwater runoff of the ever-green broad-leaf forest on the dynamic characteristics of base cations in Simian Mountain were investigated from September 2012 to August 2013. The results showed that the rainfall of Simian Mountain was apparently acidic, with average pH of 4.90 and maximum pH of 5.14. The soil and canopies could increase pH of precipitation, with soils having the maximum increment, followed by the forest canopy. Forest canopy only had the function of interception on Na⁺. And precipitation could leach out Ca2⁺, Mg2⁺ and K⁺ of the canopies. Moreover, the degradation of litter was probably the main reason for the increase of base cations concentrations in the surface litter water. The litter water leached Ca2⁺, Mg2⁺ and Na⁺ of the forest soil through downward infiltration. The total retention rates of Ca²⁺, Mg²⁺, Na⁺ and K⁺ were 33.82%, -7.06%, 74.36% and 42.87%, respectively. Ca²⁺, Na⁺, K⁺ were found to be reserved in the forest ecosystem, and the highest interception rate was found for Na⁺. PMID:27011975

  13. Evaluating Spatial-Temporal Dynamics of Net Primary Productivity of Different Forest Types in Northeastern China Based on Improved FORCCHN

    PubMed Central

    Zhao, Junfang; Yan, Xiaodong; Guo, Jianping; Jia, Gensuo

    2012-01-01

    An improved individual-based forest ecosystem carbon budget model for China (FORCCHN) was applied to investigate the spatial-temporal dynamics of net primary productivity of different forest types in northeastern China. In this study, the forests of northeastern China were categorized into four ecological types according to their habitats and generic characteristics (evergreen broadleaf forest, deciduous broadleaf forest, evergreen needleleaf forest and deciduous needleleaf forest). The results showed that distribution and change of forest NPP in northeastern China were related to the different forest types. From 1981 to 2002, among the forest types in northeastern China, per unit area NPP and total NPP of deciduous broadleaf forest were the highest, with the values of 729.4 gC/(m2•yr) and 106.0 TgC/yr, respectively, followed by mixed broadleaf- needleleaf forest, deciduous needleleaf forest and evergreen needleleaf forest. From 1981 to 2002, per unit area NPP and total NPP of different forest types in northeastern China exhibited significant trends of interannual increase, and rapid increase was found between the 1980s and 1990s. The contribution of the different forest type’s NPP to total NPP in northeastern China was clearly different. The greatest was deciduous broadleaf forest, followed by mixed broadleaf- needleleaf forest and deciduous needleleaf forest. The smallest was evergreen needleleaf forest. Spatial difference in NPP between different forest types was remarkable. High NPP values of deciduous needleleaf forest, mixed broadleaf- needleleaf forest and deciduous broadleaf forest were found in the Daxing’anling region, the southeastern of Xiaoxing’anling and Jilin province, and the Changbai Mountain, respectively. However, no regional differences were found for evergreen needleleaf NPP. This study provided not only an estimation NPP of different forest types in northeastern China but also a useful methodology for estimating forest carbon storage

  14. Evaluating spatial-temporal dynamics of net primary productivity of different forest types in northeastern China based on improved FORCCHN.

    PubMed

    Zhao, Junfang; Yan, Xiaodong; Guo, Jianping; Jia, Gensuo

    2012-01-01

    An improved individual-based forest ecosystem carbon budget model for China (FORCCHN) was applied to investigate the spatial-temporal dynamics of net primary productivity of different forest types in northeastern China. In this study, the forests of northeastern China were categorized into four ecological types according to their habitats and generic characteristics (evergreen broadleaf forest, deciduous broadleaf forest, evergreen needleleaf forest and deciduous needleleaf forest). The results showed that distribution and change of forest NPP in northeastern China were related to the different forest types. From 1981 to 2002, among the forest types in northeastern China, per unit area NPP and total NPP of deciduous broadleaf forest were the highest, with the values of 729.4 gC/(m(2)•yr) and 106.0 TgC/yr, respectively, followed by mixed broadleaf- needleleaf forest, deciduous needleleaf forest and evergreen needleleaf forest. From 1981 to 2002, per unit area NPP and total NPP of different forest types in northeastern China exhibited significant trends of interannual increase, and rapid increase was found between the 1980s and 1990s. The contribution of the different forest type's NPP to total NPP in northeastern China was clearly different. The greatest was deciduous broadleaf forest, followed by mixed broadleaf- needleleaf forest and deciduous needleleaf forest. The smallest was evergreen needleleaf forest. Spatial difference in NPP between different forest types was remarkable. High NPP values of deciduous needleleaf forest, mixed broadleaf- needleleaf forest and deciduous broadleaf forest were found in the Daxing'anling region, the southeastern of Xiaoxing'anling and Jilin province, and the Changbai Mountain, respectively. However, no regional differences were found for evergreen needleleaf NPP. This study provided not only an estimation NPP of different forest types in northeastern China but also a useful methodology for estimating forest carbon storage at

  15. FIELD INVESTIGATION OF SULFITE FLUXES TO A DECIDUOUS FOREST

    EPA Science Inventory

    An intensive investigation of particulate sulfur fluxes to a deciduous forest was conducted at Oak Ridge, Tennessee, during May 1983. ddy correlation methods were used to measure fluxes of submicron particulate sulfur, of submicron particles in three different size ranges, and of...

  16. Estimations of deciduous forest biomass by analyzing vegetation microwave emission

    NASA Astrophysics Data System (ADS)

    Zhang, Zhongjun; Zhang, Lixin; Zhao, Shaojie; Wang, Huan

    2011-09-01

    Forest is important in global carbon cycle and has potential impact on global climatic change. Whether the soil moisture under forest area can be detected by microwave emission signature is unknown due to the dense forest cover. Also, the relationship between forest biomass and its microwave emissivity and transmissivity is of interest to be studied. The microwave emission contribution received by the radiometer above the forest canopy comes from both the soil surface and vegetation layer. In this study, a high-order emission model, Matrix-Doubling, was employed to simulate the emissivity of a young deciduous forest. A field experiment before and after watering the deciduous tree stand was carried in June 5, 2011 in Baoding, China to verify the model, and to measure the tree transmissivity. A tree was selected to be cut to measure the tree parameters and weighed its biomass. Assuming the forest as a non-scattering medium, the effective single-scattering albedo is obtained for 0th-order model by fitting the same emissivity from Matrix-Doubling model. For lower albedo which could be ignored, transmissivity of trees can be deduced by measured Brightness Temperatures before and after watering the underlying soil. The relationship between forest biomass and its transmissivity is presented in this paper.

  17. Soil bacterial endemism and potential functional redundancy in natural broadleaf forest along a latitudinal gradient.

    PubMed

    Zhang, Yuguang; Cong, Jing; Lu, Hui; Deng, Ye; Liu, Xiao; Zhou, Jizhong; Li, Diqiang

    2016-01-01

    Microorganisms play key roles in ecosystem processes and biogeochemical cycling, however, the relationship between soil microbial taxa diversity and their function in natural ecosystems is largely unknown. To determine how soil bacteria community and function are linked from the local to regional scale, we studied soil bacteria community composition, potential function and environmental conditions in natural and mature broadleaf forests along a latitudinal gradient in China, using the Illumina 16S rRNA sequencing and GeoChip technologies. The results showed strong biogeographic endemism pattern in soil bacteria were existed, and the spatial distance and climatic variables were the key controlling factors for this pattern. Therefore, dispersal limitation and environmental selection may represent two key processes in generating and maintaining the soil bacterial biogeographic pattern. By contrast, the soil bacterial potential function is highly convergent along the latitudinal gradient and there were highly differing bacterial community compositions, and the soil chemistry may include the main factors active in shaping the soil bacterial potential function. Therefore, the soil bacterial potential function may be affected by local gradients in resource availability, and predicting soil bacterial potential function requires knowledge of abiotic and biotic environmental factors. PMID:27357005

  18. Soil bacterial endemism and potential functional redundancy in natural broadleaf forest along a latitudinal gradient

    NASA Astrophysics Data System (ADS)

    Zhang, Yuguang; Cong, Jing; Lu, Hui; Deng, Ye; Liu, Xiao; Zhou, Jizhong; Li, Diqiang

    2016-06-01

    Microorganisms play key roles in ecosystem processes and biogeochemical cycling, however, the relationship between soil microbial taxa diversity and their function in natural ecosystems is largely unknown. To determine how soil bacteria community and function are linked from the local to regional scale, we studied soil bacteria community composition, potential function and environmental conditions in natural and mature broadleaf forests along a latitudinal gradient in China, using the Illumina 16S rRNA sequencing and GeoChip technologies. The results showed strong biogeographic endemism pattern in soil bacteria were existed, and the spatial distance and climatic variables were the key controlling factors for this pattern. Therefore, dispersal limitation and environmental selection may represent two key processes in generating and maintaining the soil bacterial biogeographic pattern. By contrast, the soil bacterial potential function is highly convergent along the latitudinal gradient and there were highly differing bacterial community compositions, and the soil chemistry may include the main factors active in shaping the soil bacterial potential function. Therefore, the soil bacterial potential function may be affected by local gradients in resource availability, and predicting soil bacterial potential function requires knowledge of abiotic and biotic environmental factors.

  19. Soil bacterial endemism and potential functional redundancy in natural broadleaf forest along a latitudinal gradient

    PubMed Central

    Zhang, Yuguang; Cong, Jing; Lu, Hui; Deng, Ye; Liu, Xiao; Zhou, Jizhong; Li, Diqiang

    2016-01-01

    Microorganisms play key roles in ecosystem processes and biogeochemical cycling, however, the relationship between soil microbial taxa diversity and their function in natural ecosystems is largely unknown. To determine how soil bacteria community and function are linked from the local to regional scale, we studied soil bacteria community composition, potential function and environmental conditions in natural and mature broadleaf forests along a latitudinal gradient in China, using the Illumina 16S rRNA sequencing and GeoChip technologies. The results showed strong biogeographic endemism pattern in soil bacteria were existed, and the spatial distance and climatic variables were the key controlling factors for this pattern. Therefore, dispersal limitation and environmental selection may represent two key processes in generating and maintaining the soil bacterial biogeographic pattern. By contrast, the soil bacterial potential function is highly convergent along the latitudinal gradient and there were highly differing bacterial community compositions, and the soil chemistry may include the main factors active in shaping the soil bacterial potential function. Therefore, the soil bacterial potential function may be affected by local gradients in resource availability, and predicting soil bacterial potential function requires knowledge of abiotic and biotic environmental factors. PMID:27357005

  20. [Sensitivity of parameters in net primary productivity model of broadleaf-Korean pine mixed forest].

    PubMed

    Zhou, Chun-Hua; Hao, Zhan-Qing; He, Hong-Shi; Zhou, Dan-Hui

    2008-05-01

    PnET-II (photosynthesis and evapotranspiration) model is an ecosystem process model, which requires extensive input parameters, including vegetation parameters, soil parameters and climate parameters, to simulate net primary productivity (NPP). This study estimated the total and wood (stem and branch) NPPs of Korean pine and broadleaf species in Fenglin Natural Reserve, and examined the responses of the NPPs to the variations of the input parameters in PnET-II model. The simulation results indicated that among the vegetation parameters in PnET-II model, the variation of canopy parameters, had greater effects on the simulated NPPs of Korean pine and broadleaf species, and the response of Korean pine's total NPP to vegetation parameters was larger than that of broadleaf species'. The variation of soil water holding capacity (WHC) had smaller effects on the NPPs of Korean pine and broadleaf species, and the response of Korean pine's NPP to the WHC was somewhat smaller than that of broadleaf trees'. In climate scenarios, the variation of air temperature had the greatest effects on the simulated NPP of Korean pine and broadleaf trees, followed by precipitation and radiation. Different climate scenarios had different effects on the predicted results. The total and wood NPPs of Korean pine and broadleaf trees had different responses to the input parameters. PMID:18655573

  1. Thinned Mature Deciduous Forest Silvopastures for Appalachia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Little information is available on effective management and utilization of silvopastures developed from the ubiquitous mature woodlots which comprise 40-50% of small Appalachian farm acreage. We thinned a white oak dominated mature second growth forested area establishing two 0.5 ha, eight-paddock,...

  2. A Black Swan and Sub-continental Scale Dynamics in Humid, Late-Holocene Broadleaf Forests

    NASA Astrophysics Data System (ADS)

    Pederson, N.; Dyer, J.; McEwan, R.; Hessl, A. E.; Mock, C. J.; Orwig, D.; Rieder, H. E.; Cook, B. I.

    2012-12-01

    In humid regions with dense broadleaf-dominated forests where gap-dynamics is the prevailing disturbance regime, paleoecological evidence shows regional-scale changes in forest composition associated with climatic change. To investigate the potential for regional events in late-Holocene forests, we use tree-ring data from 76 populations covering 840,000 km2 and 5.3k tree recruitment dates spanning 1.4 million km2 in the eastern US to investigate the occurrence of simultaneous forest dynamics across a humid region. We compare regional forest dynamics with an independent set of annually-resolved tree ring record of hydroclimate to examine whether climate dynamics might drive forest dynamics in this humid region. In forests where light availability is an important limitation for tree recruitment, we document a pulse of tree recruitment during the mid- to late-1600s across the eastern US. This pulse, which can be inferred as large-scale canopy opening, occurred during an era that multiple proxies indicate as extended drought between two intense pluvial. Principal component analysis of the 76 populations indicates a step-change increase in average ring width during the late-1770s resembling a potential canopy accession event over 42,800 km2 of the southeastern US. Growth-release analysis of populations loading strongly on this eigenvector indicates severe canopy disturbance from 1775-1779 that peaked in 1776. The 1776 event follows a period with extended droughts and severe large-scale frost event. We hypothesize these climatic events lead to elevated tree mortality in the late-1770s and canopy accession for understory trees. Superposed epoch analysis reveals that spikes of elevated canopy disturbance from 1685-1850 CE are significantly associated with drought. Extreme value theory statistics indicates the 1776 event lies beyond the 99.9 quantile and nearly 7 sigmas above the 1685-1850 mean rate of disturbance. The time-series of canopy disturbance from 1685-1850 is so

  3. Light compensation points in shade-grown seedlings of deciduous broadleaf tree species with different successional traits raised under elevated CO2.

    PubMed

    Kitao, M; Hida, T; Eguchi, N; Tobita, H; Utsugi, H; Uemura, A; Kitaoka, S; Koike, T

    2016-01-01

    We measured leaf photosynthetic traits in shade-grown seedlings of four tree species native to northern Japan, raised under an elevated CO2 condition, to investigate the effects of elevated CO2 on shade tolerance of deciduous broadleaf tree species with different successional traits. We considered Betula platyphylla var. japonica and Betula maximowicziana as pioneer species, Quercus mongolica var. crispula as a mid-successional species, and Acer mono as a climax species. The plants were grown under shade conditions (10% of full sunlight) in a CO2 -regulated phytotron. Light compensation points (LCPs) decreased in all tree species when grown under elevated CO2 (720 μmol·mol(-1) ), which were accompanied by higher apparent quantum yields but no photosynthetic down-regulation. LCPs in Q. mongolica and A. mono grown under elevated CO2 were lower than those in the two pioneer birch species. The LCP in Q. mongolica seedlings was not different from that of A. mono in each CO2 treatment. However, lower dark respiration rates were observed in A. mono than in Q. mongolica, suggesting higher shade tolerance in A. mono as a climax species in relation to carbon loss at night. Thus, elevated CO2 may have enhanced shade tolerance by lowering LCPs in all species, but the ranking of shade tolerance related to successional traits did not change among species under elevated CO2 , i.e. the highest shade tolerance was observed in the climax species (A. mono), followed by a gap-dependent species (Q. mongolica), while lower shade tolerance was observed in the pioneer species (B. platyphylla and B. maximowicziana). PMID:26404633

  4. Ammonia emissions from deciduous forest after leaf fall

    NASA Astrophysics Data System (ADS)

    Hansen, K.; Sørensen, L. L.; Hertel, O.; Geels, C.; Skjøth, C. A.; Jensen, B.; Boegh, E.

    2013-07-01

    The understanding of biochemical feedback mechanisms in the climate system is lacking knowledge in relation to bi-directional ammonia (NH3) exchange between natural ecosystems and the atmosphere. We therefore study the atmospheric NH3 fluxes during a 25-day period during autumn 2010 (21 October to 15 November) for the Danish beech forest Lille Bøgeskov to address the hypothesis that NH3 emissions occur from deciduous forests in relation to leaf fall. This is accomplished by using observations of vegetation status, NH3 fluxes and model calculations. Vegetation status was observed using plant area index (PAI) and leaf area index (LAI). NH3 fluxes were measured using the relaxed eddy accumulation (REA) method. The REA-based NH3 concentrations were compared to NH3 denuder measurements. Model calculations of the atmospheric NH3 concentration were obtained with the Danish Ammonia MOdelling System (DAMOS). The relative contribution from the forest components to the atmospheric NH3 flux was assessed using a simple two-layer bi-directional canopy compensation point model. A total of 57.7% of the fluxes measured showed emission and 19.5% showed deposition. A clear tendency of the flux going from deposition of -0.25 ± 0.30 μg NH3-N m-2 s-1 to emission of up to 0.67 ± 0.28 μg NH3-N m-2 s-1 throughout the measurement period was found. In the leaf fall period (23 October to 8 November), an increase in the atmospheric NH3 concentrations was related to the increasing forest NH3 flux. Following leaf fall, the magnitude and temporal structure of the measured NH3 emission fluxes could be adequately reproduced with the bi-directional resistance model; it suggested the forest ground layer (soil and litter) to be the main contributing component to the NH3 emissions. The modelled concentration from DAMOS fits well the measured concentrations before leaf fall, but during and after leaf fall, the modelled concentrations are too low. The results indicate that the missing contribution

  5. Spatial heterogeneity of radiocesium concentration on a forest floor soil in a broadleaf and mixed forest in Fukushima, Japan

    NASA Astrophysics Data System (ADS)

    Takada, Momo; Yamada, Toshihiro; Takahara, Teruhiko; Okuda, Toshinori

    2015-04-01

    Radiocesium in Fukushima forests derived from the nuclear power plant accident still remains in the surface of forest floors. Its distribution is known to show spatial heterogeneity, but little is reported about causes generating it. Horizontal distribution of radiocesium within a forest community needs to be clarified for understanding spatio-temporal dynamics of radiocesium within a forest community and its outflow from the ecosystem to others (e.g. downstream). Here, we hypothesized as follows; environmental spatial heterogeneity of a forest floor within a forest community generated by vegetation creates the spatial variation of distribution of radiocesium. We examined whether the radiocesium accumulates at the bases of trees, and the amount of the radiocesium is related to tree size and morphological characteristics of the tree such as tree species and bark properties. The field surveys were conducted in a broadleaf and mixed forest dominated by Japanese oak (Quercus crispula) and Japanese fir (Abies firma) in Soma city in Fukushima Prefecture in August and November, 2014. A 20 m × 20 m plot was established in the study site. Top soils (0 - 5 cm) were collected from 121 points in a grid system of every 2 m interval within the plot and additional 136 points from south and north sides at bases of all trees (≥ 5 cm of diameters at breast height) in the plot. Diameters at breast height of all the trees were measured, and the tree species were identified. The soil samples were dried and measured by a germanium detector. Activity concentrations of Cs-137 were decay-correlated to the data of the first field survey. Average concentration of Cs-137 radioactivity in the plot was 14,007 Bq/kg and its coefficient of variance was 74 %, showing large spatial variation of radiocesium distribution on the forest floor. Average concentration collected in the grid points 2 m apart each other was 10,826 Bq/kg, while average concentration from the bases of all trees was 16

  6. Biogenic isoprene emission: Model evaluation in a southeastern United States bottomland deciduous forest

    NASA Astrophysics Data System (ADS)

    Geron, Christopher D.; Nie, Dalin; Arnts, Robert R.; Sharkey, Thomas D.; Singsaas, Eric L.; Vanderveer, Peter J.; Guenther, Alex; Sickles, Joe E.; Kleindienst, Tad E.

    1997-08-01

    Isoprene is usually the dominant natural volatile organic compound emission from forest ecosystems, especially those with a major broadleaf deciduous component. Here we report isoprene emission model performance versus leaf and canopy level isoprene emission measurements made at the Duke University Research Forest near Chapel Hill, North Carolina. Emission factors, light and temperature response, canopy environment models, foliar mass, leaf area, and canopy level isoprene emission were evaluated in the field and compared with model estimates. Model components performed reasonably well and generally yielded estimates within 20% of values measured at the site. However, measured emission factors were much higher in early summer following an unusually dry spring. These decreased later in the summer but remained higher than values currently used in emission models. There was also a pronounced decline in basal emission rates in lower portions of the canopy which could not be entirely explained by decreasing specific leaf weight. Foliar biomass estimates by genera using basal area ratios adjusted for crown form were in excellent agreement with values measured by litterfall. Overall, the stand level isoprene emissions determined by relaxed eddy accumulation techniques agreed reasonably well with those predicted by the model, although there is some evidence for underprediction at ambient temperatures approaching 30°C, and overprediction during October as the canopy foliage senesced. A "Big Leaf" model considers the canopy as a single multispecies layer and expresses isoprene emission as a function of leaf area rather than mass. This simple model performs nearly as well as the other biomass-based models. We speculate that seasonal water balance may impact isoprene emission. Possible improvements to the canopy environment model and other components are discussed.

  7. Modelling spatio-temporal variations in leaf chlorophyll content for broadleaf and needle forest canopies

    NASA Astrophysics Data System (ADS)

    Croft, H.; Chen, J. M.; Zhang, Y.; Simic, A.

    2012-04-01

    Foliar chlorophyll content in forested ecosystems plays a fundamental role in plant photosynthesis, determines plant productivity and can indicate vegetation stress and disturbance. Obtaining accurate measurements of leaf chlorophyll content across a range of spatial and temporal scales is crucial for monitoring vegetation productivity and providing inputs to photosynthesis and carbon cycle models. However, leaf chlorophyll retrieval is complicated as canopy reflectance in the visible and near-infrared wavelengths is affected not only by leaf pigment concentration but also by leaf area index (LAI), canopy architecture, illumination and viewing geometry and understory vegetation. Consequently, empirical indices, often developed at leaf-level, are species, site and time specific. In order to investigate the potential of monitoring chlorophyll dynamics over a growing season at the canopy scale, a process modeling approach is needed to account for the variation of other variables affecting canopy reflectance. Canopy radiative transfer models use physical laws to describe the interaction of solar radiation inside the canopy between scattering elements, which could provide a more accurate estimate of chlorophyll content over multiple vegetation species, time-frames and across broader spatial extents. This study used a coupled canopy (4Scale) and leaf (PROSPECT) model approach to investigate the ability of radiative transfer models to estimate foliar chemistry for multiple vegetation types and species (broadleaf and needle) from optical remote sensing data. Canopy reflectance data was acquired from the Medium Resolution Imaging Spectrometer (MERIS), from 390-1040 nm in 15 wavebands at a spatial resolution of 1200 m, and inverted using a look up table (LUT) approach. Twenty sites were selected in Ontario, Canada representing different dominant vegetation species (Picea mariana, Pinus banksiana and Acer saccharum), and a variety of canopy closures and structures. These

  8. Expanding leaves of mature deciduous forest trees rapidly become autotrophic.

    PubMed

    Keel, Sonja G; Schädel, Christina

    2010-10-01

    Emerging leaves in evergreen tree species are supplied with carbon (C) from the previous year's foliage. In deciduous trees, no older leaves are present, and the early phase of leaf development must rely on C reserves from other tissues. How soon developing leaves become autotrophic and switch from being C sinks to sources has rarely been studied in mature forest trees, and simultaneous comparisons of species are scarce. Using a canopy crane and a simple (13)CO(2)-pulse-labelling technique, we demonstrate that young leaves of mature trees in three European deciduous species (Fagus sylvatica L., Quercus petraea (Matt.) Liebl., Tilia platyphyllos Scop.) start assimilating CO(2) at a very early stage of development (10-50% expanded). One month after labelling, all leaves were still strongly (13)C enriched, suggesting that recent photosynthates had been incorporated into slow turnover pools such as cellulose or lignin and thus had contributed to leaf growth. In line with previous studies performed at the same site, we found stronger incorporation of recent photosynthates into growing tissues of T. platyphyllos compared with F. sylvatica and Q. petraea. Non-structural carbohydrate (NSC) concentrations analysed for one of the three study species (F. sylvatica) showed that sugar and starch pools rapidly increased during leaf development, suggesting that newly developed leaves soon produce more NSC than can be used for growth. In conclusion, our findings indicate that expanding leaves of mature deciduous trees become C autonomous at an early stage of development despite the presence of vast amounts of mobile carbohydrate reserves. PMID:20688879

  9. Diurnal and Seasonal Trends in Canopy Transpiration and Conductance of Pristine Forest Types in Belize, Central America

    NASA Technical Reports Server (NTRS)

    Zimmermann, R.; Oren, R.; Billings, S.; Muller-Ezards, C.; Schaaff, C.; Strohmeier, P.; Obermaier, E.

    1994-01-01

    Five semi-deciduous broadleaf forest types growing over tropical karst in Belize, Central America, were monitored for three years to study diurnal and seasonal changes of transpiration and micro-meteorologic conditions.

  10. Movements, cover-type selection, and survival of fledgling Ovenbirds in managed deciduous and mixed coniferous-deciduous forests

    USGS Publications Warehouse

    Streby, Henry M.; Andersen, David E.

    2013-01-01

    We used radio telemetry to monitor movements, cover-type selection, and survival for fledglings of the mature-forest nesting Ovenbird (Seiurus aurocapilla) at two managed forest sites in north-central Minnesota. Both sites contained forested wetlands, regenerating clearcut stands of various ages, and logging roads, but differed in mature forest composition; one deciduous with open understory, and the other mixed coniferous-deciduous with dense understory. We used compositional analysis, modified to incorporate age-specific limitations in fledgling movements, to assess cover-type selection by fledglings throughout the dependent (on adult care) post-fledging period. Compared to those that were depredated, fledglings from nests in deciduous forest that survived the early post-fledging period had more older (sapling-dominated) clearcut available, directed movements toward older clearcuts and forested wetlands, and used older clearcuts more than other cover types relative to availability. Fledglings that were depredated had more young (shrub-dominated) clearcut and unpaved logging road available, and used mature forest and roads more than expected based on availability. For birds from nests in mixed mature forest with dense understory, movements and cover-type selection were similar between fledglings that survived and those that were depredated. However, fledglings that were depredated at that site also had more young clearcut available than fledglings that survived. We conclude that Ovenbird fledgling survival is influenced by distance of their nest to various non-nesting cover types, and by the subsequent selection among those cover types, but that the influence of non-nesting cover types varies depending on the availability of dense understory vegetation in mature forest.

  11. Wavelet analysis for aboveground biomass estimate in temperate deciduous forests

    NASA Astrophysics Data System (ADS)

    Wei, Xiao-Fang

    2008-10-01

    The ever-increasing concentration of anthropogenic greenhouse gases (CO2, CH4, and CFCs) has been identified as a likely (greater than 90% confidence) cause of the observed increase of global mean temperatures since the mid-20th century (IPCC, 2007). The effect of human-induced climate change could be unprecedented and far-reaching. Carbon sequestration into trees and forests is an effective and inexpensive way for mitigating the CO2 level in the atmosphere. Hence, accurate measurement of biomass will be of great importance to global carbon cycle and climate change. This study performed a wavelet-based forest aboveground biomass estimation approach in a temperate deciduous forest, the Hoosier National Forest, in Indiana. Wavelet analysis, specifically two-dimensional discrete wavelet transform (DWT) was applied to ASTER images to obtain wavelet coefficients (WCs), which were correlated with forest inventory data using multiple linear regression analysis to investigate the relationship. Different mother wavelets and level of decomposition were tested. Moreover, vegetation indices, RATIO, normalized difference vegetation index (NDVI), and principal component analyses (PCA) were computed and correlated with field biomass measurements. The results indicate that wavelet coefficients correlate better with field biomass data than vegetation indices. For level one decomposition, the correlation coefficients are 0.3 to 0.5, while 0.1-0.3 for vegetation indices; for level two decomposition, the overall R value increased by 0.2, and for level three, the R value can be increased to 0.6-0.7. Meanwhile, tree per acre and basal area were also examined and correlated with field measurements. This study demonstrates that wavelet-based biomass estimation could be a very promising approach for solving the uncertainty between reflectance value from satellite images and forest biomass and therefore providing better biomass estimation; however, further research is needed for identifying

  12. Aerosol Production in a Mixed Deciduous/Coniferous Forest

    NASA Astrophysics Data System (ADS)

    Slade, N.; Mielke, L.; Alaghmand, M.; Galloway, M.; Kammrath, A.; Keutsch, F.; Hansen, R.; Griffith, S.; Dusanter, S.; Stevens, P.; Carroll, M.; Bertman, S.; Shepson, P.

    2008-12-01

    Aerosols are of fundamental concern because of their impacts on air quality, human health and radiative forcing. Recent studies have focused on secondary organic aerosol (SOA) production due to oxidation of volatile organic compounds (VOCs), and more importantly biogenic-VOCs (BVOCs), in particular, isoprene. However, the SOA precursors are not well understood because the mechanisms have shown that isoprene oxidation can contribute to aerosol production through multiple generation oxidation products. For terpenes, it is more likely that primary or secondary oxidation products lead to particle formation. In the present study, we measured the aerosol size distribution, along with O3, HOx, NOx, NOy and BVOCs, in a mixed deciduous forest that is undergoing successional transition to a conifer-dominated species mix. This study was conducted in a rural forest environment in northern Michigan as a part of the summer 2008 PROPHET campaign at the University of Michigan Biological Station (UMBS). We examine here the potential BVOC contribution to aerosol formation. A TSI, inc. Scanning Mobility Particle Sizer (SMPS) was used to measure aerosol number density in the size range, 15 nm < x < 711 nm and a Proton Transfer Reaction - Linear Ion Trap (PTR-LIT) mass spectrometer for quantifying isoprene and other BVOCs, including methyl vinyl ketone and methacrolein, and total monoterpenes. Preliminary results show periods of new particle production. Here we use a unique set of BVOC, HOx, NOx, NOy, O3 and meteorological data to examine conditions leading to new particle production.

  13. Landscape Risk Factors for Lyme Disease in the Eastern Broadleaf Forest Province of the Hudson River Valley and the Effect of Explanatory Data Classification Resolution

    EPA Science Inventory

    This study assessed how landcover classification affects associations between landscape characteristics and Lyme disease rate. Landscape variables were derived from the National Land Cover Database (NLCD), including native classes (e.g., deciduous forest, developed low intensity)...

  14. Fluxes of Ultrafine Particles Over and In a Deciduous Forest

    NASA Astrophysics Data System (ADS)

    Pryor, S. C.; Hornsby, K. E.

    2013-12-01

    Given the importance of forests to land surface cover and particle removal (due to the very high deposition velocities and well-developed turbulence) there is a specific need to understand removal to, and in, forests. Fluxes of size-resolved and total particle number fluxes over (at 46 m) and in (at 7 m) a deciduous forest over a 14 month period are presented based on data from two Gill 3-D WindMaster Pro sonic anemometers, an Ultrafine Condensation Particle Counter (UCPC) operated at 10 Hz and a Fast Mobility Particle Sizer (FMPS) operated at 1 Hz. Size-resolved particle profiles during the same period are measured using a separate FMPS scanning at three measurement heights across the canopy (top, middle and bottom). Three methods are being applied to derive the total number and size-resolved fluxes from the UCPC and FMPS respectively; eddy covariance, inertial dissipation and the co-spectral approach. The results are integrated with fluxes of sensible heat, momentum and carbon dioxide derived using a Licor LI-7200. Results for the total number flux concentrations and the size-resolved concentrations derived using the three different approaches applied to the above canopy sampling level show a high degree of accord, but that the eddy-covariance fluxes are generally of smaller magnitude than those derived using the spectral methods. In keeping with prior research our results show a considerable number of fluxes are characterized by upward fluxes. Further our results show distinctly different flux diurnal profiles for the nucleation versus Aitken mode particles indicating some differential control on fluxes of particles of different sizes (including a role for aerosol dynamics). This presentation will provide details regarding the experimental approach, flux and gradient estimation methodologies, diagnose the size dependence of the fluxes, and compare and contrast the canopy and ground partitioning of the particle fluxes during leaf-on and leaf-off periods.

  15. Distribution of deciduous stands in villages located in coniferous forest landscapes in Sweden.

    PubMed

    Mikusiński, Grzegorz; Angelstam, Per; Sporrong, Ulf

    2003-12-01

    Termination of fire along with active removal of deciduous trees in favor of conifers together with anthropogenic transformation of productive forest into agricultural land, have transformed northern European coniferous forests and reduced their deciduous component. Locally, however, in the villages, deciduous trees and stands were maintained, and have more recently regenerated on abandoned agricultural land. We hypothesize that the present distribution of the deciduous component is related to the village in-field/out-field zonation in different regions, which emerges from physical conditions and recent economic development expressed as land-use change. We analyzed the spatial distribution of deciduous stands in in-field and out-field zones of villages in 6 boreal/hemiboreal Swedish regions (Norrbotten, Angermanland, Jämtland, Dalarna, Bergslagen, Småland). In each region 6 individual quadrates 5 x 5 km centered on village areas were selected. We found significant regional differences in the deciduous component (DEC) in different village zones. At the scale of villages Angermanland had the highest mean proportion of DEC (17%) and Jämtland the lowest (2%). However, the amounts of the DEC varied systematically in in-field and out-field zones. DEC was highest in the in-field in the south (Småland), but generally low further north. By contrast, the amount of DEC in the out-field was highest in the north. The relative amount of DEC in the forest edge peaked in landscapes with the strongest decline in active agriculture (Angermanland, Dalarna, Bergslagen). Because former and present local villages are vital for biodiversity linked to the deciduous component, our results indicate a need for integrated management of deciduous forest within entire landscapes. This study shows that simplified satellite data are useful for estimating the spatial distribution of deciduous trees and stands at the landscape scale. However, for detailed studies better thematic resolution is

  16. Coleoptera Associated with Decaying Wood in a Tropical Deciduous Forest.

    PubMed

    Muñoz-López, N Z; Andrés-Hernández, A R; Carrillo-Ruiz, H; Rivas-Arancibia, S P

    2016-08-01

    Coleoptera is the largest and diverse group of organisms, but few studies are dedicated to determine the diversity and feeding guilds of saproxylic Coleoptera. We demonstrate the diversity, abundance, feeding guilds, and succession process of Coleoptera associated with decaying wood in a tropical deciduous forest in the Mixteca Poblana, Mexico. Decaying wood was sampled and classified into four stages of decay, and the associated Coleoptera. The wood was identified according to their anatomy. Diversity was estimated using the Simpson index, while abundance was estimated using a Kruskal-Wallis test; the association of Coleoptera with wood species and decay was assessed using canonical correspondence analysis. Decay wood stage I is the most abundant (51%), followed by stage III (21%). We collected 93 Coleoptera belonging to 14 families, 41 genera, and 44 species. The family Cerambycidae was the most abundant, with 29% of individuals, followed by Tenebrionidae with 27% and Carabidae with 13%. We recognized six feeding guilds. The greatest diversity of Coleoptera was recorded in decaying Acacia farnesiana and Bursera linanoe. Kruskal-Wallis analysis indicated that the abundance of Coleoptera varied according to the species and stage of decay of the wood. The canonical analysis showed that the species and stage of decay of wood determined the composition and community structure of Coleoptera. PMID:26911160

  17. Ecophysiological Remote Sensing of Leaf-Canopy Photosynthetic Characteristics in a Cool-Temperate Deciduous Forest in Japan

    NASA Astrophysics Data System (ADS)

    Noda, H. M.; Muraoka, H.

    2014-12-01

    Satellite remote sensing of structure and function of canopy is crucial to detect temporal and spatial distributions of forest ecosystems dynamics in changing environments. The spectral reflectance of the canopy is determined by optical properties (spectral reflectance and transmittance) of single leaves and their spatial arrangements in the canopy. The optical properties of leaves reflect their pigments contents and anatomical structures. Thus detailed information and understandings of the consequence between ecophysiological traits and optical properties from single leaf to canopy level are essential for remote sensing of canopy ecophysiology. To develop the ecophysiological remote sensing of forest canopy, we have been promoting multiple and cross-scale measurements in "Takayama site" belonging to AsiaFlux and JaLTER networks, located in a cool-temperate deciduous broadleaf forest on a mountainous landscape in Japan. In this forest, in situ measurement of canopy spectral reflectance has been conducted continuously by a spectroradiometer as part of the "Phenological Eyes Network (PEN)" since 2004. To analyze the canopy spectral reflectance from leaf ecophysiological viewpoints, leaf mass per area, nitrogen content, chlorophyll contents, photosynthetic capacities and the optical properties have been measured for dominant canopy tree species Quercus crispla and Betula ermanii throughout the seasons for multiple years.Photosynthetic capacity was largely correlated with chlorophyll contents throughout the growing season in both Q. crispla and B. ermanii. In these leaves, the reflectance at "red edge" (710 nm) changed by corresponding to the changes of chlorophyll contents throughout the seasons. Our canopy-level examination showed that vegetation indices obtained by red edge reflectance have linear relationship with leaf chlorophyll contents and photosynthetic capacity. Finally we apply this knowledge to the Rapid Eye satellite imagery around Takayama site to scale

  18. [Spatial heterogeneity of natural regeneration in a spruce-fir mixed broadleaf-conifer forest in Changbai Mountains].

    PubMed

    Li, Yan-Li; Yang, Hua; Kang, Xin-Gang; Wang, Yan; Yue, Gang; Shen, Lin

    2014-02-01

    Based on fieldwork on a plot of 60 m x 60 m in the Changbai Mountain area of Northeast China in August 2012, the spatial distribution pattern and heterogeneity of natural regeneration in the spruce-fir mixed broadleaf-conifer forest were analyzed using semi-variograms, fractal dimensions and Kriging interpolation methods. The results showed that Abies nephrolepis and Acer mono were the most common regeneration species, accounting for 87.4% of the total. The regeneration seedlings and saplings presented an aggregate distribution pattern with the biggest radius of 9.93 m. Distinct spatial autocorrelation existed among regeneration seedlings and saplings, with 88.7% of variation coming from structure factors (biological and ecological properties and environmental heterogeneity) and 11.3% from random factors. The spatial distribution of the regeneration seedlings and saplings presented anisotropy, with the smallest fractal dimension and strongest spatial heterogeneity from north to south, and the highest fractal dimension and weakest spatial heterogeneity from northeast to southwest. The spatial heterogeneity of heights of seedlings and saplings was greater than that of root collar diameters. The distance of spatial autocorrelation for tree root collar diameters was 29.97 m, and that for heights was 31.86 m. Random factors and structure factors were found to contribute equally to the spatial heterogeneity. PMID:24830227

  19. Patterns of small mammal microhabitat utilization in cedar glade and deciduous forest habitats

    SciTech Connect

    Seagle, S.W.

    1985-01-01

    Differential microhabitat use by the small mammals inhabiting a cedar glade and a deciduous forest was investigated using discriminant function analysis of 30 structural parameters measured around the capture site of each animal. Ochrotomys nuttalli and Peromyscus leucopus utilize different microhabitats in the cedar glade, as do Blarina brevicauda and P. leucopus in the deciduous forest. P. leucopus was found to be a microhabitat generalist in the deciduous forest and a specialist in the cedar glade, whereas O. nuttalli and B. bravicauda were a microhabitat generalist and specialist, respectively. The sexes of P. leucopus were found to occupy different microhabitats in the deciduous forest but not in the cedar glade. Female P. leucopus occupied microhabitat with better protective cover in the deciduous forest. Comparisons of microhabitats used by the two species captured in each habitat with a random microhabitat sample and trap sites at which no animals were captured indicate that each habitat is a complex matrix of microhabitats, some of which are used by small mammals and some of which are not. 24 references, 5 figures, 5 tables.

  20. Rainfall Reduction Increases Soil Methane Uptake in Broadleaf Evergreen Eucalypt Forest - a Negative Feedback to Climate Change

    NASA Astrophysics Data System (ADS)

    Fest, B. J.; Hinko-Najera, N.; Livesley, S. J.; Arndt, S. K.

    2013-12-01

    Well-drained aerated soils are important sinks for atmospheric methane (CH4), a process driven by CH4 oxidation through methanotrophic bacteria. Soils in temperate forest ecosystems represent the greatest terrestrial CH4 sink and soil moisture is one of the key regulators of soil CH4 flux in these systems. Most climate change models predict a decrease in average rainfall, an increase in extreme rainfall events and an increase in temperatures for mid-latitude and sub-arid regions. However, most studies of soil CH4 flux under altered rainfall scenarios have been conducted in mid-latitude forest and grassland systems of the northern hemisphere or in tropical forest systems and have often investigated extended drought rather than an reduction in long-term average rainfall. We measured soil CH4 flux for 18 months (October 2010 - April 2012) after installing a passive rainfall reduction system to intercept approximately 40% of canopy throughfall (as compared to control plots) in a temperate broadleaf evergreen eucalypt forest in south-eastern Australia. Throughfall reduction caused an average reduction of 15.1 × 6.4 (SE) % in soil volumetric water content, a reduction of 19.8 × 6.9 (SE) % in soil water filled pore space (WFPS) and a 20.1 × 6.8 (SE) % increase in soil air filled porosity (AFP). In response to these changes, soil CH4 uptake increased by 54.7 × 19.8 (SE) %. Relative changes in CH4 uptake related better to relative changes in AFP than to relative changes in WFPS, indicating a close relationship between AFP and soil gas diffusivity. Our data indicated that soil moisture was the dominant regulating factor of seasonality in soil CH4 uptake explaining up to 80% of the seasonal variability and accounting for the observed throughfall reduction treatment effect. This was confirmed by additional soil diffusivity measurements and passive soil warming treatments. We investigated non-linear functions to describe the relationship between soil moisture and soil CH4

  1. Environmental control on eastern broadleaf forest species' leaf wax distributions and D/H ratios

    NASA Astrophysics Data System (ADS)

    Tipple, Brett J.; Pagani, Mark

    2013-06-01

    Local climate and environment broadly affect the deuterium/hydrogen (D/H) ratios of plant materials, however the degree to which an individual plant's leaf waxes D/H ratios are affected by these parameters remains in question. Understanding these issues is particularly important in order to reconstruct past floral transitions and changes in the paleohydrologic cycle. For this study, we sampled five co-occurring tree species, Acer rubrum, Platanus occidentalis, Juniperus virginiana, Pinus taeda, and Pinus strobus and soils at forty sites along the East Coast of the US, from Florida to Maine. Hydrogen isotopic compositions of leaf wax n-alkanes, stem and surface waters were analyzed and compared against high-resolution temperature, precipitation, relative humidity, and vapor pressure deficit data to determine environmental controls on isotopic composition. Our results demonstrate that each tree species produce a unique distribution of n-alkanes with distinct chain length pattern. Average n-alkane chain lengths recovered from soils, A. rubrum, and J. virginiana leaves show significant correlations with mean annual temperature. δD values of A. rubrum leaf n-alkanes were strongly correlated to modeled mean annual precipitation δD values and other climate parameters related to latitude (i.e. temperature, relative humidity, vapor pressure deficit), while the δD values of J. virginiana n-alkanes were not. Differences in correspondence may reflect the timing of leaf wax synthesis between the two species. Further, soil n-alkane D/H compositions were strongly correlated to modeled mean annual precipitation δD values, while the apparent hydrogen isotopic fractionation was not. These findings indicate that the isotope ratio of n-alkanes from soils in Eastern North American forests and similar ecosystems likely represents a time-averaged value that smooth out the environmental influence any one plant experiences.

  2. Leaf Area Influence on Surface Layer in a Deciduous Forest. Part I; Site Description

    NASA Technical Reports Server (NTRS)

    Sakai, Ricardo K.; Fitzjarrald, David R.; Moore, Kathleen E.; Sicker, John W.; Munger, William; Goulden, Michael L.; Wofsy, Steven C.

    1996-01-01

    A study over a deciduous forest located in middle Massachusetts (USA) has been performed to examine the role of leaves in the forest-atmosphere interaction. Due to the seasonal presence of leaves, a deciduous forest is a 'good laboratory' to study this interaction. In this first part, a description of a 30 m micrometeorological tower as well a qualitative description of some meteorological parameters are presented. The presence of leaves affects the forest in several ways. There is a decrease of upward PAR (Photosynthetically Active Radiation) due to absorption of visible light in the canopy. Water vapor concentration increases, and the CO2 concentration decreases in the surface layer as the canopy starts to be foliated. The physical presence of the leaves is felt in other quantities such as the global albedo and the subcanopy environment.

  3. FLUXES OF GASES AND PARTICLES ABOVE A DECIDUOUS FOREST IN WINTERTIME

    EPA Science Inventory

    Eddy-correlation measurements of the vertical fluxes of ozone, carbon dioxide, fine particles with diameter near 0.1 micrometers, and particulate sulfur, as well as of momentum, heat and water vapor, have been taken above a tall leafless deciduous forest in wintertime. During the...

  4. Mercury in coniferous and deciduous upland forests in northern New England, USA: implications of climate change

    NASA Astrophysics Data System (ADS)

    Richardson, J. B.; Friedland, A. J.

    2015-11-01

    Climatic changes in the northeastern US are expected to cause coniferous stands to transition to deciduous stands over the next hundred years. Mercury (Hg) sequestration in forest soils may change as a result. In order to understand potential effects of such a transition, we studied aboveground vegetation and soils at paired coniferous and deciduous stands on eight mountains in Vermont and New Hampshire, USA. Organic horizons at coniferous stands accumulated more total Hg (THg; 42 ± 6 g ha-1) than deciduous stands (30 ± 4 g ha-1). Total Hg pools in the mineral horizons were similar for coniferous (46 ± 8 g ha-1) and deciduous stands (45 ± 7 g ha-1). Soil properties (C, % clay, and pH) explained 56 % of the variation in mineral soil Hg concentration when multiply regressed. Foliar and bole wood Hg concentrations were generally greater for coniferous species than deciduous species. Using allometric equations, we estimated that aboveground accumulation of Hg in foliage and woody biomass was similar between vegetation types but that coniferous stands have significantly smaller annual litterfall fluxes (0.03 g ha-1 yr-1) than deciduous stands (0.24 g ha-1 yr-1). We conclude that organic horizon Hg accumulation is influenced by vegetation type but mineral horizon Hg accumulation is primarily controlled by soil properties. Further investigations into the effect of vegetation type on volatilization, atmospheric deposition, and leaching rates are needed to constrain regional Hg cycling rates.

  5. Mercury in coniferous and deciduous upland forests in Northern New England, USA: implications from climate change

    NASA Astrophysics Data System (ADS)

    Richardson, J. B.; Friedland, A. J.

    2015-07-01

    Climatic changes in the northeastern US are expected to cause coniferous stands to transition to deciduous stands over the next hundred years. Mercury (Hg) sequestration in forest soils may change as a result. In order to understand potential effects of this transition, we studied aboveground vegetation and soils at paired coniferous and deciduous stands on eight mountains in Vermont and New Hampshire, US. Organic horizons at coniferous stands accumulated more Total Hg (THg) (42 ± 6 g ha-1) than deciduous stands (30 ± 4 g ha-1). Total Hg pools in the mineral horizons were similar for coniferous (46 ± 8 g ha-1) and deciduous stands (45 ± 7 g ha-1). Soil properties (C, % clay, and pH) explained 56 % of the variation in mineral soil Hg concentration when multiple regressed. Foliar and bole wood Hg concentrations were generally greater for coniferous species than deciduous species. We estimated Hg mean residence time (MRT) in the organic and mineral horizons at coniferous and deciduous stands using a simple two-box model. Organic horizon MRT were longer at coniferous stands (183 ± 44 yr) than deciduous stands (65 ± 15 yr). Mineral soil horizon MRT values were also longer for coniferous stands (386 ± 57 yr) than for deciduous stands (188 ± 27 yr). We concluded that organic horizon Hg accumulation is influenced by vegetation type but mineral horizons are primarily affected by soil properties. Further investigations into the effect of vegetation type on volatilization, atmospheric deposition, and leaching rates are needed to constrain regional Hg cycling rates.

  6. Deciduous forest responses to temperature, precipitation, and drought imply complex climate change impacts.

    PubMed

    Xie, Yingying; Wang, Xiaojing; Silander, John A

    2015-11-01

    Changes in spring and autumn phenology of temperate plants in recent decades have become iconic bio-indicators of rapid climate change. These changes have substantial ecological and economic impacts. However, autumn phenology remains surprisingly little studied. Although the effects of unfavorable environmental conditions (e.g., frost, heat, wetness, and drought) on autumn phenology have been observed for over 60 y, how these factors interact to influence autumn phenological events remain poorly understood. Using remotely sensed phenology data from 2001 to 2012, this study identified and quantified significant effects of a suite of environmental factors on the timing of fall dormancy of deciduous forest communities in New England, United States. Cold, frost, and wet conditions, and high heat-stress tended to induce earlier dormancy of deciduous forests, whereas moderate heat- and drought-stress delayed dormancy. Deciduous forests in two eco-regions showed contrasting, nonlinear responses to variation in these explanatory factors. Based on future climate projection over two periods (2041-2050 and 2090-2099), later dormancy dates were predicted in northern areas. However, in coastal areas earlier dormancy dates were predicted. Our models suggest that besides warming in climate change, changes in frost and moisture conditions as well as extreme weather events (e.g., drought- and heat-stress, and flooding), should also be considered in future predictions of autumn phenology in temperate deciduous forests. This study improves our understanding of how multiple environmental variables interact to affect autumn phenology in temperate deciduous forest ecosystems, and points the way to building more mechanistic and predictive models. PMID:26483475

  7. Deciduous forest responses to temperature, precipitation, and drought imply complex climate change impacts

    PubMed Central

    Xie, Yingying; Wang, Xiaojing; Silander, John A.

    2015-01-01

    Changes in spring and autumn phenology of temperate plants in recent decades have become iconic bio-indicators of rapid climate change. These changes have substantial ecological and economic impacts. However, autumn phenology remains surprisingly little studied. Although the effects of unfavorable environmental conditions (e.g., frost, heat, wetness, and drought) on autumn phenology have been observed for over 60 y, how these factors interact to influence autumn phenological events remain poorly understood. Using remotely sensed phenology data from 2001 to 2012, this study identified and quantified significant effects of a suite of environmental factors on the timing of fall dormancy of deciduous forest communities in New England, United States. Cold, frost, and wet conditions, and high heat-stress tended to induce earlier dormancy of deciduous forests, whereas moderate heat- and drought-stress delayed dormancy. Deciduous forests in two eco-regions showed contrasting, nonlinear responses to variation in these explanatory factors. Based on future climate projection over two periods (2041–2050 and 2090–2099), later dormancy dates were predicted in northern areas. However, in coastal areas earlier dormancy dates were predicted. Our models suggest that besides warming in climate change, changes in frost and moisture conditions as well as extreme weather events (e.g., drought- and heat-stress, and flooding), should also be considered in future predictions of autumn phenology in temperate deciduous forests. This study improves our understanding of how multiple environmental variables interact to affect autumn phenology in temperate deciduous forest ecosystems, and points the way to building more mechanistic and predictive models. PMID:26483475

  8. Landscape risk factors for Lyme disease in the eastern broadleaf forest province of the Hudson River valley and the effect of explanatory data classification resolution.

    PubMed

    Messier, Kyle P; Jackson, Laura E; White, Jennifer L; Hilborn, Elizabeth D

    2015-01-01

    This study assessed how landcover classification affects associations between landscape characteristics and Lyme disease rate. Landscape variables were derived from the National Land Cover Database (NLCD), including native classes (e.g., deciduous forest, developed low intensity) and aggregate classes (e.g., forest, developed). Percent of each landcover type, median income, and centroid coordinates were calculated by census tract. Regression results from individual and aggregate variable models were compared with the dispersion parameter-based R(2) (Rα(2)) and AIC. The maximum Rα(2) was 0.82 and 0.83 for the best aggregate and individual model, respectively. The AICs for the best models differed by less than 0.5%. The aggregate model variables included forest, developed, agriculture, agriculture-squared, y-coordinate, y-coordinate-squared, income and income-squared. The individual model variables included deciduous forest, deciduous forest-squared, developed low intensity, pasture, y-coordinate, y-coordinate-squared, income, and income-squared. Results indicate that regional landscape models for Lyme disease rate are robust to NLCD landcover classification resolution. PMID:25779905

  9. Remote sensing-based estimation of annual soil respiration at two contrasting forest sites

    DOE PAGESBeta

    Gu, Lianhong; Huang, Ni; Black, T. Andrew; Wang, Li; Niu, Zheng

    2015-11-23

    Soil respiration (Rs), an important component of the global carbon cycle, can be estimated using remotely sensed data, but the accuracy of this technique has not been thoroughly investigated. In this article, we proposed a methodology for the remote estimation of annual Rs at two contrasting FLUXNET forest sites (a deciduous broadleaf forest and an evergreen needleleaf forest).

  10. HNO 3 fluxes to a deciduous forest derived using gradient and REA methods

    NASA Astrophysics Data System (ADS)

    Pryor, S. C.; Barthelmie, R. J.; Jensen, B.; Jensen, N. O.; Sørensen, L. L.

    Summertime nitric acid concentrations over a deciduous forest in the midwestern United States are reported, which range between 0.36 and 3.3 μg m -3. Fluxes to the forest are computed using the relaxed eddy accumulation technique and gradient methods. In accord with previous studies, the results indicate substantial uncertainties in the gradient-based calculations. The relaxed eddy accumulation (REA) derived fluxes are physically reasonable and are shown to be of similar magnitude to dry deposition estimates from gradient sampling. The REA derived mean deposition velocity is approximately 3 cm s -1, which is also comparable to growing season estimates derived by Meyers et al. for a similar deciduous forest. Occasional inverted concentration gradients and fluxes are observed but most are not statistically significant. Data are also presented that indicate substantial through canopy penetration of nitric acid.

  11. The Pleistocene biogeography of eastern North America: A nonmigration scenario for deciduous forest

    SciTech Connect

    Loehle, C.; Iltis, H.

    1998-12-31

    The current reconstruction of the vegetation of eastern North America at the last glacial maximum postulates a very wide zone of tundra and boreal forest south of the ice. This reconstruction requires that the deciduous forest retreated far to the south. The authors believe that this reconstruction is seriously in error. Geologic evidence for glacial activity or tundra is absent from the southern Appalachians. Positive evidence for boreal forest is based on pollen identifications for Picea, Betula, and Pinus, when in reality southern members of these genera have pollen that cannot be distinguished from that of northern members. Further, pollen of typical southern species such as oaks and hickories occurs throughout profiles that past authors had labeled boreal. Pollen evidence for a far southern deciduous forest refuge is lacking. Data on endemics are particularly challenging for the scenario in which deciduous forest migrated to the south and back. The southern Appalachian region is rife with endemics that are often extreme-habitat specialists unable to migrate. The previously glaciated zone is almost completely lacking in endemics. Outlier populations, range boundaries, and absence of certain hybrids all argue against a large boreal zone. The new reconstruction postulates a cold zone no more than 75--100 miles wide south of the ice in the East.

  12. Deciduous trees are a large and overlooked sink for snowmelt water in the boreal forest

    PubMed Central

    Young-Robertson, Jessica M.; Bolton, W. Robert; Bhatt, Uma S.; Cristóbal, Jordi; Thoman, Richard

    2016-01-01

    The terrestrial water cycle contains large uncertainties that impact our understanding of water budgets and climate dynamics. Water storage is a key uncertainty in the boreal water budget, with tree water storage often ignored. The goal of this study is to quantify tree water content during the snowmelt and growing season periods for Alaskan and western Canadian boreal forests. Deciduous trees reached saturation between snowmelt and leaf-out, taking up 21–25% of the available snowmelt water, while coniferous trees removed <1%. We found that deciduous trees removed 17.8–20.9 billion m3 of snowmelt water, which is equivalent to 8.7–10.2% of the Yukon River’s annual discharge. Deciduous trees transpired 2–12% (0.4–2.2 billion m3) of the absorbed snowmelt water immediately after leaf-out, increasing favorable conditions for atmospheric convection, and an additional 10–30% (2.0–5.2 billion m3) between leaf-out and mid-summer. By 2100, boreal deciduous tree area is expected to increase by 1–15%, potentially resulting in an additional 0.3–3 billion m3 of snowmelt water removed from the soil per year. This study is the first to show that deciduous tree water uptake of snowmelt water represents a large but overlooked aspect of the water balance in boreal watersheds. PMID:27404274

  13. Deciduous trees are a large and overlooked sink for snowmelt water in the boreal forest

    NASA Astrophysics Data System (ADS)

    Young-Robertson, Jessica M.; Bolton, W. Robert; Bhatt, Uma S.; Cristóbal, Jordi; Thoman, Richard

    2016-07-01

    The terrestrial water cycle contains large uncertainties that impact our understanding of water budgets and climate dynamics. Water storage is a key uncertainty in the boreal water budget, with tree water storage often ignored. The goal of this study is to quantify tree water content during the snowmelt and growing season periods for Alaskan and western Canadian boreal forests. Deciduous trees reached saturation between snowmelt and leaf-out, taking up 21–25% of the available snowmelt water, while coniferous trees removed <1%. We found that deciduous trees removed 17.8–20.9 billion m3 of snowmelt water, which is equivalent to 8.7–10.2% of the Yukon River’s annual discharge. Deciduous trees transpired 2–12% (0.4–2.2 billion m3) of the absorbed snowmelt water immediately after leaf-out, increasing favorable conditions for atmospheric convection, and an additional 10–30% (2.0–5.2 billion m3) between leaf-out and mid-summer. By 2100, boreal deciduous tree area is expected to increase by 1–15%, potentially resulting in an additional 0.3–3 billion m3 of snowmelt water removed from the soil per year. This study is the first to show that deciduous tree water uptake of snowmelt water represents a large but overlooked aspect of the water balance in boreal watersheds.

  14. Deciduous trees are a large and overlooked sink for snowmelt water in the boreal forest.

    PubMed

    Young-Robertson, Jessica M; Bolton, W Robert; Bhatt, Uma S; Cristóbal, Jordi; Thoman, Richard

    2016-01-01

    The terrestrial water cycle contains large uncertainties that impact our understanding of water budgets and climate dynamics. Water storage is a key uncertainty in the boreal water budget, with tree water storage often ignored. The goal of this study is to quantify tree water content during the snowmelt and growing season periods for Alaskan and western Canadian boreal forests. Deciduous trees reached saturation between snowmelt and leaf-out, taking up 21-25% of the available snowmelt water, while coniferous trees removed <1%. We found that deciduous trees removed 17.8-20.9 billion m(3) of snowmelt water, which is equivalent to 8.7-10.2% of the Yukon River's annual discharge. Deciduous trees transpired 2-12% (0.4-2.2 billion m(3)) of the absorbed snowmelt water immediately after leaf-out, increasing favorable conditions for atmospheric convection, and an additional 10-30% (2.0-5.2 billion m(3)) between leaf-out and mid-summer. By 2100, boreal deciduous tree area is expected to increase by 1-15%, potentially resulting in an additional 0.3-3 billion m(3) of snowmelt water removed from the soil per year. This study is the first to show that deciduous tree water uptake of snowmelt water represents a large but overlooked aspect of the water balance in boreal watersheds. PMID:27404274

  15. Effect of hemlock and deciduous forest canopy on chemistry of throughfall, West Whately, Massachusetts

    NASA Astrophysics Data System (ADS)

    Rhodes, A. L.; Guswa, A. J.; McNicholas, J.; Mehter, S.; Spence, C.

    2009-12-01

    Ecological forest successions associated with climate change and human disturbance may alter chemical loads to forested New England watersheds. Spread of the invasive insect hemlock wooly adelgid (Adelges tsugae) to eastern North America is causing decline and mortality of the eastern hemlock (Tsuga Canadensis). To begin an evaluation of whether changes in nutrient cycling and rainfall amounts could be altered by this disturbance, we investigated differences in chemistry and volume of rain and throughfall between predominately hemlock and deciduous tree stands in a secondary growth forest located in West Whately, Massachusetts. From 3 June to 25 July 2009, we sampled 14 rain events from two plots: one dominated by eastern hemlock (LAI = 5.6 with 64% of stems as hemlock) and the other dominated by a mix of deciduous species (LAI = 4.7 with 47% of stems as maple and 42% of basal area accounted as white ash). Plots consisted of a 5 x 6 meter grid of 30 collectors for measuring throughfall volume. Half of these were combined into a composite sample and analyzed for pH, acid neutralizing capacity (ANC), dissolved organic carbon (DOC), base cations (Ca2+, Mg2+, Na+, K+), anions (Cl-, NO3-, SO42+), dissolved silica, and specific conductance. Throughfall results were compared against precipitation sampled from a collector located in a nearby field. Over the period of the study, rainfall totaled 311 mm. Throughfall amounted to 242 mm (78%) in the hemlock plot and 276 mm (89%) in the deciduous plot. On an event-by-event basis, the fraction of precipitation that appears as throughfall increases with amount. Throughfall from both hemlock and deciduous plots showed significantly (p < 0.05) higher pH, ANC, DOC, K+, Ca2+, and Mg2+ concentrations than open precipitation, suggesting that the canopy counteracts some acidity in rain and adds organic carbon and nutrients to throughfall. ANC is positively correlated with K+, Ca2+, Mg2+, and DOC, indicating that cation exchange between

  16. High rates of carbon storage in old deciduous forests: Emerging mechanisms from the Forest Accelerated Succession ExperimenT (FASET)

    NASA Astrophysics Data System (ADS)

    Gough, C. M.; Nave, L. E.; Hardiman, B. S.; Bohrer, G.; Halperin, A.; Maurer, K.; Le Moine, J.; Nadelhoffer, K.; Vogel, C. S.; Curtis, P.; University Of Michigan Biological Station Forest Ecosystem Study (Umbs-Fest) Team

    2010-12-01

    Deciduous forests of the eastern US are broadly approaching an ecological threshold in which early successional dominant trees are senescing and giving way to later successional species, with unknown consequences for regional carbon (C) cycling. Though recent research demonstrates that forests may accumulate C for centuries, the mechanisms behind sustained rates of C storage in old, particularly deciduous, forests have not been identified. In a regionally representative forest at the University of Michigan Biological Station, we are combining observational and experimental C cycling studies to forecast how forest C storage responds to climate variation, disturbance, and succession. The Forest Accelerated Succession ExperimenT (FASET), in which >6,700 aspen and birch trees (~35 % LAI) were stem girdled within a 39 ha area, is testing the hypothesis that forest production will increase rather than decline with age, due to increases in nitrogen (N) availability, N allocation to the canopy, and the concurrent development of a more biologically and structurally complex canopy. Results thus far support our hypothesis that aging forests in the region may sustain high rates of C storage through shifts in N cycling and increased canopy complexity. Girdling-induced mortality of early successional species reduced soil respiration, accelerated fine root turnover, and prompted the redistribution of N from the foliage of early to later successional species. Nitrogen redistribution increased leaf area index (LAI) production by later successional species, offsetting declines in LAI from senescing early successional species. High rates of net primary production (NPP) were sustained in stands comprising a diverse assemblage of early and later successional species because later successional species, when already present in the canopy, rapidly compensated for declining growth of early successional species. Canopy structural complexity, which increased with forest age, was positively

  17. Stemflow acid neutralization capacity in a broadleaved deciduous forest: the role of edge effects.

    PubMed

    Shiklomanov, Alexey N; Levia, Delphis F

    2014-10-01

    Atmospheric deposition is an important pathway for moisture, nutrient, and pollutant exchange among the atmosphere, forest, and soils. Previous work has shown the importance of proximity to the forest edge to chemical fluxes in throughfall, but far less research has considered stemflow. This study examined the difference in acid neutralization capacity (ANC) of stemflow of nineteen Liriodendron tulipifera L. (yellow poplar) trees between the forest edge and interior in a rural area of northeastern Maryland. We measured ANC directly via potentiometric titration. Stemflow from trees at the forest edge was found to have significantly higher and more variable pH and ANC than in the forest interior (p < 0.01). No mathematical trend between ANC and distance to the forest edge was observed, indicating the importance of individual tree characteristics in stemflow production and chemistry. These results reaffirm the importance of stemflow for acid neutralization by deciduous tree species. PMID:25005886

  18. Modeling gross primary production of deciduous forest using remotely sensed radiation and ecosystem variables

    NASA Astrophysics Data System (ADS)

    Jahan, Nasreen; Gan, Thian Yew

    2009-12-01

    We explored the potential application of two remotely sensed (RS) variables, the Global Vegetation Moisture Index (GVMI) and the near-infrared albedo (AlbedoNIR), in modeling the gross primary production (GPP) of three deciduous forests. For the Harvard Forest (deciduous) of Massachusetts, it was found that GPP is strongly correlated with GVMI (coefficient of determination, R2 = 0.60) during the growing season, and with AlbedoNIR (R2 = 0.82) throughout the year. Subsequently, a statistical model called the Remotely Sensed GPP (R-GPP) model was developed to estimate GPP using remotely sensed radiation (land surface temperature (LST), AlbedoNIR) and ecosystem variables (enhanced vegetation index (EVI) and GVMI). The R-GPP model, calibrated and validated against the GPP estimates derived from the eddy covariance flux tower of the Harvard Forest, could explain 95% and 92% of the observed GPP variability for the study site during the calibration (2000-2003) and the validation (2004-2005) periods, respectively. It outperformed the primary RS-based GPP algorithm of Moderate Resolution Imaging Spectroradiometer (MODIS), which explained 80% and 77% of the GPP variability during 2000-2003 and 2004-2005, respectively. The calibrated R-GPP model also explained 93% and 94% of the observed GPP variation for two other independent validation sites, the Morgan Monroe State Forest and the University of Michigan Biological Station, respectively, which demonstrates its transferability to other deciduous ecoregions of northeastern United States.

  19. Water relations of evergreen and drought-deciduous trees along a seasonally dry tropical forest chronosequence.

    PubMed

    Hasselquist, Niles J; Allen, Michael F; Santiago, Louis S

    2010-12-01

    Seasonally dry tropical forests (SDTF) are characterized by pronounced seasonality in rainfall, and as a result trees in these forests must endure seasonal variation in soil water availability. Furthermore, SDTF on the northern Yucatan Peninsula, Mexico, have a legacy of disturbances, thereby creating a patchy mosaic of different seral stages undergoing secondary succession. We examined the water status of six canopy tree species, representing contrasting leaf phenology (evergreen vs. drought-deciduous) at three seral stages along a fire chronosequence in order to better understand strategies that trees use to overcome seasonal water limitations. The early-seral forest was characterized by high soil water evaporation and low soil moisture, and consequently early-seral trees exhibited lower midday bulk leaf water potentials (Ψ(L)) relative to late-seral trees (-1.01 ± 0.14 and -0.54 ± 0.07 MPa, respectively). Although Ψ(L) did not differ between evergreen and drought-deciduous trees, results from stable isotope analyses indicated different strategies to overcome seasonal water limitations. Differences were especially pronounced in the early-seral stage where evergreen trees had significantly lower xylem water δ(18)O values relative to drought-deciduous trees (-2.6 ± 0.5 and 0.3 ± 0.6‰, respectively), indicating evergreen species used deeper sources of water. In contrast, drought-deciduous trees showed greater enrichment of foliar (18)O (∆(18)O(l)) and (13)C, suggesting lower stomatal conductance and greater water-use efficiency. Thus, the rapid development of deep roots appears to be an important strategy enabling evergreen species to overcome seasonal water limitation, whereas, in addition to losing a portion of their leaves, drought-deciduous trees minimize water loss from remaining leaves during the dry season. PMID:20658152

  20. Water relations of evergreen and drought-deciduous trees along a seasonally dry tropical forest chronosequence

    PubMed Central

    Allen, Michael F.; Santiago, Louis S.

    2010-01-01

    Seasonally dry tropical forests (SDTF) are characterized by pronounced seasonality in rainfall, and as a result trees in these forests must endure seasonal variation in soil water availability. Furthermore, SDTF on the northern Yucatan Peninsula, Mexico, have a legacy of disturbances, thereby creating a patchy mosaic of different seral stages undergoing secondary succession. We examined the water status of six canopy tree species, representing contrasting leaf phenology (evergreen vs. drought-deciduous) at three seral stages along a fire chronosequence in order to better understand strategies that trees use to overcome seasonal water limitations. The early-seral forest was characterized by high soil water evaporation and low soil moisture, and consequently early-seral trees exhibited lower midday bulk leaf water potentials (ΨL) relative to late-seral trees (−1.01 ± 0.14 and −0.54 ± 0.07 MPa, respectively). Although ΨL did not differ between evergreen and drought-deciduous trees, results from stable isotope analyses indicated different strategies to overcome seasonal water limitations. Differences were especially pronounced in the early-seral stage where evergreen trees had significantly lower xylem water δ18O values relative to drought-deciduous trees (−2.6 ± 0.5 and 0.3 ± 0.6‰, respectively), indicating evergreen species used deeper sources of water. In contrast, drought-deciduous trees showed greater enrichment of foliar 18O (∆18Ol) and 13C, suggesting lower stomatal conductance and greater water-use efficiency. Thus, the rapid development of deep roots appears to be an important strategy enabling evergreen species to overcome seasonal water limitation, whereas, in addition to losing a portion of their leaves, drought-deciduous trees minimize water loss from remaining leaves during the dry season. PMID:20658152

  1. The impact of boreal deciduous and evergreen forests on atmospheric CO2 seasonality

    NASA Astrophysics Data System (ADS)

    Welp, L.; Graven, H. D.; Keeling, R. F.; Bi, J.

    2015-12-01

    The seasonal cycle of atmospheric CO2 is largely controlled by the terrestrial biosphere. It is well known that the seasonal amplitude of net ecosystem productivity (NEP) is the largest in the far north, where forest productivity is compressed into a short growing season. Since 1960, the seasonal amplitude of atmospheric CO2 north of 45N has increased by 35-55%. The increase in the seasonal amplitude is a difficult benchmark for coupled climate-carbon models to replicate. In fact, the models vary widely in their mean seasonal cycle representation. The boreal region has a strong influence on CO2 seasonality at Barrow. Deciduous and evergreen plant functional types (PFTs) have different patterns of NEP. We identified four pairs of nearby deciduous and evergreen forest PFTs with eddy covariance measurements. Evergreen forests show an early peak in NEP in May-June, while deciduous forests have a larger peak in NEP later in June-July. The influence of each PFT on the seasonal cycle at Barrow was computed from atmospheric transport results. We normalized the amplitude influence by the growing season NEP of the tower-based PFT flux and found that deciduous forests have 1.4 to 1.8 times more influence (per unit of growing season NEP) at Barrow than evergreen PFT. This diagnosis depends on the timing of the sharp seasonal draw-down at Barrow, which occurs too late to be explained by evergreen forests. The cycle at Barrow therefore appears to be strongly influenced by deciduous PFT, despite the dominance of evergreen PFTs in boreal forests. This paradoxical conclusion is also reached when examining the seasonality of land surface fluxes calculated using atmospheric inverse methods. We examine how these different PFTs, and possible trends in relative abundance, affect the seasonality of atmosphere CO2 using FluxNet data and atmospheric transport modelling. Our results highlight the importance of parameterizing multiple PFTs or individual species within grid cells in models in

  2. Study on identifying deciduous forest by the method of feature space transformation

    NASA Astrophysics Data System (ADS)

    Zhang, Xuexia; Wu, Pengfei

    2009-10-01

    The thematic remotely sensed information extraction is always one of puzzling nuts which the remote sensing science faces, so many remote sensing scientists devotes diligently to this domain research. The methods of thematic information extraction include two kinds of the visual interpretation and the computer interpretation, the developing direction of which is intellectualization and comprehensive modularization. The paper tries to develop the intelligent extraction method of feature space transformation for the deciduous forest thematic information extraction in Changping district of Beijing city. The whole Chinese-Brazil resources satellite images received in 2005 are used to extract the deciduous forest coverage area by feature space transformation method and linear spectral decomposing method, and the result from remote sensing is similar to woodland resource census data by Chinese forestry bureau in 2004.

  3. The microwave emission and transmission characters of deciduous forest at L-band

    NASA Astrophysics Data System (ADS)

    Zhang, Zhongjun; Yuan, Yu; Zheng, Xingming; Zhu, Xiaoming; Fu, Xiuli

    2014-11-01

    Forest covers about 30% of earth surface, which plays an important role in global forecast and carbon cycle. Monitoring forest biomass, and retrieving soil moisture at forest area, are the main goals of most passive microwave sensors on satellite missions. L-band is the most sensitive frequency among all the frequencies due to its good penetration ability. Because of its variety of the size of scattering components, the complicated structures and species of forest, it is difficult to describe the scattering and attenuation characters of forest in modeling microwave emission at forest area. In this paper, we studied the emissivity and transmissivity of deciduous forest at L(1.4GHz) by model simulation and field experiment. The microwave emission model was based on Matrix-Doubling algorithm. The comparison between simulated emissivity and measured data collected during an experiment at Maryland, USA in 2007 was good. Since theoretical model like Matrix-Doubling is too complicated to be used in retrial application, we mapped the results of Matrix-Doubling to a simple 0th-order model, also called ω-τ model, by setting the simulated emissivity to be the emissivity of 0th-order model at the same environment, which 2 unknown variables---opacity τ and effective single scattering albedo ω need to be determined. To valited τ (transmissivity of forest) simulated by Matrix-Doubling, we took an deciduous forest experiment by an L band microwave radiometer under trees at JingYueTan area, Changchun, Jilin Province in April to June in 2014. Thus the ω of forest can be determined. The matching results are presented in this paper. The relationship between LAI and forest microwave characters are discussed.

  4. An Individual Tree Detection Algorithm for Dense Deciduous Forests with Spreading Branches

    NASA Astrophysics Data System (ADS)

    Shao, G.

    2015-12-01

    Individual tree information derived from LiDAR may have the potential to assist forest inventory and improve the assessment of forest structure and composition for sustainable forest management. The algorithms developed for individual tree detection are commonly focusing on finding tree tops to allocation the tree positions. However, the spreading branches (cylinder crowns) in deciduous forests cause such kind of algorithms work less effectively on dense canopy. This research applies a machine learning algorithm, mean shift, to position individual trees based on the density of LiDAR point could instead of detecting tree tops. The study site locates in a dense oak forest in Indiana, US. The selection of mean shift kernels is discussed. The constant and dynamic bandwidths of mean shit algorithms are applied and compared.

  5. SEASONAL COURSE OF ISOPRENE EMISSIONS FROM A MIDLATITUDE DECIDUOUS FOREST

    EPA Science Inventory

    Continuous measurements of whole canopy isoprene emissions over an entire growing season are reported from Harvard Forest (42E32'N, 72E11'W). Emissions were calculated from the ratio of observed CO2 flux and gradient multiplied by the observed hydrocarbon gradients. In summer 199...

  6. Boron stemflow chemistry in relation to species and season in a temperate deciduous forest

    NASA Astrophysics Data System (ADS)

    Frost, E. E.; Levia, D. F.

    2013-12-01

    Boron is an essential micronutrient that contributes to cell wall development and other critical plant functions. Boron deficiency is not uncommon in many forest types and plantations but may be difficult to differentiate from other impacts. The magnitude and timing of B transfer to the forest floor via stemflow is poorly understood and little is known about its variation as a function of species and season in temperate deciduous forests. We characterized this transfer in a mid-Atlantic broadleaved deciduous forest where we collected and analyzed stemflow from dominant canopy species of Fagus grandifolia (Ehrh.) [American beech] and Liriodendron tulipifera (L.) [yellow poplar]. Boron concentrations in stemflow were found to be greater from L. tulipifera compared with F. grandifolia over both seasons. Increased stemflow volume from F. grandifolia resulted in greater overall B contributions from these stems as well as greater enrichment ratios in both leaf and leafless conditions. When expressed on the basis of basal area, contributions of B to the forest floor were many times greater than gross precipitation and varied with season and meteorologic conditions.

  7. Quantification of Carbon Fluxes in Tropical Deciduous Forests Using Satellite Data

    NASA Astrophysics Data System (ADS)

    Prasad, V. Krishna; Rajagopal, T.; Kant, Yogesh; Badarinath, K. V. S.

    Biomass burning in tropics is causing drastic changes in physical, chemical and biological properties of earth's atmosphere. Biomass burning associated with slash and burn agriculture is one of the major cause of Green House Gas emissions. In the present study, study area covering tropical deciduous forests having slash and burn agriculture practice, has been considered for studying carbon dynamics. Satellite data pertaining to IRS-1C LISS III satellite data has been used for stratification of vegetation into different communities. Second order texture measures Semivariograms, Angular Second Moment (ASM) and Inverse Difference Moment (IDM) and NDVI textural algorithm have been used to capture spatial information from forest stands. Biomass estimations have been done through regression equations by using girth measurements obtained through field studies. Satellite data has been used to quantify the amount of biomass burnt in respective vegetation types. Results of the study through textural measures suggest high heterogeneity in canopy diversity for mixed dry deciduous forests. ASM and IDM are found to be high for pure stands of dry deciduous forests. NDVI textural algorithm detected a low spatial variability with respect to mixed dry deciduous forests suggesting homogeneity in plant biomass spatial variability. The average mean carbon storage has been found to be 64.34 t ha-1 C for dry deciduous forests, 129.0 t ha-1 C for mixed dry deciduous forests and 0.02 t ha-1 C for mixed scrub forests. Potential Net primary productivity for the forests ranged from 26.07 to 11.73 t ha-1 yr-1, when compared to actual productivity of 0.1 t ha-1 yr-1 to 4.6 t ha-1 yr-1. Mean carbon storage for plantations, above ground, below ground and total carbon has been found to be 16.84, 3.36 and 20.2 t ha-1 C respectively. Dry matter burnt in gms (M) obtained from satellite derived areal estimates has been found to be 1.344 × 1012 gms. Area weighted carbon release for the total study

  8. Remote Sensing Based Biophysical Characterization of Tropical Deciduous Forest in Central India

    NASA Astrophysics Data System (ADS)

    Singh, R. P.; Goroshi, S.; Sharma, N. K.; Bairagi, G. D.; Sharma, R.; Jalil, P.; Jain, A.; Sonakia, A.; Parihar, J. S.

    2011-09-01

    The paper reports the measurements of biophysical parameters using field and satellite data over a tropical deciduous forest Kanha National Park (KNP), central India. Field measurement (GBH, LAI, litter, soil moisture) was carried out over ten quadrates of 0.1ha in KNP for characterization of biophysical parameters with specified measurement protocol and sampling. Satellite based remote sensing analysis (LAI, Phenology, and NPP) was carried out using multi date observations of IRS-LISS-III, IMS-1MX, SPOT-VEGETATION and EOS-MODIS instruments. Rank correlation analysis using field data collected in the selected quadrates at KNP showed Sal (Shorea robusta) is dominant forest species followed by Lendia, Jamun (Syzygium cumini), Saja, Harra and Dhawda etc. Field measurement of Sal showed GBH range from 20 cm to 170 cm. Different forest classes such as Sal; Sal mixed with Jamun, Bamboo (Dendrocalamus strictus) etc, including grasslands/scrubland were classified with overall accuracy of 85.56 percent using March, May and October multi spectral data. Sal has distinct growth characteristics (low vegetation growth/ leaf fall in March instead of May) as compared to other vegetation species. As per the Leaf Area Index (LAI) measurement using hemispherical photographs, Sal showed the highest LAI (6.95 m2/m2) during September and lowest LAI (2.63 m2/m2) during March. Overall good agreement (r= 0.79) was found between the LAI generated from LISS-III and MODIS data product. It was observed from SPOT-VEGETATION analysis that NPP varied from 8.4 tC/ha/year (dry deciduous forest) to 14.25 tC/ha/year (Moist deciduous forest) in KNP.

  9. Monitoring Spring Recovery of Photosynthesis and Spectral Reflectance in Temperate Evergreen and Mixed Deciduous Forests

    NASA Astrophysics Data System (ADS)

    Wong, C. Y.; Arain, M. A.; Ensminger, I.

    2015-12-01

    Evergreen conifers in boreal and temperate regions undergo strong seasonal changes in photoperiod and temperatures, which characterizes their photosynthetic activity with high activity in the growing season and downregulation during the winter season. Monitoring the timing of the transitions in evergreens is difficult since it's a largely invisible process, unlike deciduous trees that have a visible budding and senescence sequence. Spectral reflectance and the photochemical reflectance index (PRI), often used as a proxy for photosynthetic light-use efficiency, provides a promising tool to track the transition of evergreens between inactive and active photosynthetic states. To better understand the relationship between PRI and photosynthetic activity and to contrast this relationship between plant functional types, the spring recovery of an evergreen forest and mixed deciduous forest was monitored using spectral reflectance, chlorophyll fluorescence and gas exchange. All metrics indicate photosynthetic recovery during the spring season. These findings indicate that PRI can be used to observe the spring recovery of photosynthesis in evergreen conifers but may not be best suited for deciduous trees. These findings have implications for remote sensing, which provides a promising long-term monitoring system of whole ecosystems, which is important since their roles in the carbon cycle may shift in response to climate change.

  10. Influence of physiological phenology on the seasonal pattern of ecosystem respiration in deciduous forests

    NASA Astrophysics Data System (ADS)

    Migliavacca, Mirco

    2014-05-01

    In this contribution we present a study on the role of physiological phenology (defined as seasonal changes in physiological properties) as an additional driver of the ecosystem respiration (RECO) in deciduous forests. With a model-data integration approach we analyzed the RECO data from 19 deciduous sites belonging to the FLUXNET La Thuile database. We analyzed the performance of two semi-empirical models, one with (TPdGPP) and the other without (TPLinGPP) the explicit dependency of RECO on the rate at which gross primary productivity (GPP) changes in spring, the latter used as proxy of physiological phenology. We identified a clear effect of physiological phenology on RECO that needs to be included as a driver of RECO in addition to the GPP, temperature and precipitation. The semi-empirical model developed led to a decrease in root mean square error (RMSE) of about 8% and an increase in the modeling efficiency (EF) of about 6% of modeled RECO. The reduction of the model-observation bias occurred mainly in spring and in summer, while less reduction was observed at the annual time-scale. For few sites the use of the explicit description of physiological phenology did not reduce the bias in modeled RECO consistently. This might be partly related to the spatial heterogeneity of the canopy at these sites. The results obtained point toward the need of improving the current approach used for modeling the RECO in deciduous forests by including the phenological cycle of the canopy.

  11. Overcoming the Challenges of Estimating Water Use in Temperate, Mixed Deciduous Forest of S. Korea

    NASA Astrophysics Data System (ADS)

    Jung, E.; Otieno Dennis, O.; Tenhunen, J. D.

    2009-12-01

    About 80% of forests in Korea occur in mountainous regions and are composed of a rich diversity of mixed deciduous tree species. Mountains in this region receive more rainfall and act as fountains that supply fresh water to the lowland and quantifying the hydrologic components of the forested mountain catchments is critical for sustainable water resource management. Forest trees play a significant role in ecosystem water budget and understanding of forest water use is crucial for water budgeting. High diversity in tree species, however, complicates the upscaling of forest water use by mixed forests, since trees are likely to function differently. A simplified approach is to identify common functionality gradients that define tree water use irrespective of phylogeny. A research initiative established under the International Training Group: Complex Terrain and Ecological Heterogeneity (TERRECO) sought to identify common structure and functionality among tree species that could allow for a convergent definition of water use in mixed deciduous forests in S. Korea. Using a wide range of thermal techniques to quantify water use in 7 different species located in 3 mountains with unidentical climates, we have related forest and tree structural properties to species water use. To understand spatial differences in tree water use, two species (Quercus dentata and Q. mongolica) were chosen as comparative species common to the three locations. Water use was significantly correlated with diameter at breast height (DBH) for all overstory species. The maximum transpiration was about 3 mm d-1 in all three different locations and daily transpiration was well described by microclimate and DBH irrespective of the location as long as soil moisture was not limiting. These initial findings are aiding our upscaling procedures.

  12. Nitrogen Deposition to and Cycling in a Deciduous Forest

    DOE PAGESBeta

    Pryor, Sara C.; Barthelmie, Rebecca J.; Carreiro, Margaret; Davis, Melissa L.; Hartley, Anne; Jensen, Bjame; Oliphant, Andrew; Randolph, Melissa J. C.; Schoof, Justin T.

    2001-01-01

    The project described here seeks to answer questions regarding the role increased nitrogen (N) deposition is playing in enhanced carbon (C) sequestration in temperate mid-latitude forests, using detailed measurements from an AmeriFlux tower in southern Indiana (Morgan-Monroe State Forest, or MMSF). The measurements indicate an average atmosphere-surface N flux of approximately 6 mg-N m -2 day -1 during the 2000 growing season, with approximately 40% coming from dry deposition of ammonia (NH 3 ), nitric acid (HNO 3 ), and particle-bound N. Wet deposition and throughfall measurements indicate significant canopy uptake of N (particularly NH 4 +) at themore » site, leading to a net canopy exchange (NCE) of –6 kg-N ha -1 for the growing season. These data are used in combination with data on the aboveground C:N ratio, litterfall flux, and soil net N mineralization rates to indicate the level of potential perturbation of C sequestration at this site.« less

  13. Ozone-induced stomatal sluggishness changes carbon and water balance of temperate deciduous forests

    NASA Astrophysics Data System (ADS)

    Hoshika, Yasutomo; Katata, Genki; Deushi, Makoto; Watanabe, Makoto; Koike, Takayoshi; Paoletti, Elena

    2015-05-01

    Tropospheric ozone concentrations have increased by 60-100% in the Northern Hemisphere since the 19th century. The phytotoxic nature of ozone can impair forest productivity. In addition, ozone affects stomatal functions, by both favoring stomatal closure and impairing stomatal control. Ozone-induced stomatal sluggishness, i.e., a delay in stomatal responses to fluctuating stimuli, has the potential to change the carbon and water balance of forests. This effect has to be included in models for ozone risk assessment. Here we examine the effects of ozone-induced stomatal sluggishness on carbon assimilation and transpiration of temperate deciduous forests in the Northern Hemisphere in 2006-2009 by combining a detailed multi-layer land surface model and a global atmospheric chemistry model. An analysis of results by ozone FACE (Free-Air Controlled Exposure) experiments suggested that ozone-induced stomatal sluggishness can be incorporated into modelling based on a simple parameter (gmin, minimum stomatal conductance) which is used in the coupled photosynthesis-stomatal model. Our simulation showed that ozone can decrease water use efficiency, i.e., the ratio of net CO2 assimilation to transpiration, of temperate deciduous forests up to 20% when ozone-induced stomatal sluggishness is considered, and up to only 5% when the stomatal sluggishness is neglected.

  14. Ozone-induced stomatal sluggishness changes carbon and water balance of temperate deciduous forests

    PubMed Central

    Hoshika, Yasutomo; Katata, Genki; Deushi, Makoto; Watanabe, Makoto; Koike, Takayoshi; Paoletti, Elena

    2015-01-01

    Tropospheric ozone concentrations have increased by 60–100% in the Northern Hemisphere since the 19th century. The phytotoxic nature of ozone can impair forest productivity. In addition, ozone affects stomatal functions, by both favoring stomatal closure and impairing stomatal control. Ozone-induced stomatal sluggishness, i.e., a delay in stomatal responses to fluctuating stimuli, has the potential to change the carbon and water balance of forests. This effect has to be included in models for ozone risk assessment. Here we examine the effects of ozone-induced stomatal sluggishness on carbon assimilation and transpiration of temperate deciduous forests in the Northern Hemisphere in 2006-2009 by combining a detailed multi-layer land surface model and a global atmospheric chemistry model. An analysis of results by ozone FACE (Free-Air Controlled Exposure) experiments suggested that ozone-induced stomatal sluggishness can be incorporated into modelling based on a simple parameter (gmin, minimum stomatal conductance) which is used in the coupled photosynthesis-stomatal model. Our simulation showed that ozone can decrease water use efficiency, i.e., the ratio of net CO2 assimilation to transpiration, of temperate deciduous forests up to 20% when ozone-induced stomatal sluggishness is considered, and up to only 5% when the stomatal sluggishness is neglected. PMID:25943276

  15. Estimating leaf area index in coniferous and deciduous forests in Sweden using Landsat optical sensor data

    NASA Astrophysics Data System (ADS)

    Eklundh, Lars

    2003-03-01

    This paper reports on research to estimate leaf area index (LAI) in Swedish forests with satellite sensor data. The study is part of a research programme that aims at generating input data for process-oriented forest carbon models. Field-work was carried out in two areas in Sweden about 530 km apart, in the nemoral and boreo-nemoral forest regions. Various ways of estimating LAI in the field were tested, including litter-traps, allometric equations, and light transmission measurements. The capability of Landsat TM and ETM+ for LAI-mapping was investigated with the Nilson and Kuusk forest reflectance model. Results point to channel 3 and the mid-IR channels as particularly important for LAI estimation in coniferous stands, however, modelled reflectances were strongly influenced by background reflectances (particularly at low densities) and leaf optical properties. Top-of-canopy reflectances were derived from Landsat TM and ETM+, and their relationships with field-estimated LAI analysed. Among several vegetation indices tested, the Moisture Stress Index (TM5 / TM4) was one of the best indices for LAI in coniferous stands. In deciduous stands relationships based on the Simple Ratio were superior, however, the explanatory power in deciduous stands was lower than in coniferous stands.

  16. Ozone-induced stomatal sluggishness changes carbon and water balance of temperate deciduous forests.

    PubMed

    Hoshika, Yasutomo; Katata, Genki; Deushi, Makoto; Watanabe, Makoto; Koike, Takayoshi; Paoletti, Elena

    2015-01-01

    Tropospheric ozone concentrations have increased by 60-100% in the Northern Hemisphere since the 19(th) century. The phytotoxic nature of ozone can impair forest productivity. In addition, ozone affects stomatal functions, by both favoring stomatal closure and impairing stomatal control. Ozone-induced stomatal sluggishness, i.e., a delay in stomatal responses to fluctuating stimuli, has the potential to change the carbon and water balance of forests. This effect has to be included in models for ozone risk assessment. Here we examine the effects of ozone-induced stomatal sluggishness on carbon assimilation and transpiration of temperate deciduous forests in the Northern Hemisphere in 2006-2009 by combining a detailed multi-layer land surface model and a global atmospheric chemistry model. An analysis of results by ozone FACE (Free-Air Controlled Exposure) experiments suggested that ozone-induced stomatal sluggishness can be incorporated into modelling based on a simple parameter (gmin, minimum stomatal conductance) which is used in the coupled photosynthesis-stomatal model. Our simulation showed that ozone can decrease water use efficiency, i.e., the ratio of net CO2 assimilation to transpiration, of temperate deciduous forests up to 20% when ozone-induced stomatal sluggishness is considered, and up to only 5% when the stomatal sluggishness is neglected. PMID:25943276

  17. Deciduous and Evergreen Trees Rely on Deep Water Throughout the Year in a Subtropical Seasonal Forest

    NASA Astrophysics Data System (ADS)

    Ellsworth, P.

    2010-12-01

    In subtropical and tropical seasonal forests, trees have adapted to low shallow soil water availability during the dry season by modifying root density, rooting depth, and leaf phenology. Here we test the well known hypothesis that water uptake in deciduous trees is restricted to the shallow soil layer, which prevents them from sustaining transpiring leaves during the dry season. Evergreens, on the other hand, access perennially available deep water sources, allowing them to maintain their transpiring leaves during the dry season. To determine where in the soil profile deciduous and evergreen trees take up water, we used stable isotope analysis to measure water source use of two deciduous and three evergreen species for a period of 13 months. In addition, to test the possibility that leaflessness could alter the isotopic composition of stem water, we measured the isotopic variation in stem water caused by artificial defoliation of an evergreen species. Deciduous and evergreen trees took up water from the same depths in both the wet and dry seasons. Deciduous and evergreen trees used approximately 51% deep water (50-150cm) throughout the year, while soil from 0-20cm was the least important water source with 24 and 6% of water uptake for wet and dry seasons, respectively. Low use of shallow water (0-20cm) in the wet season was due to inconstant water availability. Though the top 20cm of soil is the location of most nutrients, the soil’s limited water availability requires plants to have access to a more reliable deep water source to meet both their dry and wet season transpirational demands. This apparent spatial uncoupling in water and nutrient uptake denotes separate resource allocation for nutrient and water acquisition. Deciduous trees showed isotopic enrichment of stem water compared to evergreen plants only during the period that deciduous trees were leafless. We explain this as isotopic enrichment of fixed pool of stem water by evaporation as our defoliation

  18. The effect of increased air humidity on northern deciduous forest ecosystem - a FAHM study.

    NASA Astrophysics Data System (ADS)

    Ostonen, Ivika; Rosenvald, Katrin; Tullus, Arvo; Parts, Kaarin; Sellin, Arne; Kupper, Priit; Sõber, Jaak; Sõber, Anu; Uri, Veiko; Aosaar, Jürgen; Varik, Mats; Lõhmus, Krista

    2013-04-01

    At northern latitudes a rise in atmospheric humidity and precipitation is predicted as a consequence of global climate change. In 2006 an unique experimental facility for free air humidity manipulation (FAHM) was established in Estonia to study the functioning of deciduous forest ecosystem under altered humidity conditions. The experimental site contains humidified and control plots, each includes four types of forest ecosystem: two overstorey species (planted hybrid aspen (Populus tremula L. × P. tremuloides Michx. and silver birch (Betula pendula Roth.)) both split into two types according to understorey vegetation (diverse "forest" understory and early successional grasses). We investigated the productivity, biomass allocation and functioning of silver birch forest ecosystem in response to elevated atmospheric humidity (on average 7% over the ambient level) during four growing seasons (2008-2011). We hypothesized that elevated air humidity facilitates both above- and below-ground growth and accumulation of plant biomass. During the first three experimental seasons height, stem diameter, and stem volume (D2H) increments of trees, biomass of understory in aboveground and fine root biomass in belowground were similar or significantly reduced in humidified plots. Only the fine root and rhizome biomass of the understory was twice higher in humidified plots. However, fine root turnover speeded up for both tree and understory roots. The trends in above-ground growth changed in 2011, when current annual increments of trees height, diameter, stem volume and fine root biomass were higher in humidified plots. Functionally, trees hydraulic conductance was significantly higher and stem sap flux lower for humidified trees coinciding with significantly higher biomass of primary (in majority ectomycorrhizal) roots, morphologically thinner and longer root tips and higher specific root length. Humidification caused a shift in the root tips colonizing fungal community towards the

  19. Early spring leaf out enhances growth and survival of saplings in a temperate deciduous forest.

    PubMed

    Augspurger, Carol K

    2008-05-01

    Saplings of many canopy tree species in winter deciduous forests receive the major portion of their light budget for their growing season prior to canopy closure in the spring. This period of high light may be critical for achieving a positive carbon (C) gain, thus contributing strongly to their growth and survival. This study of saplings of Aesculus glabra and Acer saccharum in Trelease Woods, Illinois, USA, tested this hypothesis experimentally by placing tents of shade cloth over saplings during their spring period of high light prior to canopy closure in three consecutive years. Leaf senescence began 16 days (year 0) and 60 days (year 1) earlier for shaded A. glabra saplings than control saplings. No change in senescence occurred for A. saccharum. The annual absolute growth in stem diameter of both species was negligible or negative for shaded saplings, but positive for control saplings. Only 7% of the shaded A. glabra saplings were alive after 2 years, while all control saplings survived for 3 years; only 20% of the shaded A. saccharum saplings survived for 3 years, while 73% of control saplings were alive after the same period. Early spring leaf out is a critical mechanism that allows the long-term persistence of saplings of these species in this winter deciduous forest. Studies and models of C gain, growth, and survival of saplings in deciduous forests may need to take into account their spring phenology because saplings of many species are actually "sun" individuals in the spring prior to their longer period in the summer shade. PMID:18347817

  20. Invaders do not require high resource levels to maintain physiological advantages in a temperate deciduous forest.

    PubMed

    Heberling, J Mason; Fridley, Jason D

    2016-04-01

    Non-native, invasive plants are commonly typified by trait strategies associated with high resource demands and plant invasions are often thought to be dependent upon site resource availability or disturbance. However, the invasion of shade-tolerant woody species into deciduous forests of the Eastern United States seems to contradict such generalization, as growth in this ecosystem is strongly constrained by light and, secondarily, nutrient stress. In a factorial manipulation of light and soil nitrogen availability, we established an experimental resource gradient in a secondary deciduous forest to test whether three common, woody, invasive species displayed increased metabolic performance and biomass production compared to six co-occurring woody native species, and whether these predicted differences depend upon resource supply. Using hierarchical Bayesian models of photosynthesis that included leaf trait effects, we found that invasive species exhibited functional strategies associated with higher rates of carbon gain. Further, invader metabolic and growth-related attributes were more responsive to increasing light availability than those of natives, but did not fall below average native responses even in low light. Surprisingly, neither group showed direct trait or growth responses to soil N additions. However, invasive species showed increased photosynthetic nitrogen use efficiencies with decreasing N availability, while that of natives remained constant. Although invader advantage over natives was amplified in higher resource conditions in this forest, our results indicate that some invasive species can maintain physiological advantages over co-occurring natives regardless of resource conditions. PMID:27220204

  1. Contrasting seasonal leaf habits of canopy trees between tropical dry-deciduous and evergreen forests in Thailand.

    PubMed

    Ishida, Atsushi; Diloksumpun, Sapit; Ladpala, Phanumard; Staporn, Duriya; Panuthai, Samreong; Gamo, Minoru; Yazaki, Kenichi; Ishizuka, Moriyoshi; Puangchit, Ladawan

    2006-05-01

    We compared differences in leaf properties, leaf gas exchange and photochemical properties between drought-deciduous and evergreen trees in tropical dry forests, where soil nutrients differed but rainfall was similar. Three canopy trees (Shorea siamensis Miq., Xylia xylocarpa (Roxb.) W. Theob. and Vitex peduncularis Wall. ex Schauer) in a drought-deciduous forest and a canopy tree (Hopea ferrea Lanessan) in an evergreen forest were selected. Soil nutrient availability is lower in the evergreen forest than in the deciduous forest. Compared with the evergreen tree, the deciduous trees had shorter leaf life spans, lower leaf masses per area, higher leaf mass-based nitrogen (N) contents, higher leaf mass-based photosynthetic rates (mass-based P(n)), higher leaf N-based P(n), higher daily maximum stomatal conductance (g(s)) and wider conduits in wood xylem. Mass-based P(n) decreased from the wet to the dry season for all species. Following onset of the dry season, daily maximum g(s) and sensitivity of g(s) to leaf-to-air vapor pressure deficit remained relatively unchanged in the deciduous trees, whereas both properties decreased in the evergreen tree during the dry season. Photochemical capacity and non-photochemical quenching (NPQ) of photosystem II (PSII) also remained relatively unchanged in the deciduous trees even after the onset of the dry season. In contrast, photochemical capacity decreased and NPQ increased in the evergreen tree during the dry season, indicating that the leaves coped with prolonged drought by down-regulating PSII. Thus, the drought-avoidant deciduous species were characterized by high N allocation for leaf carbon assimilation, high water use and photoinhibition avoidance, whereas the drought-tolerant evergreen was characterized by low N allocation for leaf carbon assimilation, conservative water use and photoinhibition tolerance. PMID:16452078

  2. Intercomparison of techniques to model water stress effects on CO2 and energy exchange in temperate and boreal deciduous forests

    SciTech Connect

    Grant, Robert F.; Zhang, Y.; Yuan, F.; Wang, S.; Hanson, Paul J; Gaumont-Guay, D.; Chen, j.; Black, T. A.; Barr, A.; Baldocchi, D. D.; Arain, A.

    2006-01-01

    Soil water deficits are a key controller of net ecosystem productivity (NEP) in deciduous broadleaf forests. Mathematical models of forest NEP need to represent the processes by which this control is exerted if they are to be used to predict the impacts of changing hydrology on forest C stocks. The key processes controlling NEP during soil water deficits are hydraulic limitations to water transfer in soil, roots, stems and leaves that impose constraints on gross primary productivity (GPP). We compare five ecosystem models with different techniques to simulate these processes for their ability to model reduced latent versus sensible heat fluxes, earlier diurnal declines in CO2 influxes and reduced soil CO2 effluxes during soil drying. Model accuracy was assessed using energy and CO2 fluxes measured by eddy covariance and surface chambers in a warm temperate and a cool boreal deciduous forest during a drying period. Diurnal declines in CO2 influxes during soil drying were consistently simulated by models in which soil drying lowered root and canopy water potentials ( c) and raised soil and root hydraulic resistances. Leaf stomatal conductance (gl), derived in these models from non-linear functions of c, then became more sensitive to diurnal changes in vapor pressure deficits (D). Diurnal declines in CO2 influxes could be simulated with comparable accuracy under most conditions by a model in which gl was empirically related to soil water potential and D, although these declines were sometimes not fully simulated. CO2 influxes declined too rapidly with diurnal rises in D in another model in which gl was calculated from CO2 fixation which was empirically related to soil water content. Divergences in modeled versus measured half-hourly or hourly CO2 exchange were also apparent in modeled versus measured annual GPP, net primary productivity (NPP) and NEP. The ability to distinguish among alternative algorithms for their accuracy in calculating CO2 and energy fluxes was

  3. Carbon Exchange of Central New England Deciduous Forests: Variability Related to Age and Topography

    NASA Astrophysics Data System (ADS)

    Hadley, J. L.; Kuzeja, P. S.; Schedlbauer, J. L.; Munger, J. W.

    2004-12-01

    Forests in much of the northeastern U.S. occur in hilly or mountainous terrain and vary widely in age, due to forest harvesting and natural disturbances. Sites in the NE U.S. with relatively long-term C exchange records represent two very different major tree species associations (boreal coniferous forest and oak-maple dominated deciduous forest) but cover relatively little variation in topography and age. All of the forests measured are in somewhat low-lying areas and are fairly mature, ranging from 65 to >120 years in age. Data are needed from younger forests and forests with higher slope position in order to accurately estimate forest C storage in the NE U.S. In May 2002 we began the first eddy covariance (EC) measurements in a higher deciduous forest, about 1.1 km from the Harvard Forest Environmental Measurement Site (HFEMS), where C exchange has been measured since 1991. The higher site has similar tree species composition to HFEMS, but most trees within 300 m of the higher eddy covariance tower (and some beyond) originated after a fire in 1957. Wind direction and nocturnal turbulence strongly affect EC data at the higher site. With wind between 30 and 210 o from N, we observe large apparent C effluxes (>30 µmol m-2 s-1) at night, and sometimes during the day. Such large C effluxes have very seldom been observed at HFEMS, and at the higher site we interpret them as artifacts generated by lee-slope turbulence, due to airflow over forest that is 20-30 m higher than the point of EC measurements. With other wind directions, nocturnal C flux at the higher site increases with increasing turbulence. We attribute this to cold air drainage on the long approximately 10% slope to the W and NW. This inference is supported by very low measured C fluxes when air 20 cm from the ground is > 1.5 oC colder than air above the canopy. Accordingly, at the higher site we only accept C flux data if wind direction is between 215 and 360o and u* > 0.35 m/s. Under these conditions

  4. Deciduous Tree Species Alter Nitrogen and Phosphorus Availability in Mid-successional Alaskan Boreal Forest

    NASA Astrophysics Data System (ADS)

    Melvin, A. M.; Mack, M. C.; Johnstone, J. F.; Schuur, E. A.

    2013-12-01

    In Alaskan boreal forest, increased fire severity associated with climate change is altering successional processes and ecosystem nutrient dynamics. Fire is a common disturbance in Interior Alaska and typically burns forests dominated by black spruce (Picea mariana), a tree species associated with slow nutrient turnover and high soil organic matter accumulation rates. Historically, low severity fires have driven black spruce regeneration post-fire, thereby maintaining slow nutrient cycling rates and large soil organic matter stocks. In contrast, high severity fires consume the organic layer and can lead to the establishment of deciduous tree species on exposed mineral soil, which produce less recalcitrant leaf litter and exhibit faster nutrient cycling rates. To improve our understanding of the long-term impacts of tree species composition on nutrient cycling in boreal forest, we quantified nitrogen (N) cycling rates and estimated soil N, phosphorus (P), and base cation pools in adjacent, mid-successional stands of black spruce and Alaska paper birch (Betula neoalaskana) that established following a 1960 fire near Fairbanks, Alaska. Results indicate significantly higher net N mineralization in paper birch soils relative to black spruce for both the fibric organic layer and top 10 cm of mineral soil during 30-day and 90-day lab incubation studies. Net nitrification was significantly higher in the paper birch fibric layer after 90 days. Total soil N concentrations did not differ between paper birch and black spruce stands, however the black spruce organic layer was significantly larger than that of birch, resulting in larger organic layer N stocks (130 vs. 87 g N m2). In contrast, total P concentrations were significantly higher in the organic layer in birch forest, but the total P stocks did not differ significantly between species because of the larger mass of soil organic matter in the black spruce. These findings suggest that a shift towards greater deciduous

  5. Altered soil organic carbon stability in eastern deciduous forest: interplay between forest successional Stage and invasive earthworm activity

    NASA Astrophysics Data System (ADS)

    Ma, Y.; Filley, T. R.; McCormick, M.; Szlavecz, K. A.

    2012-12-01

    Detritivore -mediated decomposition and incorporation of aboveground litter is an important processes in soil carbon cycle of forest ecosystems that can be a major control on the proportion of stable and unstable soil carbon pools. We investigated how earthworm activity interacts with litter type to alter the stability of soil organic carbon (SOC) in an eastern deciduous successional forest within at the Smithsonian Environmental Research Center (SERC). Soil C and N content and chemistry (lignin and fatty acids) among particulate and mineral-bound fractions was shifted after 5 years of litter (wood and leaf) addition but with significant differences among the forest successional stages and with earthworm activity. Results from a 6 month laboratory incubation (25°C and 15°C) of bulk soil samples taken from the treatments and incubated at 25°C and 15°C demonstrate that litter addition type and earthworm activity interacted to control the proportion of labile and stable carbon. Specifically, the labile C pools in double wood and control treatments were highest in young successional forest with higher earthworm activity. However, in the double leaf treatment, the labile C pool was higher in old successional forests with less worm activity. In general, the stable C pool, released after one month, was higher in old successional forests for all three treatments. The difference of the stable pool between young and old successional forest was the largest with double wood treatment, followed by control treatment and the lowest with double leaf treatment. In summary, wood treatment shifted SOC pool to relatively more stable pool in old successional forests decreasing labile C pool but not the young sites. While double leaf treatment increased the labile pool in old forests but in young successional forests, SOC shifted to relatively more stable pool by decreasing the labile pool and increasing the stable pool. This result indicates that the type of aboveground litter

  6. Factors for Microbial Carbon Sources in Organic and Mineral Soils from Eastern United States Deciduous Forests

    NASA Astrophysics Data System (ADS)

    Stitt, C.; McFarlane, K. J.

    2013-12-01

    Forest soils represent a large portion of global terrestrial carbon; however, which soil carbon sources are used by soil microbes and respired as carbon dioxide (CO2) is not well known. This study will focus on characterizing microbial carbon sources from organic and mineral soils from four eastern United States deciduous forests using the unique radiocarbon tracer, 14C. Results from the dark incubation of the organic and mineral soils are heavily influenced by site characteristics when incubated at microbial optimal activity temperature. The sites with the most similarities are statically the same (p> 0.10). The sites with considerable differences in temperature, texture, and location are statically different concluding that site characteristics play a role in soil respiration.

  7. Impacts of experimentally applied mountain biking and hiking on vegetation and soil of a deciduous forest.

    PubMed

    Thurston, E; Reader, R J

    2001-03-01

    Many recent trail degradation problems have been attributed to mountain biking because of its alleged capacity to do more damage than other activities, particularly hiking. This study compared the effects of experimentally applied mountain biking and hiking on the understory vegetation and soil of a deciduous forest. Five different intensities of biking and hiking (i.e., 0, 25, 75, 200 and 500 passes) were applied to 4-m-long x 1-m-wide lanes in Boyne Valley Provincial Park, Ontario, Canada. Measurements of plant stem density, species richness, and soil exposure were made before treatment, two weeks after treatment, and again one year after treatment. Biking and hiking generally had similar effects on vegetation and soil. Two weeks after treatment, stem density and species richness were reduced by up to 100% of pretreatment values. In addition, the amount of soil exposed increased by up to 54%. One year later, these treatment effects were no longer detectable. These results indicate that at a similar intensity of activity, the short-term impacts of mountain biking and hiking may not differ greatly in the undisturbed area of a deciduous forest habitat. The immediate impacts of both activities can be severe but rapid recovery should be expected when the activities are not allowed to continue. Implications of these results for trail recreation are discussed. PMID:11148765

  8. Measurement of soil moisture with cosmic-ray neutrons in deciduous forests

    NASA Astrophysics Data System (ADS)

    Heidbüchel, Ingo; Blume, Theresa; Güntner, Andreas

    2014-05-01

    In deciduous forests the calibration of cosmic-ray soil moisture sensors is difficult since the amount of water stored inside and on vegetation (leaves, branches, stems) varies seasonally. A one-time calibration conducted during summer can therefore introduce errors to the method that are especially pronounced in the winter season. We performed calibration in a deciduous forest at the TERENO observatory in north-eastern Germany at different times throughout the year to capture the changing influence of water in the vegetation on the calibration results. Additionally, we calibrated the cosmic-ray neutron sensor with soil samples from different soil depths (0-10 cm, 0-20 cm, 0-30 cm). We compared the resulting soil moisture time series with time series of FDR-based soil moisture point measurements at different depths. This allows us to estimate the error introduced by the influence of organic layers at the soil surface (litter, decomposed organic material) which can vary temporally. The same sensor setup was also used to look at time-lags between the cosmic-ray soil moisture signal and measurements of precipitation, intercepted water and soil moisture point measurements at different depths. Recorded time lags between point measurements and cosmic-ray soil moisture results can potentially help in tracking precipitation on its way through the canopy, the organic layer and into the soils.

  9. Application of PTR-MS for measurements of biogenic VOC in a deciduous forest

    NASA Astrophysics Data System (ADS)

    Ammann, C.; Spirig, C.; Neftel, A.; Steinbacher, M.; Komenda, M.; Schaub, A.

    2004-12-01

    The vegetation-atmosphere-exchange is an important process controlling the atmospheric concentration of various volatile organic compounds (VOCs) that play a major role in atmospheric chemistry. However, the quantification of VOC exchange on the ecosystem scale is still an analytical challenge. In the present study we tested and applied a proton-transfer-reaction mass spectrometry system (PTR-MS) for the measurement of biogenic VOCs in a mixed deciduous forest. VOC concentrations were calculated from the raw instrument signals based on physical principles. This method allows a consistent quantification also of compounds for which regular calibration with a gas standard is not available. It requires a regular and careful investigation of the mass-dependent ion detection characteristics of the PTR-MS, which otherwise could become a considerable error source. The PTR-MS method was tested in the laboratory for a range of oxygenated and non-oxygenated VOCs using a permeation source. The agreement was within 16% or better, which is well within the expected uncertainty. During the field measurement campaign in a deciduous forest stand, an on-line intercomparison with a state-of-the-art gas-chromatography system showed a generally good agreement. However, the relatively low ambient VOC concentrations revealed some systematic difference for acetone and isoprene, that may indicate an error in the determination of the PTR-MS offset or an interference of an unidentified isobaric compound on the detected ion mass. With the presentation of selected field results, we demonstrate the ability of the PTR-MS system to measure continuous vertical concentration profiles of biogenic VOCs throughout a forest canopy at a time resolution of 20 min. The resulting datasets provide valuable information for the study of the interactions between emission, photochemical transformation and transport processes within and above the forest canopy.

  10. Effects of Warming on Tree Species’ Recruitment in Deciduous Forests of the Eastern United States

    SciTech Connect

    Melillo, Jerry M.; Clark, James S.; Mohan, Jacqueline

    2015-03-25

    Climate change is restructuring forests of the United States, although the details of this restructuring are currently uncertain. Rising temperatures of 2 to 8oC and associated changes in soil moisture will shift the competitive balance between species that compete for light and water, and so change their abilities to produce seed, germinate, grow, and survive. We have used large-scale experiments to determine the effects of warming on the most sensitive stage of species distributions, i.e., recruitment, in mixed deciduous forests in southern New England and in the Piedmont region of North Carolina. Two questions organized our research: (1) Might temperate tree species near the “warm” end of their range in the eastern United States decline in abundance during the coming century due to projected warming? and (2) Might trees near the “cool” end of their range in the eastern United States increase in abundance, or extend their range, during the coming 100 years because of projected warming? To explore these questions, we exposed seedlings to air and soil warming experiments in two eastern deciduous forest sites; one at the Harvard Forest (HF) in central Massachusetts, and the other at the Duke Forest (DF) in the Piedmont region of North Carolina. We focused on tree species common to both Harvard and Duke Forests (such as red, black, and white oaks), those near northern range limits (black oak, flowing dogwood, tulip poplar), and those near southern range limits (yellow birch, sugar maple, Virginia pine). At each site, we planted seeds and seedlings in common gardens established in temperature-controlled, open-top chambers. The experimental design was replicated and fully factorial and involved three temperature regimes (ambient, +3oC and +5oC) and two light regimes (closed forest canopy (low light) and gap conditions (high light)). Measured variables included Winter/Spring responses to temperature and mid-Summer responses to low soil moisture. This research

  11. The impact of growing-season length variability on carbon assimilation and evapotranspiration over 88 years in the eastern US deciduous forest

    PubMed

    White; Running; Thornton

    1999-02-01

    Recent research suggests that increases in growing-season length (GSL) in mid-northern latitudes may be partially responsible for increased forest growth and carbon sequestration. We used the BIOME-BGC ecosystem model to investigate the impacts of including a dynamically regulated GSL on simulated carbon and water balance over a historical 88-year record (1900-1987) for 12 sites in the eastern USA deciduous broadleaf forest. For individual sites, the predicted GSL regularly varied by more than 15 days. When grouped into three climatic zones, GSL variability was still large and rapid. There is a recent trend in colder, northern sites toward a longer GSL, but not in moderate and warm climates. The results show that, for all sites, prediction of a long GSL versus using the mean GSL increased net ecosystem production (NEP), gross primary production (GPP), and evapotranspiration (ET); conversely a short GSL is predicted to decrease these parameters. On an absolute basis, differences in GPP between the dynamic and mean GSL simulations were larger than the differences in NEP. As a percentage difference, though, NEP was much more sensitive to changes in GSL than were either GPP or ET. On average, a 1-day change in GSL changed NEP by 1.6%, GPP by 0.5%, and ET by 0.2%. Predictions of NEP and GPP in cold climates were more sensitive to changes in GSL than were predictions in warm climates. ET was not similarly sensitive. First, our results strongly agree with field measurements showing a high correlation between NEP and dates of spring growth, and second they suggest that persistent increases in GSL may lead to long-term increases in carbon storage. PMID:10083835

  12. Effects of simulated acid rain on soil respiration and its components in a subtropical mixed conifer and broadleaf forest in southern China.

    PubMed

    Liang, Guohua; Hui, Dafeng; Wu, Xiaoying; Wu, Jianping; Liu, Juxiu; Zhou, Guoyi; Zhang, Deqiang

    2016-02-01

    Soil respiration is a major pathway in the global carbon cycle and its response to environmental changes is an increasing concern. Here we explored how total soil respiration (RT) and its components respond to elevated acid rain in a mixed conifer and broadleaf forest, one of the major forest types in southern China. RT was measured twice a month in the first year under four treatment levels of simulated acid rain (SAR: CK, the local lake water, pH 4.7; T1, water pH 4.0; T2, water pH 3.25; and T3, water pH 2.5), and in the second year, RT, litter-free soil respiration (RS), and litter respiration (RL) were measured simultaneously. The results indicated that the mean rate of RT was 2.84 ± 0.20 μmol CO2 m(-2) s(-1) in the CK plots, and RS and RL contributed 60.7% and 39.3% to RT, respectively. SAR marginally reduced (P = 0.08) RT in the first year, but significantly reduced RT and its two components in the second year (P < 0.05). The negative effects were correlated with the decrease in soil microbial biomass and fine root biomass due to soil acidification under the SAR. The temperature coefficients (Q10) of RT and its two components generally decreased with increasing levels of the SAR, but only the decrease of RT and RL was significant (P < 0.05). In addition, the contribution of RL to RT decreased significantly under the SAR, indicating that RL was more sensitive to the SAR than RS. In the context of elevated acid rain, the decline trend of RT in the forests in southern China appears to be attributable to the decline of soil respiration in the litter layer. PMID:26755128

  13. Variability in Soil Moisture in a Temperate Deciduous Forest Using Electrical Resistivity and Throughfall Data

    NASA Astrophysics Data System (ADS)

    Ma, Y.; Van Dam, R. L.; Jayawickreme, D.

    2013-12-01

    In deciduous forests, soil moisture is an important driver of energy and carbon cycling, as well as ecosystem dynamics. The amount and distribution of soil moisture also influences soil microbial activity, nutrient fluxes, and groundwater recharge. Consequently, accurate characterization of interactions and interdependencies between vegetation and soil moisture is critical to forecast water resources and ecosystem health in a changing climate. Such relationships and processes are nevertheless difficult to measure, both in time and space because of our limited ability to monitor the subsurface at necessary scales and frequencies. Several recent studies have shown that electrical resistivity tomography (ERT), using an array of minimally invasive surface electrodes, is a promising method for in-situ soil moisture monitoring. To this point, however, only few studies have used ERT to investigate spatial variability of soil moisture in temperate deciduous forests and to explore any links between soil water and above ground ecosystem variables. In our study in a central Michigan (USA) maple forest during the 2012 growing season, we combined ERT with detailed vegetation surveys and throughfall measurements to obtain better insight into spatial variations in rainwater input and soil water patterns. Resistivity data were collected on a weekly basis along an array of 84 electrodes with a spacing of 1.5 m. The inversion results were temperature corrected, converted to soil moisture, and differenced to obtain 2D images of soil moisture changes. The throughfall data were obtained using a novel method based on dissolution of plaster-of-paris tablets that were positioned below funnels, at 19 locations in the forest. Our results show that: 1) resistivity changes spatially with vegetation distribution, 2) in-season temporal changes in resistivity are related to plant characteristics, in particular to tree count and basal area, and 3) our low-budget throughfall method was capable of

  14. Comparing Temporal Variations in LUE and GPP across Evergreen and Deciduous Forest Types

    NASA Astrophysics Data System (ADS)

    Zhou, Y.; Hilker, T.; Ju, W.; Coops, N. C.; Black, T. A.; Chen, J.

    2015-12-01

    Estimating gross primary production (GPP) is an important goal of global change research. However, the relationship between GPP and its environmental drivers is highly complex and as a result, accurate modeling of GPP is difficult. One possible technique to help constrain the uncertainties is by using remote sensing data to try and determine the factors driving GPP directly from satellite imagery. In this study, we used GPP from flux data (GPP_EC) and meteorological observations of a deciduous (SOA) and a coniferous evergreen forest (DF-49) to optimize light use efficiency of sunlit (LUEsun) and shaded (LUEshaded) canopies. We based our analysis on the two-leave light use efficiency model (TL-LUE) at daily, 8 day, and 16 day scales by using the Markov chain Monte Carlo (MCMC). The photochemical reflectance index (PRI) of sunlit (PRIsun) and shaded (PRIshaded) leaves was calculated from spectral observations and related to tower based GPP at the three temporal scales. We found that the coefficient of determination (R2) between PRIsun and LUEsun, as well as PRIshaded and LUEshaded at the evergreen forest was lower than that at the deciduous forest. The modeled GPP was closely to the GPP_EC at the three temporal scales. The R2 between the GPP_EC and modeled daily GPP was the highest when using daily measures of LUE, and lowest when uisng16-day LUEsun and LUEshaded. The results indicated that LUE is an important parameter when modeling instantaneous GPP and the short term variations of it. The results help to obtain a better understanding of how many satellite observations are needed to reliably constrain existing GPP models from remote sensing data.

  15. Whole-Ecosystem Labile Carbon Production in a North Temperate Deciduous Forest

    NASA Astrophysics Data System (ADS)

    Gough, C. M.; Flower, C. E.; Vogel, C. S.; Dragoni, D.; Curtis, P. S.

    2008-12-01

    Management for forest carbon (C) sequestration requires knowledge of the fate of photosynthetic C. Labile C is an essential intermediary between C assimilation and growth in deciduous forests, accumulating when photosynthetic C supply exceeds demand and later depleting when reallocated to growth during periods of depressed photosynthesis. We developed a new approach that combined meteorological and biometric C cycling data for a mixed deciduous forest in Michigan, USA, to provide novel estimates of whole-ecosystem labile C production (PLC) and reallocation to growth inferred from the temporal imbalance between carbon supply from canopy net C assimilation (Ac) and C demand for net primary production (NPP). We substantiated these estimates with measurements of Populus grandidentata and Quercus rubra wood non-structural carbohydrate (NSC) concentration and mass over two years. Our analysis showed that half of annual Ac was allocated to PLC rather than to immediate growth. Labile C produced during the latter half of summer later supported dormant-season growth and respiration, with 35% of NPP in a given year requiring labile C stored during previous years. Seasonal changes in wood NSC concentration and mass generally corroborated patterns of labile C production and reallocation to growth. We observed a negative relationship between current-year PLC and NPP, indicating that disparities between same-year meteorological and biometric net ecosystem production (NEP) estimates can arise when C assimilated via photosynthesis, a flux incorporated into meteorological NEP estimates, is diverted away from NPP, a flux included in biometric NEP estimates, and instead allocated to PLC. A large, annually recharging pool of labile C also may buffer growth from climate conditions that immediately affect Ac. We conclude that a broader understanding of labile C production and reallocation across ecosystems may be important to interpreting lagged canopy C cycling and growth processes.

  16. Ecological effects of pipeline construction through deciduous forested wetlands, Midland County, Michigan

    SciTech Connect

    Zellmer, S.D. ); Rastorfer, J.R. . Dept. of Biological Sciences ANL Van Dyke, G.D. . Dept. of Biology)

    1991-07-01

    Implementation of recent federal and state regulations promulgated to protect wetlands makes information on effects of gas pipeline rights-of-way (ROWs) in wetlands essential to the gas pipeline industry. This study is designed to record vegetational changes induced by the construction of a large-diameter gas pipeline through deciduous forested wetlands. Two second-growth forested wetland sites mapped as Lenawee soils, one mature and one subjected to recent selective logging, were selected in Midland County, Michigan. Changes in the adjacent forest and successional development on the ROW are being documented. Cover-class estimates are being made for understory and ROW plant species using 1 {times}1-m quadrats. Counts are also being made for all woody species with stems < 2 cm in diameter at breast height (dbh) in the same plots used for cover-class estimates. Individual stem diameters and species counts are being recorded for all woody understory and overstory plants with stems {ge}2 cm dbh in 10 {times} 10-m plots. Although analyses of the data have not been completed, preliminary analyses indicate that some destruction of vegetation at the ROW forest edge may have been avoidable during pipeline construction. Rapid regrowth of many native wetland plant species on the ROW occurred because remnants of native vegetation and soil-bearing propagules of existing species survived on the ROW after pipeline construction and seeding operations. 91 refs., 11 figs., 3 tabs.

  17. Quantification of soil respiration in forest ecosystems across China

    NASA Astrophysics Data System (ADS)

    Song, Xinzhang; Peng, Changhui; Zhao, Zhengyong; Zhang, Zhiting; Guo, Baohua; Wang, Weifeng; Jiang, Hong; Zhu, Qiuan

    2014-09-01

    We collected 139 estimates of the annual forest soil CO2 flux and 173 estimates of the Q10 value (the temperature sensitivity) assembled from 90 published studies across Chinese forest ecosystems. We analyzed the annual soil respiration (Rs) rates and the temperature sensitivities of seven forest ecosystems, including evergreen broadleaf forests (EBF), deciduous broadleaf forests (DBF), broadleaf and needleleaf mixed forests (BNMF), evergreen needleleaf forests (ENF), deciduous needleleaf forests (DNF), bamboo forests (BF) and shrubs (SF). The results showed that the mean annual Rs rate was 33.65 t CO2 ha-1 year-1 across Chinese forest ecosystems. Rs rates were significantly different (P < 0.001) among the seven forest types, and were significantly and positively influenced by mean annual temperature (MAT), mean annual precipitation (MAP), and actual evapotranspiration (AET); but negatively affected by latitude and elevation. The mean Q10 value of 1.28 was lower than the world average (1.4-2.0). The Q10 values derived from the soil temperature at a depth of 5 cm varied among forest ecosystems by an average of 2.46 and significantly decreased with the MAT but increased with elevation and latitude. Moreover, our results suggested that an artificial neural network (ANN) model can effectively predict Rs across Chinese forest ecosystems. This study contributes to better understanding of Rs across Chinese forest ecosystems and their possible responses to global warming.

  18. Modelled and field measurements of biogenic hydrocarbon emissions from a Canadian deciduous forest

    NASA Astrophysics Data System (ADS)

    Fuentes, J. D.; Wang, D.; Den Hartog, G.; Neumann, H. H.; Dann, T. F.; Puckett, K. J.

    The Biogenic Emission Inventory System (BEIS) used by the United States Environmental Protection Agency (Lamb et al., 1993, Atmospheric Environment21, 1695-1705; Pierce and Waldruff, 1991, J. Air Waste Man. Ass.41, 937-941) was tested for its ability to provide realistic microclimate descriptions within a deciduous forest in Canada. The microclimate description within plant canopies is required because isoprene emission rates from plants are strongly influenced by foliage temperature and photosynthetically active radiation impinging on leaves while monoterpene emissions depend primarily on leaf temperature. Model microclimate results combined with plant emission rates and local biomass distribution were used to derive isoprene and α-pinene emissions from the deciduous forest canopy. In addition, modelled isoprene emission estimates were compared to measured emission rates at the leaf level. The current model formulation provides realistic microclimatic conditions for the forest crown where modelled and measured air and foliage temperature are within 3°C. However, the model provides inadequate microclimate characterizations in the lower canopy where estimated and measured foliage temperatures differ by as much as 10°C. This poor agreement may be partly due to improper model characterization of relative humidity and ambient temperature within the canopy. These uncertainties in estimated foliage temperature can lead to underestimates of hydrocarbon emission estimates of two-fold. Moreover, the model overestimates hydrocarbon emissions during the early part of the growing season and underestimates emissions during the middle and latter part of the growing season. These emission uncertainties arise because of the assumed constant biomass distribution of the forest and constant hydrocarbon emission rates throughout the season. The BEIS model, which is presently used in Canada to estimate inventories of hydrocarbon emissions from vegetation, underestimates emission

  19. Seasonal effects on the estimation of height of boreal and deciduous forests from interferometric TanDEM-X coherence data

    NASA Astrophysics Data System (ADS)

    Olesk, Aire; Voormansik, Kaupo; Tamm, Tanel; Noorma, Mart; Praks, Jaan

    2015-10-01

    The aim of this study is to assess the performance of single-pass X-band bistatic SAR interferometric forest height estimation of boreal and temperate deciduous forests under variable seasonal conditions. For this, twelve acquisitions of single- and dual-polarized TanDEM-X coherence images over 118 forest stands were analyzed and compared against LiDAR forest height maps. Strong correlations were found between interferometric coherence magnitude and LiDAR derived forest stand height for pine forests (r2=0.94) and spruce forest (r2=0.87) as well as for deciduous trees (r2=0.94) during leaf-off conditions with temperatures below 0°C. It was found that coherence magnitude based forest height estimation is influenced by leaf-on and leaf-off conditions as well as daily temperature fluctuations, height of ambiguity and effective baseline. These factors alter the correlation and should be taken into account for accurate coherence-based height retrieval. Despite the influence of the mentioned factors, generally a strong relationship in regression analysis between X-band SAR coherence and LiDAR derived forest stand height can be found. Moreover, a simple semi empirical model, derived from Random Volume over Ground model, is presented. The model takes into account all imaging geometry dependent parameters and allows to derive tree height estimate without a priori knowledge. Our results show that X-band SAR interferometry can be used to estimate forest canopy height for boreal and deciduous forests in both summer and winter, but the conditions should be stable.

  20. Phenology of two Ficus species in seasonal semi-deciduous forest in Southern Brazil.

    PubMed

    Bianchini, E; Emmerick, J M; Messetti, A V L; Pimenta, J A

    2015-11-01

    We analyzed the phenology of Ficus adhatodifolia Schott ex Spreng. (23 fig tree) and F. eximia Schott (12 fig tree) for 74 months in a remnant of seasonal semi-deciduous forest (23° 27'S and 51° 15'W), Southern Brazil and discussed their importance to frugivorous. Leaf drop, leaf flush, syconia production and dispersal were recorded. These phenophases occurred year-round, but seasonal peaks were recorded in both leaf phenophases for F. eximia and leaf flushing for F. adhatodifolia. Climatic variables analyzed were positively correlated with reproductive phenophases of F. adhatodifolia and negatively correlated with the vegetative phenophases of F. eximia. In despite of environmental seasonality, little seasonality in the phenology of two species was observed, especially in the reproductive phenology. Both species were important to frugivorous, but F. adhatodifolia can play a relevant role in the remnant. PMID:26602353

  1. Exchange of carbon dioxide by a deciduous forest: Response to interannual climate variability

    SciTech Connect

    Goulden, M.L.; Munger, J.W.; Fan, S.M.; Daube, B.C.; Wofsy, S.C.

    1996-03-15

    The annual net uptake of CO{sub 2} by a deciduous forest in New England varied from 1.4 to 2.8 metric tons of carbon per hectare between 1991 and 1995. Carbon sequestration was higher than average in 1991 because of increased photosynthesis and in 1995 because of decreased respiration. Interannual shifts in photosynthesis were associated with the timing of leaf expansion and senescence. Shifts in annual respiration were associated with anomalies in soil temperature, deep snow in winter, and drought in summer. If this ecosystem is typical of northern biomes, interannual climate variations on seasonal time scales may modify annual CO{sub 2} exchange in the Northern Hemisphere by 1 gigaton of carbon or more each year. 26 refs., 4 figs., 1 tab.

  2. Parametric analysis of synthetic aperture radar data for characterization of deciduous forest stands

    NASA Technical Reports Server (NTRS)

    Wu, Shih-Tseng

    1987-01-01

    The SAR sensor parameters that affect the estimation of deciduous forest stand characteristics were examined using data sets for the Gulf Coastal Plain region, acquired by the NASA/JPL multipolarization airborne SAR. In the regression analysis, the mean digital-number values of the three polarization data are used as the independent variables to estimate the average tree height (HT), basal area (BA), and total-tree biomass (TBM). The following results were obtained: (1) in the case of simple regression and using 28 plots, vertical-vertical (VV) polarization yielded the largest correlation coefficients (r) in estimating HT, BA, and TBM; (2) in the case of multiple regression, the horizontal-horizontal (HH) and VV polarization combination yielded the largest r value in estimating HT, while the VH and HH polarization combination yielded the largest r values in estimating BA and TBM. With the addition of a third polarization, the increase in r values is insignificant.

  3. Inter- and intra-specific variation in stemflow for evergreen species and deciduous tree species in a subtropical forest

    NASA Astrophysics Data System (ADS)

    Su, Lei; Xu, Wenting; Zhao, Changming; Xie, Zongqiang; Ju, Hua

    2016-06-01

    Quantification of stemflow is necessary for the assessment of forest ecosystem hydrological effects. Nevertheless, variation of stemflow among plant functional groups is currently not well understood. Stemflow production of co-occurring evergreen broadleaved trees (Cyclobalanopsis multinervis and Cyclobalanopsis oxyodon) and deciduous broadleaved trees (Fagus engleriana and Quercus serrata var. brevipetiolata) was quantified through field observations in a mixed evergreen and deciduous broadleaved forest. The research results revealed that stemflow increased linearly with increasing rainfall magnitude, with precipitation depths of 6.9, 7.2, 10.0 and 14.8 mm required for the initiation of stemflow for C. multinervis, C. oxyodon, F. engleriana and Q. serrata, respectively. Stemflow percentage and funneling ratio (FR) increased with increasing rainfall in a logarithmic fashion. Stemflow percentage and FR tended to grow rapidly with increasing rainfall magnitude up to a rainfall threshold of 50 mm, above which, further rainfall increases brought about only small increases. For C. multinervis, C. oxyodon, F. engleriana and Q. serrata, FR averaged 19.8, 14.8, 8.9 and 2.8, respectively. The stemflow generating rainfall thresholds for evergreen species were smaller than for deciduous species. Furthermore, stemflow percentage and FR of the former was greater than the latter. For both evergreen species and deciduous species, overall funneling ratio (FRs) decreased with increasing basal area. We concluded that: (1) although stemflow partitioning represented a fairly low percentage of gross rainfall in mixed evergreen and deciduous broadleaved forests, it was capable of providing substantial amount of rainwater to tree boles; (2) the evergreen species were more likely to generate stemflow than deciduous species, and directed more intercepted rainwater to the root zone; (3) small trees were more productive in funneling stemflow than larger trees, which may provide a favorable

  4. Unmanned Aerial Survey of Fallen Trees in a Deciduous Broadleaved Forest in Eastern Japan

    PubMed Central

    Inoue, Tomoharu; Nagai, Shin; Yamashita, Satoshi; Fadaei, Hadi; Ishii, Reiichiro; Okabe, Kimiko; Taki, Hisatomo; Honda, Yoshiaki; Kajiwara, Koji; Suzuki, Rikie

    2014-01-01

    Since fallen trees are a key factor in biodiversity and biogeochemical cycling, information about their spatial distribution is of use in determining species distribution and nutrient and carbon cycling in forest ecosystems. Ground-based surveys are both time consuming and labour intensive. Remote-sensing technology can reduce these costs. Here, we used high-spatial-resolution aerial photographs (0.5–1.0 cm per pixel) taken from an unmanned aerial vehicle (UAV) to survey fallen trees in a deciduous broadleaved forest in eastern Japan. In nine sub-plots we found a total of 44 fallen trees by ground survey. From the aerial photographs, we identified 80% to 90% of fallen trees that were >30 cm in diameter or >10 m in length, but missed many that were narrower or shorter. This failure may be due to the similarity of fallen trees to trunks and branches of standing trees or masking by standing trees. Views of the same point from different angles may improve the detection rate because they would provide more opportunity to detect fallen trees hidden by standing trees. Our results suggest that UAV surveys will make it possible to monitor the spatial and temporal variations in forest structure and function at lower cost. PMID:25279817

  5. Plant functional traits with particular reference to tropical deciduous forests: a review.

    PubMed

    Chaturvedi, R K; Raghubanshi, A S; Singh, J S

    2011-12-01

    Functional traits (FTs) integrate the ecological and evolutionary history of a species, and can potentially be used to predict its response as well as its influence on ecosystem functioning. Study of inter-specific variation in the FTs of plants aids in classifying species into plant functional types (PFTs) and provides insights into fundamental patterns and trade-offs in plant form and functioning and the effect of changing species composition on ecosystem functions. Specifically, this paper focuses on those FTs that make a species successful in the dry tropical environment. Following a brief overview, we discuss plant FTs that may be particularly relevant to tropical deciduous forests (TDFs). We consider the traits under the following categories: leaf traits, stem and root traits, reproductive traits, and traits particularly relevant to water availability. We compile quantitative information on functional traits of dry tropical forest species. We also discuss trait-based grouping of plants into PFTs. We recognize that there is incomplete knowledge about many FTs and their effects on TDFs and point out the need for further research on PFTs of TDF species, which can enable prediction of the dynamics of these forests in the face of disturbance and global climate change. Correlations between structural and ecophysiological traits and ecosystem functioning should also be established which could make it possible to generate predictions of changes in ecosystem services from changes in functional composition. PMID:22116295

  6. Unmanned aerial survey of fallen trees in a deciduous broadleaved forest in eastern Japan.

    PubMed

    Inoue, Tomoharu; Nagai, Shin; Yamashita, Satoshi; Fadaei, Hadi; Ishii, Reiichiro; Okabe, Kimiko; Taki, Hisatomo; Honda, Yoshiaki; Kajiwara, Koji; Suzuki, Rikie

    2014-01-01

    Since fallen trees are a key factor in biodiversity and biogeochemical cycling, information about their spatial distribution is of use in determining species distribution and nutrient and carbon cycling in forest ecosystems. Ground-based surveys are both time consuming and labour intensive. Remote-sensing technology can reduce these costs. Here, we used high-spatial-resolution aerial photographs (0.5-1.0 cm per pixel) taken from an unmanned aerial vehicle (UAV) to survey fallen trees in a deciduous broadleaved forest in eastern Japan. In nine sub-plots we found a total of 44 fallen trees by ground survey. From the aerial photographs, we identified 80% to 90% of fallen trees that were >30 cm in diameter or >10 m in length, but missed many that were narrower or shorter. This failure may be due to the similarity of fallen trees to trunks and branches of standing trees or masking by standing trees. Views of the same point from different angles may improve the detection rate because they would provide more opportunity to detect fallen trees hidden by standing trees. Our results suggest that UAV surveys will make it possible to monitor the spatial and temporal variations in forest structure and function at lower cost. PMID:25279817

  7. Spectral anisotropy of subtropical deciduous forest using MISR and MODIS data acquired under large seasonal variation in solar zenith angle

    NASA Astrophysics Data System (ADS)

    Breunig, Fábio Marcelo; Galvão, Lênio Soares; dos Santos, João Roberto; Gitelson, Anatoly A.; de Moura, Yhasmin Mendes; Teles, Thiago Sousa; Gaida, William

    2015-03-01

    Recent studies in Amazonian tropical evergreen forests using the Multi-angle Imaging SpectroRadiometer (MISR) and the Moderate Resolution Imaging Spectroradiometer (MODIS) have highlighted the importance of considering the view-illumination geometry in satellite data analysis. However, contrary to the observed for evergreen forests, bidirectional effects have not been evaluated in Brazilian subtropical deciduous forests. In this study, we used MISR data to characterize the reflectance and vegetation index anisotropies in subtropical deciduous forest from south Brazil under large seasonal solar zenith angle (SZA) variation and decreasing leaf area index (LAI) from the summer to winter. MODIS data were used to observe seasonal changes in the normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI). Topographic effects on their determination were inspected by dividing data from the summer to winter and projecting results over a digital elevation model (DEM). By using the PROSAIL, we investigated the relative contribution of LAI and SZA to vegetation indices (VI) of deciduous forest. We also simulated and compared the MISR NDVI and EVI response of subtropical deciduous and tropical evergreen forests as a function of the large seasonal SZA amplitude of 33°. Results showed that the MODIS-MISR NDVI and EVI presented higher values in the summer and lower ones in the winter with decreasing LAI and increasing SZA or greater amounts of canopy shadows viewed by the sensors. In the winter, NDVI reduced local topographic effects due to the red-near infrared (NIR) band normalization. However, the contrary was observed for the three-band EVI that enhanced local variations in shaded and sunlit surfaces due to its strong dependence on the NIR band response. The reflectance anisotropy of the MISR bands increased from the summer to winter and was stronger in the backscattering direction at large view zenith angles (VZA). EVI was much more anisotropic than

  8. Identifying patterns of forest hydrologic and biogeochemical fluxes using weather map classification in a Mid-Atlantic deciduous forest

    NASA Astrophysics Data System (ADS)

    Siegert, C. M.; Levia, D. F., Jr.; Leathers, D. J.; Van Stan, J. T., II; Mitchell, M. J.

    2014-12-01

    The partitioning of precipitation within the forest canopy into throughfall and stemflow is controlled by biotic and abiotic factors, which include storm characteristics (e.g., intensity, duration, and magnitude) and canopy structural parameters. Our research uses novel applications of weather map classification to relate synoptic scale weather patterns to the surface environment. A daily synoptic calendar was developed in the Mid-Atlantic (USA) to categorize the subcanopy hydrologic and biogeochemical fluxes during storm events in an eastern deciduous forest. Synoptic classification identified 6 low pressure systems, 4 high pressure systems, 1 cold front, 3 northerly flow regimes, 3 southerly flow regimes, and 5 weak patterns across 4 seasons. The low pressure systems were commonly associated with the largest average flux-based enrichment ratios of solutes in throughfall and stemflow compared to rainfall solute concentrations. Low pressures such as the Weak Coastal Low, centered off the Mid-Atlantic coast with easterly winds over the study region, were associated with large rainfall events with moderate intensities falling over a long period of time. This combination of meteorological conditions allowed complete washoff of antecedent atmospheric deposition and maximum canopy leaching as storm systems of this magnitude were able to wet the entire canopy. The lowest flux-based enrichment ratios occurred during the passage of cold fronts and under weak southwest flow regimes, which were both characterized by moderately high rainfall amounts that occurred over short periods of time (i.e., < 0.5 days) with high intensities (i.e., > 5 mm h-1). As a result, the water from these storm systems passed through the forest canopy very quickly and with minimal contact time thus resulting in minimal enrichment of throughfall and stemflow. The distinct chemical signatures of synoptic types provide evidence that this novel application of storm classification in forest hydrology is

  9. Greenhouse Gas Fluxes from Deciduous and Boreal Forest Soils in Eastern Canada

    NASA Astrophysics Data System (ADS)

    Ullah, S.; Moore, T.

    2012-04-01

    The exchange of the important trace gases, methane (CH4), nitrous oxide (N2O) and carbon dioxide (CO2), between forested soils and the atmosphere can show great temporal and spatial variability. We investigated the fluxes of CH4, N2O, and CO2 from deciduous and boreal forest soils in eastern Canada from 2006 to 2008 in 20 sites representative of different soil drainage classes, management schemes and natural disturbance. Well-drained soils consumed atmospheric CH4, while poorly-drained 'cryptic' wetland soils embedded in depressions were a source. CH4 fluxes could be predicted primarily by temperature and moisture, and tree cover exerted an influence mainly through the creation of large soil porosity, leading to increased consumption rates. In contrast, there were very poor relationships between N2O fluxes and environmental variables, reflecting the complex microbial, edpahic and N cycling processes, such as nitrification in well-drained soils and denitrification in poorly-drained soils, which lead to N2O production (or consumption) in soils. At the broad temporal and spatial scale, however, soil C:N ratio was a good predictor of N2O emission rates, through its influence upon N cycling processes. Soil CO2 emission rates showed less spatial and temporal variability, and were controlled by temperature and moisture. Poorly-drained soils in these forests play a critical role in the net global warming potential of forested landscapes. Therefore, soil drainage class integrates many of the biogeochemical processes controlling the flux of these gases and provides a framework for extrapolating results spatially and currently we are developing an estimate of the flux of these gases for the forest regions of Canada.

  10. [Effects of exotic Larix kaempferi on forest soil quality and bacterial diversity].

    PubMed

    Yang, Xin; Cao, Jing; Dong, Mao-Xing; Ma, Xiao-Jun

    2008-10-01

    The study on the soil quality and bacterial diversity under 8-30 years old exotic Larix kaempferi, native Pinus tabulaeformis, and secondary deciduous broadleaf forest stands in Xiaolong-shan Mountains of Gansu, Northwest China showed that the soil pH under different forest stands had no distinct variation, but soil moisture content was increased with increasing age of forest stands. Soil organic matter and nitrogen contents were the highest under secondary deciduous forest, followed by under L. kaermpferi, and P. tabulaeformis. However, the soils under different ages of forest stands had no obvious variations in their organic matter and nitrogen contents, suggesting that tree species was the main factor affecting soil quality. Compared with P. tabulaeformis, exotic L. kaempferi could significantly increase soil organic matter and nitrogen contents. PCR-DGGE banding patterns suggested that the soil under secondary deciduous broadleaf forest had the highest bacterial diversity, followed by under L. kaempferi, and P. tabulaeformis. The sequenced DGGE bands were classified into three bacterial groups, i. e., Proteobacteria, Cytophaga - Flavobacterium - Bacteroides, and high G + C content gram-positive type, among which, Proteobacteria occurred most frequently. Further detailed analyses suggested that the soil bacterial compositions under exotic Larix stands were more similar to each other than those under pine and secondary deciduous broadleaf forests. It was concluded that exotic L. kaempferi induced the changes of microbial diversity in the forest soils of this region. PMID:19123342

  11. Estimation of leaf area index and foliage clumping in deciduous forests using digital photography

    NASA Astrophysics Data System (ADS)

    Chianucci, Francesco; Cutini, Andrea

    2013-04-01

    Rapid, reliable and meaningful estimates of leaf area index (LAI) are essential to the characterization of forest ecosystems. In this contribution the accuracy of both fisheye and non-fisheye digital photography for the estimation of forest leaf area in deciduous stands was evaluated. We compared digital hemispherical photography (DHP), the most widely used technique that measures the gap fraction at multiple zenith angles, with methods that measure the gap fraction at a single zenith angle, namely 57.5 degree photography and cover photography (DCP). Comparison with other different gap fraction methods used to calculate LAI such as canopy transmittance measurements from AccuPAR ceptometer and LAI- 2000 Plant Canopy Analyzer (PCA) were also performed. LAI estimated from all these indirect methods were compared with direct measurements obtained by litter traps (LAILT). We applied these methods in 10 deciduous stands of Quercus cerris, Castanea sativa and Fagus sylvatica, the most common deciduous species in Italy, where LAILT ranged from 3.9 to 7.3. DHP and DCP provided good indirect estimates of LAILT, and outperformed the other indirect methods. The DCP method provided estimates of crown porosity, crown cover, foliage cover and the clumping index at the zenith, but required assumptions about the light extinction coefficient at the zenith (k), to accurately estimate LAI. Cover photography provided good indirect estimates of LAI assuming a spherical leaf angle distribution, even though k appeared to decrease as LAI increased, thus affecting the accuracy of LAI estimates in DCP. In contrast, the accuracy of LAI estimates in DHP appeared insensitive to LAILT values, but the method was sensitive to photographic exposure, gamma-correction and was more time-consuming than DCP. Foliage clumping was estimated from all the photographic methods by analyzing either gap size distribution (DCP) or gap fraction distribution (DHP). Foliage clumping was also calculated from PCA and

  12. Comparative efficacy of three epigeic earthworms under different deciduous forest litters decomposition.

    PubMed

    Manna, M C; Jha, S; Ghosh, P K; Acharya, C L

    2003-07-01

    An experiment was conducted during 1998-1999, in a deciduous forest located in the semi-arid tropics of central India, to evaluate the suitability of different forest litters as food material for the tropical epigeic earthworms i.e. Eisenia fetida (Savigny), Perionyx excavatus (Perrier) and Dicogaster bolaui (michaelsen). The aim was to examine the influence of these earthworms on the decomposition processes of three types of forest litters i.e. Tectona grandis (teak), Madhuca indica (mahua) and Butea monosperma (palas), on the maintenance of quality in a vermicomposting system, and to assess the effect of applications of in situ prepared vermicomposts on the growth of forest trees. The results indicated that T. grandis litter was the most suitable food material for the earthworms possibly because it contained high reserves of mineral nutrients. Comparisons of the survival and reproduction rates of the three epigeic earthworm species indicated that a higher reproduction rate was maintained for E. fetida compared to P. excavatus and D. bolaui in the decomposition of these forest litters. The rates of growth and population increases of E. fetida approximately doubled after 12 weeks of litter decomposition. The litter decomposition process was associated strongly with the quality of the materials and their chemical composition. Irrespective of earthworm inoculations, the levels of available nutrient such as NH(4)-N, NO(3)-N, available P and K increased significantly (pM. indica litter compost>B. monosperma litter compost. The mature decomposed litter had lower C/N ratios (11.3-24.8:1), water-soluble carbon (0.30-0.58%), water-soluble carbohydrates (0.35-0.71%) and larger cation exchange capacity/total organic carbon ratios than the values in the parent forest litter. The lignin content increased with maturation with a concomitant decrease in cellulose resulting in higher lignin/cellulose ratios. Application of all three

  13. The use of proton transfer mass spectrometry to characterize VOC concentrations within a deciduous forest

    NASA Astrophysics Data System (ADS)

    Ammann, C.; Spirig, C.; Neftel, A.; Schaub, A.; Komenda, M.

    2003-04-01

    Proton Transfer Mass Spectrometry (PTR-MS) has become an important technique for fast measurements of biogenic volatile organic compounds (VOC). As part of the German ECHO project (Emission and chemical transformation of biogenic volatile organic compounds), a PTR-MS instrument was calibrated and applied for a range of VOC including isoprene, sum of monoterpenes, methanol, acetaldehyde, acetone and others. During the first ECHO field campaign in June and July 2002 continuous four-level concentration profiles were measured within and above a mixed deciduous forest stand on an hourly basis. VOC concentrations obtained by PTR-MS agreed reasonably well with parallel gas chromatography measurements. The spatial and temporal distribution of the biogenic VOC such as monoterpenes and isoprene generally reflect the local source with maximum concentrations during daytime within the canopy. Gradients of monoterpenes at the canopy top were more consistent than those of isoprene, which is attributed to the inhomogeneous emission pattern, i.e. the direct surrounding of the measurement tower was dominated by monoterpene-emitting trees (beeches) whereas the dominant isoprene emitters (oaks) were mainly located further upwind. Acetone and the aromatic compounds frequently showed high nighttime concentration peaks reflecting advection of anthropogenic emissions from outside the forest.

  14. Impact of post-mining subsidence on nitrogen transformation in southern tropical dry deciduous forest, India.

    PubMed

    Tripathi, N; Singh, R S; Singh, J S

    2009-04-01

    The goal of our research was to assess the impact of post-mining land subsidence, caused due to underground coal mining operations, on fine root biomass and root tips count; plant available nutrient status, microbial biomass N (MBN) and N-mineralization rates of a Southern tropical dry deciduous forest of Singareni Coalfields of India. The changes were quantified in all the three (rainy, winter and summer) seasons, in slope and depression microsites of the subsided land and an adjacent undamaged forest microsite. Physico-chemical characteristics were found to be altered after subsidence, showing a positive impact of subsidence on soil moisture, bulk density, water holding capacity, organic carbon content, total N and total P. The increase in all the parameters was found in depression microsites, while in slope microsites, the values were lower. Fine root biomass and root tips count increased in the subsided depression microsites, as demonstrated by increases of 62% and 45%, respectively. Soil nitrate-N and phosphate-P concentrations were also found to be higher in depression microsite, showing an increase of 35.68% and 24.74%, respectively. Depression microsite has also shown the higher MBN value with an increase over control. Net nitrification, net N-mineralization and MBN were increased in depression microsite by 29.77%, 25.72% and 34%, respectively. There was a positive relation of microbial N with organic C, fine root biomass and root tips. PMID:19147131

  15. Ecophysiological roles of abaxial anthocyanins in a perennial understorey herb from temperate deciduous forests

    PubMed Central

    Fernández-Marín, Beatriz; Esteban, Raquel; Míguez, Fátima; Artetxe, Unai; Castañeda, Verónica; Pintó-Marijuan, Marta; Becerril, José María; García-Plazaola, José Ignacio

    2015-01-01

    Accumulation of abaxial anthocyanins is an intriguing leaf trait particularly common among deeply shaded understorey plants of tropical and temperate forests whose ecological significance is still not properly understood. To shed light on it, possible ecophysiological roles of abaxial anthocyanins were tested in the perennial understorey herb of temperate deciduous forests Saxifraga hirsuta, chosen as a model species due to the coexistence of green and anthocyanic leaves and the presence of an easily removable lower anthocyanic epidermis. Anthocyanins accumulated during autumn, which temporally matched the overstorey leaf fall. Patterns of development of abaxial anthocyanins and direct measurements of photochemical efficiency under monochromatic light were not consistent with a photoprotective hypothesis. Enhancement of light capture also seemed unlikely since the back-scattering of red light towards the lower mesophyll was negligible. Seed germination was similar under acyanic and anthocyanic leaves. A relevant consequence of abaxial anthocyanins was the dramatic reduction of light transmission through the leaf. The dark environment generated underneath the Saxifraga canopy was enhanced by the horizontal repositioning of leaves, which occurs in parallel with reddening. This might play a role in biotic interactions by inhibiting vital processes of competitors, which may be of especial importance in spring before the overstorey leaves sprout. PMID:25922298

  16. Accumulated phytotoxic ozone dose estimation for deciduous forest in Kanto, Japan in summer

    NASA Astrophysics Data System (ADS)

    Watanabe, Takanori; Izumi, Takeki; Matsuyama, Hiroshi

    2016-03-01

    With ozone concentrations simulated using a regional chemical transport model (ADMER-PRO) and high-spatial resolution meteorological data, we investigated the influence of ozone concentration on deciduous forests in the Kanto region of Japan in summer during 2003, 2004, and 2009: three years for which weather characteristics differed greatly. Ozone risk for plants was assessed by the accumulated phytotoxic ozone dose (POD), a flux-based index. The effects were analyzed by particularly addressing the relation between the stomatal ozone flux and meteorological elements. Results revealed high absorption areas not only where injury to forests had been visually detected in previous studies, but also where injury had not been observed to date. Regarding the relation between the stomatal ozone flux and meteorological elements, air temperature and vapor pressure deficit strongly affected POD in 2004, when high temperature and little rainfall were observed. Additionally, the ozone concentration and irradiance strongly affected POD in 2003 when low temperatures and heavy rainfall were observed. The meteorological elements affecting POD differed from year to year. Results demonstrate the importance of multi-year simulations and analyses in the field of ozone risk assessment.

  17. Impact of post-mining subsidence on nitrogen transformation in southern tropical dry deciduous forest, India

    SciTech Connect

    Tripathi, N.; Singh, R.S.; Singh, J.S.

    2009-04-15

    The goal of our research was to assess the impact of post-mining land subsidence, caused due to underground coal mining operations, on fine root biomass and root tips count; plant available nutrient status, microbial biomass N (MBN) and N-mineralization rates of a Southern tropical dry deciduous forest of Singareni Coalfields of India. The changes were quantified in all the three (rainy, winter and summer) seasons, in slope and depression microsites of the subsided land and an adjacent undamaged forest microsite. Physico-chemical characteristics were found to be altered after subsidence, showing a positive impact of subsidence on soil moisture, bulk density, water holding capacity, organic carbon content, total N and total P. The increase in all the parameters was found in depression microsites, while in slope microsites, the values were lower. Fine root biomass and root tips count increased in the subsided depression microsites, as demonstrated by increases of 62% and 45%, respectively. Soil nitrate-N and phosphate-P concentrations were also found to be higher in depression microsite, showing an increase of 35.68% and 24.74%, respectively. Depression microsite has also shown the higher MBN value with an increase over control. Net nitrification, net N-mineralization and MBN were increased in depression microsite by 29.77%, 25.72% and 34%, respectively. There was a positive relation of microbial N with organic C, fine root biomass and root tips.

  18. Soil Macroinvertebrate Communities Across a Productivity Gradient in Deciduous Forests of Eastern North America

    DOE PAGESBeta

    Wenk, Evelyn S.; Callaham, Mac A.; O'Brien, Joseph J.; Hanson, Paul J.

    2016-03-01

    We describe how, within the temperate, deciduous forests of the eastern US, diverse soil-fauna communities are structured by a combination of environmental gradients and interactions with other biota. The introduction of non-native soil taxa has altered communities and soil processes, and adds another degree of variability to these systems. We sampled soil macroinvertebrate abundance from forested sites in Missouri (MO), Michigan (MI), Massachusetts (MA), and New Hampshire (NH), with the objective of comparing community assemblages and evaluating the role of invasive earthworms along the temperature—productivity gradient represented by the sites. The primary detritivores encountered were earthworms and millipedes. Earthworms weremore » collected only in MO and MI, and at much greater density in MO. Millipedes were found at every site except in MO, and at their highest mean density in NH. Warmer temperatures, higher litter productivity, and low Oa horizon depth (as found in MO) were correlated with high earthworm activity. Oa horizon depth was the greatest in NH, where the macroinvertebrate community was dominated (in terms of abundance) by predators and herbivores, not detritivores. Our results are suggestive of, and congruent with, the concept of earthworms as ecosystem engineers, as we found that the presence of non-native earthworm species was associated with significant differences in soil characteristics such as apparent rapid decomposition rates and reduced carbon storage in the Oa horizon.« less

  19. Evergreen broadleaf forest transition zone changes in Japan from 1961 to 2008 detected by aerial ortho-photos

    NASA Astrophysics Data System (ADS)

    Nakazono, Etsuko; Tanaka, Nobuyuki; Yasuda, Masatsugu; Daimaru, Hiromu; Takeuchi, Wataru

    2016-06-01

    In order to detect the distribution change of evergreen broad-leaved trees (EBTs) in a old-growth forest on the transitional zone of cool-temperate and warm-temperate zones, we used the ortho-photo data conversed from the aerial photos. Comparing the crown map of EBTs in the 1-ha verification plot with the ground truth data of individual tree inventory, 14 out of 17 (82%) upper layer trees were found to be visually read on the aerial photo We chose two indices for detecting the distribution change of EBTs, crown number and total crown area. We made crown maps of the 20-ha plot based on ortho-photos in 1961, 1975, 1985, 2003, 2005 and 2008, and calculated crown number and total crown area for each photos. The crown number increased at a rate 0.18/year/ha from 1961 to 2000’s, and total crown area also increased at a rate 0.21% for the 20-ha plot. The total crow area increase was highly probable because errors of area in orthophotos were smaller than secular changes of the area.

  20. The Influence of Anthropogenic Sources on Fluxes of Secondary Organic Aerosol Precursors From a Deciduous Forest in the Southeastern United States

    NASA Astrophysics Data System (ADS)

    Saylor, R. D.; Stein, A. F.

    2012-12-01

    broadleaf deciduous consisting of chestnut oak (Quercus prinus), tulip poplar (Liriodendron tulipifera), white oak (Quercus alba), red oak (Quercus rubra), red maple (Acer rubrum), and various hickory species (Carya sp.) in order of decreasing biomass density. At the time of isoprene flux measurements made at the tower in 1999, the stand was approximately 50 years old, the overstory canopy height was 24 m, and the whole canopy leaf area index was 4.9 m2 leaf/m2 ground area. In this presentation, the model formulation is described and results from the application of ACCESS to the WBW forest are presented and compared to measurements made at the site to investigate the influence of background anthropogenic sources on above canopy fluxes of SOA precursors in an isoprene emission dominated landscape in the unique atmospheric chemical environment of the southeastern United States. In particular, levels of background NOx concentrations are found to significantly influence both the magnitude and chemical composition of fluxes of SOA precursors from the canopy.

  1. Remote sensing-based estimation of annual soil respiration at two contrasting forest sites

    SciTech Connect

    Gu, Lianhong; Huang, Ni; Black, T. Andrew; Wang, Li; Niu, Zheng

    2015-11-23

    Soil respiration (Rs), an important component of the global carbon cycle, can be estimated using remotely sensed data, but the accuracy of this technique has not been thoroughly investigated. In this article, we proposed a methodology for the remote estimation of annual Rs at two contrasting FLUXNET forest sites (a deciduous broadleaf forest and an evergreen needleleaf forest).

  2. An Assessment of Worldview-2 Imagery for the Classification Of a Mixed Deciduous Forest

    NASA Astrophysics Data System (ADS)

    Carter, Nahid

    Remote sensing provides a variety of methods for classifying forest communities and can be a valuable tool for the impact assessment of invasive species. The emerald ash borer (Agrilus planipennis) infestation of ash trees (Fraxinus) in the United States has resulted in the mortality of large stands of ash throughout the Northeast. This study assessed the suitability of multi-temporal Worldview-2 multispectral satellite imagery for classifying a mixed deciduous forest in Upstate New York. Training sites were collected using a Global Positioning System (GPS) receiver, with each training site consisting of a single tree of a corresponding class. Six classes were collected; Ash, Maple, Oak, Beech, Evergreen, and Other. Three different classifications were investigated on four data sets. A six class classification (6C), a two class classification consisting of ash and all other classes combined (2C), and a merging of the ash and maple classes for a five class classification (5C). The four data sets included Worldview-2 multispectral data collection from June 2010 (J-WV2) and September 2010 (S-WV2), a layer stacked data set using J-WV2 and S-WV2 (LS-WV2), and a reduced data set (RD-WV2). RD-WV2 was created using a statistical analysis of the processed and unprocessed imagery. Statistical analysis was used to reduce the dimensionality of the data and identify key bands to create a fourth data set (RD-WV2). Overall accuracy varied considerably depending upon the classification type, but results indicated that ash was confused with maple in a majority of the classifications. Ash was most accurately identified using the 2C classification and RD-WV2 data set (81.48%). A combination of the ash and maple classes yielded an accuracy of 89.41%. Future work should focus on separating the ash and maple classifiers by using data sources such as hyperspectral imagery, LiDAR, or extensive forest surveys.

  3. Charcoal reflectance reveals early holocene boreal deciduous forests burned at high intensities.

    PubMed

    Hudspith, Victoria A; Belcher, Claire M; Kelly, Ryan; Hu, Feng Sheng

    2015-01-01

    Wildfire size, frequency, and severity are increasing in the Alaskan boreal forest in response to climate warming. One of the potential impacts of this changing fire regime is the alteration of successional trajectories, from black spruce to mixed stands dominated by aspen, a vegetation composition not experienced since the early Holocene. Such changes in vegetation composition may consequently alter the intensity of fires, influencing fire feedbacks to the ecosystem. Paleorecords document past wildfire-vegetation dynamics and as such, are imperative for our understanding of how these ecosystems will respond to future climate warming. For the first time, we have used reflectance measurements of macroscopic charcoal particles (>180μm) from an Alaskan lake-sediment record to estimate ancient charring temperatures (termed pyrolysis intensity). We demonstrate that pyrolysis intensity increased markedly from an interval of birch tundra 11 ky ago (mean 1.52%Ro; 485°C), to the expansion of trees on the landscape ~10.5 ky ago, remaining high to the present (mean 3.54%Ro; 640°C) irrespective of stand composition. Despite differing flammabilities and adaptations to fire, the highest pyrolysis intensities derive from two intervals with distinct vegetation compositions. 1) the expansion of mixed aspen and spruce woodland at 10 cal. kyr BP, and 2) the establishment of black spruce, and the modern boreal forest at 4 cal. kyr BP. Based on our analysis, we infer that predicted expansion of deciduous trees into the boreal forest in the future could lead to high intensity, but low severity fires, potentially moderating future climate-fire feedbacks. PMID:25853712

  4. Assimilating Multiple Data Types in the Community Land Model (CLM) for Deciduous Forests in North America

    NASA Astrophysics Data System (ADS)

    Montane, F.; Fox, A. M.; Hoar, T. J.; Arellano, A. F.; Liu, Y.; Moreno, G.; Quaife, T. L.; Richardson, A. D.; Trouet, V.; Alexander, M. R.; Chen, M.; Hollinger, D. Y.; Moore, D. J.

    2014-12-01

    Networks of eddy covariance towers like AmeriFlux provide the infrastructure necessary to study relationships between ecosystem processes and environmental forcing across a range of spatial and temporal scales. Recent syntheses of comparisons between observations from eddy covariance tower sites in North America and output from several Land Surface Models showed that the characterization of phenology was not accurate in most of the models. In order to improve phenological models, a continental-scale phenological observatory, the PhenoCam network, provides high-frequency observations of vegetation phenology, which can be used to derive a greenness index, the green chromatic coordinate (gcc). In this study we run the Community Land Model (CLM4.5) for 10 deciduous forests sites in North America, included in the AmeriFlux and PhenoCam networks, to assimilate multiple data types including one of the key variables in most ecosystem models, fPAR, the radiometric equivalent of Leaf Area Index (LAI). fPAR characterizes vegetation canopy function and energy absorption capacity and therefore it is important for estimating canopy photosynthesis. We use fPAR data from Moderate Resolution Imaging Spectroradiometer (MODIS), with a pixel resolution of 1 km x 1 km and a temporal resolution of 8 days. Data is assimilated in CLM with an Ensemble Kalman Filter, a sequential data assimilation technique, within the Data Assimilation Research Testbed (DART). In our study, we also compare observations available for Harvard Forest (LAI, NEE and gcc) with model output. The CLM output for LAI and NEE is sometimes located out of the observation space delimited by LAI and NEE measurements for Harvard Forest. After assimilating data, we compare observations and mean CLM model output from all the sites for a free run, an assimilation run and an assimilation run with inflation. We investigate the impact of assimilating these observations and the resultant model state updates on ecosystem carbon

  5. The effect of wind velocity on transpiration in a mixed broadleaved deciduous forest

    NASA Astrophysics Data System (ADS)

    Kim, D.; Oren, R.; Oishi, A. C.; Hsieh, C.; Phillips, N. G.; Novick, K. A.; Stoy, P. C.

    2013-12-01

    Wind velocity (U) within and above forest canopies can alter the coupling between the vapor-saturated sub-stomatal airspace and the drier atmosphere aloft, thereby influencing transpiration rates. In practice, however, the actual increase in transpiration with increasing U depends on the aerodynamic resistance (RA) to vapor transfer compared to canopy resistance to water vapor flux out of leaves (RC, dominated by stomatal resistance, Rstom), and the rate at which RA decreases with increasing U. We investigated the effect of U on transpiration at the canopy scale using filtered meteorological data and sap flux measurements gathered from six diverse species of a mature broadleaved deciduous forest. Only under high light conditions, stand transpiration (EC) increased slightly (6.5%) with increasing U ranging from ~0.7 to ~4.7 m s-1. Under other conditions, sap flux density (Js) and EC responded weakly or did not change with U. RA, estimated from Monin-Obukhov similarity theory, decreased with increasing U, but this decline was offset by increasing RC, estimated from a rearranged Penman-Monteith equation, due to a concurrent increase in vapor pressure deficit (D). The increase of RC with D over the observed range of U was consistent with increased Rstom by ~40% based on hydraulic theory. Except for very rare half-hourly values, the proportion of RA to total resistance (RT) remained < 15% over the observed range of conditions. These results suggest that in similar forests and conditions, accounting for the effects of U-D relationship on Rstom would reduce the uncertainty of modeling canopy gas exchange more than accounting for the direct effect of U on RA.

  6. Charcoal Reflectance Reveals Early Holocene Boreal Deciduous Forests Burned at High Intensities

    PubMed Central

    Hudspith, Victoria A.; Belcher, Claire M.; Kelly, Ryan; Hu, Feng Sheng

    2015-01-01

    Wildfire size, frequency, and severity are increasing in the Alaskan boreal forest in response to climate warming. One of the potential impacts of this changing fire regime is the alteration of successional trajectories, from black spruce to mixed stands dominated by aspen, a vegetation composition not experienced since the early Holocene. Such changes in vegetation composition may consequently alter the intensity of fires, influencing fire feedbacks to the ecosystem. Paleorecords document past wildfire-vegetation dynamics and as such, are imperative for our understanding of how these ecosystems will respond to future climate warming. For the first time, we have used reflectance measurements of macroscopic charcoal particles (>180μm) from an Alaskan lake-sediment record to estimate ancient charring temperatures (termed pyrolysis intensity). We demonstrate that pyrolysis intensity increased markedly from an interval of birch tundra 11 ky ago (mean 1.52%Ro; 485°C), to the expansion of trees on the landscape ∼10.5 ky ago, remaining high to the present (mean 3.54%Ro; 640°C) irrespective of stand composition. Despite differing flammabilities and adaptations to fire, the highest pyrolysis intensities derive from two intervals with distinct vegetation compositions. 1) the expansion of mixed aspen and spruce woodland at 10 cal. kyr BP, and 2) the establishment of black spruce, and the modern boreal forest at 4 cal. kyr BP. Based on our analysis, we infer that predicted expansion of deciduous trees into the boreal forest in the future could lead to high intensity, but low severity fires, potentially moderating future climate-fire feedbacks. PMID:25853712

  7. Effects of Habitat Structure and Fragmentation on Diversity and Abundance of Primates in Tropical Deciduous Forests in Bolivia

    PubMed Central

    Büntge, Anna B. S.; Herzog, Sebastian K.; Kessler, Michael

    2010-01-01

    Habitat structure and anthropogenic disturbance are known to affect primate diversity and abundance. However, researchers have focused on lowland rain forests, whereas endangered deciduous forests have been neglected. We aimed to investigate the relationships between primate diversity and abundance and habitat parameters in 10 deciduous forest fragments southeast of Santa Cruz, Bolivia. We obtained primate data via line-transect surveys and visual and acoustic observations. In addition, we assessed the vegetation structure (canopy height, understory density), size, isolation time, and surrounding forest area of the fragments. We interpreted our results in the context of the historical distribution data for primates in the area before fragmentation and interviews with local people. We detected 5 of the 8 historically observed primate species: Alouatta caraya, Aotus azarae boliviensis, Callithrix melanura, Callicebus donacophilus, and Cebus libidinosus juruanus. Total species number and detection rates decreased with understory density. Detection rates also negatively correlated with forest areas in the surroundings of a fragment, which may be due to variables not assessed, i.e., fragment shape, distance to nearest town. Observations for Alouatta and Aotus were too few to conduct further statistics. Cebus and Callicebus were present in 90% and 70% of the sites, respectively, and their density did not correlate with any of the habitat variables assessed, signaling high ecological plasticity and adaptability to anthropogenic impact in these species. Detections of Callithrix were higher in areas with low forest strata. Our study provides baseline data for future fragmentation studies in Neotropical dry deciduous forests and sets a base for specific conservation measures. PMID:20949116

  8. Effects of Forest Age on Soil Autotrophic and Heterotrophic Respiration Differ between Evergreen and Deciduous Forests

    PubMed Central

    Wang, Wei; Zeng, Wenjing; Chen, Weile; Yang, Yuanhe; Zeng, Hui

    2013-01-01

    We examined the effects of forest stand age on soil respiration (SR) including the heterotrophic respiration (HR) and autotrophic respiration (AR) of two forest types. We measured soil respiration and partitioned the HR and AR components across three age classes ∼15, ∼25, and ∼35-year-old Pinus sylvestris var. mongolica (Mongolia pine) and Larix principis-rupprechtii (larch) in a forest-steppe ecotone, northern China (June 2006 to October 2009). We analyzed the relationship between seasonal dynamics of SR, HR, AR and soil temperature (ST), soil water content (SWC) and normalized difference vegetation index (NDVI, a plant greenness and net primary productivity indicator). Our results showed that ST and SWC were driving factors for the seasonal dynamics of SR rather than plant greenness, irrespective of stand age and forest type. For ∼15-year-old stands, the seasonal dynamics of both AR and HR were dependent on ST. Higher Q10 of HR compared with AR occurred in larch. However, in Mongolia pine a similar Q10 occurred between HR and AR. With stand age, Q10 of both HR and AR increased in larch. For Mongolia pine, Q10 of HR increased with stand age, but AR showed no significant relationship with ST. As stand age increased, HR was correlated with SWC in Mongolia pine, but for larch AR correlated with SWC. The dependence of AR on NDVI occurred in ∼35-year-old Mongolia pine. Our study demonstrated the importance of separating autotrophic and heterotrophic respiration components of SR when stimulating the response of soil carbon efflux to environmental changes. When estimating the response of autotrophic and heterotrophic respiration to environmental changes, the effect of forest type on age-related trends is required. PMID:24282560

  9. Soil Organic Carbon and Total Nitrogen Gains in an Old Growth Deciduous Forest in Germany

    PubMed Central

    Schrumpf, Marion; Kaiser, Klaus; Schulze, Ernst-Detlef

    2014-01-01

    Temperate forests are assumed to be organic carbon (OC) sinks, either because of biomass increases upon elevated CO2 in the atmosphere and large nitrogen deposition, or due to their age structure. Respective changes in soil OC and total nitrogen (TN) storage have rarely been proven. We analysed OC, TN, and bulk densities of 100 soil cores sampled along a regular grid in an old-growth deciduous forest at the Hainich National Park, Germany, in 2004 and again in 2009. Concentrations of OC and TN increased significantly from 2004 to 2009, mostly in the upper 0–20 cm of the mineral soil. Changes in the fine earth masses per soil volume impeded the detection of OC changes based on fixed soil volumes. When calculated on average fine earth masses, OC stocks increased by 323±146 g m−2 and TN stocks by 39±10 g m−2 at 0–20 cm soil depth from 2004 to 2009, giving average annual accumulation rates of 65±29 g OC m−2 yr−1 and 7.8±2 g N m−2 yr−1. Accumulation rates were largest in the upper part of the B horizon. Regional increases in forest biomass, either due to recovery of forest biomass from previous forest management or to fertilization by elevated CO2 and N deposition, are likely causes for the gains in soil OC and TN. As TN increased stronger (1.3% yr−1 of existing stocks) than OC (0.9% yr−1), the OC-to-TN ratios declined significantly. Results of regression analyses between changes in OC and TN stocks suggest that at no change in OC, still 3.8 g TN m−2 yr−1 accumulated. Potential causes for the increase in TN in excess to OC are fixation of inorganic N by the clay-rich soil or changes in microbial communities. The increase in soil OC corresponded on average to 6–13% of the estimated increase in net biome productivity. PMID:24586720

  10. Soil organic carbon and total nitrogen gains in an old growth deciduous forest in Germany.

    PubMed

    Schrumpf, Marion; Kaiser, Klaus; Schulze, Ernst-Detlef

    2014-01-01

    Temperate forests are assumed to be organic carbon (OC) sinks, either because of biomass increases upon elevated CO2 in the atmosphere and large nitrogen deposition, or due to their age structure. Respective changes in soil OC and total nitrogen (TN) storage have rarely been proven. We analysed OC, TN, and bulk densities of 100 soil cores sampled along a regular grid in an old-growth deciduous forest at the Hainich National Park, Germany, in 2004 and again in 2009. Concentrations of OC and TN increased significantly from 2004 to 2009, mostly in the upper 0-20 cm of the mineral soil. Changes in the fine earth masses per soil volume impeded the detection of OC changes based on fixed soil volumes. When calculated on average fine earth masses, OC stocks increased by 323 ± 146 g m(-2) and TN stocks by 39 ± 10 g m(-2) at 0-20 cm soil depth from 2004 to 2009, giving average annual accumulation rates of 65 ± 29 g OC m(-2) yr(-1) and 7.8 ± 2 g N m(-2) yr(-1). Accumulation rates were largest in the upper part of the B horizon. Regional increases in forest biomass, either due to recovery of forest biomass from previous forest management or to fertilization by elevated CO2 and N deposition, are likely causes for the gains in soil OC and TN. As TN increased stronger (1.3% yr(-1) of existing stocks) than OC (0.9% yr(-1)), the OC-to-TN ratios declined significantly. Results of regression analyses between changes in OC and TN stocks suggest that at no change in OC, still 3.8 g TN m(-2) yr(-1) accumulated. Potential causes for the increase in TN in excess to OC are fixation of inorganic N by the clay-rich soil or changes in microbial communities. The increase in soil OC corresponded on average to 6-13% of the estimated increase in net biome productivity. PMID:24586720

  11. Soil organic matter composition and quality across fire severity gradients in coniferous and deciduous forests of the southern boreal region

    NASA Astrophysics Data System (ADS)

    Miesel, Jessica R.; Hockaday, William C.; Kolka, Randall K.; Townsend, Philip A.

    2015-06-01

    Recent patterns of prolonged regional drought in southern boreal forests of the Great Lakes region, USA, suggest that the ecological effects of disturbance by wildfire may become increasingly severe. Losses of forest soil organic matter (SOM) during fire can limit soil nutrient availability and forest regeneration. These processes are also influenced by the composition of postfire SOM. We sampled the forest floor layer (i.e., full organic horizon) and 0-10 cm mineral soil from stands dominated by coniferous (Pinus banksiana Lamb.) or deciduous (Populus tremuloides Michx.) species 1-2 months after the 2011 Pagami Creek wildfire in northern Minnesota. We used solid-state 13C NMR to characterize SOM composition across a gradient of fire severity in both forest cover types. SOM composition was affected by fire, even when no statistically significant losses of total C stocks were evident. The most pronounced differences in SOM composition between burned and unburned reference areas occurred in the forest floor for both cover types. Carbohydrate stocks in forest floor and mineral horizons decreased with severity level in both cover types, whereas pyrogenic C stocks increased with severity in the coniferous forest floor and decreased in only the highest severity level in the deciduous forest floor. Loss of carbohydrate and lignin pools contributed to a decreased SOM stability index and increased decomposition index. Our results suggest that increases in fire severity expected to occur under future climate scenarios may lead to changes in SOM composition and dynamics with consequences for postfire forest recovery and C uptake.

  12. Microhabitat of small mammals at ground and understorey levels in a deciduous, southern Atlantic forest.

    PubMed

    Melo, Geruza L; Miotto, Barbara; Peres, Brisa; Cáceres, Nilton C

    2013-01-01

    Each animal species selects specific microhabitats for protection, foraging, or micro-climate. To understand the distribution patterns of small mammals on the ground and in the understorey, we investigated the use of microhabitats by small mammals in a deciduous forest of southern Brazil. Ten trap stations with seven capture points were used to sample the following microhabitats: liana, fallen log, ground litter, terrestrial ferns, simple-trunk tree, forked tree, and Piper sp. shrubs. Seven field phases were conducted, each for eight consecutive days, from September 2006 through January 2008. Four species of rodents (Akodon montensis, Sooretamys angouya, Oligoryzomys nigripes and Mus musculus) and two species of marsupials (Didelphis albiventris and Gracilinanus microtarsus) were captured. Captured species presented significant differences on their microhabitat use (ANOVA, p = 0.003), particularly between ground and understorey sites. Akodon montensis selected positively terrestrial ferns and trunks, S. angouya selected lianas, D. albiventris selected fallen trunks and Piper sp., and G. microtarsus choose tree trunks and lianas. We demonstrated that the local small-mammal assemblage does select microhabitats, with different types of associations between species and habitats. Besides, there is a strong evidence of habitat selection in order to diminish predation. PMID:23828340

  13. HO x budgets in a deciduous forest: Results from the PROPHET summer 1998 campaign

    NASA Astrophysics Data System (ADS)

    Tan, D.; Faloona, I.; Simpas, J. B.; Brune, W.; Shepson, P. B.; Couch, T. L.; Sumner, A. L.; Carroll, M. A.; Thornberry, T.; Apel, E.; Riemer, D.; Stockwell, W.

    2001-10-01

    Results from a tightly constrained photochemical point model for OH and HO2 are compared to OH and HO2 data collected during the Program for Research on Oxidants: Photochemistry, Emissions, and Transport (PROPHET) summer 1998 intensive campaign held in northern Michigan. The PROPHET campaign was located in a deciduous forest marked by relatively low NOx levels and high isoprene emissions. Detailed HOx budgets are presented. The model is generally unable to match the measured OH, with the observations 2.7 times greater than the model on average. The model HO2, however, is in good agreement with the measured HO2. Even with an additional postulated OH source from the ozonolysis of unmeasured terpenes, the measured OH is 1.5 times greater than the model; the model HO2 with this added source is 15% to 30% higher than the measured HO2. Moreover, the HO2/OH ratios as modeled are 2.5 to 4 times higher than the measured ratios, indicating that the cycling between OH and HO2 is poorly described by the model. We discuss possible reasons for the discrepancies.

  14. Habitat selection by owls in a seasonal semi-deciduous forest in southern Brazil.

    PubMed

    Menq, W; Anjos, L

    2015-11-01

    This paper tested the hypothesis that the structural components of vegetation have impact over the distribution of owl species in a fragment of a semi-deciduous seasonal forest. This paper also determined which vegetation variables contributed to the spatial distribution of owl species. It was developed in the Perobas Biological Reserve (PBR) between September and December 2011. To conduct the owl census, a playback technique was applied at hearing points distributed to cover different vegetation types in the study area. A total of 56 individual owls of six species were recorded: Tropical Screech-Owl (Megascops choliba), Black-capped Screech-Owl (Megascops atricapilla), Tawny-browed Owl (Pulsatrix koeniswaldiana), Ferruginous Pygmy-Owl (Glaucidium brasilianum), Mottled Owl (Strix virgata) and Stygian Owl (Asio stygius). The results suggest that the variables of vegetation structure have impact on the occurrence of owls. The canopy height, the presence of hollow trees, fallen trees and glades are the most important structural components influencing owl distribution in the sampled area. PMID:26602354

  15. Fine-root production dominates response of a deciduous forest to atmospheric CO2 enrichment

    PubMed Central

    Norby, Richard J.; Ledford, Joanne; Reilly, Carolyn D.; Miller, Nicole E.; O'Neill, Elizabeth G.

    2004-01-01

    Fine-root production and turnover are important regulators of the biogeochemical cycles of ecosystems and key components of their response to global change. We present a nearly continuous 6-year record of fine-root production and mortality from minirhizotron analysis of a closed-canopy, deciduous sweetgum forest in a free-air CO2 enrichment experiment. Annual production of fine roots was more than doubled in plots with 550 ppm CO2 compared with plots in ambient air. This response was the primary component of the sustained 22% increase in net primary productivity. Annual fine-root mortality matched annual production, and the mean residence time of roots was not altered by elevated CO2, but peak fine-root standing crop in midsummer was significantly higher in CO2-enriched plots, especially deeper in the soil profile. The preferential allocation of additional carbon to fine roots, which have a fast turnover rate in this species, rather than to stemwood reduces the possibility of long-term enhancement by elevated CO2 of carbon sequestration in biomass. However, sequestration of some of the fine-root carbon in soil pools is not precluded, and there may be other benefits to the tree from a seasonally larger and deeper fine-root system. Root-system dynamics can explain differences among ecosystems in their response to elevated atmospheric CO2; hence, accurate assessments of carbon flux and storage in forests in a globally changing atmosphere must account for this unseen and difficult-to-measure component. PMID:15210962

  16. Soil processes drive seasonal variation in retention of 15N tracers in a deciduous forest catchment.

    PubMed

    Goodale, Christine L; Fredriksen, Guinevere; Weiss, Marissa S; McCalley, K; Sparks, Jed P; Thomas, Steven A

    2015-10-01

    Seasonal patterns of stream nitrate concentration have long been interpreted as demonstrating the central role of plant uptake in regulating stream nitrogen loss from forested catchments. Soil processes are rarely considered as important drivers of these patterns. We examined seasonal variation in N retention in a deciduous forest using three whole-ecosystem 15N tracer additions: in late April (post-snowmelt, pre-leaf-out), late July (mid-growing- season), and late October (end of leaf-fall). We expected that plant 15N uptake would peak in late spring and midsummer, that immobilization in surface litter and soil would peak the following autumn leaf-fall, and that leaching losses would vary inversely with 15N retention. Similar to most other 15N tracer studies, we found that litter and soils dominated ecosystem retention of added 15N. However, 15N recovery in detrital pools varied tremendously by season, with > 90% retention in spring and autumn and sharply reduced 15N retention in late summer. During spring, over half of the 15N retained in soil occurred within one day in the heavy (mineral-associated) soil fraction. During summer, a large decrease in 15N retention one week after addition coincided with increased losses of 15NO3- to soil leachate and seasonal increases in soil and stream NO3- concentrations, although leaching accounted for only a small fraction of the lost 15N (< 0.2%). Uptake of 15N into roots did not vary by season and accounted for < 4% of each tracer addition. Denitrification or other processes that lead to N gas loss may have consumed the rest. These measurements of 15N movement provide strong evidence for the dominant role of soil processes in regulating seasonal N retention and losses in this catchment and perhaps others with similar soils. PMID:26649387

  17. Probing the past 30 year phenology trend of US deciduous forests

    NASA Astrophysics Data System (ADS)

    Yue, X.; Unger, N.; Keenan, T. F.; Zhang, X.; Vogel, C. S.

    2015-04-01

    Phenology is experiencing dramatic changes over deciduous forests in the US. Estimates of trends in phenology on the continental scale are uncertain, however, with studies failing to agree on both the magnitude and spatial distribution of trends in spring and autumn. This is due to the sparsity of in situ records, uncertainties associated with remote sensing data, and the regional focus of many studies. It has been suggested that reported trends are a result of recent temperature changes, though multiple processes are thought to be involved and the nature of the temperature forcing remains unknown. To date, no study has directly attributed long-term phenological trends to individual forcings across the US through integrating observations with models. Here, we construct an extensive database of ground measurements of phenological events across the US, and use it to calibrate and evaluate a suite of phenology models. The models use variations of the accumulative temperature summation, with additional chilling requirements for spring phenology and photoperiod limitation for autumn. Including a chilling requirement or photoperiod limitation does not improve model performance, suggesting that temperature change, especially in spring and autumn, is the dominant driver of the observed trend during the past 3 decades. Our results show that phenological trends are not uniform over the contiguous US, with a significant advance of 0.34 day yr-1 for the spring budburst in the East, a delay of 0.15 day yr-1 for the autumn dormancy onset in the Northeast and West, but no evidence of change elsewhere. Relative to the 1980s, the growing season in the 2000s is extended by about 1 week (3-4%) in the East, New England, and the upper Rocky Mountains forests. These results help reconcile conflicting reports of phenological trends in the literature, and directly attribute observed trends to long-term changes in temperature.

  18. Probing the past 30-year phenology trend of US deciduous forests

    NASA Astrophysics Data System (ADS)

    Yue, X.; Unger, N.; Keenan, T. F.; Zhang, X.; Vogel, C. S.

    2015-08-01

    Phenology is experiencing dramatic changes over deciduous forests in the USA. Estimates of trends in phenology on the continental scale are uncertain, however, with studies failing to agree on both the magnitude and spatial distribution of trends in spring and autumn. This is due to the sparsity of in situ records, uncertainties associated with remote sensing data, and the regional focus of many studies. It has been suggested that reported trends are a result of recent temperature changes, though multiple processes are thought to be involved and the nature of the temperature forcing remains unknown. To date, no study has directly attributed long-term phenological trends to individual forcings across the USA through integrating observations with models. Here, we construct an extensive database of ground measurements of phenological events across the USA, and use it to calibrate and evaluate a suite of phenology models. The models use variations of the accumulative temperature summation, with additional chilling requirements for spring phenology and photoperiod limitation for autumn. Including a chilling requirement or photoperiod limitation does not improve model performance, suggesting that temperature change, especially in spring and autumn, is likely the dominant driver of the observed trend during the past 3 decades. Our results show that phenological trends are not uniform over the contiguous USA, with a significant advance of 0.34 day yr-1 for the spring budburst in the east, a delay of 0.15 day yr-1 for the autumn dormancy onset in the northeast and west, but no evidence of change elsewhere. Relative to the 1980s, the growing season in the 2000s is extended by about 1 week (3-4 %) in the east, New England, and the upper Rocky Mountains forests. Additional sensitivity tests show that intraspecific variations may not influence the predicted phenological trends. These results help reconcile conflicting reports of phenological trends in the literature, and

  19. Temperature-independent diel variation in soil respiration observed from a temperate deciduous forest

    SciTech Connect

    Post, Wilfred M; Liu, Qing; Edwards, Nelson T; Gu, Lianhong; Childs, Joanne; Lenhart, Suzanne M

    2006-01-01

    The response of soil respiration (Rs) to temperature depends largely on the temporal and spatial scales of interest and how other environmental factors interact with this response. They are often represented by empirical exponential equations in many ecosystem analyses because of the difficulties in separating covarying environmental responses and in observing below ground processes. The objective of this study was to quantify a soil temperature-independent component in Rs by examining the diel variation of an Rs time series measured in a temperate deciduous forest located at Oak Ridge, TN, USA between March and December 2003. By fitting 2 hourly, continuous automatic chamber measurements of CO2 efflux at the soil surface to a Q10 function to obtain the temperature-dependent respiration (Rt) and plotting the diel cycles of Rt, Rs, and their difference (Ri), we found that an obvious temperature-independent component exists in Rs during the growing season. The diel cycle of this component has a distinct day/night pattern and agrees well with diel variations in photosynthetically active radiation (PAR) and air temperature. Elevated canopy CO2 concentration resulted in similar patterns in the diel cycle of the temperature-independent component but with different daily average rates in different stages of growing season. We speculate that photosynthesis of the stand is one of the main contributors to this temperature-independent respiration component although more experiments are needed to draw a firm conclusion. We also found that despite its relatively small magnitude compared with the temperature-dependent component, the diel variation in the temperature-independent component can lead to significantly different estimates of the temperature sensitivity of soil respiration in the study forest. As a result, the common practice of using fitted temperature-dependent function from night-time measurements to extrapolate soil respiration during the daytime may underestimate

  20. Fine-root production dominates response of a deciduous forest to atmospheric CO2 enrichment.

    PubMed

    Norby, Richard J; Ledford, Joanne; Reilly, Carolyn D; Miller, Nicole E; O'Neill, Elizabeth G

    2004-06-29

    Fine-root production and turnover are important regulators of the biogeochemical cycles of ecosystems and key components of their response to global change. We present a nearly continuous 6-year record of fine-root production and mortality from minirhizotron analysis of a closed-canopy, deciduous sweetgum forest in a free-air CO(2) enrichment experiment. Annual production of fine roots was more than doubled in plots with 550 ppm CO(2) compared with plots in ambient air. This response was the primary component of the sustained 22% increase in net primary productivity. Annual fine-root mortality matched annual production, and the mean residence time of roots was not altered by elevated CO(2), but peak fine-root standing crop in midsummer was significantly higher in CO(2)-enriched plots, especially deeper in the soil profile. The preferential allocation of additional carbon to fine roots, which have a fast turnover rate in this species, rather than to stemwood reduces the possibility of long-term enhancement by elevated CO(2) of carbon sequestration in biomass. However, sequestration of some of the fine-root carbon in soil pools is not precluded, and there may be other benefits to the tree from a seasonally larger and deeper fine-root system. Root-system dynamics can explain differences among ecosystems in their response to elevated atmospheric CO(2); hence, accurate assessments of carbon flux and storage in forests in a globally changing atmosphere must account for this unseen and difficult-to-measure component. PMID:15210962

  1. Radio-cesium accumulation during decomposition of leaf litter in a deciduous forest after the Fukushima NPP accident.

    NASA Astrophysics Data System (ADS)

    Kaneko, Nobuhiro; Huang, Yao; Nakamori, Taizo; Tanaka, Yoichiro; Nonaka, Masanori

    2013-04-01

    Fukusima NPP accident contaminated vast area in eastern Japan with radio isotopes. Most of the area is covered by natural and plantation forest. The forest floor in deciduous forests, and canopy of evergreen forest were most contaminated by fall out. Radio-cesium is known to stay bioavailable in forest ecosystems for long time, and it is necessary to cut the cycling process to decontaminate the forest ecosystem. Ecological process to recycle radio-Cs in forest ecosystem should be studied to enhance decontamination of radio-Cs. Mushrooms show high concentration of Cs. Although mushroom biomass in a forest ecosystem is small, fungal mycelium in detritus and soil is large, thus fungi contain substantial amount of radio-Cs. It is well known that concentration of some nutrients, such as nitrogen and phosphorus, increase, whereas potassium decreases during the leaf litter decomposition. We observed radio-Cs concentration of leaf litter during decomposition on a forest floor where 134-Cs and 137-Cs of surface soil were 5,700, and 6,800 Bq/kg, respectively. We put 16 g (dry weight) of newly fallen mixed deciduous leaf litter (half of which was oak, Quercus serrata) into 25 cm x 25 cm litter bag (2 mm mesh size) in a deciduous forest about 50 km from Fukushima NPP. Fresh litter 137-Cs concentration was ca. 1,000 Bq/kg in December 2011. During the decomposition process on the forest floor, litter Cs increased exponentially and exceeded 10,000 Bq/kg after 6 months, indicating that Cs and K show contrasting dynamics during early decomposition phase. Increase in fungal biomass in the early stage of litter decomposition was observed. Therefore, this upward movement of Cs from humus and soil layer suggests fungal translocation of nutrients from outside of litter substrate. Retrieving the litter after 6 months can remove 18.0% of 134-Cs. Interaction between fungal species, grazing effect on fungi by fungivorous invertebrates will change the amount of translocation of radio-Cs from

  2. Sapling herbivory, invertebrate herbivores and predators across a natural tree diversity gradient in Germany's largest connected deciduous forest.

    PubMed

    Sobek, Stephanie; Scherber, Christoph; Steffan-Dewenter, Ingolf; Tscharntke, Teja

    2009-05-01

    Tree species-rich forests are hypothesised to be less susceptible to insect herbivores, but so far herbivory-diversity relationships have rarely been tested for tree saplings, and no such study has been published for deciduous forests in Central Europe. We expected that diverse tree communities reduce the probability of detection of host plants and increase abundance of predators, thereby reducing herbivory. We examined levels of herbivory suffered by beech (Fagus sylvatica L.) and maple saplings (Acer pseudoplatanus L. and Acer platanoides L.) across a tree species diversity gradient within Germany's largest remaining deciduous forest area, and investigated whether simple beech or mixed stands were less prone to damage caused by herbivorous insects. Leaf area loss and the frequency of galls and mines were recorded for 1,040 saplings (>13,000 leaves) in June and August 2006. In addition, relative abundance of predators was assessed to test for potential top-down control. Leaf area loss was generally higher in the two species of maple compared to beech saplings, while only beech showed a decline in damage caused by leaf-chewing herbivores across the tree diversity gradient. No significant patterns were found for galls and mines. Relative abundance of predators on beech showed a seasonal response and increased on species-rich plots in June, suggesting higher biological control. We conclude that, in temperate deciduous forests, herbivory-tree diversity relationships are significant, but are tree species-dependent with bottom-up and top-down control as possible mechanisms. In contrast to maple, beech profits from growing in a neighbourhood of higher tree richness, which implies that species identity effects may be of greater importance than tree diversity effects per se. Hence, herbivory on beech appeared to be mediated bottom-up by resource concentration in the sampled forest stands, as well as regulated top-down through biocontrol by natural enemies. PMID:19238448

  3. More than Drought: Precipitation Variance, Excessive Wetness, Pathogens and the Future of the Western Edge of the Eastern Deciduous Forest.

    PubMed

    Hubbart, Jason A; Guyette, Richard; Muzika, Rose-Marie

    2016-10-01

    For many regions of the Earth, anthropogenic climate change is expected to result in increasingly divergent climate extremes. However, little is known about how increasing climate variance may affect ecosystem productivity. Forest ecosystems may be particularly susceptible to this problem considering the complex organizational structure of specialized species niche adaptations. Forest decline is often attributable to multiple stressors including prolonged heat, wildfire and insect outbreaks. These disturbances, often categorized as megadisturbances, can push temperate forests beyond sustainability thresholds. Absent from much of the contemporary forest health literature, however, is the discussion of excessive precipitation that may affect other disturbances synergistically or that might represent a principal stressor. Here, specific points of evidence are provided including historic climatology, variance predictions from global change modeling, Midwestern paleo climate data, local climate influences on net ecosystem exchange and productivity, and pathogen influences on oak mortality. Data sources reveal potential trends, deserving further investigation, indicating that the western edge of the Eastern Deciduous forest may be impacted by ongoing increased precipitation, precipitation variance and excessive wetness. Data presented, in conjunction with recent regional forest health concerns, suggest that climate variance including drought and excessive wetness should be equally considered for forest ecosystem resilience against increasingly dynamic climate. This communication serves as an alert to the need for studies on potential impacts of increasing climate variance and excessive wetness in forest ecosystem health and productivity in the Midwest US and similar forest ecosystems globally. PMID:27232973

  4. Diurnal resting in brown lemurs in a dry deciduous forest, northwestern Madagascar: implications for seasonal thermoregulation.

    PubMed

    Sato, Hiroki

    2012-07-01

    Decreased activity has been reported in both nocturnal and diurnal primates during the prolonged dry season in western Madagascar, and this has been interpreted as a reaction to the severe environment, with its food scarcity and/or thermal stress. Several day-active lemurs rest more as trees defoliate, although the reason for this is unclear. To understand the mechanism underpinning the diurnal resting of lemurs in seasonal deciduous forests, I observed common brown lemurs (Eulemur fulvus fulvus) for one year in Ankarafantsika National Park, northwestern Madagascar. In Ankarafantsika, despite high fruit availability during the dry season, brown lemurs are known to engage in diurnal resting. To examine the effects of thermal factors and defoliation on lemur inactivity, I recorded the activity of a troop at 1 min intervals, hourly ambient temperature, daily rainfall, and weather during observations (06:00-18:00). I quantified the amount of leaves biweekly for 680 trees. I tested correlations between percentages of resting time and each factor across hours during the day and across seasons. During the rainy season, resting time did not differ between sunny and cloudy days, and lemurs were active throughout the daytime. At the hourly level during the dry season, lemurs rested exclusively at midday, apparently at peak sunlight intensity rather than at peak ambient temperature. At seasonal level, percentages of total resting time from 08:00 to 16:00 were greater during dry season (81.9%) than during rainy season (62.6%), and percentages increased as ambient temperatures increased. Defoliation was related to seasonal decrease in weekly rainfall, which served as an index of water retained in the forest. Defoliation probably reflected aridification as well as the penetration of sunlight into the forest. Diurnal resting increased as both the amount of leaves and weekly rainfall decreased seasonally. These results suggest that heat stress under dry conditions may promote

  5. Leaf dynamics of a deciduous forest canopy: no response to elevated CO2.

    PubMed

    Norby, Richard J; Sholtis, Johnna D; Gunderson, Carla A; Jawdy, Sara S

    2003-08-01

    Leaf area index (LAI) and its seasonal dynamics are key determinants of terrestrial productivity and, therefore, of the response of ecosystems to a rising atmospheric CO(2) concentration. Despite the central importance of LAI, there is very little evidence from which to assess how forest LAI will respond to increasing [CO(2)]. We assessed LAI and related leaf indices of a closed-canopy deciduous forest for 4 years in 25-m-diameter plots that were exposed to ambient or elevated CO(2) (542 ppm) in a free-air CO(2) enrichment (FACE) experiment. LAI of this Liquidambar styraciflua (sweetgum) stand was about 6 and was relatively constant year-to-year, including the 2 years prior to the onset of CO(2) treatment. LAI throughout the 1999-2002 growing seasons was assessed through a combination of data on photosynthetically active radiation (PAR) transmittance, mass of litter collected in traps, and leaf mass per unit area (LMA). There was no effect of [CO(2)] on any expression of leaf area, including peak LAI, average LAI, or leaf area duration. Canopy mass and LMA, however, were significantly increased by CO(2) enrichment. The hypothesized connection between light compensation point (LCP) and LAI was rejected because LCP was reduced by [CO(2)] enrichment only in leaves under full sun, but not in shaded leaves. Data on PAR interception also permitted calculation of absorbed PAR (APAR) and light use efficiency (LUE), which are key parameters connecting satellite assessments of terrestrial productivity with ecosystem models of future productivity. There was no effect of [CO(2)] on APAR, and the observed increase in net primary productivity in elevated [CO(2)] was ascribed to an increase in LUE, which ranged from 1.4 to 2.4 g MJ(-1). The current evidence seems convincing that LAI of non-expanding forest stands will not be different in a future CO(2)-enriched atmosphere and that increases in LUE and productivity in elevated [CO(2)] are driven primarily by functional responses

  6. Nitrogen Limitation is Reducing the Enhancement of NPP by Elevated CO2 in a Deciduous Forest

    SciTech Connect

    Norby, Richard J; Warren, Jeffrey; Iversen, Colleen M; Medlyn, Belinda; McMurtrie, Ross; Hoffman, Forrest M

    2008-01-01

    Accurate model representation of the long-term response of forested ecosystems to elevated atmospheric CO2 concentrations (eCO2) is important for predictions of future concentrations of CO2. For biogeochemical models that predict the response of net primary productivity (NPP) to eCO2, free-air CO2 enrichment (FACE) experiments provide the only source of data for comparison. A synthesis of forest FACE experiments reported a 23% increase in NPP in eCO2, and this result has been used as a model benchmark. Here, we provide new evidence from a FACE experiment in a deciduous forest in Tennessee that N limitation has significantly reduced the stimulation of NPP by eCO2, consistent with predictions from ecosystem and global models that incorporate N feedbacks. The Liquidambar styraciflua stand has been exposed to current ambient atmospheric CO2 or air enriched with CO2 to 550 ppm since 1998. Results from the first 6 years of the experiment indicated that NPP was significantly enhanced by eCO2 and that this was a consistent and sustained response. Now, with 10 years of data, our analysis must be revised. The response of NPP to eCO2 has declined from 24% in 2001-2003 to 9% in 2007. The diminishing response to eCO2 since 2004 coincides with declining NPP in ambient CO2 plots. Productivity of this forest stand is limited by N availability, and the steady decline in forest NPP is closely related to changes in the N economy, as evidenced by declining foliar N concentrations. There is a strong linear relationship between foliar [N] and NPP, and the steeper slope in eCO2 indicates that the NPP response to eCO2 should diminish as foliar N declines. Increased fine-root production and root proliferation deeper in the soil have sustained N uptake, but not to an extent sufficient to benefit aboveground production. The mechanistic basis of the N effect on NPP resides in the photosynthetic machinery. The linear relationships between Jmax and Vcmax with foliar [N] did not change from 1998

  7. Nitrogen Limitation is Reducing the Enhancement of NPP by Elevated CO2 in a Deciduous Forest

    NASA Astrophysics Data System (ADS)

    Norby, R. J.; Warren, J. M.; Iversen, C. M.; Medlyn, B. E.; McMurtrie, R. E.; Hoffman, F. M.

    2008-12-01

    Accurate model representation of the long-term response of forested ecosystems to elevated atmospheric CO2 concentrations (eCO2) is important for predictions of future concentrations of CO2. For biogeochemical models that predict the response of net primary productivity (NPP) to eCO2, free-air CO2 enrichment (FACE) experiments provide the only source of data for comparison. A synthesis of forest FACE experiments reported a 23% increase in NPP in eCO2, and this result has been used as a model benchmark. Here, we provide new evidence from a FACE experiment in a deciduous forest in Tennessee that N limitation has significantly reduced the stimulation of NPP by eCO2, consistent with predictions from ecosystem and global models that incorporate N feedbacks. The Liquidambar styraciflua stand has been exposed to current ambient atmospheric CO2 or air enriched with CO2 to 550 ppm since 1998. Results from the first 6 years of the experiment indicated that NPP was significantly enhanced by eCO2 and that this was a consistent and sustained response. Now, with 10 years of data, our analysis must be revised. The response of NPP to eCO2 has declined from 24% in 2001-2003 to 9% in 2007. The diminishing response to eCO2 since 2004 coincides with declining NPP in ambient CO2 plots. Productivity of this forest stand is limited by N availability, and the steady decline in forest NPP is closely related to changes in the N economy, as evidenced by declining foliar N concentrations. There is a strong linear relationship between foliar [N] and NPP, and the steeper slope in eCO2 indicates that the NPP response to eCO2 should diminish as foliar N declines. Increased fine-root production and root proliferation deeper in the soil have sustained N uptake, but not to an extent sufficient to benefit aboveground production. The mechanistic basis of the N effect on NPP resides in the photosynthetic machinery. The linear relationships between Jmax and Vcmax with foliar [N] did not change from 1998

  8. Changes in carbon isotope ratios of soil organic matter following conversion of tropical deciduous forest to pasture

    SciTech Connect

    Garcia-Oliva, F.; Maass, J.M. ); Casar, I. )

    1993-06-01

    Near the Chamela Biological Station in Jalisco Mexico, tropical deciduous forest was cut, burned and planted with C, grasses for conversion to cattle pastures by local farmers. We estimated soil organic matter (SOM) turnover under intact forest and in a pasture chronosequence (1, 3, 7, and 11 years old). Total SOM in the surface soil under intact forest was 30,098 kg ha[sup [minus]1] (0-12 cm depth) with more than 50% in the uppermost 4 cm. Total SOM increased by 18% following cutting and burning, but exhibited a net decrease of 19% in the 11 year old pasture. Carbon ratios were determined by mass spectrometry; the dominant forest trees are C[sub 3], and the [delta][sup 13]C of forest huer was [minus]27.4, while the [delta][sup 13]C of pasture litter was [minus]15.9. The [delta][sup 13]C signatures of the 7 and 11 year old pastures were significantly different than the forest (p < 0.0001, R[sup 2]=0.77) and in the 11 year old pasture, only 54% of the original forest SOM remained. The estimated turnover rate for forest SOM following clearing was 1.024 kg ha[sup [minus]1] yr[sup [minus]1] and interestingly, the SOM associated with the sand fraction displays a turnover rate considerably higher than that associated with the silt or clay fractions.

  9. Effects of seasonal variation of photosynthetic capacity on the carbon fluxes of a temperate deciduous forest

    NASA Astrophysics Data System (ADS)

    Medvigy, David; Jeong, Su-Jong; Clark, Kenneth L.; Skowronski, Nicholas S.; Schäfer, Karina V. R.

    2013-12-01

    Seasonal variation in photosynthetic capacity is an important part of the overall seasonal variability of temperate deciduous forests. However, it has only recently been introduced in a few terrestrial biosphere models, and many models still do not include it. The biases that result from this omission are not well understood. In this study, we use the Ecosystem Demography 2 model to simulate an oak-dominated stand in the New Jersey Pine Barrens. Two alternative model configurations are presented, one with seasonal variation of photosynthetic capacity (SPC-ON) and one without seasonal variation of photosynthetic capacity (SPC-OFF). Under typical climate conditions, the two configurations simulate values of monthly gross primary productivity (GPP) as different as 0.05 kg C m-2 month-1 in the early summer and 0.04 kg C m-2 month-1 in the fall. The differences between SPC-ON and SPC-OFF are amplified when there is temporal correlation between photosynthetic capacity and climate anomalies or disturbances. Warmer spring temperatures enhance GPP in SPC-ON more than in SPC-OFF, but warmer fall temperatures enhance GPP in SPC-OFF more than in SPC-ON. Defoliation by gypsy moth, a class of disturbance that typically happens in late spring in the New Jersey Pine Barrens, has a disproportionately negative impact on GPP in SPC-ON. It is concluded that including seasonal variation of photosynthetic capacity in models will improve simulations of monthly scale ecosystem functioning as well as of longer-term responses to climate change and disturbances.

  10. Carbon Sequestration of Caesalpinia platyloba S. Watt (Leguminosae) (Lott 1985) in the Tropical Deciduous Forest

    PubMed Central

    Diaz-Gustavo, Norma; Martínez-Salvador, Martín; García-Hernández, José Luís; Norzagaray-Campos, Mariano; Luna-González, Antonio; González-Ocampo, Héctor Abelardo

    2015-01-01

    Caesalpinia platyloba was evaluated as an alternative for the retention of atmospheric carbon and as a feasible and viable economic activity in terms of income for tropical deciduous forest (TDF) peasants in the carbon markets. A total of 110 trees of C. platyloba from plantations and a TDF in the Northwest of Mexico were sampled. Growth (increase in height, diameter, and volume curves) was adjusted to assess their growth. Growth of individuals (height, diameter at breast height [DBH], age, and tree crown cover) was recorded. The Schumacher model (H = β0eβ1•E-1), by means of the guided curve method, was used to adjust growth models. Information analysis was made through the non-linear procedure with the multivariate secant or false position (DUD) method using the SAS software. Growth and increase models revealed acceptable adjustments (pseudo R2>0.8). C. platyloba reaches >8m of height with 12cm in diameter and 550cm3 of volume, presenting the highest increase at 11 years considered as basal age. Highest significant density of wood was in good quality sites (0.80g•cm-3), with a carbon content (average of 99.15tC•ha-1) at the highest density of 2500 trees•ha-1 (without thinning). Average incomes of US$483.33tC•ha-1 are expected. The profitability values (NPW = US$81,646.65, IRR = 472%, and B/C = 0.82) for C. platyloba make its cultivation a viable and profitable activity, considering a management scheme of the income derived from wood selling and from carbon credits. PMID:25992905

  11. Leaf litter decomposition in temperate deciduous forest stands with a decreasing fraction of beech (Fagus sylvatica)

    PubMed Central

    Jacob, Mascha; Viedenz, Karin; Polle, Andrea

    2010-01-01

    We hypothesised that the decomposition rates of leaf litter will increase along a gradient of decreasing fraction of the European beech (Fagus sylvatica) and increasing tree species diversity in the generally beech-dominated Central European temperate deciduous forests due to an increase in litter quality. We studied the decomposition of leaf litter including its lignin fraction in monospecific (pure beech) stands and in stands with up to five tree genera (Acer spp., Carpinus betulus, Fagus sylvatica, Fraxinus excelsior, Tilia spp.) using a litterbag approach. Litter and lignin decomposition was more rapid in stand-representative litter from multispecific stands than in litter from pure beech stands. Except for beech litter, the decomposition rates of species-specific tree litter did not differ significantly among the stand types, but were most rapid in Fraxinus excelsior and slowest in beech in an interspecific comparison. Pairwise comparisons of the decomposition of beech litter with litter of the other tree species (except for Acerplatanoides) revealed a “home field advantage” of up to 20% (more rapid litter decomposition in stands with a high fraction of its own species than in stands with a different tree species composition). Decomposition of stand-representative litter mixtures displayed additive characteristics, not significantly more rapid than predicted by the decomposition of litter from the individual tree species. Leaf litter decomposition rates were positively correlated with the initial N and Ca concentrations of the litter, and negatively with the initial C:N, C:P and lignin:N ratios. The results support our hypothesis that the overall decomposition rates are mainly influenced by the chemical composition of the individual litter species. Thus, the fraction of individual tree species in the species composition seems to be more important for the litter decomposition rates than tree species diversity itself. PMID:20596729

  12. Occurrence of culturable soil fungi in a tropical moist deciduous forest Similipal Biosphere Reserve, Odisha, India

    PubMed Central

    Jena, Santanu K.; Tayung, Kumanand; Rath, Chandi C.; Parida, Debraj

    2015-01-01

    Similipal Biosphere Reserve (SBR) is a tropical moist deciduous forest dominated by the species Shorea robusta . To the best of our knowledge their rich biodiversity has not been explored in term of its microbial wealth. In the present investigation, soil samples were collected from ten selected sites inside SBR and studied for their physicochemical parameters and culturable soil fungal diversity. The soil samples were found to be acidic in nature with a pH ranging from of 5.1–6.0. Highest percentage of organic carbon and moisture content were observed in the samples collected from the sites, Chahala-1 and Chahala-2. The plate count revealed that fungal population ranged from 3.6 × 10 4 –2.1 × 10 5 and 5.1 × 10 4 –4.7 × 10 5 cfu/gm of soil in summer and winter seasons respectively. The soil fungus, Aspergillus niger was found to be the most dominant species and Species Important Values Index (SIVI) was 43.4 and 28.6 in summer and winter seasons respectively. Among the sites studied, highest fungal diversity indices were observed during summer in the sites, Natto-2 and Natto-1. The Shannon-Wiener and Simpson indices in these two sites were found to be 3.12 and 3.022 and 0.9425 and 0.9373 respectively. However, the highest Fisher’s alpha was observed during winter in the sites Joranda, Natto-2, Chahala-1 and Natto-1 and the values were 3.780, 3.683, 3.575 and 3.418 respectively. Our investigation revealed that, fungal population was dependent on moisture and organic carbon (%) of the soil but its diversity was found to be regulated by sporulating species like Aspergillus and Penicillium . PMID:26221092

  13. Carbon Sequestration of Caesalpinia platyloba S. Watt (Leguminosae) (Lott 1985) in the Tropical Deciduous Forest.

    PubMed

    Diaz-Gustavo, Norma; Martínez-Salvador, Martín; García-Hernández, José Luís; Norzagaray-Campos, Mariano; Luna-González, Antonio; González-Ocampo, Héctor Abelardo

    2015-01-01

    Caesalpinia platyloba was evaluated as an alternative for the retention of atmospheric carbon and as a feasible and viable economic activity in terms of income for tropical deciduous forest (TDF) peasants in the carbon markets. A total of 110 trees of C. platyloba from plantations and a TDF in the Northwest of Mexico were sampled. Growth (increase in height, diameter, and volume curves) was adjusted to assess their growth. Growth of individuals (height, diameter at breast height [DBH], age, and tree crown cover) was recorded. The Schumacher model (H = β(0)e(β1 • E-1)), by means of the guided curve method, was used to adjust growth models. Information analysis was made through the non-linear procedure with the multivariate secant or false position (DUD) method using the SAS software. Growth and increase models revealed acceptable adjustments (pseudo R(2)>0.8). C. platyloba reaches >8m of height with 12 cm in diameter and 550 cm(3) of volume, presenting the highest increase at 11 years considered as basal age. Highest significant density of wood was in good quality sites (0.80 g • cm(-3)), with a carbon content (average of 99.15tC • ha(-1)) at the highest density of 2500 trees • ha(-1) (without thinning). Average incomes of US$483.33tC • ha(-1) are expected. The profitability values (NPW = US$81,646.65, IRR = 472%, and B/C = 0.82) for C. platyloba make its cultivation a viable and profitable activity, considering a management scheme of the income derived from wood selling and from carbon credits. PMID:25992905

  14. Soil respiration under mature deciduous forest trees after 7 years of CO2 enrichment

    NASA Astrophysics Data System (ADS)

    Bader, Martin; Körner, Christian

    2010-05-01

    The anthropogenic rise in atmospheric CO2 is expected to impact carbon fluxes not only at ecosystem level but also at the global scale by altering carbon cycle processes in soils. At the Swiss Canopy Crane (SCC), we examined how 7 years of free air CO2 enrichment (FACE) affected soil CO2 dynamics in a c. 100-year-old mixed deciduous forest. The use of 13C-depleted CO2 for canopy enrichment allowed us to trace the flow of recently fixed carbon (C). In the seventh year of growth at ~550 ppm CO2, soil respiratory CO2 consisted of 39% labelled C. During the growing season, soil air CO2 concentration was significantly enhanced under CO2-exposed trees. However, elevated CO2 failed to stimulate cumulative soil respiration (Rs) over the growing season. We found periodic reductions as well as increases in instantaneous rates of Rs in response to elevated CO2, depending on soil temperature and soil volumetric water content (VWC; significant 3-way interaction). During wet periods, soil water savings under CO2-enriched trees led to excessive VWC (>45%) that suppressed Rs. Elevated CO2 stimulated Rs only when VWC was ≤40% and concurrent soil temperature was high (>15 °C). Seasonal Q10 estimates of Rs were significantly lower under elevated (Q10 = 3.30) compared to ambient CO2 (Q10 = 3.97). However, this effect disappeared when 3 consecutive sampling dates of extremely high VWC were disregarded. This suggests that elevated CO2 affected Q10 mainly indirectly through changes in VWC. Fine root respiration did not differ significantly between treatments but soil microbial biomass (Cmic) increased by 14% under elevated CO2 (marginally significant). Our findings do not indicate enhanced soil C emissions in such stands under future atmospheric CO2. It remains to be shown whether C losses via leaching of dissolved organic or inorganic C (DOC, DIC) help to balance the carbon budget in this forest.

  15. Investigation of soil carbon sequestration processes in a temperate deciduous forest using soil respiration experiments

    NASA Astrophysics Data System (ADS)

    Schütze, Claudia; Marañón-Jiménez, Sara; Zöphel, Hendrik; Gimper, Sebastian; Dienstbach, Laura; Garcia Quirós, Inmaculada; Cuntz, Matthias; Rebmann, Corinna

    2016-04-01

    Considering the carbon cycles of terrestrial ecosystems, soils represent a major long-term carbon storage pool. However, the storage capacity depends on several impact parameters based on biotic factors (e.g. vegetation activity, microbial activity, nutrient availability, interactions between vegetation and microbial activity) and abiotic driving factors (e.g. soil moisture, soil temperature, soil composition). Especially, increases in vegetation and microbial activity can lead to raised soil carbon release detectable as higher soil respiration rates. Within the frame of the ICOS project, several soil respiration experiments are under consideration at the temperate deciduous forest site "Hohes Holz" (Central Germany). These experiments started in May 2014. Soil respiration data acquisition was carried out using 8 automatic continuous chambers (LI-COR) and 60 different plots for bi-weekly survey chamber measurements in order to clarify the controlling factors for soil CO2 emissions such as litter availability, above- and belowground vegetation, and activation of microbial activity with temperature, soil moisture and root occurrence. Hence, several treatments (trenched, non-trenched, litter supply) were investigated on different plots within the research area. The data analysis of the 20-month observation period reveals preliminary results of the study. Obviously, significant differences between the trenched and the non-trenched plots concerning the CO2 emissions occurred. Increased soil carbon releases are supposed to be associated to the activation of microbial mineralization of soil organic matter by root inputs. Furthermore, depending on the amount of litter supply, different levels of activation were observed. The data of the continuous chamber measurements with a temporal resolution of one hour sampling interval can be used to show the dependence on above described biogeochemical processes due to abiotic controlling factors. Especially, soil moisture as a

  16. Radiocesium immobilization to leaf litter by fungi during first-year decomposition in a deciduous forest in Fukushima.

    PubMed

    Huang, Yao; Kaneko, Nobuhiro; Nakamori, Taizo; Miura, Toshiko; Tanaka, Yoichiro; Nonaka, Masanori; Takenaka, Chisato

    2016-02-01

    Vast forest areas in eastern Japan have been contaminated with radio-isotopes by the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident. Radiocesium (radioCs) is known to remain bioavailable in forest ecosystems for a long time, and it is necessary to terminate the cycling process to decontaminate the forest ecosystem. We observed radiocesium concentrations of leaf litter during decomposition on a forest floor where radiocesium ((137)Cs) contamination was ∼155 kBq/m(2). Litter bag experiments were conducted with newly fallen mixed deciduous leaf litter in a deciduous forest (alt. 610 m) about 50 km from the FDNPP. Litter bags were retrieved in April, June, August, October, and December 2012. Fresh litter (137)Cs concentration was ∼3000 Bq/kg in December 2011. During the decomposition process on the forest floor, litter (137)Cs concentration increased rapidly and exceeded 25,000 Bq/kg after 6 months, whereas potassium (K) concentration in the litter was rather stable, indicating that radiocesium and K showed contrasting dynamics during the early decomposition phase. Nitrogen, phosphorus, and (137)Cs contents were positively correlated to fungal biomass, evaluated by phospholipid fatty acids in the litter during decomposition. The increase of radiocesium concentration mainly occurred during from April to October, when fungal growth peaked. Therefore, this suggests fungal translocation of nutrients from outside the litter substrate (immobilization) is the mechanism to increase radiocesium in the decomposing litter. The amount of (137)Cs contained in the 1-year-old decomposed leaf litter was estimated to be 4% per area of the soil-contaminated (137)Cs. PMID:26630038

  17. Soil Carbon Response to Soil Warming and Nitrogen Deposition in a Temperate Deciduous Forest

    NASA Astrophysics Data System (ADS)

    Parton, W. J.; Savage, K. E.; Davidson, E. A.; Trumbore, S.; Frey, S. D.

    2011-12-01

    While estimates of global soil C stocks vary widely, it is clear that soils store several times more C than is present in the atmosphere as CO2, and a significant fraction of soil C stocks are potentially subject to faster rates of decomposition in a warmer world. We address, through field based studies and modeling efforts, whether manipulations of soil temperature and nitrogen supply affect the magnitude and relative age of soil C substrates that are respired from a temperate deciduous forest located at Harvard Forest, MA. A soil warming and nitrogen addition experiment was initiated at the Harvard Forest in 2006. The experiment consists of six replicates of four treatments, control, heated, nitrogen, and heat+nitrogen addition. Soil temperatures in the heated plots are continuously elevated 5 oC above ambient and for the fertilized plots an aqueous solution of NH4NO3 is applied at a rate of 5 g m-2 yr-1. Soil C efflux from these plots was measured (n=24, 6 per treatment) biweekly throughout the year, while 14CO2 was measured (3 samples per treatment) several times during the summer months from 2006-2010. Following treatment, observed rates of annual C efflux increased under heating and nitrogen additions with heating treatments showing the greatest increase in respired C. The difference between control and treatments was greatest during the initial year following treatment; however this difference decreased in the subsequent 3 years of measurement. The plots designated for heating had a higher 14C signature from CO2 efflux prior to the heating (presumably due to spatial heterogeneity). However, because of the high spatial heterogeneity in measured 14C among treatments, no significant difference among treatments was observed from 2006 through 2010. Long term datasets (1995 through 2010) of soil C stocks, radiocarbon content, and CO2 efflux were used to parameterize the ForCent model for Harvard forest. The model was then run with the same treatment parameters as

  18. Inter-annual variations of GPP and NEP above a cool-temperate deciduous forest at Takayama (AsiaFlux) in the last decade

    NASA Astrophysics Data System (ADS)

    Saigusa, N.; Yamamoto, S.; Murayama, S.; Kondo, H.

    2003-12-01

    Broadleaf deciduous forest is one of the major vegetative constituents of the main island of Japan. Natural ecosystem dominated by oak is widespread in Japan, Korean Peninsula, northeastern China, and eastern Mongolia. Studying the environmental controls on gross primary production (GPP) and net ecosystem exchange (NEE) of the ecosystem is, then, one of the main subjects for understanding the carbon cycle of terrestrial ecosystems in eastern Asia. The study site is about 15 km east of Takayama City, in the central part of Japan. Flux of CO2 has been measured since September 1993 by the aerodynamic method using the vertical gradient of CO2 concentration and diffusion coefficient (Yamamoto et al., 1999). Fluxes of sensible heat, water vapor, and CO2 have been measured continuously since July 1998 by the eddy covariance method (Saigusa et al., 2002) using a three-dimensional ultrasonic anemometer and a closed-path infrared gas analyzer. The nighttime NEE was estimated with and without correction, depending on the atmospheric stability. The annual carbon uptake for 1999, 2000, and 2001 were estimated as 198, 309, 290 gC m-2 year-1 with the correction, and 251, 376, and 342 gC m-2 year-1 without the correction, respectively. The nocturnal correction is responsible for the uncertainty in annual NEE in this site of about 52-67 gC m-2 year-1. The NEP has been calculated for almost ten years, and it is the longest record at any particular site in Asia as a result of the flux measurements. The annual NEP was 224 +/- 82 gC m-2 year-1 (mean +/- SD; 1994-2001). A large year-to-year variability of up to 158 gC m-2 year-1 was observed in NEP. The annual NEP was highest in 1998, mainly caused by high CO2 uptake observed during the first half of the growing period. The air temperature was significantly higher in April 1998 than in a usual year. The result in the present study suggests that the increase in CO2 uptake due to a long growing period in 1998 was more remarkable than the

  19. A global assessment of forest surface albedo and its relationships with climate and atmospheric nitrogen deposition.

    PubMed

    Leonardi, Stefano; Magnani, Federico; Nolè, Angelo; Van Noije, Twan; Borghetti, Marco

    2015-01-01

    We present a global assessment of the relationships between the short-wave surface albedo of forests, derived from the MODIS satellite instrument product at 0.5° spatial resolution, with simulated atmospheric nitrogen deposition rates (Ndep ), and climatic variables (mean annual temperature Tm and total annual precipitation P), compiled at the same spatial resolution. The analysis was performed on the following five forest plant functional types (PFTs): evergreen needle-leaf forests (ENF); evergreen broad-leaf forests (EBF); deciduous needle-leaf forests (DNF); deciduous broad-leaf forests (DBF); and mixed-forests (MF). Generalized additive models (GAMs) were applied in the exploratory analysis to assess the functional nature of short-wave surface albedo relations to environmental variables. The analysis showed evident correlations of albedo with environmental predictors when data were pooled across PFTs: Tm and Ndep displayed a positive relationship with forest albedo, while a negative relationship was detected with P. These correlations are primarily due to surface albedo differences between conifer and broad-leaf species, and different species geographical distributions. However, the analysis performed within individual PFTs, strengthened by attempts to select 'pure' pixels in terms of species composition, showed significant correlations with annual precipitation and nitrogen deposition, pointing toward the potential effect of environmental variables on forest surface albedo at the ecosystem level. Overall, our global assessment emphasizes the importance of elucidating the ecological mechanisms that link environmental conditions and forest canopy properties for an improved parameterization of surface albedo in climate models. PMID:25044609

  20. Above-ground sulfur cycling in adjacent coniferous and deciduous forest and watershed sulfur retention in the Georgia Piedmont, U.S.A.

    USGS Publications Warehouse

    Cappellato, R.; Peters, N.E.; Meyers, T.P.

    1998-01-01

    Atmospheric deposition and above-ground cycling of sulfur (S) were evaluated in adjacent deciduous and coniferous forests at the Panola Mountain Research Watershed (PMRW), Georgia U.S.A. Total atmospheric S deposition (wet plus dry) was 12.9 and 12.7 kg ha-1 yr-1 for the deciduous and coniferous forests, respectively, from October 1987 through November 1989. Dry deposition contributes more than 40% to the total atmospheric S deposition, and SO2 is the major source (~55%) of total dry S deposition. Dry deposition to these canopies is similar to regional estimates suggesting that 60-km proximity to emission sources does not noticeably impact dry deposition at PMRW. Below-canopy S fluxes (throughfall plus stemflow) in each forest are 37% higher annually in the deciduous forest than in the coniferous forest. An excess in below-canopy S flux in the deciduous forest is attributed to leaching and higher dry deposition than in the coniferous forest. Total S deposition to the forest floor by throughfall, stemflow and litterfall was 2.4 and 2.8 times higher in the deciduous and coniferous forests, respectively, than annual S growth requirement for foliage and wood. Although A deposition exceeds growth requirement, more than 95% of the total atmospheric S deposition was retained by the watershed in 1988 and 1989. The S retention at PMRW is primarily due to SO2+4 adsorption by iron oxides and hydroxides in watershed soils. The S content in while oak and loblolly pine boles have increased more than 200% in the last 20 yr, possibly reflecting increases in emissions.

  1. Ground-based imaging spectrometry of canopy phenology and chemistry in a deciduous forest

    NASA Astrophysics Data System (ADS)

    Toomey, M. P.; Friedl, M. A.; Frolking, S. E.; Hilker, T.; O'Keefe, J.; Richardson, A. D.

    2013-12-01

    Phenology, annual life cycles of plants and animals, is a dynamic ecosystem attribute and an important feedback to climate change. Vegetation phenology is commonly monitored at canopy to continental scales using ground based digital repeat photography and satellite remote sensing, respectively. Existing systems which provide sufficient temporal resolution for phenological monitoring, however, lack the spectral resolution necessary to investigate the coupling of phenology with canopy chemistry (e.g. chlorophyll, nitrogen, lignin-cellulose content). Some researchers have used narrowband (<10 nm resolution) spectrometers at phenology monitoring sites, yielding new insights into seasonal changes in leaf biochemistry. Such instruments integrate the spectral characteristics of the entire canopy, however, masking considerable variability between species and plant functional types. There is an opportunity, then, for exploring the potential of imaging spectrometers to investigate the coupling of canopy phenology and the leaf biochemistry of individual trees. During the growing season of April-October 2013 we deployed an imaging spectrometer with a spectral range of 371-1042 nm and resolution of ~5 nm (Surface Optics Corporation 710; San Diego, CA) on a 35 m tall tower at the Harvard Forest, Massachusetts. The image resolution was ~0.25 megapixels and the field of view encompassed approximately 20 individual tree crowns at a distance of 20-40 m. The instrument was focused on a mixed hardwoods canopy composed of 4 deciduous tree species and one coniferous tree species. Scanning was performed daily with an acquisition frequency of 30 minutes during daylight hours. Derived imagery were used to calculate a suite of published spectral indices used to estimate foliar content of key pigments: cholorophyll, carotenoids and anthocyanins. Additionally, we calculated the photochemical reflectance index (PRI) as well as the position and slope of the red edge as indicators of mid- to

  2. Effects of acid irrigation on carbon dioxide evolution, extractable nitrogen, phosphorus, and aluminum in a deciduous forest soil

    SciTech Connect

    Johnson, D.W.; Todd, D.E.

    1984-01-01

    A study was initiated to determine the effects of sulfuric and nitric acid irrigation on CO/sub 2/ evolution, and N, P, and Al availability in a deciduous forest soil. Irrigation with H/sub 2/O, H/sub 2/SO/sub 4/, or HNO/sub 3/ at 0.05 mol (p/sup +/) m/sup -2/ and 0.5 mol (p/sup +/) m/sup -2/ for 1 yr had no consistent effect on CO/sub 2/ evolution, soil NH/sub 4//sup +/, extractable P, or extractable Al in a deciduous forest soil under field conditions. Irrigation with HNO/sub 3/ caused temporary increases in soil NO/sub 3//sup -/, but irrigation with H/sub 2/SO/sub 4/ had no effect on soil NO/sub 3//sup -/. Nitrogen mineralization and nitrification by aerobic incubation were also unaffected by treatments. Seasonal variations in CO/sub 2/ evolution, NH/sub 4//sup +/, and extractable P were pronounced, with peaks in CO/sub 2/ evolution, NH/sub 4//sup +/, in June and a peak extractable P in August. 19 references, 2 tables.

  3. Reassessment of the use of fire as a management tool in deciduous forests of eastern North America.

    PubMed

    Matlack, Glenn R

    2013-10-01

    Prescribed burning is increasingly being used in the deciduous forests of eastern North America. Recent work suggests that historical fire frequency has been overestimated east of the prairie-woodland transition zone, and its introduction could potentially reduce forest herb and shrub diversity. Fire-history recreations derived from sedimentary charcoal, tree fire scars, and estimates of Native American burning suggest point-return times ranging from 5-10 years to centuries and millennia. Actual return times were probably longer because such records suffer from selective sampling, small sample sizes, and a probable publication bias toward frequent fire. Archeological evidence shows the environmental effect of fire could be severe in the immediate neighborhood of a Native American village. Population density appears to have been low through most of the Holocene, however, and villages were strongly clustered at a regional scale. Thus, it appears that the majority of forests of the eastern United States were little affected by burning before European settlement. Use of prescribed burning assumes that most forest species are tolerant of fire and that burning will have only a minimal effect on diversity. However, common adaptations such as serotiny, epicormic sprouting, resprouting from rhizomes, and smoke-cued germination are unknown across most of the deciduous region. Experimental studies of burning show vegetation responses similar to other forms of disturbance that remove stems and litter and do not necessarily imply adaptation to fire. The general lack of adaptation could potentially cause a reduction in diversity if burning were introduced. These observations suggest a need for a fine-grained examination of fire history with systematic sampling in which all subregions, landscape positions, and community types are represented. Responses to burning need to be examined in noncommercial and nonwoody species in rigorous manipulative experiments. Until such information

  4. Ecosystem-Atmosphere Exchange of Carbon, Water and Energy over a Mixed Deciduous Forest in the Midwest

    SciTech Connect

    Danilo Dragoni; Hans Peter Schmid; C.S.B. Grimmond; J.C. Randolph; J.R. White

    2012-12-17

    During the project period we continued to conduct long-term (multi-year) measurements, analysis, and modeling of energy and mass exchange in and over a deciduous forest in the Midwestern United States, to enhance the understanding of soil-vegetation-atmosphere exchange of carbon. At the time when this report was prepared, results from nine years of measurements (1998 - 2006) of above canopy CO2 and energy fluxes at the AmeriFlux site in the Morgan-Monroe State Forest, Indiana, USA (see Table 1), were available on the Fluxnet database, and the hourly CO2 fluxes for 2007 are presented here (see Figure 1). The annual sequestration of atmospheric carbon by the forest is determined to be between 240 and 420 g C m-2 a-1 for the first ten years. These estimates are based on eddy covariance measurements above the forest, with a gap-filling scheme based on soil temperature and photosynthetically active radiation. Data gaps result from missing data or measurements that were rejected in qua)lity control (e.g., during calm nights). Complementary measurements of ecological variables (i.e. inventory method), provided an alternative method to quantify net carbon uptake by the forest, partition carbon allocation in each ecosystem components, and reduce uncertainty on annual net ecosystem productivity (NEP). Biometric datasets are available on the Fluxnext database since 1998 (with the exclusion of 2006). Analysis for year 2007 is under completion.

  5. Spatial variation in the (137)Cs inventory in soils in a mixed deciduous forest in Fukushima, Japan.

    PubMed

    Takada, Momo; Yamada, Toshihiro; Takahara, Teruhiko; Okuda, Toshinori

    2016-09-01

    The spatial variation of the radiocesium inventory in forest soil was studied c.a. 44 km northwest of the Fukushima Daiichi Nuclear Power Plant, Japan. This study focuses on the effects of canopy interception and downward transfer from the forest canopy to the forest floor via stemflow and throughfall. We established a study plot (400 m(2)) in the canopy layer of a secondary mixed deciduous forest dominated by Japanese oak (Quercus crispula) and Japanese fir (Abies firma), in August and November 2014. Soil was sampled from 0 to 5 cm depth and (137)Cs was measured under the canopy using a 2-m grid and also at the tree trunk bases. We divided the study plot into the five different types of subplot according to the canopy projection areas and the tree species for the analysis. The geometric mean and coefficient of variation of the (137)Cs inventory were 202 kBq m(-2) and 0.11 (0.52 in the arithmetic coefficient of variation), respectively. Within the forest, the variation in the (137)Cs inventory under trees was larger than in crown gap areas. The large spatial variation may be attributed to canopy interception of the initial deposition and downward transfer of radiocesium via stemflow and throughfall. PMID:27173786

  6. Small mammal abundance and habitat relationships on deciduous forested sites with different susceptibility to gypsy moth defoliation

    NASA Astrophysics Data System (ADS)

    Yahner, Richard H.; Smith, Harvey R.

    1991-01-01

    Small mammals are important predators of gypsy moths ( Lymantria dispar L.), which are major defoliators of deciduous forests in the northeastern United States. Abundance and habitat relationships of small mammals were studied during summers 1984 and 1985 on forested sites at Moshannon and Rothrock state forests in two physiographic regions of Pennsylvania (Allegheny High Plateaus Province and Valley and Ridge Province, respectively) that varied in potential susceptibility to defoliation. The white-footed mouse ( Peromyscus leucopus), which is a major vertebrate predator of gypsy moths, was the most common small mammal on all sites. Of the four common species, northern short-tailed shrews ( Blarina brevicauda), southern red-backed voles ( Clethrionomys gapperi), and white-footed mice were more abundant at Moshannon compared to Rothrock State Forest, but masked shrews ( Sorex cinereus) were more abundant at Rothrock. Elevation was a major factor affecting abundance and distribution of small mammals. Because of the greater abundance of small mammals and more suitable physiographic features at Moshannon compared to Rothrock State Forest, small mammals may be more effective as predators on gypsy moths in the Allegheny High Plateaus than the Valley and Ridge Province of Pennsylvania.

  7. Spatial and Temporal Variation in Feather Moss Associated Nitrogen Fixation in Coniferous and Deciduous Dominated Alaskan Boreal Forests

    NASA Astrophysics Data System (ADS)

    Jean, M.; Mack, M. C.; Johnstone, J. F.

    2015-12-01

    Dominant canopy tree species have strong effects on the composition and function of understory species. In boreal forests, forest floor bryophytes and their associated microbes are a primary source of ecosystem nitrogen (N) inputs, and thus an important process regulating ecosystem productivity. Bryophyte composition and abundance varies with forest composition, yet how such changes can affect ecosystem processes such as N fixation is still poorly understood. Our goal is to investigate how cyanobacteria-based N fixation occurring in the two most common feather mosses in the Alaskan boreal forest (Pleurozium schreberi and Hylocomium splendens) varies among coniferous and deciduous forest types, over the growing season, and across a nutrient availability gradient. Twelve patches of H. splendens and P. schreberi were identified in three pairs (blocks) of adjacent stands of paper birch (Betula neoalaskana) and black spruce (Picea mariana) near Fairbanks, interior Alaska. Sampling occurred in one block in June, July, August, and September 2014, and in the three blocks once in August 2014. Moss leaf area, moisture and weight, as well as environmental variables such as air temperature and canopy cover were recorded. Fixation rates were consistently higher for P. schreberi than for H. splendens. Overall, N fixation rates were lower in birch than in spruce stands and peaked in August, or July for P. schreberi in birch stands. Moreover, fixation rates varied along the nutrient availability gradient, with fixation rates higher where nutrient availability was lower. This difference was especially clear in spruce stands. Our preliminary results suggest that moss species, canopy type, and environmental factors all influence N fixation rates in Alaskan boreal forests. Our results will enhance the knowledge of the processes that drive N fixation in boreal forests, which is important for predicting ecosystem consequences of changing forest composition.

  8. The effects of phenoseason and storm characteristics on throughfall solute washoff and leaching dynamics from a temperate deciduous forest canopy.

    PubMed

    Van Stan, John T; Levia, Delphis F; Inamdar, Shreeram P; Lepori-Bui, Michelle; Mitchell, Myron J

    2012-07-15

    Seasonal variations in the washoff and leaching dynamics of throughfall ionic fluxes represent a significant process affecting the biogeochemical cycling of forested ecosystems-particularly for temperate deciduous forests with distinct phenological seasons (or "phenoseasons"). Most studies on temperate deciduous forests aggregate seasonal throughfall fluxes to the leafed (growing) and leafless (dormant) periods, yet the phenological conditions controlling seasonality demand finer-scale demarcations that include the transitional phenoseasons (leaf senescence and emergence). To fill these gaps our study examines the washoff and leaching dynamics of Na(+), Mg(2+), K(+), Ca(2+), Cl(-), SO(4)(2-), and NO(3)(-) throughfall derived from bulk and sequentially sampled rain events across leafed, leafless and both transitional phenoseasons over a 3-year period (2008-2010). As throughfall washoff and leached solute fluxes are also closely-coupled to rainfall conditions, we further examine the effects of storm characteristics on phenoseasonal washoff-dominated (Na(+) and Cl(-)) and leaching-dominated (K(+), Ca(2+), Mg(2+)) fluxes through intrastorm event comparison plots and factorial MANOVA. Highly significant differences in leached and washoff solute fluxes were found across meteorological conditions (p<0.001) nested within phenoseasonal divisions (p<0.00001). Phenoseasonal washoff Na(+) and Cl(-) fluxes seemed to be more closely related to leaf area; whereas, leaching flux and canopy exchange of all solutes to correspond more with major phenological changes (when the canopies tend to be most metabolically active). The greatest differences in leached Mg(2+), K(+), Ca(2+), and SO(4)(2-) fluxes were not between the full leafed and leafless phenoseasons (33-80% difference), but between the transitional periods (80 to 200 fold greater during leaf senescence than leaf emergence). Intrastorm average canopy NO(3)(-) leaching, however, ranged from low losses (1 μmol(c)m(-2)h(-1)) to

  9. Comparison of throughfall chemistry in a mature hemlock forest and an early-successional deciduous forest resulting from salvage logging in Whately, Massachusetts

    NASA Astrophysics Data System (ADS)

    Zukswert, J. M.; Rhodes, A. L.; Dwyer, C. H.; Sweezy, T.

    2012-12-01

    Removal of foundation species as a result of disturbance events such as exotic species invasions can alter community composition and ecosystem function. The current hemlock woolly adelgid (Adelges tsugae) infestation in eastern North America that threatens the eastern hemlock (Tsuga canadensis), a foundation species, has motivated salvage logging efforts. Ecological succession resulting from salvage logging of hemlock would eventually produce a deciduous hardwood forest. The chemistry of throughfall beneath a mature hemlock forest canopy is expected to be more acidic than throughfall from a mature deciduous forest canopy because hemlock foliage releases more organic acids and fewer base cations. The chemical composition of throughfall during the early successional transition from hemlock to deciduous is less understood. We hypothesize that throughfall chemistry in a deciduous forest consisting primarily of juvenile trees may be more similar to direct precipitation because leaf area index is smaller. Differences between hemlock throughfall and direct precipitation may be larger due to the denser canopy of these mature trees. We compared the chemical composition of precipitation, hemlock throughfall, and black birch throughfall for 26 precipitation events from 4 March to 30 July 2012. The black birch (Betula lenta) forest patch resulted from salvage logging of hemlocks twenty years ago at the MacLeish Field Station in Whately, MA. From the three plots we measured the volume of water collected and pH, acid neutralizing capacity, dissolved organic carbon (DOC), and concentrations of cations (Ca2+, K+, Na+, Mg2+, NH4+), anions (Cl-, NO3-, SO42-), and dissolved silica. Precipitation totaled 405 mm during the course of the study. Throughfall totaled 347 mm in the black birch plot and 315 mm in the hemlock plot. The proportion of precipitation passing through the forest canopy was smaller in hemlock throughfall than black birch throughfall during small precipitation events

  10. The role of fire during climate change in an eastern deciduous forest at Devil`s Bathtub, New York

    SciTech Connect

    Clark, J.S.; Royall, P.D.; Chumbley, C.

    1996-10-01

    Annual record of charcoal and sedimentation rate were compared with fossil pollen to investigate the role of fire in eastern deciduous forest around Devil`s Bathtub, New York, USA. Changes in peak and background charcoal suggest that changes in fire regime have accompanied the principal vegetation and climatic changes of the last 10 400 yr. A distribution of return times (50-200-yr intervals) similar to parts of modern boreal Canada prevailed when late-Glacial spruce woodland dominated the site. Expansion of Pinus banksiana appears to have altered the fire regime to one of crown fires with high particulate emissions, but return intervals similar to those of the preceding Picea forest. Expansion of Pinus strobus might be linked to change in fire occurrence, but the broad dispersal of Pinus pollen makes interpretation difficult. If Pinus strobus expansion around the site is reflected in its pollen curve, then that expansion coincides with a time of frequent fire. Alternatively, if increasing pollen abundance precedes the local expansion of trees, as has been observed elsewhere, then local expansion might correspond to an abrupt decline in fire frequency and in regional importance of fire. An abrupt decline in background charcoal follows a fire and coincides ({+-} 100 yr) with the expansion of hardwood taxa such as Fagus. The decline in background charcoal occurs over several years, suggesting that it may be linked to effects of hardwood expansion on fuels. Fires do not appear to have occurred during the time of hardwood dominance, suggesting that fire may not be an explanation for maintenance of species diversity in this deciduous forest. However, frequent occurrence of thick varves during the latter half of the Holocene suggests that the frequency of other types of disturbance may have increased. 85 refs., 13 figs., 2 tabs.

  11. An evaluation of Community Land Model version 3.5 - Dynamic Global Vegetation Model over deciduous forest in Korea and sensitivity test

    NASA Astrophysics Data System (ADS)

    Lim, Hee Jeong; Lee, Young Hee; Kwon, Hyojung

    2010-05-01

    The performance of Community Land Model version 3.5 - Dynamic Global Vegetation Model (CLM-DGVM) has been evaluated through a comparison with the observation over temperate deciduous forest in Gwangneung, Korea. In this study, the influence of plant phenology, plant composition, and climate variability on carbon exchange was focalized. To get an equilibrium carbon storage, the model was run for 400 years driven by the observed atmospheric data at the deciduous forest of the year 2006. We have run the model for 2006 with the equilibrium carbon storage at Gwangneung forest and compared the model output with the observation. A comparison of leaf area index (LAI) between the model and observation indicated that the phenology module poorly represented the timing of budburst, leaf fall and evolution of canopy LAI of the deciduous forest. Senescence of the phenology was delayed about four weeks and the simulated maximum LAI (of 5.8 m2 m-2) was greater than the observed value (of 4.5 m2 m-2). However, the simulated tree carbon storage was comparable with the reported values at the site. Although the observed phenology is used for carbon exchange in the model, the model overestimated both gross primary productivity and ecosystem respiration. The coexistence of deciduous and needle leaf forests did not make a significant difference in carbon exchange amounts compared to the amount generated from single existence of deciduous forest. When the influence of climate variability on carbon exchange was examined, the simulated inter-annual variation of carbon exchange depended on annual mean air temperature and total insolation amount but not precipitation amount.

  12. Seasonal variations of gas exchange and water relations in deciduous and evergreen trees in monsoonal dry forests of Thailand.

    PubMed

    Ishida, Atsushi; Harayama, Hisanori; Yazaki, Kenichi; Ladpala, Phanumard; Sasrisang, Amornrat; Kaewpakasit, Kanokwan; Panuthai, Samreong; Staporn, Duriya; Maeda, Takahisa; Gamo, Minoru; Diloksumpun, Sapit; Puangchit, Ladawan; Ishizuka, Moriyoshi

    2010-08-01

    This study compared leaf gas exchange, leaf hydraulic conductance, twig hydraulic conductivity and leaf osmotic potential at full turgor between two drought-deciduous trees, Vitex peduncularis Wall. and Xylia xylocarpa (Roxb.) W. Theob., and two evergreen trees, Hopea ferrea Lanessan and Syzygium cumini (L.) Skeels, at the uppermost canopies in tropical dry forests in Thailand. The aims were to examine (i) whether leaf and twig hydraulic properties differ in relation to leaf phenology and (ii) whether xylem cavitation is a determinant of leaf shedding during the dry season. The variations in almost all hydraulic traits were more dependent on species than on leaf phenology. Evergreen Hopea exhibited the lowest leaf-area-specific twig hydraulic conductivity (leaf-area-specific K(twig)), lamina hydraulic conductance (K(lamina)) and leaf osmotic potential at full turgor (Ψ(o)) among species, whereas evergreen Syzygium exhibited the highest leaf-area-specific K(twig), K(lamina) and Ψ(o). Deciduous Xylia had the highest sapwood-area-specific K(twig), along with the lowest Huber value (sapwood area/leaf area). More negative osmotic Ψ(o) and leaf osmotic adjustment during the dry season were found in deciduous Vitex and evergreen Hopea, accompanied by low sapwood-area-specific K(twig). Regarding seasonal changes in hydraulics, no remarkable decrease in K(lamina) and K(twig) was found during the dry season in any species. Results suggest that leaf shedding during the dry season is not always associated with extensive xylem cavitation. PMID:20581012

  13. Comparison of vegetation patterns and soil nutrient relations in an oak-pine forest and a mixed deciduous forest on Long Island, New York

    SciTech Connect

    Peterson, S.C.; Curtis, P.S.

    1980-11-01

    An analysis of soil nutrient relations in two forest communities on Long Island, NY, yielded a correlation between the fertility of the top-soil and vegetational composition. The oak-pine forest soils at Brookhaven National Laboratory contain lower average concentrations of NH/sub 3/, Ca, K, and organic matter than the mixed deciduous forest soils in the Stony Brook area. The pH of the topsoil is also more acidic at Brookhaven. The observed differences between localities are greater than within-locality differences between the two soil series tested (Plymouth and Riverhead), which are common to both localities. Nutrient concentrations in the subsoil are not consistently correlated with either locality or soil series, although organic matter and NH/sub 3/ show significantly higher concentrations at Stony Brook. Supporting data on density and basal area of trees and coverage of shrubs and herbs also reveals significant variation between the two forest communities. An ordination of the vegetation data shows higher similarity within than between localities, while no obvious pattern of within-locality variation due to soil series treatments is apparent. These data support the hypothesis that fertility gradients may influence forest community composition and structure. This hypothesis is discussed with reference to vegetation-soil interactions and other factors, such as frequency of burning, which may direct the future development of the Brookhaven oak-pine forest.

  14. Carbon and water exchange of a younger, drier deciduous forest compared to the long-term study site at Harvard Forest, Massachusetts

    NASA Astrophysics Data System (ADS)

    Hadley, J. L.; Kuzeja, P. S.

    2004-05-01

    We measured carbon and water exchange by the eddy covariance method at a younger, drier deciduous forest and compared it to the well-known Harvard Forest deciduous site during two growing seasons (2002 and 2003) and an intervening dormant season. Forests at both sites are dominated by red oak (Quercus rubra) and red maple (Acer rubrum), but the younger forest is situated near a hilltop, as opposed to the long-term Harvard Forest site, which is in a lowland area within 100 m of a stream and about 200 m from a bog. The younger forest had a maximum tree age of about 44 years within 200 m of the eddy flux tower (owing to an intense fire in the autumn of 1957); this compares to maximum tree ages of 65 to 90 years, depending on exact location, near the long-term site. The younger, drier forest stored about 1.7 Mg C/ha from May 2002 through April 2003. We estimate that this was about 30% less than annual storage in the older, moister forest at the long-term site, but as the 12-month periods on which this comparison is based are not completely overlapping for the two sites, this comparison may change slightly. Light-saturated net ecosystem carbon uptake of both sites was about 22 μ mol m-2 s-1 in June 2002, but by August the value for the drier site was only about 20 μ mol m-2 s-1 compared to about 24 μ mol m-2 s-1 for the long-term site, suggesting that water availability may have become a limiting factor for photosynthesis in the drier forest. At the younger site in 2003 compared to 2002, we estimated less C storage in May and June but more C storage in July, August and September, with an overall increase in growing season C storage of about 0.4 Mg/ha. Lower early-growing season in carbon storage in 2003 versus 2002 was associated with slightly lower net ecosystem carbon uptake at all light levels in June 2003 compared to a year earlier. Cloudy and cool weather in May and early June 2003 reduced C uptake directly by reducing light available for photosynthesis, and

  15. Coordination between growth, phenology and carbon storage in three coexisting deciduous tree species in a temperate forest.

    PubMed

    Klein, Tamir; Vitasse, Yann; Hoch, Günter

    2016-07-01

    In deciduous trees growing in temperate forests, bud break and growth in spring must rely on intrinsic carbon (C) reserves. Yet it is unclear whether growth and C storage occur simultaneously, and whether starch C in branches is sufficient for refoliation. To test in situ the relationships between growth, phenology and C utilization, we monitored stem growth, leaf phenology and stem and branch nonstructural carbohydrate (NSC) dynamics in three deciduous species: Carpinus betulus L., Fagus sylvatica L. and Quercus petraea (Matt.) Liebl. To quantify the role of NSC in C investment into growth, a C balance approach was applied. Across the three species, >95% of branchlet starch was consumed during bud break, confirming the importance of C reserves for refoliation in spring. The C balance calculation showed that 90% of the C investment in foliage (7.0-10.5 kg tree(-1) and 5-17 times the C needed for annual stem growth) was explained by simultaneous branchlet starch degradation. Carbon reserves were recovered sooner than expected, after leaf expansion, in parallel with stem growth. Carpinus had earlier leaf phenology (by ∼25 days) but delayed cambial growth (by ∼15 days) than Fagus and Quercus, the result of a competitive strategy to flush early, while having lower NSC levels. PMID:27126226

  16. Carbon of Woody Debris in Plateau-type Karst Evergreen and Deciduous Broad-leaved Mixed Forest of Central Guizhou Province

    NASA Astrophysics Data System (ADS)

    Wu, Y.; Ni, J.; Liu, L.; Guo, C.

    2014-12-01

    Woody debris (WD) is an essential structural and functional component of forest ecosystems, and plays very significant roles for the biogeochemical cycling of carbon and nutrients. Coarse woody debris (CWD) is considered to be the major part in forest WD and it is primarily composed of logs, snags, stumps and large branches, while fine woody debris (FWD) mainly consists of small twigs. Composition, spatial distribution and carbon storage of WD have been studied in plateau-type karst evergreen and deciduous broad-leaved mixed forest in Tianlong Mountain of central Guizhou Province. Results showed that the carbon storage of WD in karst forests was less than non-karst forests. The major components of WD were fallen trees and snags with 10-20 cm in diameter. Fallen trees and snags with diameter greater than 20 cm were the smallest part of WD. The situation of WD in this region reflects the structural characteristics of WD in mid-late stage of plateau-type karst evergreen and deciduous broad-leaved mixed forest succession. The potential contribution of WD to the regional carbon cycle, and its relationship with climate change were finally discussed. The WD (especially CWD) plays an important role in the carbon cycle of karst forest. Forest WD production and decay rates may partially depend on climatic conditions, the accumulation of CWD and FWD carbon stocks in forests may be correlated with climate. Key words: woody debris, karst forests, carbon storage, spatial distribution, CWD, FWD.

  17. VOLATILE ORGANIC COMPOUND EMISSION RATES FROM MIXED DECIDUOUS AND CONIFEROUS FORESTS IN NORTHERN WISCONSIN, USA

    EPA Science Inventory

    Biogenic emissions of volatile organic compounds (VOC) from forests play an important role in regulating the atmospheric trace gas composition including global tropospheric ozone concentrations. However, more information is needed on VOC emission rates from different forest regio...

  18. Diurnal and Seasonal Cycles of CO2 Fluxes in the low Deciduous Forest in the South of Sonora, Mexico

    NASA Astrophysics Data System (ADS)

    Perez-Ruiz, E.; Garatuza-Payan, J.; Garcia-Calleja, M. T.; Watts, C. J.

    2007-05-01

    The Deciduous Seasonal Forest or Low Deciduous Forest (LDF) is one of the most diverse and most contrasting ecosystems in Mexico. It can be found from the south of the northern state of Sonora to the border of Mexico with Guatemala. This ecosystem is very important to the region since it represents a big area of vegetal cover close to the biggest cities of South Sonora (hence, endangered), and can be considered as a sink of carbon dioxide. In the present study, the CO2 fluxes over the LDF were analyzed in the period from June 2004 to December 2006. The CO2, latent and sensible heat, and momentum fluxes were measured using the Eddy covariance method. The Eddy covariance system consists of a 3-D sonic anemometer (CSAT3, Campbell Scientific), a gas analyzer (LI-7500, LI-COR), and diverse meteorological equipment controlled by a datalogger (CR5000, Campbell Scientific). The measures were made at 10Hz, collecting, storing and averaging the measurements every 30 minutes. The same type of cover is present in, at least, 3 km around the tower. The results show a large range in the diurnal variation of the CO2 fluxes, with values from -1.5 (day) to 0.8 (night) mg CO2 m- 2s-1 (negative values indicate uptake) in the summer, and from -0.5 to 0.15 mg CO2 m-2s- 1 during the winter. This ecosystems presents a clear growing season corresponding to the rain season in the summer, nevertheless, even in the dry season, the LDF can be considered as a sink of carbon dioxide during some hours around the midday.

  19. Relative Linkages of Canopy-Level CO2 Fluxes with the Climatic and Environmental Variables for US Deciduous Forests

    NASA Astrophysics Data System (ADS)

    Ishtiaq, Khandker S.; Abdul-Aziz, Omar I.

    2015-04-01

    We used a simple, systematic data-analytics approach to determine the relative linkages of different climate and environmental variables with the canopy-level, half-hourly CO2 fluxes of US deciduous forests. Multivariate pattern recognition techniques of principal component and factor analyses were utilized to classify and group climatic, environmental, and ecological variables based on their similarity as drivers, examining their interrelation patterns at different sites. Explanatory partial least squares regression models were developed to estimate the relative linkages of CO2 fluxes with the climatic and environmental variables. Three biophysical process components adequately described the system-data variances. The `radiation-energy' component had the strongest linkage with CO2 fluxes, whereas the `aerodynamic' and `temperature-hydrology' components were low to moderately linked with the carbon fluxes. On average, the `radiation-energy' component showed 5 and 8 times stronger carbon flux linkages than that of the `temperature-hydrology' and `aerodynamic' components, respectively. The similarity of observed patterns among different study sites (representing gradients in climate, canopy heights and soil-formations) indicates that the findings are potentially transferable to other deciduous forests. The similarities also highlight the scope of developing parsimonious data-driven models to predict the potential sequestration of ecosystem carbon under a changing climate and environment. The presented data-analytics provides an objective, empirical foundation to obtain crucial mechanistic insights; complementing process-based model building with a warranted complexity. Model efficiency and accuracy ( R 2 = 0.55-0.81; ratio of root-mean-square error to the observed standard deviations, RSR = 0.44-0.67) reiterate the usefulness of multivariate analytics models for gap-filling of instantaneous flux data.

  20. Relative linkages of canopy-level CO₂ fluxes with the climatic and environmental variables for US deciduous forests.

    PubMed

    Ishtiaq, Khandker S; Abdul-Aziz, Omar I

    2015-04-01

    We used a simple, systematic data-analytics approach to determine the relative linkages of different climate and environmental variables with the canopy-level, half-hourly CO2 fluxes of US deciduous forests. Multivariate pattern recognition techniques of principal component and factor analyses were utilized to classify and group climatic, environmental, and ecological variables based on their similarity as drivers, examining their interrelation patterns at different sites. Explanatory partial least squares regression models were developed to estimate the relative linkages of CO2 fluxes with the climatic and environmental variables. Three biophysical process components adequately described the system-data variances. The 'radiation-energy' component had the strongest linkage with CO2 fluxes, whereas the 'aerodynamic' and 'temperature-hydrology' components were low to moderately linked with the carbon fluxes. On average, the 'radiation-energy' component showed 5 and 8 times stronger carbon flux linkages than that of the 'temperature-hydrology' and 'aerodynamic' components, respectively. The similarity of observed patterns among different study sites (representing gradients in climate, canopy heights and soil-formations) indicates that the findings are potentially transferable to other deciduous forests. The similarities also highlight the scope of developing parsimonious data-driven models to predict the potential sequestration of ecosystem carbon under a changing climate and environment. The presented data-analytics provides an objective, empirical foundation to obtain crucial mechanistic insights; complementing process-based model building with a warranted complexity. Model efficiency and accuracy (R(2) = 0.55-0.81; ratio of root-mean-square error to the observed standard deviations, RSR = 0.44-0.67) reiterate the usefulness of multivariate analytics models for gap-filling of instantaneous flux data. PMID:25566833

  1. Ecological effects of pipeline construction through deciduous forested wetlands, Midland County, Michigan. Topical report, October 1990--August 1992

    SciTech Connect

    Rastorfer, J.R.; Van Dyke, G.D.; Zellmer, S.D.; Wilkey, P.L.

    1995-04-01

    This study is designed to record vegetational changes induced by the construction of a large-diameter gas pipeline through deciduous forested wetlands. Two second-growth wetland sites mapped Lenawee soils were selected in Midland County, Michigan: Site 1, a younger stand subjected to recent selective logging, and Site 2, a more mature stand. The collection of ecological data to analyze plant succession on the right-of-way (ROW) and the effects of the developing ROW plant communities on adjacent forest communities was initiated in 1989. Cover class estimates were made for understory and ROW plant species on the basis of 1 {times} 1{minus}m quadrats. Individual stem diameters and species counts were recorded for overstory plants in 10{minus}m quadrats. Although long-term studies have not been completed, firm baseline data were established for comparative analyses with future sampling. Current data indicate that vegetation became well-established on the ROW within one year and subsequently increased in coverage. About 65% of the species were wetland indicators, and the dominants included seeded and natural invading species; nevertheless, some elements of the original flora regenerated and persist. The plants of the ecotone understories of both sites changed from their original composition as a result of the installation of the gas pipeline. Although some forest species persist at both sites, the ecotone of Site I was influenced more by the seeded species, whereas the natural invaders were more important at Site 2.

  2. Canopy CO2 enrichment permits tracing the fate of recently assimilated carbon in a mature deciduous forest.

    PubMed

    Keel, Sonja G; Siegwolf, Rolf T W; Körner, Christian

    2006-01-01

    How rapidly newly assimilated carbon (C) is invested into recalcitrant structures of forests, and how closely C pools and fluxes are tied to photosynthesis, is largely unknown. A crane and a purpose-built free-air CO2 enrichment (FACE) system permitted us to label the canopy of a mature deciduous forest with 13C-depleted CO2 for 4 yr and continuously trace the flow of recent C through the forest without disturbance. Potted C4 grasses in the canopy ('isometers') served as a reference for the C-isotope input signal. After four growing seasons, leaves were completely labelled, while newly formed wood (tree rings) still contained 9% old C. Distinct labels were found in fine roots (38%) and sporocarps of mycorrhizal fungi (62%). Soil particles attached to fine roots contained 9% new C, whereas no measurable signal was detected in bulk soil. Soil-air CO2 consisted of 35% new C, indicating that considerable amounts of assimilates were rapidly returned back to the atmosphere. These data illustrate a relatively slow dilution of old mobile C pools in trees, but a pronounced allocation of very recent assimilates to C pools of short residence times. PMID:16995919

  3. Estimation of aboveground woody biomass using HJ-1 and Radarsat-2 data for deciduous forests in Daxing'anling, China

    NASA Astrophysics Data System (ADS)

    Liu, Qian; Yang, Le; Liu, Qinhuo; Li, Jing

    2014-11-01

    Accurate estimation of forest aboveground biomass is important for global carbon budgets and ecosystem change studies. Most algorithms for regional or global aboveground biomass estimation using optical and microwave remote sensing data are based on empirical regression and non-parametric training methods, which require large amount of ground measurements for training and are lacking of explicit interaction mechanisms between electromagnetic wave and vegetation. In this study, we proposed an optical/microwave synergy method based on a coherent polarimetric SAR model to estimate woody biomass. The study area is sparse deciduous forest dominated by birch with understory of shrubs and herbs in Daxing'anling, China. HJ-1, Radarsat-2 images, and field LAI were collected during May to August in 2013, tree biophysical parameters were measured at the field campaign during August to September in 2012. The effects of understory and wet ground were evaluated by introducing the NDVI derived from HJ-1 image and rain rate. Field measured LAI was used as an input to the SAR model to define the scattering and attenuation of the green canopy to the total backscatter. Finally, an logarithmic equation between the backscatter coefficient of direct forest scattering mechanism and woody biomass was generated (R2=0.582). The retrieval results were validated with the ground biomass measurements (RMSE=29.01ton/ha). The results indicated the synergy of optical and microwave remote sensing data based on SAR model has the potential to improve the accuracy of woody biomass estimation.

  4. Diurnal and seasonal carbon sequestration potential of seven broadleaved species in a mixed deciduous forest in India

    NASA Astrophysics Data System (ADS)

    Biswas, Soumyajit; Bala, Sanjay; Mazumdar, Asis

    2014-06-01

    The objective of the study was to measure annual carbon sequestration rate of mixed deciduous forest by measuring that of seven young broadleaved tree species (6 years age) as well as selection of better carbon sequestered plant species for future plantation. The diurnal net assimilation rate of Carbon dioxide (CO2) at leaf level was measured with LI-6400 Portable Photosynthesis System at daytime on seasonal basis in a man-made forest at Budge Budge (N 22°28‧ E 88°08‧) of South 24 Parganas, West Bengal, INDIA. Net assimilation rate of carbon at canopy level was calculated by measuring Leaf Area Index with LAI-2200 and using analytical model with non-rectangular hyperbolic light response curve. The average net assimilation rate of CO2 at leaf level was found maximum in Albizzia lebbek (8.13 μmol m-2 s-1) and that of canopy level in Eucalyptus spp. (4.851 g h-1). The minimum was found for Swietenia mahagoni (1.058 g h-1). The annual carbon sequestration rate of the mixed forest in natural condition was estimated 6.01 t ha-1 year-1 by consolidating the potential of all seven species.

  5. Stemflow Acid Neutralization Capacity in a Broadleaved Deciduous Forest: The Role of Edge Effects

    NASA Astrophysics Data System (ADS)

    Levia, D. F., Jr.; Shiklomanov, A.

    2014-12-01

    The fragmentation of forests is occurring at an accelerated rate in parts of the United States. Forest fragmentation creates edge habitat that affects the biogeochemistry of forests. Atmospheric deposition is known to increase at the forest edge in comparison to the forest interior. Past research has demonstrated the critical role of edge effects on throughfall chemistry but no known work has examined the relationship between stemflow chemistry and edge effects. To fill this data gap, we quantified the stemflow acid neutralization capacity (ANC) of nineteen Liriodendron tulipifera L. (yellow poplar) trees between forest edge and interior locations in the Piedmont of the mid-Atlantic USA. ANC was measured directly by potentiometric titration. Both stemflow pH and ANC were higher for L. tulipifera trees on the forest edge as opposed to those in interior locations (p < 0.01), although marked variability was observed among individual trees. It is critical to note that the ANC of stemflow of edge trees is almost certainly contextual, depending on geographic locality. This is to say that stemflow from edge trees may neutralize acid inputs in some locations (as in our case) but lead to enhanced acidification of aqueous inputs to forest soils in other locales where the dry deposition of acid anions is high. The experimental results have ramifications for forest management schema seeking to increase or decrease the extent of edge habitat in forest fragments.

  6. Community composition and cellulase activity of cellulolytic bacteria from forest soils planted with broad-leaved deciduous and evergreen trees.

    PubMed

    Yang, Jiang-Ke; Zhang, Jing-Jing; Yu, Heng-Yu; Cheng, Jian-Wen; Miao, Li-Hong

    2014-02-01

    Cellulolytic bacteria in forest soil provide carbon sources to improve the soil fertility and sustain the nutrient balance of the forest ecological system through the decomposition of cellulosic remains. These bacteria can also be utilized for the biological conversion of biomass into renewable biofuels. In this study, the community compositions and activities of cellulolytic bacteria in the soils of forests planted with broad-leaved deciduous (Chang Qing Garden, CQG) and broad-leaved evergreen (Forest Park, FP) trees in Wuhan, China were resolved through restriction fragment length polymorphism (RFLP) and sequencing analysis of the 16S rRNA gene. All of the isolates exhibited 35 RFLP fingerprint patterns and were clustered into six groups at a similarity level of 50 %. The phylogeny analysis based on the 16S rRNA gene sequence revealed that these RFLP groups could be clustered into three phylogenetic groups and further divided into six subgroups at a higher resolution. Group I consists of isolates from Bacillus cereus, Bacillus subtilis complex (I-A) and from Paenibacillus amylolyticus-related complex (I-B) and exhibited the highest cellulase activity among all of the cellulolytic bacteria isolates. Cluster II consists of isolates belonging to Microbacterium testaceum (II-A), Chryseobacterium indoltheticum (II-B), and Flavobacterium pectinovorum and the related complex (II-C). Cluster III consists of isolates belonging to Pseudomonas putida-related species. The community shift with respect to the plant species and the soil properties was evidenced by the phylogenetic composition of the communities. Groups I-A and I-B, which account for 36.0 % of the cellulolytic communities in the CQG site, are the dominant groups (88.4 %) in the FP site. Alternatively, the ratio of the bacteria belonging to group III (P. putida-related isolates) shifted from 28.0 % in CQG to 4.0 % in FP. The soil nutrient analysis revealed that the CQG site planted with deciduous broad

  7. Density and pathogenic activity of soil microbes associated with windthrows of temperate deciduous forests in the Allegany national Forest, Pennsylvania

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background/Question/Methods Forest disturbance caused by windthrow events has obvious impacts on forest structure and composition above-ground; however, changes in soil microbial communities are less obvious. Windthrows causing the formation of multiple forest gaps occurred in 2003 throughout the...

  8. Biomass of Secondary Evergreen and Deciduous Broadleaved Mixed Forest in Plateau-type Karst Terrain of Guizhou Province, SW China

    NASA Astrophysics Data System (ADS)

    Liu, L.

    2014-12-01

    Using allometric functions, harvest and soil column methods, we investigated the biomass of a secondary evergreen and deciduous broadleaved mixed forest in Tianlongshan permanent monitoring plot (a horizontally-projected area of 2 hectares) of Puding Karst Ecosystem Research Station, Guizhou Province, southwestern China. Results showed that the total biomass of the forest is 165.4 Mg·hm-2. The aboveground biomass and root biomass are 137.7 Mg·hm-2 and 27.7 Mg·hm-2, respectively. Among the aboveground biomass, the tree layer accounts for 97.76%, which is obviously greater than the shrub layer and herb layer. Larger trees (the diameter at breast height, DBH is between 5 cm and 20 cm) occupies 76.85% of the aboveground biomass, especially the five dominant species(Lithocarpus confinis, Platycarya longipes, Itea yunnanensis, Machilus cavaleriei and Carpinus pubescens). Shrubs and lianas (DBH = 1 cm) account for more than 30% of total shrub and liana biomass, although their individuals are less than 2% of total shrub individuals and 1% of total liana individuals, respectively. The root biomass differs in root diameters, i.e. coarse root > medium root > fine root. Root biomass decreases with the increase of soil depth. Within soil depth of 20 cm, the root biomass is 20.1 Mg·hm-2, which is more than 70% of total root biomass. Within soil depth of 50 cm, the root biomass is 26.7 Mg·hm-2, which is 96.39% of total root biomass. Compared with non-karst forests in the same climate zone, karst forest has lower biomass and carbon stock, but it further has greater potential of carbon sink.

  9. Biometric and Eddy-covariance Based Estimates of Ecosystem Carbon Storage in Five Eastern North American Deciduous Forests.

    NASA Astrophysics Data System (ADS)

    Curtis, P. S.; Hanson, P. J.; Bolstad, P.; Barford, C.; Randolph, J. C.; Schmid, H. P.; Wilson, K. B.

    2001-12-01

    Quantifying net carbon (C) storage by forests is a necessary step in the validation of C sequestration estimates and in assessing the possible role of these ecosystems in offsetting fossil fuel emissions. In eastern North America, five sites were established in deciduous forests to provide measurements of net ecosystem CO2 exchange using micro-meteorological methods (NEE), and measures of major C pools and fluxes, using a combination of forest mensurational, eco-physiological, and other biometric methods. The five study sites, part of the AmeriFlux network, ranged across 10° of latitude and 18° of longitude, but were all of similar age, canopy height, and stand basal area. Here we present a cross-site synthesis of C storage estimates, comparing meteorological and biometric approaches, and also comparing biometric estimates based on analyses of autotrophic C pools and heterotrophic C fluxes (net ecosystem production, NEP) versus those based on measurements of change in two major C pools (Δ C). Annual above-ground net primary production varied nearly two-fold among sites and was strongly correlated with average annual temperature and with annual soil nitrogen mineralization (Nmin). Estimates of NEP ranged from a low of 0.3 Mg C ha-1 yr-1 in northern Michigan to a high of 3.5 Mg C ha-1 yr-1 in central Indiana, and were also well correlated with Nmin. There was less variation among sites in estimates of Δ C (range, 1.8 - 3.2 Mg C ha-1 yr-1). In general, Δ C more closely matched NEE than did NEP, but there was no systematic pattern among sites in over- versus under-estimation of the biometric compared to the meteorologically based measures. Root and soil C dynamics were significant sources of uncertainty in our biometric measures and represent a prerequisite area of study needed for accurate estimates of forest C storage.

  10. Rainfall distribution is the main driver of runoff under future CO2-concentration in a temperate deciduous forest

    NASA Astrophysics Data System (ADS)

    Leuzinger, S.; Körner, C.

    2009-04-01

    Reduced stomatal conductance under elevated CO2 results in increased soil moisture, provided all other factors remain constant. Whether this results in increased runoff critically depends on the interaction of rainfall patterns, soil water storage capacity and plant responses. To test the sensitivity of runoff to these parameters under elevated CO2, we combine transpiration and soil moisture data from the Swiss Canopy Crane (SCC) FACE experiment with 104 years of daily precipitation data from an adjacent weather station to drive a three-layer bucket model (mean yearly precipitation 794 mm). The model adequately predicts the water budget of a temperate deciduous forest and runoff from a nearby gauging station. A simulation run over all 104 years based on sap flow responses resulted in only 5.5 mm (2.9 %) increased ecosystem runoff under elevated CO2. Out of the 37986 days (1.1.1901 to 31.12.2004), only 576 days produce higher runoff under in the elevated CO2 scenario. Only 1 out of 17 years produces a CO2-signal greater than 20 mma-1, which mostly depends on a few single days when runoff under elevated CO2 exceeds runoff under ambient conditions. The maximum signal for a double pre-industrial CO2-concentration under the past century daily rainfall regime is an additional runoff of 46 mm (year 1938). More than half of all years produce a signal of less than 5 mma-1, because trees consume the 'extra' moisture during prolonged dry weather. Increased runoff under elevated CO2 is 9 times more sensitive to variations in rain pattern than to the applied reduction in transpiration under elevated CO2. Thus the key driver of increased runoff under future CO2-concentration is the day by day rainfall pattern. We argue that increased runoff due to a first-order plant physiological CO2-effect will be very small (<3 %) in the landscape dominated by temperate deciduous forests, and will hardly increase flooding risk in forest catchments. It is likely that these results are equally

  11. Ozone phytotoxic potential with regard to fragments of the Atlantic Semi-deciduous Forest downwind of Sao Paulo, Brazil.

    PubMed

    Moura, Bárbara B; Alves, Edenise S; de Souza, Silvia R; Domingos, Marisa; Vollenweider, Pierre

    2014-09-01

    In the Metropolitan Region of Campinas (MRC), Brazil, high levels of primary pollutants contribute to ozone (O3) formation. However, little is known regarding the O3 effects in the tropics. Objectives in this study were to characterize the present levels of O3 pollution and to evaluate the relevance of current concentration-based indices for assessing the phytotoxic potential of O3. Changes in O3 concentrations and precursors at 5 monitoring stations within towns of MRC were analyzed. The daily O3 profile was typical for urban sites and showed little yearly variation. Given the permanently foliated forest canopy, yearly rather than seasonal O3 indices were thus more appropriate for estimating the effective ozone dose. With yearly SUM00, SUM60 and AOT40 of 156, 16 and 14 ppm h and confirmed by evidence of O3 injury in foliage, oxidative stress in the MRC has reached levels high enough to affect trees from the Atlantic Semi-deciduous Forest. PMID:24892227

  12. Seasonal Nutrient Dynamics of Foliage and Litterfall on Walker Branch Watershed, a Deciduous Forest Ecosystem

    SciTech Connect

    Grizzard, T. Henderson, G.S. Clebsch, E.

    1999-01-01

    A detailed twelve-month study of litterfall, live foliage biomass, and seasonal nutrient (nitrogen, phosphorus, potassium, calcium, sodium, and magnesium) dynamics in tree components was performed for forest types on Walker Branch Watershed, Oak Ridge, Tennessee. Biomass and nutrient content of foliage, reproductive parts and branches were examined for ten dominant trees in order to assess the relative importance of litterfall in returning nutrients to the forest floor in four different forest types. Litterfall, measured in pine, pine-oak-hickory, oak-hickory, and mesophytic hardwood forests, was separated into three components (leaves, reproductive parts, and branches). Seasonal comparisons of those forest types were made for biomass and nutrient inputs for each component and for total litterfall. Each forest types was characterized by total annual input to the forest floor of biomass and individual nutrients for each component as well as total litterfall. Canonical analysis was performed on the yearly totals to test for significant differences among the forest types. Live foliage from the ten predominant species of trees on the watershed, determined by order of total basal area, was analyzed for biomass, nutrient concentration, and changes in nutrient content through the growth season. Seasonal trends for these variables, including the ranking of nutrient concentrations for spring versus fall, were discussed in relation to differential growth, translocation, and leaching factors. Most of the litterfall in all forest types (77-85%) was in leaves with fall maximum. Reproductive parts (8-14% with spring and fall maxima) and branches (8-11% with no seasonal trend) contributed the remainder. The ranking of nutrient content in litterfall was similar in spring and fall, except for the replacement of nitrogen by calcium in autumn as the predominant nutrient (followed by K > Mg > P > Na). Comparisons were made between weight and nutrient content for living leaves and leaf

  13. Soil-Earthworm-Litter System Controls on the Soil Aggregates and Soil Organic Matter Dynamics in Eastern Deciduous Forests

    NASA Astrophysics Data System (ADS)

    Ma, Yini; Filley, Timothy; Johnston, Cliff; Szlavecz, Kathy; McCormick, Melissa

    2010-05-01

    Many soils from forests in northern North America are undergoing a recent invasion of European Lumbricid earthworms with important implications for soil organic carbon (SOC) dynamics. Our work seeks to identify how native and invasive earthworm (EW) activity alters the relative importance of physical, chemical, and biochemical protection mechanisms controlling SOM stabilization in deciduous forests by changing the dynamics of soil particulate organic matter (POM) and aggregates. Within forests of the Smithsonian Environmental Research Center (SERC) in coastal Maryland, USA, wood and litter amendment plots were established in high, low and no EW activity areas within forests of different stand age and land use history to study EW impacts to litter-soil systems. Older, mature successional forests have relatively fewer or no earthworms while forests with agricultural disturbance less than 75 years exhibit the greatest number of individuals. Our previous work demonstrated that the plant biopolymer chemistry of both decayed litter and soil (0-5 cm) POM is driven by differences in EW activity and is responsible for the differences observed in lignin and root aliphatic matter accumulation in this system. In the present study we compare soils to a depth of 15 cm among plots with 5 years of wood and litter amendment to track the control of EW activity on the vertical transport and microaggregation of litter. Elemental C&N, 13C, 15N abundances, and diffuse reflectance Fourier transform infrared spectra (DR-FTIR) data will be presented for bulk soil and size-density separated soil fractions. These plots have variable land use histories over the last 250 yrs which is mostly reflected in their stable 15N and 13C values of mineral bound SOC with depth but earthworm activity seems to have a control on the degree of isotope change with depth. Our results from analysis of stable isotopes and lignin phenols in soil indicate the invasive EW feeding habits and activity are a major

  14. Woody species diversity in forest plantations in a mountainous region of Beijing, China: effects of sampling scale and species selection.

    PubMed

    Zhang, Yuxin; Zhang, Shuang; Ma, Keming; Fu, Bojie; Anand, Madhur

    2014-01-01

    The role of forest plantations in biodiversity conservation has gained more attention in recent years. However, most work on evaluating the diversity of forest plantations focuses only on one spatial scale; thus, we examined the effects of sampling scale on diversity in forest plantations. We designed a hierarchical sampling strategy to collect data on woody species diversity in planted pine (Pinus tabuliformis Carr.), planted larch (Larix principis-rupprechtii Mayr.), and natural secondary deciduous broadleaf forests in a mountainous region of Beijing, China. Additive diversity partition analysis showed that, compared to natural forests, the planted pine forests had a different woody species diversity partitioning pattern at multi-scales (except the Simpson diversity in the regeneration layer), while the larch plantations did not show multi-scale diversity partitioning patterns that were obviously different from those in the natural secondary broadleaf forest. Compare to the natural secondary broadleaf forests, the effects of planted pine forests on woody species diversity are dependent on the sampling scale and layers selected for analysis. Diversity in the planted larch forest, however, was not significantly different from that in the natural forest for all diversity components at all sampling levels. Our work demonstrated that the species selected for afforestation and the sampling scales selected for data analysis alter the conclusions on the levels of diversity supported by plantations. We suggest that a wide range of scales should be considered in the evaluation of the role of forest plantations on biodiversity conservation. PMID:25545860

  15. Woody Species Diversity in Forest Plantations in a Mountainous Region of Beijing, China: Effects of Sampling Scale and Species Selection

    PubMed Central

    Zhang, Yuxin; Zhang, Shuang; Ma, Keming; Fu, Bojie; Anand, Madhur

    2014-01-01

    The role of forest plantations in biodiversity conservation has gained more attention in recent years. However, most work on evaluating the diversity of forest plantations focuses only on one spatial scale; thus, we examined the effects of sampling scale on diversity in forest plantations. We designed a hierarchical sampling strategy to collect data on woody species diversity in planted pine (Pinus tabuliformis Carr.), planted larch (Larix principis-rupprechtii Mayr.), and natural secondary deciduous broadleaf forests in a mountainous region of Beijing, China. Additive diversity partition analysis showed that, compared to natural forests, the planted pine forests had a different woody species diversity partitioning pattern at multi-scales (except the Simpson diversity in the regeneration layer), while the larch plantations did not show multi-scale diversity partitioning patterns that were obviously different from those in the natural secondary broadleaf forest. Compare to the natural secondary broadleaf forests, the effects of planted pine forests on woody species diversity are dependent on the sampling scale and layers selected for analysis. Diversity in the planted larch forest, however, was not significantly different from that in the natural forest for all diversity components at all sampling levels. Our work demonstrated that the species selected for afforestation and the sampling scales selected for data analysis alter the conclusions on the levels of diversity supported by plantations. We suggest that a wide range of scales should be considered in the evaluation of the role of forest plantations on biodiversity conservation. PMID:25545860

  16. Photoprotection of evergreen and drought-deciduous tree leaves to overcome the dry season in monsoonal tropical dry forests in Thailand.

    PubMed

    Ishida, Atsushi; Yamazaki, Jun-Ya; Harayama, Hisanori; Yazaki, Kenichi; Ladpala, Phanumard; Nakano, Takashi; Adachi, Minaco; Yoshimura, Kenichi; Panuthai, Samreong; Staporn, Duriya; Maeda, Takahisa; Maruta, Emiko; Diloksumpun, Sapit; Puangchit, Ladawan

    2014-01-01

    In tropical dry forests, uppermost-canopy leaves of evergreen trees possess the ability to use water more conservatively compared with drought-deciduous trees, which may result from significant differences in the photoprotective mechanisms between functional types. We examined the seasonal variations in leaf gas exchange, chlorophyll fluorescence and the amounts of photosynthetic pigments within lamina of the uppermost-canopy leaves of three drought-deciduous trees (Vitex peduncularis Wall., Xylia xylocarpa (Roxb.) W. Theob., Shorea siamensis Miq.), a semi-deciduous tree (Irvingia malayana Miq.) and two evergreen trees (Hopea ferrea Lanessan and Syzygium cumini (L.) Skeels) in Thailand. Area-based maximum carbon assimilation rates (Amax) decreased during the dry season, except in S. siamensis. The electron transport rate (ETR) remained unchanged in deciduous trees, but decreased during the dry season in evergreen and semi-deciduous trees. In the principal component analysis, the first axis (Axis 1) accounted for 44.3% of the total variation and distinguished deciduous from evergreen trees. Along Axis 1, evergreen trees were characterized by a high Stern-Volmer non-photochemical quenching coefficient (NPQ), high xanthophyll cycle pigments/chlorophyll and a high de-epoxidation state of the xanthophyll cycle, whereas the deciduous trees were characterized by a high ETR, a high quantum yield of PSII (ΦPSII = (Fm(') -F)/Fm(')) and a high mass-based Amax under high-light conditions. These findings indicate that drought-deciduous trees showing less conservative water use tend to dissipate a large proportion of electron flow through photosynthesis or alternative pathways. In contrast, the evergreens showed more conservative water use, reduced Amax and ETR and enhanced NPQ and xanthophyll cycle pigments/chlorophyll during the dry season, indicating that down-regulated photosynthesis with enhanced thermal dissipation of excess light energy played an important role in

  17. Soil-Earthworm-Litter System Controls on the Stabilization of Soil Organic Carbon in Eastern Deciduous Forests

    NASA Astrophysics Data System (ADS)

    Ma, Y.; Filley, T. R.; Johnston, C. T.; Szlavecz, K. A.; McCormick, M.

    2009-12-01

    Our work seeks to identify how native and invasive earthworm (EW) activity alters the relative importance of physical, chemical, and biochemical protection mechanisms controlling SOM stabilization in deciduous Forests. Within forests of the Smithsonian Environmental Research Center (SERC) in coastal Maryland, USA, wood and litter amendment plots were established in high and low EW activity areas within forests of different stand age and land use history to study EW impacts to litter-soil systems. Our previous work demonstrated that the plant biopolymer chemistry of both decayed litter and soil (0-5 cm) particulate organic matter (POM) is driven by differences in EW activity and is responsible for the differences observed in lignin and root aliphatic matter accumulation in this system. In the present study we compare soils to a depth of 15 cm among plots with 5 years of wood and litter amendment to track the control of EW activity on the vertical transport of litter and clay particle and their partitioning within soil physical fractions. Elemental C&N and δ13C, δ15N data will be presented from each depth in each core among both bulk soil and size-density separated soil fractions. Preliminary results from these analyses indicate the invasive EW feeding habits and activity are the major control on the degree of mixing of surface litter and deep soil in all of research plots. This work will have important implications for understanding how invasive EW will influence soil-atmosphere carbon budget in Northern North America in the future.

  18. [Error analysis of CO2 storage flux in a temperate deciduous broadleaved forest based on different scalar variables].

    PubMed

    Wang, Jing; Wang, Xing-chang; Wang, Chuan-kuan

    2013-04-01

    Using the measurement data from an 8-level vertical profile of CO2/H2 0 in a temperate deciduous broadleaved forest at the Maoershan Forest Ecosystem Research Station, Northeast China, this paper quantified the errors of CO2 storage flux (Fs ) calculated with three scalar variables, i. e. , CO2 density (rho c), molar fraction (cc), and molar mixing ratio relative to dry air (Xc). The dry air storage in the control volume of flux measurement was not a constant, and thus, the fluctuation of the dry air storage could cause the CO2 molecules transporting out of or into the control volume, i. e. , the variation of the dry air storage adjustment term (Fsd). During nighttime and day-night transition periods, the relative magnitude of Fsd to eddy flux was larger, and ignoring the Fsd could introduce errors in calculating the net CO2 exchange between the forest ecosystem and the atmosphere. Three error sources in the Fs calculation could be introduced from the atmospheric hydrothermal processes, i. e. , 1) air temperature fluctuation, which could cause the largest error, with one order of magnitude larger than that caused by atmospheric pressure (P) , 2) water vapor, its effect being larger than that of P in warm and moist summer but smaller in cold and dry winter, and 3) P, whose effect was generally smaller throughout the year. In estimating the effective CO2 storage (Fs_E) , the Fs value calculated with rho c, cc, and Xc was overestimated averagely by 8. 5%, suggested that in the calculation of Fs, adopting the Xc conservation to atmospheric hydrothermal processes could be more appropriate to minimize the potential errors. PMID:23898654

  19. Differential snow accumulation and melt at southern hemisphere deciduous forested sites

    NASA Astrophysics Data System (ADS)

    McPhee, James; Huerta, Marlene; Molotch, Noah

    2016-04-01

    Little is known about the differential snow dynamics resulting from forest cover in southern hemisphere alpine regions. Tree species variability and differences in local climate preclude extrapolation of northern hemisphere results and introduce uncertainty on the future impacts of climate change on snow-cover duration, maximum accumulation and melt rates. This research presents preliminary results from field observations obtained at an experimental watershed in the Nevados de Chillan region, in south-central Chile. The relatively low elevation of the Andes Cordillera and higher latitude of the site allows the existence of mixed Nothofagus forests, sometimes combined with bamboo-type undergrowth. Rain-on-snow events can be observed during winter and in the early stages of the austral spring. We installed four instrument clusters at the Valle Hermoso experimental catchments, where snow depth, air temperature and relative humidity were measured both under canopy and in forest clearings. The clusters where positioned in order to cover a range of elevations and sun exposure. Preliminary results from two winter seasons suggest that forest cover can impact accumulation rates as much as elevation does, and that melt rates are fairly sensitive to forest cover even in low LAI conditions.

  20. The relationship between fire history and an exotic fungal disease in a deciduous forest.

    PubMed

    Holzmueller, Eric J; Jose, Shibu; Jenkins, Michael A

    2008-03-01

    Exotic diseases have fundamentally altered the structure and function of forest ecosystems. Controlling exotic diseases across large expanses of forest has proven difficult, but fire may reduce the levels of diseases that are sensitive to environmental conditions. We examined Cornus florida populations in burned and unburned Quercus-Carya stands to determine if burning prior to anthracnose infection has reduced the impacts of an exotic fungal disease, dogwood anthracnose, caused by Discula destructiva. We hypothesized that fire has altered stand structure and created open conditions less conducive to dogwood anthracnose. We compared C. florida density, C. florida health, and species composition and density among four sampling categories: unburned stands, and stands that had burned once, twice, and 3 times over a 20-year period (late 1960s to late 1980s). Double burn stands contained the greatest density of C. florida stems (770 stems ha(-1)) followed by triple burn stands (233 stems ha(-1)), single burn stands (225 stems ha(-1)) and unburned stands (70 stems ha(-1); P < 0.01). We observed less crown dieback in small C. florida trees (<5 cm diameter at breast height) in burned stands than in unburned stands (P < 0.05). Indicator species analysis showed that burning favored species historically associated with Quercus-Carya forests and excluded species associated with secondary succession following nearly a century of fire suppression. Our results suggest that fire may mitigate the decline of C. florida populations under attack by an exotic pathogen by altering forest structure and composition. Further, our results suggest that the burns we sampled have had an overall restorative effect on forest communities and were within the fire return interval of the historic fire regime. Consequently, prescribed fire may offer a management tool to reduce the impacts of fungal disease in forest ecosystems that developed under historic burning regimes. PMID:18026756

  1. Establishment and production from thinned mature deciduous-forest silvopastures in Appalachia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We thinned a white oak dominated mature second growth forested area establishing two, 0.4 and 0.6 ha, eight and 12-paddock respectively, orchardgrass-perennial ryegrass-white clover silvopasture replications for comparison with two nearby open pasture replications. After thinning trees, silvopastur...

  2. VOLATILE ORGANIC COMPOUNDS AND ISOPRENE OXIDATION PRODUCTS AT A TEMPERATE DECIDUOUS FOREST SITE

    EPA Science Inventory

    Biogenic volatile compounds (BVOCs) and their role in atmospheric oxidant formation were investigated at a forest site near Oak Ridge, Tennessee, as part of the Nashville Southern Oxidants Study (SOS) in July 1995. Of 98 VOCs detected, a major fraction were anthropogenic VOCs suc...

  3. Net primary production of a temperate deciduous forest exhibits a threshold response to increasing disturbance severity.

    PubMed

    Stuart-Haëntjens, Ellen J; Curtis, Peter S; Fahey, Robert T; Vogel, Christoph S; Gough, Christopher M

    2015-09-01

    The global carbon (C) balance is vulnerable to disturbances that alter terrestrial C storage. Disturbances to forests occur along a continuum of severity, from low-intensity disturbance causing the mortality or defoliation of only a subset of trees to severe stand- replacing disturbance that kills all trees; yet considerable uncertainty remains in how forest production changes across gradients of disturbance intensity. We used a gradient of tree mortality in an upper Great Lakes forest ecosystem to: (1) quantify how aboveground wood net primary production (ANPP,) responds to a range of disturbance severities; and (2) identify mechanisms supporting ANPPw resistance or resilience following moderate disturbance. We found that ANPPw declined nonlinearly with rising disturbance severity, remaining stable until >60% of the total tree basal area senesced. As upper canopy openness increased from disturbance, greater light availability to the subcanopy enhanced the leaf-level photosynthesis and growth of this formerly light-limited canopy stratum, compensating for upper canopy production losses and a reduction in total leaf area index (LAI). As a result, whole-ecosystem production efficiency (ANPPw/LAI) increased with rising disturbance severity, except in plots beyond the disturbance threshold. These findings provide a mechanistic explanation for a nonlinear relationship between ANPPw, and disturbance severity, in which the physiological and growth enhancement of undisturbed vegetation is proportional to the level of disturbance until a threshold is exceeded. Our results have important ecological and management implications, demonstrating that in some ecosystems moderate levels of disturbance minimally alter forest production. PMID:26594704

  4. Estimating Dbh of Trees Employing Multiple Linear Regression of the best Lidar-Derived Parameter Combination Automated in Python in a Natural Broadleaf Forest in the Philippines

    NASA Astrophysics Data System (ADS)

    Ibanez, C. A. G.; Carcellar, B. G., III; Paringit, E. C.; Argamosa, R. J. L.; Faelga, R. A. G.; Posilero, M. A. V.; Zaragosa, G. P.; Dimayacyac, N. A.

    2016-06-01

    Diameter-at-Breast-Height Estimation is a prerequisite in various allometric equations estimating important forestry indices like stem volume, basal area, biomass and carbon stock. LiDAR Technology has a means of directly obtaining different forest parameters, except DBH, from the behavior and characteristics of point cloud unique in different forest classes. Extensive tree inventory was done on a two-hectare established sample plot in Mt. Makiling, Laguna for a natural growth forest. Coordinates, height, and canopy cover were measured and types of species were identified to compare to LiDAR derivatives. Multiple linear regression was used to get LiDAR-derived DBH by integrating field-derived DBH and 27 LiDAR-derived parameters at 20m, 10m, and 5m grid resolutions. To know the best combination of parameters in DBH Estimation, all possible combinations of parameters were generated and automated using python scripts and additional regression related libraries such as Numpy, Scipy, and Scikit learn were used. The combination that yields the highest r-squared or coefficient of determination and lowest AIC (Akaike's Information Criterion) and BIC (Bayesian Information Criterion) was determined to be the best equation. The equation is at its best using 11 parameters at 10mgrid size and at of 0.604 r-squared, 154.04 AIC and 175.08 BIC. Combination of parameters may differ among forest classes for further studies. Additional statistical tests can be supplemented to help determine the correlation among parameters such as Kaiser- Meyer-Olkin (KMO) Coefficient and the Barlett's Test for Spherecity (BTS).

  5. Solar-induced chlorophyll fluorescence that correlates with canopy photosynthesis on diurnal and seasonal scales in a temperate deciduous forest

    NASA Astrophysics Data System (ADS)

    Yang, Xi; Tang, Jianwu; Mustard, John F.; Lee, Jung-Eun; Rossini, Micol; Joiner, Joanna; Munger, J. William; Kornfeld, Ari; Richardson, Andrew D.

    2015-04-01

    Previous studies have suggested that solar-induced chlorophyll fluorescence (SIF) is correlated with Gross Primary Production (GPP). However, it remains unclear to what extent this relationship is due to absorbed photosynthetically active radiation (APAR) and/or light use efficiency (LUE). Here we present the first time series of near-surface measurement of canopy-scale SIF at 760 nm in temperate deciduous forests. SIF correlated with GPP estimated with eddy covariance at diurnal and seasonal scales (r2 = 0.82 and 0.73, respectively), as well as with APAR diurnally and seasonally (r2 = 0.90 and 0.80, respectively). SIF/APAR is significantly positively correlated with LUE and is higher during cloudy days than sunny days. Weekly tower-based SIF agreed with SIF from the Global Ozone Monitoring Experiment-2 (r2 = 0.82). Our results provide ground-based evidence that SIF is directly related to both APAR and LUE and thus GPP, and confirm that satellite SIF can be used as a proxy for GPP.

  6. Physiological basis of seasonal trend in leaf photosynthesis of five evergreen broad-leaved species in a temperate deciduous forest.

    PubMed

    Miyazawa, Yoshiyuki; Kikuzawa, Kihachiro

    2006-02-01

    The physiological basis of photosynthesis during winter was investigated in saplings of five evergreen broad-leaved species (Camellia japonica L., Cleyera japonica Thunb., Photinia glabra (Thunb.) Maxim., Castanopsis cuspidata (Thunb.) Schottky and Quercus glauca Thunb.) co-occurring under deciduous canopy trees in a temperate forest. We focused on temperature dependence of photosynthetic rate and capacity as important physiological parameters that determine light-saturated rates of net photosynthesis at low temperatures during winter. Under controlled temperature conditions, maximum rates of ribulose bisphosphate carboxylation and electron transport (Vcmax) and Jmax, respectively) increased exponentially with increasing leaf temperature. The temperature dependence of photosynthetic rate did not differ among species. In the field, photosynthetic capacity, determined as Vcmax and Jmax at a common temperature of 25 degrees C (Vcmax(25) and Jmax(25)), increased until autumn and then decreased in species-specific patterns. Values of Vcmax(25) and Jmax(25) differed among species during winter. There was a positive correlation of Vcmax(25) with area-based nitrogen concentration among leaves during winter in Camellia and Photinia. Interspecific differences in Vcmax(25) were responsible for interspecific differences in light-saturated rates of net photosynthesis during winter. PMID:16356922

  7. Dynamics of Litter Decomposition, Microbiota Populations, and Nutrient Movement Following Nitrogen and Phosphorus Additions to a Deciduous Forest Stand

    SciTech Connect

    Kelly, J.M.

    2002-10-29

    The objective of this study was quantification of the dynamics of litter decomposition, microbiota populations, and nutrient movement in response to nitrogen and phosphorus additions to a deciduous forest stand. Nitrogen (urea) was applied at rates of 0, 550, and 1100 kg/ha in combination with phosphorus (concentrated superphosphate) at rates of 0, 275, and 550 kg/ha. Total loss of organic material from white oak, red maple, and black gum litter bags over a 16-month period was 34, 35, and 45%, respectively. Phosphorus treatment retarded weight loss from litter bags of all species. Weight loss for the 0-, 275-, and 55-kg/ha levels of phosphorus averaged 23, 20, and 19% for white oak; 26, 25, and 25% for red maple; 29, 27 and 26% for black gum. Weight losses were increased by a small amount (1 to 2%) or not at all by nitrogen treatment. The NP interfaction weight loss means were intermediate to the main treatment means. The increase in decomposition associated with nitrogen was offset by the decrease associated with phosphorus. Litter and soil bacterial populations were significantly increased by nitrogen additions, while litter and soil fungi did not respond to nitrogen. Soil fungal populations were increased by phosphorus addition, while litter bacterial populations were reduced. Litter fungi and soil bacteria did not respond to phosphorus. Combined additions of nitrogen and phosphorus increased bacterial populations, though not as much as nitrogen alone. There was a good correlation (r = 0.70) between bacterial population and litter weight loss.

  8. The relationship between canopy structure, light dynamics and deciduousness in a seasonal tropical forest in Panama: A multiple scale study using remote sensing and allometry

    NASA Astrophysics Data System (ADS)

    Bohlman, Stephanie Ann

    This dissertation uses two tools, remote sensing and allometry, to quantify canopy structure, phenology and light interception on stand to landscape levels in a semi-deciduous tropical forest in Panama. The remote sensing studies used a multiple scale approach. First relationships between spectral and physiological data were developed on a fine spatial scale. Then the interpretations were verified at a series of plots across the landscape. Finally, interpretation was applied to satellite images of the whole Panama Canal Zone. Using this approach, the applicability of the relationship between the Normalized Difference Vegetation Index (NDVI) and fraction of intercepted photosynthetically active radiation (FPAR) was tested for the first time in a tropical forest. NDVI was more strongly related to changes in the FPAR of the upper canopy than FPAR of the whole canopy profile. Both NDVI and FPAR were driven by the contrast of deciduous and non-deciduous tree crowns in the dry season. On a landscape scale, spectral mixture analysis (SMA) of remotely-sensed images quantified the percent of deciduous tree crowns in the overstory very accurately. Using the map of deciduousness developed from a Landsat image, I found high fine scale variability in deciduousness, highly deciduous patches throughout the canal zone of 4--250 ha in size, and landscape trends related to rainfall and geologic formation. Allometric relationships between stem diameter, tree height and crown size were developed for 65 species on Barro Colorado Island. Tree height was asymptotic with stem diameter, but crown radius was not, continuing to grow at large diameters. Allometric relationships through ontongeny varied among different functional groups. Gap species are taller than shade species when both functional groups were below 10 cm dbh, but have smaller crowns than shade species above 10 cm dbh. Subcanopy species are shorter with larger canopies than tall species. A simple canopy model based on these

  9. Leaf litter and roots as sources of mineral soil organic matter in temperate deciduous forest with and without earthworms

    NASA Astrophysics Data System (ADS)

    Fahey, T.; Yavitt, J. B.

    2012-12-01

    We labeled sugar maple trees with 13C to quantify the separate contributions of decaying leaf litter and root turnover/rhizosphere C flux to mineral soil organic matter (SOM). Labeled leaf litter was applied to forest plots with and without earthworms and recovery of the label in SOM was quantified over three years. In parallel, label recovery was quantified in soils from the labeling chambers where all label was supplied by belowground C flux. In the absence of earthworms about half of the label added as leaf litter remained in the surface organic horizons after three years, with about 3% recovered in mineral SOM. The label was most enriched on silt + clay surfaces, representing precipitation of DOC derived from litter. Earthworms mixed nearly all the leaf litter into mineral soil within one year, and after two years the label was most enriched in particulate organic matter held within soil aggregates produced by worms. After three years 15-20% of the added label was recovered in mineral SOM. In the labeling chambers over 75% of belowground C allocation (BCA) was used in root and rhizosphere respiration in the first year after labeling. We recovered only 3.8% of estimated BCA in SOM after 3 years; however, expressed as a proportion of fine root production plus rhizosphere C flux, this value is 15.4%, comparable to that for leaf litter in the presence of earthworms. In conclusion, both roots and leaf litter contribute significantly to the formation of stabilized mineral SOM in temperate deciduous forests, and this process is profoundly altered by the invasion of lumbricid earthworms.

  10. Influence of gas-particle partitioning on ammonia and nitric acid fluxes above a deciduous forest in the Midwestern USA

    NASA Astrophysics Data System (ADS)

    Hansen, K.; Sørensen, L. L.; Hornsby, K. E.; Boegh, E.; Pryor, S. C.

    2013-12-01

    Quantifying the atmosphere-biosphere exchange of reactive nitrogen gasses (including ammonia (NH3) and nitric acid (HNO3)) is crucial to assessing the impact of anthropogenic activities on natural and semi-natural ecosystems. However, measuring the deposition of reactive nitrogen is challenging due to bi-directionality of the flux, and the dynamics of the chemical gas/aerosol equilibrium of NH3 and HNO3 (or other atmospheric acids) with aerosol-phase ammonium (NH4+) and nitrate (NO3-). NH3 and HNO3 are both very reactive and typically exhibit higher deposition velocities than aerosol NH4+. Therefore, the phase partitioning between gas and aerosol phases can have a significant effect on local budgets and atmospheric transport distances (Nemitz et al., Atmos. Chem. Phys., 2004). In this study, fluxes of NH3, HNO3 and carbon dioxide (CO2) along with size-resolved N-aerosol concentrations are measured above the deciduous forest, Morgan Monroe State Forest (MMSF) in south-central Indiana (39°53'N, 86°25'W) during a field campaign. Two relaxed eddy accumulation (REA) systems are used to measure fluxes and concentrations of NH3 and HNO3 at 44 m. The NH3 REA system operates based on wet effluent diffusion denuders with detection by florescence and half-hourly flux measurements are calculated. HNO3 REA system is based on gas capture on sodium chloride (NaCl) coated denuders with subsequent analysis by ion-chromatography, and the resulting fluxes have a resolution of 3-4 hours. CO2 fluxes are measured by eddy covariance using a closed-path Licor LI-7500, while two MSP MOUDI-110 impactors are used to measure the 24-hourly average inorganic and 48 hourly averaged organic ion concentrations in 11 size bins, respectively, just above the canopy level (28 m). The results of this field campaign are used to quantify the fluxes of NH3, HNO3, CO2 to/from the forest during the transition towards senescence, and to investigate process-level controls (e.g. the role of phase

  11. Influences of evergreen gymnosperm and deciduous angiosperm tree species on the functioning of temperate and boreal forests.

    PubMed

    Augusto, Laurent; De Schrijver, An; Vesterdal, Lars; Smolander, Aino; Prescott, Cindy; Ranger, Jacques

    2015-05-01

    It has been recognized for a long time that the overstorey composition of a forest partly determines its biological and physical-chemical functioning. Here, we review evidence of the influence of evergreen gymnosperm (EG) tree species and deciduous angiosperm (DA) tree species on the water balance, physical-chemical soil properties and biogeochemical cycling of carbon and nutrients. We used scientific publications based on experimental designs where all species grew on the same parent material and initial soil, and were similar in stage of stand development, former land use and current management. We present the current state of the art, define knowledge gaps, and briefly discuss how selection of tree species can be used to mitigate pollution or enhance accumulation of stable organic carbon in the soil. The presence of EGs generally induces a lower rate of precipitation input into the soil than DAs, resulting in drier soil conditions and lower water discharge. Soil temperature is generally not different, or slightly lower, under an EG canopy compared to a DA canopy. Chemical properties, such as soil pH, can also be significantly modified by taxonomic groups of tree species. Biomass production is usually similar or lower in DA stands than in stands of EGs. Aboveground production of dead organic matter appears to be of the same order of magnitude between tree species groups growing on the same site. Some DAs induce more rapid decomposition of litter than EGs because of the chemical properties of their tissues, higher soil moisture and favourable conditions for earthworms. Forest floors consequently tend to be thicker in EG forests compared to DA forests. Many factors, such as litter lignin content, influence litter decomposition and it is difficult to identify specific litter-quality parameters that distinguish litter decomposition rates of EGs from DAs. Although it has been suggested that DAs can result in higher accumulation of soil carbon stocks, evidence from

  12. An Experimental Test of Competition among Mice, Chipmunks, and Squirrels in Deciduous Forest Fragments

    PubMed Central

    Brunner, Jesse L.; Duerr, Shannon; Keesing, Felicia; Killilea, Mary; Vuong, Holly; Ostfeld, Richard S.

    2013-01-01

    Mixed hardwood forests of the northeast United States support a guild of granivorous/omnivorous rodents including gray squirrels (Sciurus carolinensis), eastern chipmunks (Tamias striatus), and white-footed mice (Peromyscus leucopus). These species coincide geographically, co-occur locally, and consume similar food resources. Despite their idiosyncratic responses to landscape and patch variables, patch occupancy models suggest that competition may influence their respective distributions and abundances, and accordingly their influence on the rest of the forest community. Experimental studies, however, are wanting. We present the result of a large-scale experiment in which we removed white-footed mice or gray squirrels from small, isolated forest fragments in Dutchess County, New York, and added these mammals to other fragments in order to alter the abundance of these two species. We then used mark–recapture analyses to quantify the population-level and individual-level effects on resident mice, squirrels, and chipmunks. Overall, we found little evidence of competition. There were essentially no within-season numerical responses to changes in the abundance of putative competitors. Moreover, while individual-level responses (apparent survival and capture probability) did vary with competitor densities in some models, these effects were often better explained by site-specific parameters and were restricted to few of the 19 sites we studied. With only weak or nonexistent competition among these three common rodent species, we expect their patterns of habitat occupancy and population dynamics to be largely independent of one another. PMID:23824654

  13. Earlier springs are causing reduced nitrogen availability in North American eastern deciduous forests.

    PubMed

    Elmore, Andrew J; Nelson, David M; Craine, Joseph M

    2016-01-01

    There is wide agreement that anthropogenic climate warming has influenced the phenology of forests during the late twentieth and early twenty-first centuries(1,2). Longer growing seasons can lead to increased photosynthesis and productivity(3), which would represent a negative feedback to rising CO2 and consequently warming(4,5). Alternatively, increased demand for soil resources because of a longer photosynthetically active period in conjunction with other global change factors might exacerbate resource limitation(6,7), restricting forest productivity response to a longer growing season(8,9). In this case, increased springtime productivity has the potential to increase plant nitrogen limitation by increasing plant demand for nitrogen more than nitrogen supplies, or increasing early-season ecosystem nitrogen losses(10,11). Here we show that for 222 trees representing three species in eastern North America earlier spring phenology during the past 30 years has caused declines in nitrogen availability to trees by increasing demand for nitrogen relative to supply. The observed decline in nitrogen availability is not associated with reduced wood production, suggesting that other environmental changes such as increased atmospheric CO2 and water availability are likely to have overwhelmed reduced nitrogen availability. Given current trajectories of environmental changes, nitrogen limitation is likely to continue to increase for these forests, possibly further limiting carbon sequestration potential. PMID:27618399

  14. Summer global atmospheric patterns enhanced the Mediterranean East-West differences on tree growth at rear-edge temperate deciduous forests

    NASA Astrophysics Data System (ADS)

    Dorado Liñán, Isabel; Zorita, Eduardo; Gea-Izquierdo, Guillermo; Martínez-Sancho, Elisabet; Levanic, Tom; Zlatanov, Tzvetan; Di Filippo, Alfredo; Zang, Christian; Gutiérrez, Emilia; Menzel, Annette

    2016-04-01

    Overlaid to a general decrease on European beech and Sessile oak tree growth over the recent decades in the Mediterranean Basin, tree-ring records from western populations display a stronger growth decrease than eastern populations. We investigate here to what extent this spatial pattern of tree growth can be explained by the impact of sustained atmospheric circulation patterns in summertime. We use Canonical Correlation Analysis, a statistical method that identifies the patterns of two multivariate variables that are optimally correlated. A generalized change in growth trends, turning from a general increase during the period 1950-1981 to a generalized decrease in growth observed during the last three decades can be attributed to increasing summer temperatures, which exerts a dominant and negative influence on tree growth across sites. However, summer precipitation has gained in importance coinciding with the intensification of the geographical differences in tree sensitivity across the Mediterranean Basin. This intensification of the geographical differences in tree- growth during the last three decades can be traced back to an intensification of the Summer North Atlantic Oscillation that imparts an east-west dipole in summer precipitation. Under persistent positive SNAO, western populations are expected to face harsher summer conditions than central and eastern rear-edge populations, due to stronger decrease of precipitation in the west Mediterranean Basin. This increase in xericity will likely be negative for temperate deciduous broadleaf species at the rear-edge of their distribution in the Mediterranean Basin.

  15. Climatic and management influence on the carbon sequestration capacity of a deciduous oak coppice forest in Italy

    NASA Astrophysics Data System (ADS)

    Belelli Marchesini, L.; Rey Simó, A.; Papale, D.; Valentini, R.

    2010-12-01

    Recent updated estimates of the carbon balance of European forests based on a suite of ecological inventories and models confirmed their active role as sink (Ciais at al. 2008, Luyssaert et al. 2010), determined primarily by the management applied in the last decades with wood removals being lower than Net Primary Productivity (NPP). Eddy covariance (EC) continuous measurements of CO2 fluxes can detect responses of the carbon dynamics to environmental or management factors in the short term, overcoming the limitation of inventories representing a snapshot of the carbon pools typically at temporal resolution of several years or decades. However the majority of EC studies, so far performed mostly on middle-aged or mature stands, still have poorly investigated the role of actively managed forest types such as coppices, the changes in the Net Ecosystem Produtivity (NEP) over long chronosequence data and ultimately their capacity to store the uptaken atmospheric carbon in the long term. In the framework of the Carbo-Extreme EU project, we present an analysis of Net Ecosystem Exchange (NEE) of a deciduous oak (Quercus cerris L.) coppice forest in central Italy (Roccarespampani site) monitored during the years 2000-2008 over two differently aged forest stands covering almost all the stages of the 20 years rotation period. After coppicing the forest ecosystem turned into a net C source for 1 year only, then it intensified its sink strength along with stand age (R2=0.66; P<0.001) up to a maximum observed NEE of -1077.9 gC m-2 yr-1. This trend was explained by a decreasing ratio between Ecosystem Respiration (Reco) and Gross Primary Productivity (GPP)(R2=0.70; P<0.001), underlying the noticeable effect of the harvesting on the enhancement of soil CO2 effluxes, partly because of altered microclimatic conditions but also due to changes in the availability of decomposable substrate and nutrients, as witnessed by a negative correlation of temperature independent basal

  16. Synoptic Climatological Approaches to Assessing Subcanopy Hydrologic and Nutrient Fluxes in a Temperate Deciduous Forest

    NASA Astrophysics Data System (ADS)

    Siegert, C. M.; Levia, D. F.; Leathers, D. J.

    2012-12-01

    The partitioning of precipitation incident to a forest canopy into throughfall and stemflow is controlled by biotic and abiotic factors. Biotic factors include canopy architecture, bark and leaf morphology, and leaf presence whereas abiotic factors include precipitation, antecedent moisture conditions, and wind speed. Previous studies relating the subcanopy hydrologic flux to storm events consider the aforementioned abiotic factors at the event level. This research applies atmospheric classification methods from the field of synoptic climatology to relate large scale weather patterns to local forest hydrologic conditions. A daily synoptic calendar is employed to categorize the observed subcanopy hydrologic flux during storm events and is evaluated as a tool for historical reconstruction and future prediction of forest hydrologic conditions as precipitation regimes are influenced by climate change. At the seasonal scale, the majority of precipitation occurs in 4 out of 13 synoptic types in winter, 4 out of 13 in spring, 2 out of 9 in summer, and 5 out of 11 in autumn, the remaining synoptic types are dominated by fair weather conditions (although small precipitation amounts are sometimes observed). During the study period, precipitation is correctly predicted by synoptic types 82% of the time in winter, 70% in spring, 88% in summer, and 73% in autumn. Analysis of variance (ANOVA) indicates that spring, summer, and fall precipitation-producing synoptic types predict statistically different subcanopy throughfall fluxes. The absence of foliage and more homogenous winter canopy may diminish the predictive ability of synoptic typing in regards to throughfall at that time of year. Biogeochemical canopy fluxes associated with storm events are also distinguishable using the synoptic calendar.

  17. Characterization of Transpiration in a Deciduous Forest of the US Midwest

    NASA Astrophysics Data System (ADS)

    Dragoni, D.; Caylor, K. K.; Schmid, H.

    2006-12-01

    The exchange of water between atmosphere and biosphere is an important determinant of climate and the productivity of vegetation, as transpiration involves substantial amounts of energy. Knowing how transpiration changes over seasonal and diurnal cycles can help increase the understanding of how a forest reacts to changes in the biosphere and atmosphere on both short and long time scales. A study was conducted to characterize the daily and seasonal variation of transpiration in sugar maple (Acer Saccharum) at the Morgan-Monroe State Forest (MMSF) AmeriFlux site in Indiana (USA), were this species represent more than 25% of the forest basal area. Transpiration was estimated by up-scaling single point measurements of sap flow density obtained using the heat-pulse technique. To characterize the variability of sap flow density in the deep sapwood of sugar maples, 3 to 4 radial profiles were obtained for each sampled tree at different positions around the trunk. Different approaches were then tested to scale up to whole tree sap flow. Seventeen trees of different diameter were sampled by three roving sap flow systems, taking measurements from each tree for 5-7 contiguous days. Because of the small scale but complex topography in the area and the relatively shallow soil, particular attention was given to the effect of spatial and temporal variability of soil moisture content on transpiration; for this reason, sampled trees were selected along a topographic gradient and soil water content was measured in the proximity of each tree. Meteorological measurements taken at the nearby MMSF AmeriFlux tower were used to explain transpiration variability in terms of vapor pressure deficit, and solar radiation, while eddy- covariance measurements of latent heat flux were related to the up-scaled transpiration of sugar maples in the study area.

  18. Isoprene Fluxes Measured By Eddy-correlation Over A Mixed Deciduous Forest In Italy

    NASA Astrophysics Data System (ADS)

    Finco, A.; Cieslik, S.

    A measuring campaign was conducted from July to September 2001 at a mixed de- ciduous forest located at a flat site (Nonantola, 4441' N; 1107' E) in the North- ern Italian plain to determine isoprene fluxes. The measuring station, operated by the CNR-ISAO (Bologna ) and CNR-IATA (Florence) was part of the CARBOEU- ROFLUX network, whose main goal is the study of the carbon balance in European forests. The flux measuring system used the eddy-correlation technique and consisted of a Gill sonic anemometer installed at 13 m a.g.l., and a LI-COR CO2/H2O analyser. For isoprene, a Hills Fast Isoprene Sensor was used.In this forest, about 50% of the trees (oaks, poplars and willows) are isoprene emitters. The canopy is very dense and homogeneous; its average height is 8 meters a.g.l. The general daily course of isoprene concentrations consisted in an increase during morning hours, followed with a sharp maximum and a rapid decrease. Maximum val- ues were quite high (around 15 ppb) in July and August, decreasing in September. During daytime, fluxes appeared to be strongly correlated with latent heat fluxes, con- firming the hypothesis of emission through stomata. The concentration decrease ob- served in the afternoon shows exponential decay, suggesting that no emission occurs after the concentration maximum, when stomata are progressively closing. A resistance analysis confirmed the above hypothesis : the role of stomatal emission appears essential, practically excluding other pathways. A mathematical investigation of the stationarity state of the lower atmosphere dur- ing the observations was made in order to draw attention on limitations of the eddy- correlation method. During nighttime, non-stationary situations are frequent, causing apparent peaks of isoprene flux, not due to an emission from the plants. The method developed permits to eliminate these biases.

  19. Evaluating ammonia deposition rates for deciduous forest using measurements and modelling

    NASA Astrophysics Data System (ADS)

    Hansen, K.; Geels, C.; Hertel, O.; Skjøth, C. A.; Jensen, B.; Soerensen, L. L.; Boegh, E.

    2012-04-01

    Atmospheric ammonia (NH3) is a major contributor to soil acidification and eutrophication of natural terrestrial ecosystem leading to e.g. reduced biodiversity (Erisman et al. 2007, Environmental Pollution, Stevens et al. 2004, Science, Sutton et al. 2009, Biogeoscience). In order to assess these impacts, quantifying the magnitude of the NH3 flux in the biosphere atmosphere system is essential. Model simulations using the Danish Ammonia Modelling System (DAMOS) have recently indicated that particular forest ecosystems are exposed to critical load exceedances of N (Geels et al., not yet submitted). However, there are relatively few datasets of atmospheric NH3 fluxes available for forests which can contribute verifying model results. The atmospheric dry deposition of NH3 for the beech (Fagus sylvatica) forest, Lille Bøgeskov, in Sorø, Denmark, is investigated using the high resolution micrometeorological measuring technique, Relaxed Eddy Accumulation (REA), for 26 October - 11 November 2010. Measurements of atmospheric NH3 concentrations and fluxes are compared to local-scale model simulations using the Danish Ammonia Modelling System (DAMOS). It was found that long-term measured and modelled atmospheric mean concentrations of NH3 agreed well within the range of 0.56-0.68 µg NH3-N m-3, however, observed emission fluxes of up to app. 0.8 µg NH3-N m-2 s-1 after leaf fall were not represented by DAMOS because the model system does not consider vegetative and soil NH3 emissions from non-agricultural areas (Skjøth et al. 2011, ACPD). New atmospheric NH3 flux measurements for Lille Bøgeskov have been conducted throughout 2011 and these data are presented and discussed in relation to the 2010 data of atmospheric NH3. Future studies aim to improve the description of dry deposition of NH3 for vegetative surfaces in local-scale models whereby the NH3 vegetative emission and its contribution to the atmospheric NH3 concentration and flux is considered.

  20. Observations of ultra-fine particles above a deciduous forest in Denmark

    NASA Astrophysics Data System (ADS)

    Pryor, S. C.; Barthelmie, R. J.; Prip, H.; Sørensen, L. L.

    2005-03-01

    We report physical particle size distribution and chemical composition data over a Beech forest in Denmark during May and June of 2004 with a focus on four days characterized by high concentrations of ultra-fine particles. Highest number concentrations of sub-30 nm particles were observed when net radiation >300 W m-2 and ambient particle surface area <100 μm2 cm-3. The 10-30 nm particles show growth rates of 1.5-4.5 nm hr-1 and are comprised predominantly of ammonium, sulfate and associated water.

  1. Surface forest fire spreading to the fall-off of coniferous and deciduous trees

    NASA Astrophysics Data System (ADS)

    Dolgov, A. A.; Reino, V. V.; Tsvyk, Ruvim S.; Sherstobitov, M. V.

    1999-11-01

    Experimental results on forest combustibles (FC) burning are treated in the paper. The relations V equals V0exp(-W2/W02) are proposed to describe the dependence of the burning front movement velocity on the humidity W (V0 equals 3 mm/s is the velocity of the burning front movement for dry FC). Maximum radiation temperature of the condensed phase burning within the range of the 3 to 12 micrometers , reconstructed by the blackbody radiation law at the radiation coefficient (epsilon) of 1, is 800 - 900 K for dry needles of pine and cedar. The higher is humidity, the lower is the maximum radiation temperature.

  2. Phosphorus cycling in deciduous forest soil differs between stands dominated by ecto- and arbuscular mycorrhizal trees.

    PubMed

    Rosling, Anna; Midgley, Meghan G; Cheeke, Tanya; Urbina, Hector; Fransson, Petra; Phillips, Richard P

    2016-02-01

    Although much is known about how trees and their associated microbes influence nitrogen cycling in temperate forest soils, less is known about biotic controls over phosphorus (P) cycling. Given that mycorrhizal fungi are instrumental for P acquisition and that the two dominant associations - arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) fungi - possess different strategies for acquiring P, we hypothesized that P cycling would differ in stands dominated by trees associated with AM vs ECM fungi. We quantified soil solution P, microbial biomass P, and sequentially extracted inorganic and organic P pools from May to November in plots dominated by trees forming either AM or ECM associations in south-central Indiana, USA. Overall, fungal communities in AM and ECM plots were functionally different and soils exhibited fundamental differences in P cycling. Organic forms of P were more available in ECM plots than in AM plots. Yet inorganic P decreased and organic P accumulated over the growing season in both ECM and AM plots, resulting in increasingly P-limited microbial biomass. Collectively, our results suggest that P cycling in hardwood forests is strongly influenced by biotic processes in soil and that these are driven by plant-associated fungal communities. PMID:26510093

  3. Nighttime Chemistry and Morning Isoprene Can Drive Urban Ozone Downwind of a Major Deciduous Forest.

    PubMed

    Millet, Dylan B; Baasandorj, Munkhbayar; Hu, Lu; Mitroo, Dhruv; Turner, Jay; Williams, Brent J

    2016-04-19

    Isoprene is the predominant non-methane volatile organic compound emitted to the atmosphere and shapes tropospheric composition and biogeochemistry through its effects on ozone, other oxidants, aerosols, and the nitrogen cycle. Isoprene is emitted naturally by vegetation during daytime, when its photo-oxidation is rapid, and in the presence of nitrogen oxides (NOx) produces ozone and degrades air quality in polluted regions. Here, we show for a city downwind of an isoprene-emitting forest (St. Louis, MO) that isoprene actually peaks at night; ambient levels then endure, owing to low nighttime OH radical concentrations. Nocturnal chemistry controls the fate of that isoprene and the likelihood of a high-ozone episode the following day. When nitrate (NO3) radicals are suppressed, high isoprene persists through the night, providing photochemical fuel upon daybreak and leading to a dramatic late-morning ozone peak. On nights with significant NO3, isoprene is removed before dawn; days with low morning isoprene then have lower ozone with a more typical afternoon peak. This biogenic-anthropogenic coupling expands the daily high-ozone window and likely has an opposite O3-NOx response to what would otherwise be expected, with implications for exposure and air-quality management in cities that, like St. Louis, are downwind of major isoprene-emitting forests. PMID:27010702

  4. Effects of experimental soil warming on soil, autotrophic and heterotrophic respirations in cool-temperate deciduous broad-leaved forests

    NASA Astrophysics Data System (ADS)

    Noh, N.; Kuribayashi, M.; Saitoh, T. M.; Nakamura, M.; Nakaji, T.; Hiura, T.; Muraoka, H.

    2013-12-01

    Global warming has the potential to impact on soil respiration (Rs), one of the major fluxes in the global carbon cycle. The different responses of autotrophic (Ra) and heterotrophic (Rh) components of Rs to increasing temperature are expected to have significant consequences for forest ecosystem carbon dynamics. Furthermore, clarification of site-specific difference in their temperature responses is also important for estimating future carbon dynamics in global scale. Here we report the results of open-field soil warming experiments to examine the effects of elevated temperature on the respiration rates in cool-temperate deciduous broad-leaved mature forests in Japan. The experiments were carried out in two JaLTER sites, Takayama in central Japan (TKY, 36○08'N, 137○25'E) and Tomakomai in Hokkaido island of northern Japan (TOEF, 42○40'N, 141○36'E). The dominant tree species (Quercus crispula) and annual mean air temperature (6.5-6.6○C) are similar between the sites. Our objectives were to quantify the effects of soil warming (+3○C in TKY and +4.7○C in TOEF) on the respiration rates, and to determine their sensitivities to given temperature condition. Artificial warming was conducted by installing heating cables into the soil. In addition, to assess how Rs, Ra, and Rh are affected by the treatment differently, we combined the soil warming treatment and trenching treatment in both sites. The warming treatments enhanced annual Rs by 15% (1.2 t C/ha/yr) in TKY and 34% (2.4 t C/ha/yr) in TOEF, and Rh in the first half-year after trenching treatment by 53% in TKY and 52% in TOEF, respectively. Temperature sensitivities of Rs acclimatized to the warming treatment in both sites, while Ra and Rh responded differently to temperature increase between TKY and TOEF. Our results indicate that the responses of those variables to experimental warming differ depending on soil conditions (e.g. soil properties and root distributions) even in the similar forest ecosystem

  5. Observations of 14CO2 in ecosystem respiration from a temperate deciduous forest in Northern Wisconsin

    NASA Astrophysics Data System (ADS)

    Phillips, Claire L.; McFarlane, Karis J.; LaFranchi, Brian; Desai, Ankur R.; Miller, John B.; Lehman, Scott J.

    2015-04-01

    The 14CO2 composition of plant and soil respiration can be used to determine the residence time of photosynthetically fixed carbon before it is released back to the atmosphere. To estimate the residence time of actively cycled carbon in a temperate forest, we employed two approaches for estimating the Δ14CO2 of ecosystem respiration (Δ14C-Reco) at the Willow Creek AmeriFlux site in Northern Wisconsin, USA. Our first approach was to construct nighttime Keeling plots from subcanopy profiles of Δ14CO2 and CO2, providing estimates of Δ14C-Reco of 121.7‰ in June and 42.0‰ in August 2012. These measurements are likely dominated by soil fluxes due to proximity to the ground level. Our second approach utilized samples taken over 20 months within the forest canopy and from 396 m above ground level at the nearby LEF NOAA tall tower site (Park Falls, WI). In this canopy-minus-background approach we employed a mixing model described by Miller and Tans (2003) for estimating isotopic sources by subtracting time-varying background conditions. For the period from May 2011 to December 2012 the estimated Δ14C-Reco using the Miller-Tans model was 76.8‰. Together, these Δ14C-Reco values represent mean Reco carbon ages of approximately 1-19 years. We also found that heterotrophic soil-respired Δ 14C at Willow Creek was 5-38‰ higher (i.e., 1-10 years older) than predicted by the Carnegie-Ames-Stanford Approach global biosphere carbon model for the 1 × 1 pixel nearest to the site. This study provides much needed observational constraints of ecosystem carbon residence times, which are a major source of uncertainty in terrestrial carbon cycle models.

  6. Separating physical and biological controls on long-term evapotranspiration fluctuations in a tropical deciduous forest subjected to monsoonal rainfall

    NASA Astrophysics Data System (ADS)

    Igarashi, Yasunori; Katul, Gabriel G.; Kumagai, Tomo'omi; Yoshifuji, Natsuko; Sato, Takanori; Tanaka, Nobuaki; Tanaka, Katsunori; Fujinami, Hatsuki; Suzuki, Masakazu; Tantasirin, Chatchai

    2015-07-01

    Evapotranspiration (ET), especially in the mainland of the Indochina Peninsula, can impact and is impacted by the Asian monsoonal (AM) system, thereby prompting interest in its long-term variability. To separate the physical and biological factors controlling ET variability in a tropical deciduous forest under the AM influence, 7 year eddy covariance and ancillary measurements were collected and analyzed. The 7 year mean rainfall (Pr) and ET along with their standard deviations were 1335 ± 256 and 977 ± 108 mm (about 73% of Pr), respectively, suggesting close coupling between these two hydrologic fluxes. However, other physical and biological drivers decouple seasonal and annual variations of ET from Pr. To explore them, a big-leaf model complemented by perturbation analysis was employed. The big-leaf model agreed well with the measured ET at daily to multiyear time scales, lending confidence in its ability to separate biological and physical controls on ET. Using this formulation, both first-order and second-order Taylor series expansions of the total ET derivatives were applied to the big-leaf model and compared with measured changes in ET (dET). Higher-order and joint terms in the second-order expansion were necessary for matching measured and analyzed dET. Vapor pressure deficit (D) was the primary external physical controlling driver of ET. Leaf area index (LAI) and bulk stomatal conductance (gs) were shown to be the main significant biological drivers of the transpiration component of ET. It can be surmised that rainfall variability controls long-term ET through physical (mainly D) and biological (mainly LAI and gs) factors in this ecosystem.

  7. Long-term half-hourly measurement of soil CO2 concentration and soil respiration in a temperate deciduous forest

    NASA Astrophysics Data System (ADS)

    Hirano, Takashi; Kim, Honghyun; Tanaka, Yumiko

    2003-10-01

    We conducted a field experiment in a cool-temperate deciduous forest to investigate the dynamic behavior of soil CO2 and the vertical distribution of soil respiration. Soil CO2 concentration (C) was measured half-hourly at four depths for 6 months in 2000 with infrared gas analyzers installed below ground. Using C profiles, soil surface CO2 efflux (F0), CO2 production rates of the topsoil (PA), and CO2 flux from the subsoil to topsoil (FCA) were evaluated half-hourly by applying Fick's first law. Some remarkable short-term and long-term variations were found in C, F0, PA, FCA, and the contribution of topsoil respiration to total soil respiration (PA/F0), which include (1) rapid increase in C and decrease in F0 and PA due to rainwater infiltration, (2) diurnal variation in C coupled with that of the atmosphere, (3) diurnal variation in F0 and PA similar to that of topsoil temperature, (4) decrease in C, F0, and PA following soil drying in August, (5) linearly increasing FCA between late May and mid-September, and (6) decrease in PA/F0 from around 0.9 during summer to 0.3 in November. The variation of PA was mainly controlled by soil temperature at -0.07 m between 7° and 17°C, although PA did not respond well to soil temperature above and below this temperature range. Above 17°C, PA increased linearly with soil moisture, and moisture variation accounted for the PA decrease in August. Neither temperature nor moisture explained the PA behavior below 7°C. Subsoil respiration (FCA) showed an exponential relationship with soil temperature at -1 m.

  8. Effects of redispersal of seeds by ants on the vegetation patternin a deciduous forest: A case study

    NASA Astrophysics Data System (ADS)

    Gorb, Stanislav N.; Gorb, Elena V.; Punttila, Pekka

    2000-07-01

    The floristic composition and distribution of mature plants, seedlings, and soil-seed material in both ant territories and territory borders between colonies of two ant species, Lasius fuliginosus and Formica polyctena, were compared in a deciduous forest in central Ukraine. Additional seed samples were taken from ant nests. Workers of both species collect seeds of myrmecochores, but only individuals of F. polyctena relocate seeds to territory borders after the removal of elaiosomes. Borders of F. polyctena territories are thus 'garbage dumps' of waste organic material and probably also nutrient-enriched microsites. The floristic composition of L. fuliginosus' territory differed from that of the territory borders and F. polyctena territory owing to a lower abundance of myrmecochores in the former. There were no great differences in the abundance or in the number of species (altogether fourteen species) in mature myrmecochores or non-myrmecochores among the sampling sites. However, the abundance and to some extent the number of species (altogether 21 species) of seedlings of myrmecochores (but not of non-myrmecochores) were lower in L. fuliginosus territory than in the other sampling sites. In particular, seedlings of two large-seeded myrmecochores, Asarum europaeum and Viola odorata, were more abundant in territory borders than in the territories. With a small-seeded myrmecochore, Ballota nigra, no such differences were found. Seeds of large-seeded myrmecochores, small-seeded myrmecochores and non-myrmecochores were more abundant than expected in the territory borders, in the nest of L. fuliginosus, in the nest of F. polyctena, respectively. It is suggested that seed flow from F. polyctena nests to the territory borders results in an increase in the seed-dispersal distances from the parent plant and among seeds dispersed in both small- and large-seeded myrmecochores. In large-seeded myrmecochores, this also results in a higher likelihood of reaching 'garbage dumps

  9. Temporal variability of water fluxes and surface energy exchanges over a Low Deciduous Forest in the NAM region

    NASA Astrophysics Data System (ADS)

    Garatuza-Payan, J.; Watts, C. J.; Rodriguez, J. C.

    2007-05-01

    In this study the seasonal and yearly variability of latent heat flux and surface energy exchanges over a Low Deciduous Forest (LDF) is investigated. The LDF is one of the most diverse and most contrasting ecosystems in Mexico. It can be found from the south of Sonora to the border of Mexico with Guatemala. In the present study, the CO2 fluxes over the LDF were analyzed in the period from June 2004 to December 2006. The CO2, latent and sensible heat, and momentum fluxes were measured using the Eddy covariance method. The Eddy covariance system consists of a 3-D sonic anemometer (CSAT3, Campbell Scientific), a gas analyzer (LI-7500, LI-COR), and diverse meteorological equipment controlled by a datalogger (CR5000, Campbell Scientific). The measures were made at 10Hz, collecting, storing and averaging the measurements every 30 minutes. The same type of cover is present in, at least, 3 km around the tower. The measurements show some variability in total rainfall (400-500 mm/year), average latent and sensible heat flux (30-35 and 65-72 w m-2, respectively), radiation balance (118-127 w m-2). Reflectances vary from 0.15 during the dry season to 0.05 after the rainy season and from 0.35 to 0.15 for the red and near infrared regions respectively resulting in NDVI values ranging from 0.3 to 0.85 with an abrupt change just after the monsoon starts accompanied by a decrease in surface temperature (from 329 to 300 K, during the day). Despite of these changes, albedo only varies marginally, from 0.12 to 0.09. This ecosystem presents a clear growing season corresponding to the rain season in the summer.

  10. Ecosystem-scale volatile organic compound fluxes during an extreme drought in a broadleaf temperate forest of the Missouri Ozarks (central USA)

    SciTech Connect

    Seco, Roger; Karl, Thomas; Guenther, Alex; Hosman, Kevin P.; Pallardy, Stephen G.; Gu, Lianhong; Geron, Chris; Harley, Peter; Kim, Saewung

    2015-07-07

    Considerable amounts and varieties of biogenic volatile organic compounds (BVOCs) are exchanged between vegetation and the surrounding air. These BVOCs play key ecological and atmospheric roles that must be adequately represented for accurately modeling the coupled biosphere–atmosphere–climate earth system. One key uncertainty in existing models is the response of BVOC fluxes to an important global change process: drought. Here, we describe the diurnal and seasonal variation in isoprene, monoterpene, and methanol fluxes from a temperate forest ecosystem before, during, and after an extreme 2012 drought event in the Ozark region of the central USA. BVOC fluxes were dominated by isoprene, which attained high emission rates of up to 35.4 mg m 2 h 1 at midday. Methanol fluxes were characterized by net deposition in the morning, changing to a net emission flux through the rest of the daylight hours. Net flux of CO2 reached its seasonal maximum approximately a month earlier than isoprenoid fluxes, which highlights the differential response of photosynthesis and isoprenoid emissions to progressing drought conditions. Nevertheless, both processes were strongly suppressed under extreme drought, although isoprene fluxes remained relatively high compared to reported fluxes from other ecosystems. Methanol exchange was less affected by drought throughout the season, confirming the complex processes driving biogenic methanol fluxes. The fraction of daytime (7–17 h) assimilated carbon released back to the atmosphere combining the three BVOCs measured was 2% of gross primary productivity (GPP) and 4.9% of net ecosystem exchange (NEE) on average for our whole measurement campaign, while exceeding 5% of GPP and 10% of NEE just before the strongest drought phase. In conclusion, the MEGANv2.1 model correctly predicted diurnal variations in fluxes driven mainly by light and temperature, although further research is needed to address model BVOC fluxes during drought

  11. Ecosystem-scale volatile organic compound fluxes during an extreme drought in a broadleaf temperate forest of the Missouri Ozarks (central USA)

    DOE PAGESBeta

    Seco, Roger; Karl, Thomas; Guenther, Alex; Hosman, Kevin P.; Pallardy, Stephen G.; Gu, Lianhong; Geron, Chris; Harley, Peter; Kim, Saewung

    2015-07-07

    Considerable amounts and varieties of biogenic volatile organic compounds (BVOCs) are exchanged between vegetation and the surrounding air. These BVOCs play key ecological and atmospheric roles that must be adequately represented for accurately modeling the coupled biosphere–atmosphere–climate earth system. One key uncertainty in existing models is the response of BVOC fluxes to an important global change process: drought. Here, we describe the diurnal and seasonal variation in isoprene, monoterpene, and methanol fluxes from a temperate forest ecosystem before, during, and after an extreme 2012 drought event in the Ozark region of the central USA. BVOC fluxes were dominated by isoprene,more » which attained high emission rates of up to 35.4 mg m 2 h 1 at midday. Methanol fluxes were characterized by net deposition in the morning, changing to a net emission flux through the rest of the daylight hours. Net flux of CO2 reached its seasonal maximum approximately a month earlier than isoprenoid fluxes, which highlights the differential response of photosynthesis and isoprenoid emissions to progressing drought conditions. Nevertheless, both processes were strongly suppressed under extreme drought, although isoprene fluxes remained relatively high compared to reported fluxes from other ecosystems. Methanol exchange was less affected by drought throughout the season, confirming the complex processes driving biogenic methanol fluxes. The fraction of daytime (7–17 h) assimilated carbon released back to the atmosphere combining the three BVOCs measured was 2% of gross primary productivity (GPP) and 4.9% of net ecosystem exchange (NEE) on average for our whole measurement campaign, while exceeding 5% of GPP and 10% of NEE just before the strongest drought phase. In conclusion, the MEGANv2.1 model correctly predicted diurnal variations in fluxes driven mainly by light and temperature, although further research is needed to address model BVOC fluxes during drought events.« less

  12. Ecosystem-scale volatile organic compound fluxes during an extreme drought in a broadleaf temperate forest of the Missouri Ozarks (central USA).

    PubMed

    Seco, Roger; Karl, Thomas; Guenther, Alex; Hosman, Kevin P; Pallardy, Stephen G; Gu, Lianhong; Geron, Chris; Harley, Peter; Kim, Saewung

    2015-10-01

    Considerable amounts and varieties of biogenic volatile organic compounds (BVOCs) are exchanged between vegetation and the surrounding air. These BVOCs play key ecological and atmospheric roles that must be adequately represented for accurately modeling the coupled biosphere-atmosphere-climate earth system. One key uncertainty in existing models is the response of BVOC fluxes to an important global change process: drought. We describe the diurnal and seasonal variation in isoprene, monoterpene, and methanol fluxes from a temperate forest ecosystem before, during, and after an extreme 2012 drought event in the Ozark region of the central USA. BVOC fluxes were dominated by isoprene, which attained high emission rates of up to 35.4 mg m(-2)  h(-1) at midday. Methanol fluxes were characterized by net deposition in the morning, changing to a net emission flux through the rest of the daylight hours. Net flux of CO2 reached its seasonal maximum approximately a month earlier than isoprenoid fluxes, which highlights the differential response of photosynthesis and isoprenoid emissions to progressing drought conditions. Nevertheless, both processes were strongly suppressed under extreme drought, although isoprene fluxes remained relatively high compared to reported fluxes from other ecosystems. Methanol exchange was less affected by drought throughout the season, confirming the complex processes driving biogenic methanol fluxes. The fraction of daytime (7-17 h) assimilated carbon released back to the atmosphere combining the three BVOCs measured was 2% of gross primary productivity (GPP) and 4.9% of net ecosystem exchange (NEE) on average for our whole measurement campaign, while exceeding 5% of GPP and 10% of NEE just before the strongest drought phase. The meganv2.1 model correctly predicted diurnal variations in fluxes driven mainly by light and temperature, although further research is needed to address model BVOC fluxes during drought events. PMID:25980459

  13. Ecosystem-scale volatile organic compound fluxes during an extreme drought in a broadleaf temperate forest of the Missouri Ozarks (central USA)

    SciTech Connect

    Seco, Roger; Karl, Thomas; Guenther, Alex B.; Hosman, Kevin P.; Pallardy, Stephen G.; Gu, Lianhong; Geron, Chris; Harley, Peter; Kim, Saewung

    2015-07-07

    Considerable amounts and varieties of biogenic volatile organic compounds (BVOCs) are exchanged between vegeta-tion and the surrounding air. These BVOCs play key ecological and atmospheric roles that must be adequately repre-sented for accurately modeling the coupled biosphere–atmosphere–climate earth system. One key uncertainty in existing models is the response of BVOC fluxes to an important global change process: drought. We describe the diur-nal and seasonal variation in isoprene, monoterpene, and methanol fluxes from a temperate forest ecosystem before, during, and after an extreme 2012 drought event in the Ozark region of the central USA. BVOC fluxes were domi-nated by isoprene, which attained high emission rates of up to 35.4 mg m-2h-1 at midday. Methanol fluxes were characterized by net deposition in the morning, changing to a net emission flux through the rest of the daylight hours. Net flux of CO2 reached its seasonal maximum approximately a month earlier than isoprenoid fluxes, which high-lights the differential response of photosynthesis and isoprenoid emissions to progressing drought conditions. Never-theless, both processes were strongly suppressed under extreme drought, although isoprene fluxes remained relatively high compared to reported fluxes from other ecosystems. Methanol exchange was less affected by drought throughout the season, conflrming the complex processes driving biogenic methanol fluxes. The fraction of daytime (7–17 h) assimilated carbon released back to the atmosphere combining the three BVOCs measured was 2% of gross primary productivity (GPP) and 4.9% of net ecosystem exchange (NEE) on average for our whole measurement cam-paign, while exceeding 5% of GPP and 10% of NEE just before the strongest drought phase. The MEGANv2.1 model correctly predicted diurnal variations in fluxes driven mainly by light and temperature, although further research is needed to address model BVOC fluxes

  14. CO2 enrichment increases carbon and nitrogen input from fine roots in a deciduous forest.

    PubMed

    Iversen, Colleen M; Ledford, Joanne; Norby, Richard J

    2008-01-01

    * Greater fine-root production under elevated [CO2] may increase the input of carbon (C) and nitrogen (N) to the soil profile because fine root populations turn over quickly in forested ecosystems. * Here, the effect of elevated [CO)] was assessed on root biomass and N inputs at several soil depths by combining a long-term minirhizotron dataset with continuous, root-specific measurements of root mass and [N]. The experiment was conducted in a CO(2)-enriched sweetgum (Liquidambar styraciflua) plantation. * CO2) enrichment had no effect on root tissue density or [N] within a given diameter class. Root biomass production and standing crop were doubled under elevated [CO2]. Though fine-root turnover declined under elevated [CO2], fine-root mortality was also nearly doubled under CO2 enrichment. Over 9 yr, root mortality resulted in 681 g m(-2) of extra C and 9 g m(-2) of extra N input to the soil system under elevated [CO2]. At least half of these inputs were below 30 cm soil depth. * Increased C and N input to the soil under CO2 enrichment, especially below 30 cm depth, might alter soil C storage and N mineralization. Future research should focus on quantifying root decomposition dynamics and C and N mineralization deeper in the soil. PMID:18537885

  15. Mapping of deciduous forest cover using simulated Landsat-D TM data

    NASA Technical Reports Server (NTRS)

    Rock, B. N.

    1982-01-01

    An evaluation is presented of the supervised vegetation classification images of heavily forested terrain in the eastern US produced from simulated Landsat-D Thematic Mapper data as part of the Joint NASA/Geosat Test Case study of the Lost River, West Virginia, gas field. This investigation utilized data supplied by the NS-001 aircraft multispectral scanner (15 m IFOV) of NASA. The instruments recognized a total of 9 vegetation classes and one soil class. A hybrid parallelepiped-Bayesian maximum likelihood classifier was employed to produce the supervised vegetation classifications. The data were obtained at the height of the fall foliage display for this portion of West Virginia. Results show that both classifications are highly accurate, based on a comparison of assignment of vegetation classes on each of the images with actual ground conditions. It is noted that the anomalous distribution of certain woody species found in the resulting supervised classifications may be related to the microseepage of methane from the gas reservoir.

  16. CO2 enrichment increases carbon and nitrogen input from fine roots in a deciduous forest.

    SciTech Connect

    Iversen, Colleen M; Childs, Joanne; Norby, Richard J

    2008-08-01

    Greater root production under elevated [CO2] may drive changes in soil C storage and N cycling. However, this depends on root population turnover and chemistry, and the soil depth at which the roots are produced. We assessed the effect of elevated [CO2] on root biomass and N inputs at several soil depths using a long-term minirhizotron data set combined with continuous, root-specific measurements of root mass per unit length and [N]. Our experiment was conducted in a Liquidambar styraciflua forest stand exposed to current or elevated atmospheric [CO2] for 9 years. CO2-enrichment had no effect on root tissue density or [N] within a given diameter class. Root biomass production, standing crop and mortality were doubled under elevated [CO2]. Over 9 years, root mortality resulted in 681 g m-2 of extra C and 9 g m-2 of extra N input to the soil system under elevated [CO2]. At least half of these inputs were below 30 cm soil depth. Quantification of the effects of elevated CO2 on root detritus, especially at depth in the soil, will provide critical information needed for predicting processes such as long-term soil C storage and N cycling.

  17. Drought during canopy development has lasting effect on annual carbon balance in a deciduous temperate forest.

    PubMed

    Noormets, Asko; McNulty, Steve G; DeForest, Jared L; Sun, Ge; Li, Qinglin; Chen, Jiquan

    2008-01-01

    * Climate change projections predict an intensifying hydrologic cycle and an increasing frequency of droughts, yet quantitative understanding of the effects on ecosystem carbon exchange remains limited. * Here, the effect of contrasting precipitation and soil moisture dynamics were evaluated on forest carbon exchange using 2 yr of eddy covariance and microclimate data from a 50-yr-old mixed oak woodland in northern Ohio, USA. * The stand accumulated 40% less carbon in a year with drought between bud-break and full leaf expansion (354 +/- 81 g C m(-2) yr(-1) in 2004 and 252 +/- 45 g C m(-2) yr(-1) in 2005). This was caused by greater suppression of gross ecosystem productivity (GEP; 16% = 200 g) than of ecosystem respiration (ER; 11% = 100 g) by drought. Suppressed GEP was traced to lower leaf area, lower apparent quantum yield and lower canopy conductance. The moisture sensitivity of ER may have been mediated by GEP. * The results highlight the vulnerability of the ecosystem to even a moderate drought, when it affects a critical aspect of development. Although the drought was preceded by rain, the storage capacity of the soil seemed limited to 1-2 wk, and therefore droughts longer than this are likely to impair productivity in the region. PMID:18537894

  18. Representing Sub-Plot Canopy Heterogeneity Improves Model Prediction of Net Ecosystem Exchange in a Mixed-Deciduous Forest

    NASA Astrophysics Data System (ADS)

    Frasson, R. P. M.; Bohrer, G.; Medvigy, D.; Vogel, C. S.; Gough, C. M.; Curtis, P.

    2014-12-01

    Canopy density and composition may vary within an eddy covariance tower's footprint in response to small-scale topographic features, biotic interactions such as herbivory, local disturbances, etc. We are investigating how different representations of canopy heterogeneity influence predictions of net ecosystem CO2 exchange in a mixed-deciduous forest by an age/plant functional type structured ecosystem model. Our study area is located at the University of Michigan Biological Station (UMBS) where two eddy covariance towers and periodic tree censuses provide a rich long-term record of ecosystem structure, weather, and carbon uptake. Meteorological measurements collected at the US-UMB AmeriFlux tower served to force, optimize, and evaluate the Ecosystem Demography model version 2 (ED2), while tree census information was used to initialize ED2. To test the influence that representing canopy heterogeneity has on model-tower agreement, we ran a set of ED2 site-level simulations with an increasing number of sub-grid patches. The first simulation, which we call 'aggregated', had one large patch explicitly containing all trees. The aggregated canopy represents a case where different size cohorts of each plant functional type are distributed homogeneously throughout the plot with uniform stem density. Six other simulations represented patch-level canopies with varying degrees of heterogeneity, ranging from 5 to 64 sub-plot patches; each patch represented from one to several of the 0.1 ha tree census plots. A preliminary comparison of the aggregated and the 20-plot heterogeneous simulations showed that including patch-level heterogeneity in the canopy description improved model prediction quality. For example, compared to the single-patch, aggregated simulation, including 20 sub-plot patches improved model bias in the estimated accumulated 5-year net ecosystem exchange from 17% to 5%, which is smaller than our tower observation uncertainty. As a result of this study, we will

  19. Leaf area index of a tropical semi-deciduous forest of the southern Amazon Basin

    NASA Astrophysics Data System (ADS)

    Pinto-Júnior, Osvaldo Borges; Sanches, Luciana; de Almeida Lobo, Francisco; Brandão, Adilson Amorim; de Souza Nogueira, José

    2011-03-01

    Leaf area index (LAI) is an important ecophysiological variable because leaves are the organs responsible for gas exchange between plants and the atmosphere. This variable can be calculated from primary values of leaf area assessed by destructive or non-destructive methods, which is relatively easy when crop species are investigated, but is not the case when the focus is on natural wood plants communities. In this paper, we analyze the seasonality of LAI estimated by three different methods in the Amazonia-savannah transitional forest, located 50 km north-east of Sinop city, Mato Grosso, Brazil. In the first method, we combine Monsi and Saekis' original method [Monsi M, Saeki T (1953) Jpn J Bot 14:22-52], which measures LAI using the Beer-Lambert extinction law, and the proposition of Goudriaan [Goudriaan J (1988) Agric For Meteorol 43:155-169] to estimate the extinction coefficient from solar height. The second method differed from the first only in the way in which the daily fraction of intercepted photosynthetic active radiation (FPAR) was calculated, as proposed by Charles-Edwards and Lawn (Charles-Edwards DA, Lawn RJ (1984) Plant Cell Environ 7:247-251]. In the third method, we used a remote sensing technique [MOD15_BU-collection 4, produced and distributed by EROS Data Center Distributed Active Archive Center (EDC DAAC)]. We found that the first and the second methods revealed the expected LAI dynamics, which increased during the dry-wet transition and wet season, and decreased during the wet-dry transition and dry season. From 20 randomly distributed sets in a 1.0 ha area, only 3 showed significant differences in LAI estimated from the first two methods; conversely, LAI was overestimated by the third method.

  20. Comparison of soil respiration methods in a mid-latitude deciduous forest

    SciTech Connect

    Wayson, C. A.; Randolph, J. C.; Hanson, Paul J; Schmid, H. P.; Grimmond, CSB

    2006-01-01

    In forest ecosystems the single largest respiratory flux influencing net ecosystem productivity (NEP) is the total soil CO2 efflux; however, it is difficult to make measurements of this flux that are accurate at the ecosystem scale. We examined patterns of soil CO2 efflux using five different methods: auto-chambers, portable gas analyzers, eddy covariance along and two models parameterized with the observed data. The relation between soil temperature and soil moisture with soil CO2 effluxes are also investigated, both inter-annually and seasonally, using these observations/results. Soil respiration rates (Rsoil) are greatest during the growing season when soil temperatures are between 15 and 25 C, but some soil CO2 efflux occurs throughout the year. Measured soil respiration was sensitive to soil temperature, particularly during the spring and fall. All measurement methods produced similar annual estimates. Depending on the time of the year, the eddy covariance (flux tower) estimate for ecosystem respiration is similar to or slightly lower than estimates of annual soil CO2 efflux from the other methods. As the eddy covariance estimate includes foliar and stem respiration which the other methods do not; it was expected to be larger (perhaps 15-30%). The auto-chamber system continuously measuring soil CO2 efflux rates provides a level of temporalr esolution that permits investigation of short- to longer term influences of factors on these efflux rates. The expense of building and maintaining an auto chamber system may not be necessary for those esearchers interested in estimating Rsoil annually, but auto-chambers do allow the capture of data from all seasons needed for model parameterization.

  1. Comparison of Soil Organic Matter Dynamics at Four Temperate Deciduous Forests with Physical Fractionation and Radiocarbon Measurements

    NASA Astrophysics Data System (ADS)

    McFarlane, K. J.; Torn, M. S.; Hanson, P. J.; Swanston, C.; Guilderson, T. P.; Porras, R. C.

    2009-12-01

    Forest soils represent a significant pool for C sequestration and storage, but the factors controlling soil C cycling are not well constrained. We used density fractionation and radiocarbon measurements to assess differences in soil C cycling amongst four eastern deciduous forests that are part of the AmeriFlux Network and vary in climate, soil type, parent material, and soil ecology. We collected mineral soil from 0-5 cm and 5-15 cm depth at Harvard Forest (HAF) in central Massachusetts, Bartlett Experimental Forest (BEF) in New Hampshire, the University of Michigan Biological Station (UMBS), and Baskett Wildlife Recreation and Education Area in the Missouri Ozarks (MOZ). Deeper soil samples have been collected (to 75 cm in some cases) for future analysis. We fractionated soil samples by density into free light (unprotected SOM), occluded light (physically protected SOM), and dense (mineral-protected) fractions using sodium polytungstate (1.65 g ml-1), measured C concentration and radiocarbon in bulk soil and fractions, and used a three-pool steady-state model to determine radiocarbon-based turnover times for fractions. The northeastern sites, HAF and BEF, had higher bulk soil C (65 and 40 g C kg soil-1, respectively) than did MOZ or UMBS (20 and 10 g C kg soil-1). Bulk soil radiocarbon values (Δ14C) decreased with depth and were lower at northeastern sites than Midwestern sites (36, 8, 113, and 65 ‰ for 0-5 cm at HF, BEF, MOZ, and UMBS, respectively). Soil C distribution amongst fractions was similar at HAF, BEF, and MOZ with the unprotected free light fraction containing about 40% of bulk soil C for 0-5 cm and 20% of bulk soil C for 5-15 cm. At these three sites, the physically protected occluded light fraction contained about 10% of bulk soil C, with the mineral-protected dense fraction containing the remaining 50-70%. In contrast, UMBS, the site with the sandiest soil, had a greater portion of bulk soil C recovered in the unprotected free light fraction and

  2. Leaf Area Influence on Surface Layer in a Deciduous Forest. Part 2; Detecting Leaf Area and Surface Resistance During Transition Seasons

    NASA Technical Reports Server (NTRS)

    Sakai, Ricardo K.; Fitzjarrald, David R.; Moore, Kathleen E.; Sicker, John W.; Munger, Willian J.; Goulden, Michael L.; Wofsy, Steven C.

    1996-01-01

    Temperate deciduous forest exhibit dramatic seasonal changes in surface exchange properties following on the seasonal changes in leaf area index. The canopy resistance to water vapor transport r(sub c) decreased abruptly at leaf emergence in each year but then also continued to decrease slowly during the remaining growing season due to slowly increasing LAI. Canopy resistance and PAR-albedo (albedo from photosynthetically active radiation) began to increase about one month before leaf fall with the diminishment of CO2 gradient above the canopy as well. At this time evaporation begun to be controlled as if the canopy were leafless.

  3. AmeriFlux US-MMS Morgan Monroe State Forest

    SciTech Connect

    Philip, Rich; Novick, Kim

    2016-01-01

    This is the AmeriFlux version of the carbon flux data for the site US-MMS Morgan Monroe State Forest. Site Description - Owned by the Indiana Department of Natural Resources (IDNR), the Morgan Monroe State Forest, the site's namesake, is operated thanks to the long-term agreement between Indiana University and IDNR. The first settlers cleared the surrounding ridges for farming, but were largely unsuccessful. The state of Indiana purchased the land in 1929, creating the Morgan Monroe State Forest. Many of the trees in the tower footprint are 60-80 years old, surviving selective logging that ended over the past 10 years. Today, the forest is a secondary successional broadleaf forest within the maple-beech to oak hickory transition zone of the eastern deciduous forest.

  4. Stable Isotope Fluxes of CO2 and H2O for a Temperate Deciduous Forest in Canada

    NASA Astrophysics Data System (ADS)

    Santos, E. A.; Wagner-Riddle, C.; Warland, J. S.; Brown, S. E.; Lee, X.; Kim, K.; Staebler, R. M.

    2009-12-01

    Stable isotopes of carbon dioxide and water vapor, including 13CO2, C18O16O, HDO and H218O have been used to study the carbon and water cycle. These stable isotopes are particularly useful to separate the contribution of different ecosystem components to the net flux. For example, 13CO2 can be applied as a tracer at sites where soil organic matter and plants present a different isotopic ratio. C18O16O can be used to partitioning soil from foliar respiration, since leaf water is significantly enriched in 18O during the day as a result of leaf transpiration. Continuous measurements of CO2 and H2O exchange and their isotopic values in ecosystems are necessary to better understand the processes related to isotope discrimination. The objective of this study was to investigate the isotopic fluxes of CO2 and H2O continuously in a temperate deciduous forest. The experiment was conducted at the Environment Canada research station, Camp Borden, ON, Canada from June to August 2009. Mixing ratios of C16O2, 13CO2, C18O16O, H216O, HDO and H218O in the sampled air were measured continuously using two tunable diode laser trace gas analyzers (TGA 100A, Campbell Sci., UT, USA). Air was sampled at two heights above the canopy and two heights in the under-storey. The TGA mixing ratio measurements were calibrated by regularly measuring tanks with known concentrations of CO2 isotopic species and water vapor of known isotopic ratios. Atmospheric carbon dioxide (δ13C, and δ18O) and water vapor isotope ratios were calculated, and the isotope signatures of CO2 (δ13N and δ18N) and water vapor flux were obtained based on the flux ratio method. Atmospheric δ13C ranged from -7 (during daytime) to -10 per mil during nighttime, while δ18O values ranged from -1 to -3 per mil. The isotope ratio of the CO2 fluxes in the overstorey ranged from -15 to -22 per mil for δ18N and -22 to -32 per mil for δ13N. These preliminary data will be discussed in light of H2O vapor and flux isotopic ratio

  5. Mapping tropical forests and deciduous rubber plantations in Hainan Island, China by integrating PALSAR 25-m and multi-temporal Landsat images

    NASA Astrophysics Data System (ADS)

    Chen, Bangqian; Li, Xiangping; Xiao, Xiangming; Zhao, Bin; Dong, Jinwei; Kou, Weili; Qin, Yuanwei; Yang, Chuan; Wu, Zhixiang; Sun, Rui; Lan, Guoyu; Xie, Guishui

    2016-08-01

    Updated and accurate maps of tropical forests and industrial plantations, like rubber plantations, are essential for understanding carbon cycle and optimal forest management practices, but existing optical-imagery-based efforts are greatly limited by frequent cloud cover. Here we explored the potential utility of integrating 25-m cloud-free Phased Array type L-band Synthetic Aperture Radar (PALSAR) mosaic product and multi-temporal Landsat images to map forests and rubber plantations in Hainan Island, China. Based on structure information detected by PALSAR and yearly maximum Normalized Difference Vegetation Index (NDVI), we first identified and mapped forests with a producer accuracy (PA) of 96% and user accuracy (UA) of 98%. The resultant forest map showed reasonable spatial and areal agreements with the optical-based forest maps of Fine Resolution Observation and Monitoring Global Land Clover (FROM-GLC) and GlobalLand30. We then extracted rubber plantations from the forest map according to their deciduous features (using minimum Land Surface Water Index, LSWI) and rapid changes in canopies during Rubber Defoliation and Foliation (RDF) period (using standard deviation of LSWI) and dense canopy in growing season (using maximum NDVI). The rubber plantation map yielded a high accuracy when validated by ground truth-based data (PA/UA > 86%) and evaluated with three farm-scale rubber plantation maps (PA/UA >88%). It is estimated that in 2010, Hainan Island had 2.11 × 106 ha of forest and 5.15 × 105 ha of rubber plantations. This study has demonstrated the potential of integrating 25-m PALSAR-based structure information, and Landsat-based spectral and phenology information for mapping tropical forests and rubber plantations.

  6. Transpiration by tree roots in the deep unsaturated regolith buffers the recharge process in a tropical watershed under deciduous forest (Mule Hole, India)

    NASA Astrophysics Data System (ADS)

    Ruiz, Laurent; Varma, Murari Rr; Mohan Kumar, Ms; Sekhar, Muddu; Molenat, Jerome; Marechal, Jean-Christophe; Descloitres, Marc; Riotte, Jean; Kumar, Sat; Braun, Jean-Jacques

    2010-05-01

    Accurate estimations of water balance are needed in semi-arid and sub-humid tropical regions, where water resources are scarce compared to water demand. Evapotranspiration plays a major role in this context, and the difficulty to quantify it precisely leads to major uncertainties in the groundwater recharge assessment, especially in forested catchments where deep tree root can uptake water at considerable depth. In this presentation, we assess the importance of deep unsaturated regolith and water uptake by deep tree roots on the groundwater recharge process by using the lumped conceptual model COMFORT (Ruiz et al., 2010) to simulate discharge and groundwater levels monitored during six year in an experimental watershed under dry deciduous forest (Mule Hole, South India), which is part of the project "Observatoire de Recherche en Environnement - Bassin Versant Expérimentaux Tropicaux" (http://www.ore.fr/). The model was calibrated on the first four years data, and tested on the two remaining years. The model was able to simulate the stream discharge as well as the contrasted behaviour of groundwater table along the hillslope. Water balance simulated for a 32 year climatic time series displayed a large year-to-year variability, with successions of dry and wet phases with a time period of approximately 14 years. On an average, input by the rainfall was 1090 mm.year-1 and the evapotranspiration was about 900 mm.year-1 out of which 100 mm.year-1 was uptake from the deep regolith horizons. The stream flow was 100 mm.year-1 while the groundwater underflow was 80 mm.year-1. The simulation results show that i) deciduous trees can uptake a significant amount of water from the deep regolith, ii) this uptake, combined with the spatial variability of regolith depth, can account for the variable lag time between drainage events and groundwater rise observed for the different piezometers, iii) water table response to recharge is buffered due to the long vertical travel time

  7. Variations in evapotranspiration and climate for an Amazonian semi-deciduous forest over seasonal, annual, and El Niño cycles

    NASA Astrophysics Data System (ADS)

    Vourlitis, George L.; de Souza Nogueira, José; de Almeida Lobo, Francisco; Pinto, Osvaldo Borges

    2015-02-01

    Tropical forests exchange large amounts of water and energy with the atmosphere and are important in controlling regional and global climate; however, climate and evaportranspiration ( E) vary significantly across multiple time scales. To better understand temporal patterns in E and climate, we measured the energy balance and meteorology of a semi-deciduous forest in the rainforest-savanna ecotone of northern Mato Grosso, Brazil, over a 7-year period and analyzed regional climate patterns over a 16-year period. Spectral analysis revealed that E and local climate exhibited consistent cycles over annual, seasonal, and weekly time scales. Annual and seasonal cycles were also apparent in the regional monthly rainfall and humidity time series, and a cycle on the order of 3-5.5 years was also apparent in the regional air temperature time series, which is coincident with the average return interval of El Niño. Annual rates of E were significantly affected by the 2002 El Niño. Prior to this event, annual E was on average 1,011 mm/year and accounted for 52 % of the annual rainfall, while after, annual E was 931 mm/year and accounted for 42 % of the annual rainfall. Our data also suggest that E declined significantly over the 7-year study period while air temperature significantly increased, which was coincident with a long-term, regional warming and drying trend. These results suggest that drought and warming induced by El Niño and/or climate change cause declines in E for semi-deciduous forests of the southeast Amazon Basin.

  8. Variations in evapotranspiration and climate for an Amazonian semi-deciduous forest over seasonal, annual, and El Niño cycles.

    PubMed

    Vourlitis, George L; de Souza Nogueira, José; de Almeida Lobo, Francisco; Pinto, Osvaldo Borges

    2015-02-01

    Tropical forests exchange large amounts of water and energy with the atmosphere and are important in controlling regional and global climate; however, climate and evaportranspiration (E) vary significantly across multiple time scales. To better understand temporal patterns in E and climate, we measured the energy balance and meteorology of a semi-deciduous forest in the rainforest-savanna ecotone of northern Mato Grosso, Brazil, over a 7-year period and analyzed regional climate patterns over a 16-year period. Spectral analysis revealed that E and local climate exhibited consistent cycles over annual, seasonal, and weekly time scales. Annual and seasonal cycles were also apparent in the regional monthly rainfall and humidity time series, and a cycle on the order of 3-5.5 years was also apparent in the regional air temperature time series, which is coincident with the average return interval of El Niño. Annual rates of E were significantly affected by the 2002 El Niño. Prior to this event, annual E was on average 1,011 mm/year and accounted for 52% of the annual rainfall, while after, annual E was 931 mm/year and accounted for 42% of the annual rainfall. Our data also suggest that E declined significantly over the 7-year study period while air temperature significantly increased, which was coincident with a long-term, regional warming and drying trend. These results suggest that drought and warming induced by El Niño and/or climate change cause declines in E for semi-deciduous forests of the southeast Amazon Basin. PMID:24830756

  9. On the difference in the net ecosystem exchange of CO2 between deciduous and evergreen forests in the southeastern United States.

    PubMed

    Novick, Kimberly A; Oishi, A Christopher; Ward, Eric J; Siqueira, Mario B S; Juang, Jehn-Yih; Stoy, Paul C

    2015-02-01

    The southeastern United States is experiencing a rapid regional increase in the ratio of pine to deciduous forest ecosystems at the same time it is experiencing changes in climate. This study is focused on exploring how these shifts will affect the carbon sink capacity of southeastern US forests, which we show here are among the strongest carbon sinks in the continental United States. Using eight-year-long eddy covariance records collected above a hardwood deciduous forest (HW) and a pine plantation (PP) co-located in North Carolina, USA, we show that the net ecosystem exchange of CO2 (NEE) was more variable in PP, contributing to variability in the difference in NEE between the two sites (ΔNEE) at a range of timescales, including the interannual timescale. Because the variability in evapotranspiration (ET) was nearly identical across the two sites over a range of timescales, the factors that determined the variability in ΔNEE were dominated by those that tend to decouple NEE from ET. One such factor was water use efficiency, which changed dramatically in response to drought and also tended to increase monotonically in nondrought years (P < 0.001 in PP). Factors that vary over seasonal timescales were strong determinants of the NEE in the HW site; however, seasonality was less important in the PP site, where significant amounts of carbon were assimilated outside of the active season, representing an important advantage of evergreen trees in warm, temperate climates. Additional variability in the fluxes at long-time scales may be attributable to slowly evolving factors, including canopy structure and increases in dormant season air temperature. Taken together, study results suggest that the carbon sink in the southeastern United States may become more variable in the future, owing to a predicted increase in drought frequency and an increase in the fractional cover of southern pines. PMID:25168968

  10. Monitoring phenology variations of different forest types from 2000 to 2008 in contiguous United States using MODIS LAI measurements

    NASA Astrophysics Data System (ADS)

    Li, Min; Qu, John J.

    2009-08-01

    The strong relationships between vegetation phenology and global climate change have been found in recent years, especially with increasing popularity and availability of satellite data. Accurate estimates of canopy phenology are critical to quantify carbon and water exchange between forests and the atmosphere and its response to climate change. The objective of this study is to detect the spatial distribution of vegetation phenology with remote sensing and to quantitatively examine the linkage between forest phenology and forest type in contiguous United States. In particular, we focus on phenology variation between different forest types. To achieve this goal, we utilize LAI measurements from Moderate Resolution Imaging Spectroradiometer (MODIS) from 2000 to 2007 to identify phenological transition dates. The transition dates are then related to MODIS land cover type product to assess land cover type dependent phonological variation during 8 years. The results show that both evergreen forests and deciduous forests have an annual cycle of vegetation phenology. Greenup onset days vary diversely among different forest types. The phenology variation range of deciduous needle leaf forests is larger than that of deciduous broadleaf forests. Compared to greenup days, dormancy days have a little difference between different forest types. Grow length of different land cover varies obviously during 8 years.

  11. Analysis of carbon dioxide, water vapour and energy fluxes over an Indian teak mixed deciduous forest for winter and summer months using eddy covariance technique

    NASA Astrophysics Data System (ADS)

    Jha, Chandra Shekhar; Thumaty, Kiran Chand; Rodda, Suraj Reddy; Sonakia, Ajit; Dadhwal, Vinay Kumar

    2013-10-01

    In the present study, we report initial results on analysis of carbon dioxide (CO2), water vapour (H2O), and energy fluxes (sensible and latent heat flux) over teak mixed deciduous forests of Madhya Pradesh, central India, during winter (November 2011 and January 2012) and summer (February-May 2012) seasons using eddy covariance flux tower datasets. During the study period, continuous fast response measurements of CO2, H2O and heat fluxes above the canopy were carried out at 10 Hz and averaged for 30 minutes. Concurrently, slow response measurements of meteorological parameters are also being carried out. Diurnal and seasonal variations of CO2, H2O and heat fluxes were analysed and correlated with the meteorological variables. The study showed strong influence of leaf off and on scenario on the CO2, H2O and energy fluxes due to prevalence of deciduous vegetation type in the study area. Maximum amount of CO2 was sequestered for photosynthesis during winter (monthly mean of mol/m2/s) compared to summer (monthly mean of mol/m2/s). Energy flux analysis (weekly mean) showed more energy being portioned into latent heat during winter (668 W/m2) and sensible heat during summer (718 W/m2).

  12. Expression of the Agrobacterium rhizogenes rolC Gene in a Deciduous Forest Tree Alters Growth and Development and Leads to Stem Fasciation.

    PubMed Central

    Nilsson, O.; Moritz, T.; Sundberg, B.; Sandberg, G.; Olsson, O.

    1996-01-01

    We have altered the growth and development of a deciduous forest tree by transforming hybrid aspen (Populus tremula x Populus tremuloides) with the Agrobacterium rhizogenes rolC gene expressed under the strong cauliflower mosaic virus 35S promoter. We demonstrate that the genetically manipulated perennial plants, after a period of dormancy, maintain the induced phenotypical changes during the second growing period. Furthermore, mass-spectrometrical quantifications of the free and conjugated forms of indole-3-acetic acid and cytokinins and several gibberellins on one transgenic line correlate the induced developmental alterations such as stem fasciation to changes in plant hormone metabolism. We also show that the presence of the RolC protein increases the levels of the free cytokinins, but not by a process involving hydrolysis of the inactive cytokinin conjugates. PMID:12226405

  13. Calcium and aluminum cycling in a temperate broadleaved deciduous forest of the eastern USA: relative impacts of tree species, canopy state, and flux type.

    PubMed

    Levia, Delphis F; Shiklomanov, Alexey N; Van Stan, John T; Scheick, Carrie E; Inamdar, Shreeram P; Mitchell, Myron J; McHale, Patrick J

    2015-07-01

    Ca/Al molar ratios are commonly used to assess the extent of aluminum stress in forests. This is among the first studies to quantify Ca/Al molar ratios for stemflow. Ca/Al molar ratios in bulk precipitation, throughfall, stemflow, litter leachate, near-trunk soil solution, and soil water were quantified for a deciduous forest in northeastern MD, USA. Data were collected over a 3-year period. The Ca/Al molar ratios in this study were above the threshold for aluminum stress (<1). Fagus grandifolia Ehrh. (American beech) had a median annual stemflow Ca/Al molar ratio of 15.7, with the leafed and leafless values of 12.4 and 19.2, respectively. The corresponding Ca/Al molar ratios for Liriodendron tulipifera L. (yellow poplar) were 11.9 at the annual time scale and 11.9 and 13.6 for leafed and leafless periods, respectively. Bayesian statistical analysis showed no significant effect of canopy state (leafed, leafless) on Ca/Al molar ratios. DOC was consistently an important predictor of calcium, aluminum, and Ca/Al ratios. pH was occasionally an important predictor of calcium and aluminum concentrations, but was not a good predictor of Ca/Al ratio in any of the best-fit models (of >500 examined). This study supplies new data on Ca/Al molar ratios for stemflow from two common deciduous tree species. Future work should examine Ca/Al molar ratios in stemflow of other species and examine both inorganic and organic aluminum species to better gauge the potential for, and understand the dynamics of, aluminum toxicity in the proximal area around tree boles. PMID:26100445

  14. More of the same? In situ leaf and root decomposition rates do not vary between 80 native and nonnative deciduous forest species.

    PubMed

    Jo, Insu; Fridley, Jason D; Frank, Douglas A

    2016-01-01

    Invaders often have greater rates of production and produce more labile litter than natives. The increased litter quantity and quality of invaders should increase nutrient cycling through faster litter decomposition. However, the limited number of invasive species that have been included in decomposition studies has hindered the ability to generalize their impacts on decomposition rates. Further, previous decomposition studies have neglected roots. We measured litter traits and decomposition rates of leaves for 42 native and 36 nonnative woody species, and those of fine roots for 23 native and 25 nonnative species that occur in temperate deciduous forests throughout the Eastern USA. Among the leaf and root traits that differed between native and invasive species, only leaf nitrogen was significantly associated with decomposition rate. However, native and nonnative species did not differ systematically in leaf and root decomposition rates. We found that among the parameters measured, litter decomposer activity was driven by litter chemical quality rather than tissue density and structure. Our results indicate that litter decomposition rate per se is not a pathway by which forest woody invasive species affect North American temperate forest soil carbon and nutrient processes. PMID:26333347

  15. Mercury emission from terrestrial background surfaces in the eastern USA. Part I: Air/surface exchange of mercury within a southeastern deciduous forest (Tennessee) over one year

    SciTech Connect

    Kuiken, Todd; Zhang, Hong; Gustin, Mae S.; Lindberg, Steven Eric

    2008-03-01

    This study focused on the development of a seasonal data set of the Hg air/surface exchange over soils associated with low Hg containing surfaces in a deciduous forest in the southern USA. Data were collected every month for 11 months in 2004 within Standing Stone State Forest in Tennessee using the dynamic flux chamber method. Mercury air/surface exchange associated with the litter covered forest floor was very low with the annual mean daytime flux being 0.4 0.5 ng m-2 h-1 (n = 301). The daytime Hg air/surface exchange over the year oscillated between emission (81% of samples with positive flux) and deposition (19% of samples with negative flux). A seasonal trend of lower emission in the spring and summer (closed canopy) relative to the fall and winter (open canopy) was observed. Correlations were found between the air/surface exchange and certain environmental factors on specific days sampled but not collectively over the entire year. The very low magnitude of Hg air/surface exchange as observed in this study suggests that an improved methodology for determining and reporting emission fluxes is needed when the values of fluxes and chamber blanks are both very low and comparable. This study raises questions and points to a need for more research regarding how to scale the Hg air/surface exchange for surfaces with very low emissions.

  16. Seasonal and Inter-annual Changes in Photosynthetic and Soil Respiratory Processes in a Cool-temperate Deciduous Forest on a Mountainous Landscape in Japan.

    NASA Astrophysics Data System (ADS)

    Muraoka, H.; Noh, N. J.; Saitoh, T. M.; Nagao, A.; Noda, H. M.; Kuribayashi, M.; Nagai, S.

    2015-12-01

    Carbon budget of terrestrial ecosystems is one of the most crucial themes in ecosystem sciences under current and future climate changes as it would affect our Earth system. Remote sensing and modeling analysis studies from continental to global scales have been indicating that the recent climate change is influential to photosynthetic processes in terrestrial vegetation such as forests and grasslands, by altering phenology (seasonal change) and foliage biomass. In addition, increasing temperature and possibly changing photosynthetic activities of plants are influential to soil carbon dynamics. Our deeper and broader understandings on such photosynthetic and respiratory processes governing carbon cycle and hence budget of terrestrial ecosystems are critical to detect the changes of ecosystem processes and the functions in changing environments, as they would influence the biodiversity, ecosystem services and Earth system.In order to reveal the nature of temporal changes in photosynthetic and respiratory processes in forest ecosystems, we have been conducting multi-disciplinary observations of ecophysiological and optical properties for canopy photosynthesis in a cool-temperate deciduous forest since 2003 ("Takayama site", contributing to AsiaFlux and JaLTER). In addition, open-field warming experiments have been conducted since 2011 to examine the possible influence of near-future warming condition on forest canopy photosynthesis and soil respiration. (1) Our long-term measurements of leaf and canopy photosynthesis revealed that their phenology is influenced by inter-annual variation of micrometeorological conditions. (2) Combined analysis of leaf-canopy photosynthesis and optical properties enabled us to estimate the forest photosynthetic productivity at regional scale by satellite data. (3) Open-field warming experiments suggested that tree foliage and soil processes would acclimate to near-future warming conditions.

  17. Effects of mineral characteristics on the content and stability of organic matter fractions sequentially separated from seven topsoils under temperate deciduous forest

    NASA Astrophysics Data System (ADS)

    Kaiser, Michael; Zederer, Dan P.; Ellerbrock, Ruth H.; Sommer, Michael; Ludwig, Bernard

    2015-04-01

    Mineral topsoils under forest possess high organic carbon (OC) contents and are therefore of large importance for the terrestrial C cycle. However, less is known about the mechanisms controlling the preservation of organic matter (OM) against microbial decomposition in mineral topsoils under temperate deciduous forest. We took samples from the uppermost mineral topsoil horizon (0 to 5 cm) of seven sites under mature deciduous forest in Germany showing OC contents between 69 and 164 g kg-1. The study sites showed a wide range in mineral characteristics supposed to be important for OM protection against microbial attack. At first we removed the organic particles and the water-extractable OM assumed to be less associated with the mineral phase from the soil samples. Thereafter, we sequentially separated the Na-pyrophosphate extractable organic matter (OM(PY) supposed to be indicative for OM bound via cation mediated interactions in soil and the OM remaining in the extraction residue supposed to be indicative for OM occluded in stable micro-aggregates. The OM(PY) and OM(ER) fractions were quantified and analyzed by 14C and FTIR measurements. The OC remaining in the extraction residues accounted for 38 to 59% of the bulk soil OC suggesting a much larger relevance of OM(ER) for the OM dynamic in the analyzed soils than with OM(PY) that accounted for 1.6 to 7.5% of the bulk soil OC. Regression analyses indicated an increase in the stability of OM(PY) with the content of Na-pyrophosphate soluble Mg and the soil pH. Therefore, we assume the turnover of OM(PY) in the studied forest mineral surface soils to be influenced by cation mediated interactions between organic molecules such as cross-linking. We detected an increase in the stability of OM(ER) with the contents of clay and oxalate soluble Al that were shown to be involved in the formation of aggregates smaller than 20 µm. Therefore, we assume an occlusion in highly stable micro-aggregates to be important for the

  18. Temporal disparity in leaf chlorophyll content and leaf area index across a growing season in a temperate deciduous forest

    NASA Astrophysics Data System (ADS)

    Croft, H.; Chen, J. M.; Zhang, Y.

    2014-12-01

    Spatial and temporal variations in canopy structure and leaf biochemistry have considerable influence on fluxes of CO2, water and energy and nutrient cycling in vegetation. Two vegetation indices (VI), NDVI and Macc01, were used to model the spatio-temporal variability of broadleaf chlorophyll content and leaf area index (LAI) across a growing season. Ground data including LAI, hyperspectral leaf reflectance factors (400-2500 nm) and leaf chlorophyll content were measured across the growing season and satellite-derived canopy reflectance data was acquired for 33 dates at 1200 m spatial resolution. Key phenological information was extracted using the TIMESAT software. Results showed that LAI and chlorophyll start of season (SOS) dates were at day of year (DOY) 130 and 157 respectively, and total season duration varied by 57 days. The spatial variability of chlorophyll and LAI phenology was also analyzed at the landscape scale to investigate phenological patterns over a larger spatial extent. Whilst a degree of spatial variability existed, results showed that chlorophyll SOS lagged approximately 20-35 days behind LAI SOS, and the end of season (EOS) LAI dates were predominantly between 20 and 30 days later than chlorophyll EOS. The large temporal differences between VI-derived chlorophyll content and LAI has important implications for biogeochemical models using NDVI or LAI to represent the fraction of photosynthetically active radiation absorbed by a canopy, in neglecting to account for delays in chlorophyll production and thus photosynthetic capacity.

  19. Response of Quercus velutina growth and water use efficiency to climate variability and nitrogen fertilization in a temperate deciduous forest in the northeastern USA.

    PubMed

    Jennings, Katie A; Guerrieri, Rossella; Vadeboncoeur, Matthew A; Asbjornsen, Heidi

    2016-04-01

    Nitrogen (N) deposition and changing climate patterns in the northeastern USA can influence forest productivity through effects on plant nutrient relations and water use. This study evaluates the combined effects of N fertilization, climate and rising atmospheric CO2on tree growth and ecophysiology in a temperate deciduous forest. Tree ring widths and stable carbon (δ(13)C) and oxygen (δ(18)O) isotopes were used to assess tree growth (basal area increment, BAI) and intrinsic water use efficiency (iWUE) ofQuercus velutinaLamb., the dominant tree species in a 20+ year N fertilization experiment at Harvard Forest (MA, USA). We found that fertilized trees exhibited a pronounced and sustained growth enhancement relative to control trees, with the low- and high-N treatments responding similarly. All treatments exhibited improved iWUE over the study period (1984-2011). Intrinsic water use efficiency trends in the control trees were primarily driven by changes in stomatal conductance, while a stimulation in photosynthesis, supported by an increase in foliar %N, contributed to enhancing iWUE in fertilized trees. All treatments were predominantly influenced by growing season vapor pressure deficit (VPD), with BAI responding most strongly to early season VPD and iWUE responding most strongly to late season VPD. Nitrogen fertilization increasedQ. velutinasensitivity to July temperature and precipitation. Combined, these results suggest that ambient N deposition in N-limited northeastern US forests has enhanced tree growth over the past 30 years, while rising ambient CO2has improved iWUE, with N fertilization and CO2having synergistic effects on iWUE. PMID:26917704

  20. Teasing Apart the Influence of Past Land Use and Current Invertebrate Processes on the Controls of Soil Organic Matter Stabilization in Eastern Deciduous Forests, USA

    NASA Astrophysics Data System (ADS)

    Ma, Y.; Filley, T. R.; Johnston, C. T.; Szlavecz, K. A.; McCormick, M.; Thayer, C.; Jourdain, J.; Johnson, A.

    2010-12-01

    Our work seeks to identify how earthworm (EW) activity and past land interact to control the relative importance of physical, chemical, and biochemical protection mechanisms governing SOM stabilization in deciduous forests. Within forests of the Smithsonian Environmental Research Center (SERC) in coastal Maryland, USA, wood and litter amendment plots were established in high, low and no EW activity areas within forests of different stand age and land use history to study the controlling factor for litter-soil systems. Through a detailed soil survey and litter decay study we have demonstrated that plant biopolymer chemistry of both decayed litter and soil (0-5 cm) particulate organic matter (POM) is driven by variation in EW activity and is responsible for the differences observed in lignin and root aliphatic matter accumulation in this system. In the present study we compare the chemical, spectroscopic, and isotopic composition of different soil physical fractions to a depth of 15 cm among plots that vary in past land use and earthworm activity which were amended for 5 years with wood and litter. We found significant changes in the chemistry (C/N) and isotopic composition (δ13C) among silt/clay and POM fractions within micro-aggregates in higher EW activity sites indicating the invasive worms are promoting C stabilization. Also, the Fourier Transform Infrared (FTIR) spectroscopy results provided chemical information that supports the shift to more hydrophobic structure, C-H chains, from the leaf amendments. These results indicate the EW feeding habits and activity are an important control on the degree of mixing of surface litter and deep soil in all of research plots and responsible for redistribution of SOM depth and particle patterns previously set by past land use change.. This work will have important implications for understanding how soil invertebrates will have potential influence on SOM stabilization process under different land use pattern.

  1. Broadleaf weed control in lima beans.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Broadleaf weeds are particularly troublesome in lima beans due to the long growing season which extends beyond the period in which soil residual herbicides provide control. Weeds reduce yield and quality of lima beans, reduce harvest efficiency, and increase incidence of white mold. A study was co...

  2. Ecology and pathology of European chestnut (Castanea sativa) in the deciduous forests of the Caucasus Mountains in southern Russia

    USGS Publications Warehouse

    Pridnya, M.V.; Cherpakov, V.V.; Paillet, Frederick L.

    1996-01-01

    Chestnut-dominated forests of the Caucasus Mountain area of Russia are very similar to former chestnut-dominated forests in eastern North America. The distribution, pathology, and reproductive status of European chestnut (Castanea sativa) in the Caucasus are described and compared to that of American chestnut (C. dentata). Chestnut forests are distributed continuously along the southern slope of the Caucasus mountains near the Black Sea, and are found in isolated populations on the north side of the Caucasus, at elevations ranging from 200 to 1300 meters. Chestnut blight was apparently introduced into the region after 1880 and continues to destroy chestnut forests today. Chestnut in the Caucasus is also infected by several other fungal and bacterial parasites and the joint infection of blight and bacteria may be especially dangerous for chestnut trees. Chestnut-dominated forests comprise only a few percent of total forest cover in the Caucasus Biosphere Preserve, and usually occur in mountain valleys or coves with deep brown soil. The age structure and reproductive status of chestnut in the Caucasus was investigated on six study plots in the Caucasus Biosphere Forest Preserve near the upper altitudinal limit of chestnut. Although chestnut is at least 70 percent of the overstory on these sites, there are very few trees less than 50 years old, and very few recent seedlings on any of the plots. Most large chestnut trees appear to have originated as basal spouts from previously established stems. Although chestnut seed production appears adequate, we suspect that competition with shrubs and other tree seedlings, and predation by herbivores and rodents, now prevent the establishment and survival of chestnut seedlings in the Biosphere Preserve.

  3. Hydro-ecological Effects on the Isotopic Composition of Soil and Leaf Water in Humid Deciduous Forests of Southern United States.

    NASA Astrophysics Data System (ADS)

    Mora, G.; Jahren, A. H.

    2001-05-01

    Paleoclimatic information inferred from the oxygen and hydrogen isotope abundance of fossil plant tissues and biomarkers relies on the observed close relationship between values of δ D and δ 18O for rainwater and environmental parameters (i.e., temperature, humidity, etc). However, the isotope content of rainwater can be altered during its passage through the canopy and the soil zone. Moreover, large isotope fractionations can occur after water enters the vascular system of plants as a result of leaf evaporation and biological processes. A number of studies, for instance, have addressed the effect of soil evaporation in arid and semi-arid regions that produces an enrichment of up to 20‰ in 18O and 80‰ in D in soil and stem water. Little is known, however, about fractionation effects in highly productive sub-tropical/temperate areas. With this study, we seek to evaluate evaporation effect on three humid deciduous forests of southern United States located along a 460-km transect that shows a precipitation gradient of about 200-mm in annual precipitation. The predominant tree species at the studied sites include dogwood, sugar gum, and silver maple. Rainwater was collected for isotopic determinations at the three localities, showing values that plot along the Meteoric Water Line. No significant difference (up to 0.4‰ for δ 18O and 4‰ for δ D) was observed in the isotopic composition of open rainfall and throughfall precipitation at the three sites. Soil water was cryogenically extracted from samples collected every 25-cm at the three sites during the growing season of 1997. Soil water from the upper soil horizons at the wettest site (Saint Bernard Park, Mississippi) showed isotopic values similar to those of rainfall. Moreover, isotopic values for soil water at this site were similar with depth, having a maximum difference of about 0.3‰ for δ 18O and of about 2‰ for δ D. Isotopic values for soil water at the driest locality (Natchez Lake, Arkansas

  4. MODIS Based Estimation of Forest Aboveground Biomass in China

    PubMed Central

    Sun, Yan; Wang, Tao; Zeng, Zhenzhong; Piao, Shilong

    2015-01-01

    Accurate estimation of forest biomass C stock is essential to understand carbon cycles. However, current estimates of Chinese forest biomass are mostly based on inventory-based timber volumes and empirical conversion factors at the provincial scale, which could introduce large uncertainties in forest biomass estimation. Here we provide a data-driven estimate of Chinese forest aboveground biomass from 2001 to 2013 at a spatial resolution of 1 km by integrating a recently reviewed plot-level ground-measured forest aboveground biomass database with geospatial information from 1-km Moderate-Resolution Imaging Spectroradiometer (MODIS) dataset in a machine learning algorithm (the model tree ensemble, MTE). We show that Chinese forest aboveground biomass is 8.56 Pg C, which is mainly contributed by evergreen needle-leaf forests and deciduous broadleaf forests. The mean forest aboveground biomass density is 56.1 Mg C ha−1, with high values observed in temperate humid regions. The responses of forest aboveground biomass density to mean annual temperature are closely tied to water conditions; that is, negative responses dominate regions with mean annual precipitation less than 1300 mm y−1 and positive responses prevail in regions with mean annual precipitation higher than 2800 mm y−1. During the 2000s, the forests in China sequestered C by 61.9 Tg C y−1, and this C sink is mainly distributed in north China and may be attributed to warming climate, rising CO2 concentration, N deposition, and growth of young forests. PMID:26115195

  5. MODIS Based Estimation of Forest Aboveground Biomass in China.

    PubMed

    Yin, Guodong; Zhang, Yuan; Sun, Yan; Wang, Tao; Zeng, Zhenzhong; Piao, Shilong

    2015-01-01

    Accurate estimation of forest biomass C stock is essential to understand carbon cycles. However, current estimates of Chinese forest biomass are mostly based on inventory-based timber volumes and empirical conversion factors at the provincial scale, which could introduce large uncertainties in forest biomass estimation. Here we provide a data-driven estimate of Chinese forest aboveground biomass from 2001 to 2013 at a spatial resolution of 1 km by integrating a recently reviewed plot-level ground-measured forest aboveground biomass database with geospatial information from 1-km Moderate-Resolution Imaging Spectroradiometer (MODIS) dataset in a machine learning algorithm (the model tree ensemble, MTE). We show that Chinese forest aboveground biomass is 8.56 Pg C, which is mainly contributed by evergreen needle-leaf forests and deciduous broadleaf forests. The mean forest aboveground biomass density is 56.1 Mg C ha-1, with high values observed in temperate humid regions. The responses of forest aboveground biomass density to mean annual temperature are closely tied to water conditions; that is, negative responses dominate regions with mean annual precipitation less than 1300 mm y-1 and positive responses prevail in regions with mean annual precipitation higher than 2800 mm y-1. During the 2000s, the forests in China sequestered C by 61.9 Tg C y-1, and this C sink is mainly distributed in north China and may be attributed to warming climate, rising CO2 concentration, N deposition, and growth of young forests. PMID:26115195

  6. The role of canopy structural complexity in wood net primary production of a maturing northern deciduous forest.

    PubMed

    Hardiman, Brady S; Bohrer, Gil; Gough, Christopher M; Vogel, Christoph S; Curtisi, Peter S

    2011-09-01

    The even-aged northern hardwood forests of the Upper Great Lakes Region are undergoing an ecological transition during which structural and biotic complexity is increasing. Early-successional aspen (Populus spp.) and birch (Betula papyrifera) are senescing at an accelerating rate and are being replaced by middle-successional species including northern red oak (Quercus rubra), red maple (Acer rubrum), and white pine (Pinus strobus). Canopy structural complexity may increase due to forest age, canopy disturbances, and changing species diversity. More structurally complex canopies may enhance carbon (C) sequestration in old forests. We hypothesize that these biotic and structural alterations will result in increased structural complexity of the maturing canopy with implications for forest C uptake. At the University of Michigan Biological Station (UMBS), we combined a decade of observations of net primary productivity (NPP), leaf area index (LAI), site index, canopy tree-species diversity, and stand age with canopy structure measurements made with portable canopy lidar (PCL) in 30 forested plots. We then evaluated the relative impact of stand characteristics on productivity through succession using data collected over a nine-year period. We found that effects of canopy structural complexity on wood NPP (NPPw) were similar in magnitude to the effects of total leaf area and site quality. Furthermore, our results suggest that the effect of stand age on NPPw is mediated primarily through its effect on canopy structural complexity. Stand-level diversity of canopy-tree species was not significantly related to either canopy structure or NPPw. We conclude that increasing canopy structural complexity provides a mechanism for the potential maintenance of productivity in aging forests. PMID:21939078

  7. N : P Stoichiometry in a Forested Runoff during Storm Events: Comparisons with Regions and Vegetation Types

    PubMed Central

    Guo, Lanlan; Chen, Yi; Zhang, Zhao; Fukushima, Takehiko

    2012-01-01

    Nitrogen and phosphorus are considered the most important limiting elements in terrestrial and aquatic ecosystems. however, very few studies have focused on which is from forested streams, a bridge between these two systems. To fill this gap, we examined the concentrations of dissolved N and P in storm waters from forested watersheds of five regions in Japan, to characterize nutrient limitation and its potential controlling factors. First, dissolved N and P concentrations and the N : P ratio on forested streams were higher during storm events relative to baseflow conditions. Second, significantly higher dissolved inorganic N concentrations were found in storm waters from evergreen coniferous forest streams than those from deciduous broadleaf forest streams in Aichi, Kochi, Mie, Nagano, and with the exception of Tokyo. Finally, almost all the N : P ratios in the storm water were generally higher than 34, implying that the storm water should be P-limited, especially for Tokyo. PMID:22547978

  8. Rapid rebound of soil respiration following partial stand disturbance by tree girdling in a temperate deciduous forest.

    PubMed

    Levy-Varon, Jennifer H; Schuster, William S F; Griffin, Kevin L

    2014-04-01

    Forests serve an essential role in climate change mitigation by removing CO2 from the atmosphere. Within a forest, disturbance events can greatly impact C cycling and subsequently influence the exchange of CO2 between forests and the atmosphere. This connection makes understanding the forest C cycle response to disturbance imperative for climate change research. The goal of this study was to examine the temporal response of soil respiration after differing levels of stand disturbance for 3 years at the Black Rock Forest (southeastern NY, USA; oaks comprise 67% of the stand). Tree girdling was used to mimic pathogen attack and create the following treatments: control, girdling all non-oaks (NOG), girdling half of the oak trees (O50), and girdling all the oaks (OG). Soil respiratory rates on OG plots declined for 2 years following girdling before attaining a full rebound of belowground activity in the third year. Soil respiration on NOG and O50 were statistically similar to the control for the duration of the study although a trend for a stronger decline in respiration on O50 relative to NOG occurred in the first 2 years. Respiratory responses among the various treatments were not proportional to the degree of disturbance and varied over time. The short-lived respiratory response on O50 and OG suggests that belowground activity is resilient to disturbance; however, sources of the recovered respiratory flux on these plots are likely different than they were pre-treatment. The differential taxon response between oaks and non-oaks suggests that after a defoliation or girdling event, the temporal response of the soil respiratory flux may be related to the C allocation pattern of the affected plant group. PMID:24337785

  9. Dero (Allodero) lutzi Michaelsen, 1926 (Oligochaeta: Naididae) associated with Scinax fuscovarius (Lutz, 1925) (Anura: Hylidae) from Semi-deciduous Atlantic Rain Forest, southern Brazil.

    PubMed

    Oda, F H; Petsch, D K; Ragonha, F H; Batista, V G; Takeda, A M; Takemoto, R M

    2015-01-01

    Amphibians are hosts for a wide variety of ecto- and endoparasites, such as protozoans and parasitic worms. Naididae is a family of Oligochaeta whose species live on a wide range of substrates, including mollusks, aquatic macrophytes, sponges, mosses, liverworts, and filamentous algae. However, some species are known as endoparasitic from vertebrates, such as Dero (Allodero) lutzi, which is parasitic of the urinary tracts of frogs, but also have a free-living stage. Specimens in the parasitic stage lack dorsal setae, branchial fossa, and gills. Here we report the occurrence of D. (A.) lutzi associated with anuran Scinax fuscovarius from Semi-deciduous Atlantic Rain Forest in southern Brazil. The study took place at the Caiuá Ecological Station, Diamante do Norte, Paraná, southern Brazil. Seven specimens of S. fuscovarius were examined for parasites but only one was infected. Parasites occurred in ureters and urinary bladder. Previous records of this D. (A.) lutzi include the Brazilian States of Santa Catarina, São Paulo, Rio de Janeiro, and Minas Gerais, as well as Cuba and North America. This is a new locality record for this species in Brazil. Reports of Dero (Allodero) lutzi are rare, due to difficulty of observation, and such events are restricted only the fortuitous cases. It is important to emphasize the necessity of future studies, which are fundamental to the understanding of biological and ecological aspects of this species. PMID:25945624

  10. C allocation among fine roots, above-, and belowground wood in a deciduous forest and its implication to ecosystem C cycling: a modelling analysis

    NASA Astrophysics Data System (ADS)

    Campioli, M.; Verbeeck, H.; Lemeur, R.; Samson, R.

    2008-09-01

    Knowledge about allocation of carbohydrates among tree organs with different life times and decomposition rates is crucial in determining the residence time of carbon (C) in forests and the overall ecosystem C cycling rate. A new model (named CAF) able to simulate C allocation among fine roots, above-, and belowground wood in deciduous forests was developed and integrated into the net ecosystem exchange model FORUG. CAF draws on growth rules and source-sink relationships. Maintenance and growth of the modelled sinks i.e. fine roots, coarse roots, stems, and branches, are controlled by phenology, environment, and by the reserve of non-structural carbohydrates. CAF was parameterized for 2-y and tested against 6-y observations from a beech (Fagus sylvatica L.) stand in North-East France, experiencing summer droughts of different intensities. The model reproduced well (i) the C fluxes allocated annually to assimilation, respiration and biomass production, and (ii) the interannual pattern of wood biomass accumulation. Seasonality of C reserve and wood growth was captured, but some discrepancies were detected at the onset of the growing season. The allocation pattern differed among years, although the overall net primary production decreased only in case of severe drought. During a year with severe drought, the fraction of C allocated to production of fast-decomposing C pools (e.g. fine roots, C reserve) increased by +13% than years without drought, whereas the same fraction increased on average by +18% in case of low to moderate drought. Carbon invested in biomass during a year with summer drought has therefore a shorter residence time in the ecosystem than the C stored during a year without summer drought.

  11. Radiocarbon-based Turnover Time Estimates of Soil Organic Carbon in a Cool-temperate Deciduous Forest in Asian Monsoon Region

    NASA Astrophysics Data System (ADS)

    Kondo, M.; Uchida, M.; Ohtsuka, T.; Murayama, S.; Shirato, Y.; Shibata, Y.

    2007-12-01

    Significantly more carbon is stored in the soils than in present in the atmosphere. Although the potential for C storage rates may change in the future as climate change progresses, the dynamics of soil carbon is unknown enough. We separated two density fractions on the soil down to 75 cm depth and estimated turnover time of these SOC fractions for volcanic ash soils in a cool-temperate deciduous forest in Japan, at one of AsiaFlux monitoring sites. According to the eddy-covariance based and biometric based carbon flux measurements over 10 years long in this site, this ecosystem is storing C (net ecosystem exchange (NEE): -2.4 tC ha-1 year- 1). However, the partitioning of C storage among vegetation and soils at this site is unknown. Measurements of carbon and radiocarbon (14C) inventory were used to determine the turnover time of two fractions of SOM: humified low density material < 2 g/cc and high density or mineral-associated organic matter > 2 g/cc. Total SOC stocks down to the depth of 75 cm were 26.2 kg C m-2, with the majority of SOC (52 percent) in the AB horizon (20 - 50 cm). Storage of SOC in our site was larger and differed considerably from that in other temperate forests in North America and Europe. The major part of the SOC (74 percent) was carbon in low density fraction. In the AB horizon, carbon in low density fraction accounted for 75 percent of the total SOC. The age of this fraction in lower AB horizon (35 - 50 cm) was significantly old (2490 years) as well as high density fraction (2930 years), although this fraction seems to consist of labile carbon. Turnover times in all fractions are investigated for some layers in the soil depth of 75cm, as well as fine roots, low density humified material and carbon associated with minerals. Turnover times in both fractions increased with soil depth and 11-2780 year for low density fractions and 610- 3740 year for high density fractions. The turnover times of SOC were relatively long (1760 - 3740 years) in

  12. Simulated Seasonal Spatio-Temporal Patterns of Soil Moisture, Temperature, and Net Radiation in a Deciduous Forest

    NASA Technical Reports Server (NTRS)

    Ballard, Jerrell R., Jr.; Howington, Stacy E.; Cinnella, Pasquale; Smith, James A.

    2011-01-01

    The temperature and moisture regimes in a forest are key components in the forest ecosystem dynamics. Observations and studies indicate that the internal temperature distribution and moisture content of the tree influence not only growth and development, but onset and cessation of cambial activity [1], resistance to insect predation[2], and even affect the population dynamics of the insects [3]. Moreover, temperature directly affects the uptake and metabolism of population from the soil into the tree tissue [4]. Additional studies show that soil and atmospheric temperatures are significant parameters that limit the growth of trees and impose treeline elevation limitation [5]. Directional thermal infrared radiance effects have long been observed in natural backgrounds [6]. In earlier work, we illustrated the use of physically-based models to simulate directional effects in thermal imaging [7-8]. In this paper, we illustrated the use of physically-based models to simulate directional effects in thermal, and net radiation in a adeciduous forest using our recently developed three-dimensional, macro-scale computational tool that simulates the heat and mass transfer interaction in a soil-root-stem systems (SRSS). The SRSS model includes the coupling of existing heat and mass transport tools to stimulate the diurnal internal and external temperatures, internal fluid flow and moisture distribution, and heat flow in the system.

  13. Herbivore-mediated material fluxes in a northern deciduous forest under elevated carbon dioxide and ozone concentrations.

    PubMed

    Meehan, Timothy D; Couture, John J; Bennett, Alison E; Lindroth, Richard L

    2014-10-01

    Anthropogenic changes in atmospheric carbon dioxide (CO2 ) and ozone (O3 ) are known to alter tree physiology and growth, but the cascading effects on herbivore communities and herbivore-mediated nutrient cycling are poorly understood. We sampled herbivore frass, herbivore-mediated greenfall, and leaf-litter deposition in temperate forest stands under elevated CO2 (c. 560 ppm) and O3 (c. 1.5× ambient), analyzed substrate chemical composition, and compared the quality and quantity of fluxes under multiple atmospheric treatments. Leaf-chewing herbivores fluxed 6.2 g m(-2)  yr(-1) of frass and greenfall from the canopy to the forest floor, with a carbon : nitrogen (C : N) ratio 32% lower than that of leaf litter. Herbivore fluxes of dry matter, C, condensed tannins, and N increased under elevated CO2 (35, 32, 63 and 39%, respectively), while fluxes of N decreased (18%) under elevated O3 . Herbivore-mediated dry matter inputs scaled across atmospheric treatments as a constant proportion of leaf-litter inputs. Increased fluxes under elevated CO2 were consistent with increased herbivore consumption and abundance, and with increased plant growth and soil respiration, previously reported for this experimental site. Results suggest that insect herbivory will reinforce other factors, such as photosynthetic rate and fine-root production, impacting C sequestration by forests in future environments. PMID:25078062

  14. Aluminum solute chemistry in stemflow in relation to season and tree species in a mid-Atlantic broadleaved deciduous forest

    NASA Astrophysics Data System (ADS)

    Levia, D. F.; Van Stan, J. T.; Inamdar, S. P.; Mitchell, M. J.; Scheick, C.; McHale, P.

    2011-12-01

    Aluminum toxicity is as serious concern in forest ecosystems. While much work has focused on soil solution aluminum chemistry in forests, less attention has been devoted to examining aluminum inputs from the canopy via washoff. Seasonality and the corresponding phenological conditions it triggers appears to have a detectable effect on aluminum washoff dynamics. In both leafed and leafless states, there is an intrastorm exponential decrease in aluminum inputs to forest soils. While aluminum fluxes were approximately threefold larger for American beech (Fagus grandifolia Ehrh.) in the leafless period compared to the leafed period, the opposite was true for yellow poplar (Liriodendron tulipifera L.) where leafless aluminum stemflow fluxes were half those of the leafed period. We attribute these differences to increased stemflow volumes in the leafless period for beech and the much more highly concentrated stemflow aluminum concentrations from yellow poplar during the leafed period. The Ca:Al ratio in stemflow inputs is of such a magnitude (ranging from approximately 5-80 for beech and 5-18 for yellow poplar) that it could ameliorate the lower Ca:Al ratio in the soil solution around the base of trees, thereby possibly buffering trees from some stress associated with aluminum release.

  15. Impact of a simulated pathogen attack (Sudden Oak Death) on soil carbon storage in a northern temperate deciduous forest

    NASA Astrophysics Data System (ADS)

    Levy, J.; Schuster, W. S.; Griffin, K. L.

    2011-12-01

    The goal of this study was to identify the short-term impact of a mimicked pathogen attack (Sudden Oak Death) on soil carbon stocks in a northeastern forest. Tree girdling was used to simulate the attack and trees were girdled according to five treatments: control (C), girdling all non-oaks on a plot (NO), girdling half of the oak trees on a plot (O50), girdling all the oaks on the plot (OG), and girdling all trees on a plot (ALL). Forest floor litter and soil organic carbon (SOC) at depth intervals of 0-3, 3-6, 6-9, 9-15 and 15-30cm were measured three years after girdling. We found no changes across treatments in the forest floor litter carbon, total soil organic carbon, or carbon concentration through the profile. Contrary to a recently proposed hypothesis, our study does not support a short- term decline in the belowground carbon storage following a pest or pathogen attack. We propose that shifts in the source components of carbon within the belowground carbon pool could offset carbon losses resulting from altered decomposition rates.

  16. Analyses of soil microbial community compositions and functional genes reveal potential consequences of natural forest succession

    NASA Astrophysics Data System (ADS)

    Cong, Jing; Yang, Yunfeng; Liu, Xueduan; Lu, Hui; Liu, Xiao; Zhou, Jizhong; Li, Diqiang; Yin, Huaqun; Ding, Junjun; Zhang, Yuguang

    2015-05-01

    The succession of microbial community structure and function is a central ecological topic, as microbes drive the Earth’s biogeochemical cycles. To elucidate the response and mechanistic underpinnings of soil microbial community structure and metabolic potential relevant to natural forest succession, we compared soil microbial communities from three adjacent natural forests: a coniferous forest (CF), a mixed broadleaf forest (MBF) and a deciduous broadleaf forest (DBF) on Shennongjia Mountain in central China. In contrary to plant communities, the microbial taxonomic diversity of the DBF was significantly (P < 0.05) higher than those of CF and MBF, rendering their microbial community compositions markedly different. Consistently, microbial functional diversity was also highest in the DBF. Furthermore, a network analysis of microbial carbon and nitrogen cycling genes showed the network for the DBF samples was relatively large and tight, revealing strong couplings between microbes. Soil temperature, reflective of climate regimes, was important in shaping microbial communities at both taxonomic and functional gene levels. As a first glimpse of both the taxonomic and functional compositions of soil microbial communities, our results suggest that microbial community structure and function potentials will be altered by future environmental changes, which have implications for forest succession.

  17. Analyses of soil microbial community compositions and functional genes reveal potential consequences of natural forest succession

    PubMed Central

    Cong, Jing; Yang, Yunfeng; Liu, Xueduan; Lu, Hui; Liu, Xiao; Zhou, Jizhong; Li, Diqiang; Yin, Huaqun; Ding, Junjun; Zhang, Yuguang

    2015-01-01

    The succession of microbial community structure and function is a central ecological topic, as microbes drive the Earth’s biogeochemical cycles. To elucidate the response and mechanistic underpinnings of soil microbial community structure and metabolic potential relevant to natural forest succession, we compared soil microbial communities from three adjacent natural forests: a coniferous forest (CF), a mixed broadleaf forest (MBF) and a deciduous broadleaf forest (DBF) on Shennongjia Mountain in central China. In contrary to plant communities, the microbial taxonomic diversity of the DBF was significantly (P < 0.05) higher than those of CF and MBF, rendering their microbial community compositions markedly different. Consistently, microbial functional diversity was also highest in the DBF. Furthermore, a network analysis of microbial carbon and nitrogen cycling genes showed the network for the DBF samples was relatively large and tight, revealing strong couplings between microbes. Soil temperature, reflective of climate regimes, was important in shaping microbial communities at both taxonomic and functional gene levels. As a first glimpse of both the taxonomic and functional compositions of soil microbial communities, our results suggest that microbial community structure and function potentials will be altered by future environmental changes, which have implications for forest succession. PMID:25943705

  18. Analyses of soil microbial community compositions and functional genes reveal potential consequences of natural forest succession.

    PubMed

    Cong, Jing; Yang, Yunfeng; Liu, Xueduan; Lu, Hui; Liu, Xiao; Zhou, Jizhong; Li, Diqiang; Yin, Huaqun; Ding, Junjun; Zhang, Yuguang

    2015-01-01

    The succession of microbial community structure and function is a central ecological topic, as microbes drive the Earth's biogeochemical cycles. To elucidate the response and mechanistic underpinnings of soil microbial community structure and metabolic potential relevant to natural forest succession, we compared soil microbial communities from three adjacent natural forests: a coniferous forest (CF), a mixed broadleaf forest (MBF) and a deciduous broadleaf forest (DBF) on Shennongjia Mountain in central China. In contrary to plant communities, the microbial taxonomic diversity of the DBF was significantly (P < 0.05) higher than those of CF and MBF, rendering their microbial community compositions markedly different. Consistently, microbial functional diversity was also highest in the DBF. Furthermore, a network analysis of microbial carbon and nitrogen cycling genes showed the network for the DBF samples was relatively large and tight, revealing strong couplings between microbes. Soil temperature, reflective of climate regimes, was important in shaping microbial communities at both taxonomic and functional gene levels. As a first glimpse of both the taxonomic and functional compositions of soil microbial communities, our results suggest that microbial community structure and function potentials will be altered by future environmental changes, which have implications for forest succession. PMID:25943705

  19. The Response of Net Nitrification Rates to a Clearcut in a Deciduous Forest in the Catskill Mountains of New York

    NASA Astrophysics Data System (ADS)

    Burns, D. A.; Murdoch, P. S.

    2001-12-01

    The Catskill Mountains of southeastern New York receive atmospheric nitrogen (N) deposition of 10 to 15 kg-1ha-1yr-1, and streams in the region show a wide range of nitrate (NO3^{-}) concentrations from near 0 to 100 \\mumolL^{-1}. Past research indicates that most NO_{3}- in streams in this region originates through nitrification in the soil. Past forest and soil disturbance is one of the major factors that affects nitrification. A 23-ha tributary watershed of the Neversink River was clearcut in 1997 to understand how the resulting disturbance affects the N cycle. Stream NO3^{-} concentrations briefly increased above 1000 \\mumolL^{-1} about 5 months after the cut, and remained above 200 \\mumolL^{-1} for almost 2 years. Nitrogen budgets indicate that most of the stream NO_{3}- originated through nitrification in the soil, from which increased amounts of NO3^{-}$ leached to surface water in the absence of competition with uptake by vegetation. Past research in a variety of settings across North America has shown that clearcutting increases N-mineralization and nitrification rates in forest soil, but we found no increase in the net rates of either of these processes during monthly in-situ incubations. This seeming paradox is attributed to limitations of the in-situ incubation method, which measures only the net rates of these processes in the absence of N uptake by vegetation. The clearcut in this Catskill setting (in which high net nitrification rates were measured prior to harvesting) did not cause large enough changes in physical factors that affect this microbial process, such as soil temperature and moisture, to produce a measurable change in the net rate of nitrification. Consequently, nitrate concentrations in stream water decreased sharply during the third and fourth years after the clearcut in response to a second growth forest dominated by pin cherry (Prunus pennsylvanica).

  20. Biogeochemical controls on methane, nitrous oxide, and carbon dioxide fluxes from deciduous forest soils in eastern Canada

    NASA Astrophysics Data System (ADS)

    Ullah, Sami; Moore, Tim R.

    2011-09-01

    The exchange of the important trace gases, methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2), between forested soils and the atmosphere can show great temporal and spatial variability. We measured the flux of these three gases over 2 years along catenas at two forested sites, to determine the important controls. Well-drained soils consumed atmospheric CH4, while poorly drained swamp soils embedded in depressions were a source. CH4 fluxes could be predicted primarily by temperature and moisture, and tree cover exerted an influence mainly through the creation of large soil porosity, leading to increased consumption rates. In contrast, there were very poor relationships between N2O fluxes and environmental variables, reflecting the complex interactions of microbial, edaphic, and N cycling processes, such as nitrification in well-drained soils and denitrification in poorly drained soils, which led to N2O production (or consumption) in soils and hence larger variability. At the broad temporal and spatial scale, soil C:N ratio was a good predictor of N2O emission rates, through its influence upon N cycling processes. Soil CO2 emission rates showed less spatial and temporal variability, and were controlled by temperature and moisture. The source strength, in global warming potential of CH4 and N2O fluxes in CO2 equivalents, was reduced markedly when trace gas fluxes from 5 to 15% poorly drained soils were included in the net global warming potential calculation of whole forested watersheds. Soils drainage class integrates many of the biogeochemical processes controlling the flux of these gases providing a framework for extrapolating results.

  1. Differential response by hardwood and deciduous stands in New England forests to climate change and insect-induced mortality

    NASA Astrophysics Data System (ADS)

    Munger, J. William; Wofsy, Steven C.; Orwig, David A.; Williams, Chris

    2016-04-01

    Forests in the northeastern United States include large areas dominated by mosaics of oak/maple and hemlock stands. Often the hardwood dominated stands include a significant cohort of hemlock saplings. However, long-term survival of hemlock in this region is threatened by Hemlock Wooly Adelgid (HWA), an invasive insect that is fatal to eastern hemlock. The northern limit of HWA is affected in part by winter minimum temperature and warmer winters are enabling northward expansion of HWA infestation. At the Harvard Forest in central Massachusetts, two long-term eddy flux towers are measuring carbon exchange in a >100 year old hardwood stand since 1992 (EMS- Ha1) and in a 100-200 year old hemlock stand (Ha2) since 2004. The flux measurements are complemented by vegetation dynamics plots. Carbon exchange at the two sites has distinctly different seasonality. The hardwood site has a shorter carbon uptake period, but higher peak fluxes, while the hemlock stand has a long carbon uptake period extending from spring thaw until early winter freeze. Some contribution from the evergreen hemlock in the understory is evident before canopy greenup at the EMS tower and spring and fall carbon uptake rates have been increasing and contribute in part to a trend towards larger annual carbon uptake at this site. Carbon uptake by hemlock increases with warmer temperatures in the spring and fall transition. Adelgids have reached the hemlock stand near Ha2 and have been widely distributed in the canopy since spring of 2012. The hemlock canopy in that stand is thinning and net carbon uptake and evapotranspiration have been decreasing since 2012. Adelgids have also been observed in scattered stands near the Ha1 tower, but as of 2015 the trees are still healthy. Because hemlocks stands have different seasonality and provide a distinct soil and sub-canopy light environment, their mortality and replacement by hardwood species will have significant impacts on forest dynamics, carbon balance, and

  2. Estimating the age of deciduous forests in northeast China with Enhanced Thematic Mapper Plus data acquired in different phenological seasons

    NASA Astrophysics Data System (ADS)

    Li, Dengqiu; Ju, Weimin; Fan, Wenyi; Gu, Zhujun

    2014-01-01

    This study investigated the ability of Landsat Enhanced Thematic Mapper Plus data acquired in leaf-on and leaf-off seasons to estimate stand age of Larix gmelinii and Betula platyphylla in northeast China. The relationships of six band reflectances, nine vegetation indices, and six texture measures with stand age were examined. Linear and multivariable regression models and multilayer perceptron neural network (MLP NN) were employed to estimate forest age based on these variables. The results indicate that reflectance in short-wave infrared bands and wetness are more significantly correlated with stand age in the leaf-on image, while reflectance in blue and green bands and greenness are more sensitive to stand age in leaf-off image. The MLP NN model can be effectively used to retrieve the stand age; the highest coefficient of determination and minimum root mean square error values of retrieved age are 0.47 and 21.3 years for Larix gmelinii, and 0.60 and 10.1 years for Betula platyphylla, respectively. The predicted age errors increased significantly when stand ages were >100 and >50 years for Larix gmelinii and Betula platyphylla, respectively. Remote sensing data acquired in the leaf-on season is more suitable for estimating forest age than that acquired in the leaf-off season over the study area.

  3. Temporal variability in (13)C of respired CO(2) in a pine and a hardwood forest subject to similar climatic conditions.

    PubMed

    Mortazavi, Behzad; Chanton, Jeffrey P; Prater, James L; Oishi, A Christopher; Oren, Ram; Katul, Gabriel

    2005-01-01

    Temporal variability in the (13)C of foliage (delta(13)C(F)), soil (delta(13)C(S)) and ecosystem (delta(13)C(R)) respired CO(2) was contrasted between a 17.2-m tall evenly aged loblolly pine forest and a 35-m tall unevenly aged mature second growth mixed broadleaf deciduous forest in North Carolina, USA, over a 2-year period. The two forests are located at the Duke Forest within a kilometer of each other and are subject to identical climate and have similar soil types. The delta(13)C(F), collected just prior to dawn, was primarily controlled by the time-lagged vapor pressure deficit (VPD) in both stands; it was used for calculating the ratio of intercellular to ambient CO(2) ( Ci/ Ca). A remarkable similarity was observed in the relationship between Ci/ Ca and time-lagged VPD in these two forests despite large differences in hydraulic characteristics. This similarity emerged as a result of physiological adjustments that compensated for differences in plant hydraulic characteristics, as predicted by a recently proposed equilibrium hypothesis, and has implications to ecophysiological models. We found that in the broadleaf forest, the delta(13)C of forest floor CO(2) efflux dominated the delta(13)C(R), while in the younger pine forest, the delta(13)C of foliage respired CO(2) dominated delta(13)C(R). This dependence resulted in a more variable delta(13)C(R) in the pine forest when compared to the broadleaf forest due to the larger photosynthetic contribution. Given the sensitivity of the atmospheric inversion models to delta(13)C(R), the results demonstrate that these models could be improved by accounting for stand characteristics, in addition to previously recognized effects of moisture availability, when estimating delta(13)C(R). PMID:15340829

  4. Can soil testate amoebae be used for estimating the time since death? A field experiment in a deciduous forest.

    PubMed

    Szelecz, Ildikò; Fournier, Bertrand; Seppey, Christophe; Amendt, Jens; Mitchell, Edward

    2014-03-01

    Estimation of the post-mortem interval (PMI, the time interval between death and recovery of a body) can be crucial in solving criminal cases. Today minimum PMI calculations rely mainly on medical and entomological evidence. However, beyond 4-6 weeks even entomological methods become less accurate. Thus additional tools are needed. Cadaveric fluids released by decomposing cadavers modify the soil environment and thus impact soil organisms, which may thus be used to estimate the PMI. Although the response of bacteria or fungi to the presence of a corpse has been studied, to the best of our knowledge nothing is known about other soil organisms. Testate amoebae, a group of shelled protozoa, are sensitive bioindicators of soil physico-chemical and micro-climatic conditions and are therefore good potential PMI indicators. We investigated the response of testate amoebae to three decomposing pig cadavers, and compared the pattern to two controls each, bare soils and fake cadavers, in a beach-oak forest near Neuchâtel, Switzerland. Forest litter samples collected in the three treatments over 10 months were analysed by microscopy. The pig treatment significantly impacted the testate amoeba community: after 22 and 33 days no living amoeba remained underneath the pig cadavers. Communities subsequently recovered but 10 months after the beginning of the experiment recovery was not complete. The fake cadavers also influenced the testate amoeba communities by altering the soil microclimate during a dry hot period, but less than the cadavers. These results confirm the sensitivity of soil testate amoebae to micro-climatic conditions and show that they respond fast to the presence of cadavers - and that this effect although decreasing over time lasts for months, possibly several years. This study therefore confirms that soil protozoa could potentially be useful as forensic indicators, especially in cases with a longer PMI. PMID:24529779

  5. Solar-induced Fluorescence as a Proxy for Canopy Photosynthesis in a Temperate Deciduous Forest: Comparisons between Observations and Model Results

    NASA Astrophysics Data System (ADS)

    Yang, X.; Lee, J. E.; Berry, J. A.; Tang, J.; Mustard, J. F.; Van der Tol, C.; Kellner, J. R.; Silva, C. E.

    2015-12-01

    Photosynthesis in the terrestrial ecosystems contributes to the largest carbon flux in the global carbon cycle. The use of solar-induced fluorescence (SIF) as a proxy of photosynthesis at the ecosystem scale (Gross Primary Production, GPP) is a critical emerging technology. Satellite measurements of SIF were found to be significantly correlated with GPP, and several ground campaigns suggested that SIF could improve the GPP estimation. However, it remains unclear to what extent this relationship is due to absorbed photosynthetically active radiation (APAR) and/or light use efficiency (LUE). In addition, models that simulate SIF have not been rigorously validated. Here we present the first time-series of near-surface measurement of canopy-scale SIF at 760nm in temperate deciduous forests during year 2013-2014. SIF correlated with GPP estimated with eddy covariance at diurnal and seasonal scales (r2=0.82 and 0.73, respectively), as well as with APAR diurnally and seasonally (r2=0.90 and 0.80, respectively). SIF/APAR is significantly positively correlated with LUE and is higher during cloudy days than sunny days. Weekly tower-based SIF agreed with SIF from GOME-2 (The Global Ozone Monitoring Experiment-2, r2 = 0.82). We further compared SIF observations with those simulated by Soil Canopy Observation Photochemistry and Energy fluxes (SCOPE) model. We found that key parameters in SCOPE including Vcmax, LAI, chlorophyll content, and viewing angles determine the agreement between observations and model. Our results provide support to the use of SIF to estimate canopy photosynthetic activities, and present a framework of validating fluorescence simulated by canopy radiative transfer models.

  6. Differential Growth Responses to Water Balance of Coexisting Deciduous Tree Species Are Linked to Wood Density in a Bolivian Tropical Dry Forest

    PubMed Central

    Mendivelso, Hooz A.; Camarero, J. Julio; Royo Obregón, Oriol; Gutiérrez, Emilia; Toledo, Marisol

    2013-01-01

    A seasonal period of water deficit characterizes tropical dry forests (TDFs). There, sympatric tree species exhibit a diversity of growth rates, functional traits, and responses to drought, suggesting that each species may possess different strategies to grow under different conditions of water availability. The evaluation of the long-term growth responses to changes in the soil water balance should provide an understanding of how and when coexisting tree species respond to water deficit in TDFs. Furthermore, such differential growth responses may be linked to functional traits related to water storage and conductance. We used dendrochronology and climate data to retrospectively assess how the radial growth of seven coexisting deciduous tree species responded to the seasonal soil water balance in a Bolivian TDF. Linear mixed-effects models were used to quantify the relationships between basal area increment and seasonal water balance. We related these relationships with wood density and sapwood production to assess if they affect the growth responses to climate. The growth of all species responded positively to water balance during the wet season, but such responses differed among species as a function of their wood density. For instance, species with a strong growth response to water availability averaged a low wood density which may facilitate the storage of water in the stem. By contrast, species with very dense wood were those whose growth was less sensitive to water availability. Coexisting tree species thus show differential growth responses to changes in soil water balance during the wet season. Our findings also provide a link between wood density, a trait related to the ability of trees to store water in the stem, and wood formation in response to water availability. PMID:24116001

  7. Differential growth responses to water balance of coexisting deciduous tree species are linked to wood density in a Bolivian tropical dry forest.

    PubMed

    Mendivelso, Hooz A; Camarero, J Julio; Royo Obregón, Oriol; Gutiérrez, Emilia; Toledo, Marisol

    2013-01-01

    A seasonal period of water deficit characterizes tropical dry forests (TDFs). There, sympatric tree species exhibit a diversity of growth rates, functional traits, and responses to drought, suggesting that each species may possess different strategies to grow under different conditions of water availability. The evaluation of the long-term growth responses to changes in the soil water balance should provide an understanding of how and when coexisting tree species respond to water deficit in TDFs. Furthermore, such differential growth responses may be linked to functional traits related to water storage and conductance. We used dendrochronology and climate data to retrospectively assess how the radial growth of seven coexisting deciduous tree species responded to the seasonal soil water balance in a Bolivian TDF. Linear mixed-effects models were used to quantify the relationships between basal area increment and seasonal water balance. We related these relationships with wood density and sapwood production to assess if they affect the growth responses to climate. The growth of all species responded positively to water balance during the wet season, but such responses differed among species as a function of their wood density. For instance, species with a strong growth response to water availability averaged a low wood density which may facilitate the storage of water in the stem. By contrast, species with very dense wood were those whose growth was less sensitive to water availability. Coexisting tree species thus show differential growth responses to changes in soil water balance during the wet season. Our findings also provide a link between wood density, a trait related to the ability of trees to store water in the stem, and wood formation in response to water availability. PMID:24116001

  8. Seed reserve composition in 19 tree species of a tropical deciduous forest in Mexico and its relationship to seed germination and seedling growth

    PubMed Central

    Soriano, Diana; Orozco-Segovia, Alma; Márquez-Guzmán, Judith; Kitajima, Kaoru; Gamboa-de Buen, Alicia; Huante, Pilar

    2011-01-01

    Background and Aims The size and composition of seed reserves may reflect the ecological strategy and evolutionary history of a species and also temporal variation in resource availability. The seed mass and composition of seed reserves of 19 co-existing tree species were studied, and we examined how they varied among species in relation to germination and seedling growth rates, as well as between two years with contrasting precipitation (652 and 384 mm). Methods Seeds were collected from a tropical deciduous forest in the northwest of Mexico (Chamela Biological Station). The seed dry mass, with and without the seed coat, and the concentrations of lipids, nitrogen and non-structural carbohydrates for the seed minus seed coat were determined. The anatomical localization of these reserves was examined using histochemical analysis. The germination capacity, rate and lag time were determined. The correlations among these variables, and their relationship to previously reported seedling relative growth rates, were evaluated with and without phylogenetic consideration. Key Results There were interannual differences in seed mass and reserve composition. Seed was significantly heavier after the drier year in five species. Nitrogen concentration was positively correlated with seed coat fraction, and was significantly higher after the drier year in 12 species. The rate and lag time of germination were negatively correlated with each other. These trait correlations were also supported for phylogenetic independent contrasts. Principal component analysis supported these correlations, and indicated a negative association of seedling relative growth rate with seed size, and a positive association of germination rate with nitrogen and lipid concentrations. Conclusions Nitrogen concentration tended to be higher after the drier year and, while interannual variations in seed size and reserve composition were not sufficient to affect interspecific correlations among seed and seedling

  9. Variability in Soil Properties at Different Spatial Scales (1 m to 1 km) in a Deciduous Forest Ecosystem

    SciTech Connect

    Garten Jr, Charles T; Kang, S.; Brice, Deanne Jane; Schadt, Christopher Warren; Zhou, Jizhong

    2007-01-01

    The purpose of this research was to test the hypothesis that variability in 11 soil properties, related to soil texture and soil C and N, would increase from small (1 m) to large (1 km) spatial scales in a temperate, mixed-hardwood forest ecosystem in east Tennessee, USA. The results were somewhat surprising and indicated that a fundamental assumption in geospatial analysis, namely that variability increases with increasing spatial scale, did not apply for at least five of the 11 soil properties measured over a 0.5-km2 area. Composite mineral soil samples (15 cm deep) were collected at 1, 5, 10, 50, 250, and 500 m distances from a center point along transects in a north, south, east, and westerly direction. A null hypothesis of equal variance at different spatial scales was rejected (P{le}0.05) for mineral soil C concentration, silt content, and the C-to-N ratios in particulate organic matter (POM), mineral-associated organic matter (MOM), and whole surface soil. Results from different tests of spatial variation, based on coefficients of variation or a Mantel test, led to similar conclusions about measurement variability and geographic distance for eight of the 11 variables examined. Measurements of mineral soil C and N concentrations, C concentrations in MOM, extractable soil NH{sub 4}-N, and clay contents were just as variable at smaller scales (1-10 m) as they were at larger scales (50-500 m). On the other hand, measurement variation in mineral soil C-to-N ratios, MOM C-to-N ratios, and the fraction of soil C in POM clearly increased from smaller to larger spatial scales. With the exception of extractable soil NH4-N, measured soil properties in the forest ecosystem could be estimated (with 95% confidence) to within 15% of their true mean with a relatively modest number of sampling points (n{le}25). For some variables, scaling up variation from smaller to larger spatial domains within the ecosystem could be relatively easy because small-scale variation may be

  10. Secondary stem anatomy and uses of four drought-deciduous species of a tropical dry forest in México.

    PubMed

    Isaias, Alejandra Quintanar; Velázquez Núñez, Mariana; Solares Arenas, Fortunato; de la Paz Pérez Olvera, Carmen; Torre-Blanco, Alfonso

    2005-01-01

    Wood and bark anatomy and histochemistry of Acacia bilimekii Humb. & Bonpl., Acacia cochliacantha Mcbride, Conzatia nultiflora (Rob) Stand. and Guazuma ulmifolia Lam. are described from stem samples collected in a tropical dry forest (Morelos, Mexico). Enzyme activities were tested in tangential, radial and transverse cuts of fresh material. Histochemistry and stem anatomy were studied on similar cuts previously softened in a solution of water-glicerol-PEG. Our results show that the anatomical patterns of bark and wood, as well as the histochemical patterns and specific gravity, are influenced by water accessibility and climate; these patterns could guarantee mechanical and anti-infection strategies to support extreme conditions. Enzyme cytochemistry reveals biochemical activities probably related to lipid utilization routes for the lignification processes and for synthesis of extractives; these results suggest that the formation and maturation of woody tissue is very active at the beginning of the rainy season. These species are widely used by the local population. Traditional uses include firewood, dead and live fences, fodder, construction, supporting stakes, handcrafts, farming tools, extraction of tanning products, and medicine. There is no relationship between use and abundance. Alternative uses are proposed according to a density index. PMID:17354418

  11. Impacts of precipitation variability on plant species and community water stress in a temperate deciduous forest in the central US

    DOE PAGESBeta

    Gu, Lianhong; Pallardy, Stephen G.; Hosman, Kevin P.; Sun, Ying

    2015-12-11

    Variations in precipitation regimes can shift ecosystem structure and function by altering frequency, severity and timing of plant water stress. There is a need for predictively understanding impacts of precipitation regimes on plant water stress in relation to species water use strategies. Here we first formulated two complementary, physiologically-linked measures of precipitation variability (PV) - Precipitation Variability Index (PVI) and Average Recurrence Interval of Effective Precipitation (ARIEP). We then used nine-year continuous measurements of Predawn Leaf Water Potential Integral (PLWPI) in a central US forest to relate PVI and ARIEP to actual plant water availability and comparative water stress responsesmore » of six species with different capacities to regulate their internal water status. We found that PVI and ARIEP explained nearly all inter-annual variations in PLWPI for all species as well as for the community scaled from species measurements. The six species investigated showed differential sensitivities to variations in precipitation regimes. Their sensitivities were reflected more in the responses to PVI and ARIEP than to the mean precipitation rate. Further, they exhibited tradeoffs between responses to low and high PV. Finally, PVI and ARIEP were closely correlated with temporal integrals of positive temperature anomalies and vapor pressure deficit. We suggest that the comparative responses of plant species to PV are part of species-specific water use strategies in a plant community facing the uncertainty of fluctuating precipitation regimes. In conclusion, PVI and ARIEP should be adopted as key indices to quantify physiological drought and the ecological impacts of precipitation regimes in a changing climate.« less

  12. Impacts of precipitation variability on plant species and community water stress in a temperate deciduous forest in the central US

    SciTech Connect

    Gu, Lianhong; Pallardy, Stephen G.; Hosman, Kevin P.; Sun, Ying

    2015-12-11

    Variations in precipitation regimes can shift ecosystem structure and function by altering frequency, severity and timing of plant water stress. There is a need for predictively understanding impacts of precipitation regimes on plant water stress in relation to species water use strategies. Here we first formulated two complementary, physiologically-linked measures of precipitation variability (PV) - Precipitation Variability Index (PVI) and Average Recurrence Interval of Effective Precipitation (ARIEP). We then used nine-year continuous measurements of Predawn Leaf Water Potential Integral (PLWPI) in a central US forest to relate PVI and ARIEP to actual plant water availability and comparative water stress responses of six species with different capacities to regulate their internal water status. We found that PVI and ARIEP explained nearly all inter-annual variations in PLWPI for all species as well as for the community scaled from species measurements. The six species investigated showed differential sensitivities to variations in precipitation regimes. Their sensitivities were reflected more in the responses to PVI and ARIEP than to the mean precipitation rate. Further, they exhibited tradeoffs between responses to low and high PV. Finally, PVI and ARIEP were closely correlated with temporal integrals of positive temperature anomalies and vapor pressure deficit. We suggest that the comparative responses of plant species to PV are part of species-specific water use strategies in a plant community facing the uncertainty of fluctuating precipitation regimes. In conclusion, PVI and ARIEP should be adopted as key indices to quantify physiological drought and the ecological impacts of precipitation regimes in a changing climate.

  13. Atmospheric deposition and corresponding variability of stemflow chemistry across temporal scales in a mid-Atlantic broadleaved deciduous forest

    NASA Astrophysics Data System (ADS)

    Levia, Delphis F.; Van Stan, John T.; Siegert, Courtney M.; Inamdar, Shreeram P.; Mitchell, Myron J.; Mage, Susanna M.; McHale, Patrick J.

    2011-06-01

    Despite the fact that atmospheric deposition is widely accepted to be an important process in the biogeochemical cycling of wooded ecosystems, no single study is known that has examined stemflow chemistry in relation to atmospheric deposition across time scales, from within discrete events to season, to chronicle alterations in temporal patterns of stemflow chemistry. This research partitioned stemflow solute fluxes (K +, Na +, Mg 2+, Ca 2+, Cl -, NO 3-, and SO 42-) from two tree species of differing canopy form and bark morphology into their leaching and dry deposition washoff components using a modified Kazda (1990) integration model at the intra-storm scale to examine differences within and among discrete rain events. Median annual stemflow concentrations in yellow poplar ( Liriodendron tulipifera L.) stemflow were higher than American beech ( Fagus grandifolia Ehrh.) stemflow for all ions except NO 3-. Beech median enrichment ratios were larger for all monitored ions than yellow poplar. All intra-storm stemflow ionic fluxes were initially high, exponentially decaying to a steady input, typically dominated by leaching contributions. With the exception of yellow poplar stemflow Cl - and NO 3- fluxes and beech Na + flux, all intra-storm mean ionic fluxes began with higher dry deposition percentages and transitioned to primarily leaching. Observations in the field implicate increased magnitude and rainfall intensity in the initiation of new stemflow flowpaths, evidenced by increased variability in the timing of stemflow ionic deposition and fluctuations in the proportion of washoff and leaching during some events. Beech stemflow fluxes were larger than yellow poplar for all ions during the leafed, leafless, and annual periods. Our results demonstrate: (1) the critical role of the initiation of new flowpaths and expansion and maturation of developed flowpaths on a tree's surface to solute enrichment and transport to the forest floor as a canopy wets-up; and (2) the

  14. Variation in Plant Traits Explains Global Biogeographic Variation in the Abundance of Major Forest Functional Types

    NASA Astrophysics Data System (ADS)

    Wang, Y.

    2015-12-01

    Contrasting leaf types (needle vs. broadleaf) with different lifespans (annual vs. perennial) represent different adaptive strategies of plants under different environmental conditions. Previous studies explained adaptive advantages of different strategies using empirical models but cannot adequately explain the co-dominance of multiple plant functional types (PFTs) as observed in many parts of the world. Here we used a process-based model to explore whether observed inter- and intra-PFT variation in key plant traits can explain global biogeographic variation in co-dominance of major forest functional types. Using a parameter screening method, we identified the four most important plant traits for simulating annual net primary production (NPP) using the Australian Community Atmosphere-Biosphere-Land Exchange model (CABLE). Using ensemble CABLE simulations, we estimated the fraction of global land cover attributed to each PFT by comparing the simulated NPP for all three PFTs at each land point, globally. Our results were consistent with land area cover fractions of major forest types estimated from remote sensing data products; i.e., evergreen needle-leaf forests dominate in boreal regions, evergreen broadleaf forests dominate in tropical regions, and deciduous broadleaf forests are distributed widely across a broad range of environmental conditions. More importantly our approach successfully explained a paradox that has puzzled ecologists for over a century: why evergreen leaf types dominate in both boreal and tropical regions. We conclude that variation in and co-variation between key plant traits can explain significant fractions of global biogeographic variation of three major forest types, and should be taken into account when simulating global vegetation dynamics.

  15. Comparison of different methods to assess root litter carbon input to the soil in a young deciduous forest

    NASA Astrophysics Data System (ADS)

    Panzacchi, Pietro; Boldreghini, Pietro; Cantoni, Lucia; Gioacchini, Paola; Tonon, Giustino

    2010-05-01

    Estimating fine root turnover and rhizodeposition remains a mayor challenge in natural ecosystems studies. In the present research we estimated root litter carbon (C) imputs to the soil during 2006 coupling one direct and one indirect method. The study was carried out in a fifteen-year-old mixed hardwood plantation established in northern Italy on a former agricultural land (Clay content ~60%). A first estimation of net rhizodeposition was obtained by the application of an isotopic method by using in-growth cores filled with 'C4 soil'. Plastic mesh bags (2.5 cm diameter, 60 cm long, 0.5 cm mesh size) were packed respecting the original soil bulk density with soil from a long term Zea mais crop system (δ 13C = -22.0 ± 0.2 ) and placed in the soil at different distances from the stem of trees. 'Control' bags made with a special tissue, porous to water and gases but impenetrable to roots, were also placed nearby. By using the mass balance approach the flux of C to the soil was calculated. This latter estimation was then compared to the root litter input estimated by the application of the total belowground carbon allocation (TBCA) approach for forests far from the steady state that can be simplified as follows: Ra + Lr+ ?rootC = TBCA = Rsoil --Ll+ ?litterC + ?soilC + ?rootC (1) where and Rsoil is total soil respiration, Ra is autotrophic soil respiration estimated by the 'trenching method', Lr and Ll are belowground and aboveground litter respectively, ?litterC, ?soilC and ?rootC are the variations of C of litter layer, soil and roots respectively. From equation 1 it is possible to extrapolate Lr: Lr = Rsoil --Ra+ ?litterC + ?soilC + ?rootC (2) The two methods, that have never been exploited with the aim to estimate rhizodeposition, gave similar final results. Actually, the net rhizodeposition (C input to the soil by root minus heterotrophic respiration) was 3.27 Mg of C ha-1 by isotopic approach and the total rhizodeposition was 3.22 Mg of C ha-1 by TBCA approach.

  16. A comparison of {sup 137}Cs radioactivity in localized evergreen and deciduous plant species

    SciTech Connect

    Rangel, R.C.; Schlapper, G.A.; McLain, M.E.; Pitt, W.W.

    1996-06-01

    A vegetation study at the Comanche Steam Electric Station (CPSES) in Texas was conducted in 1991 and 1992. The CPSES is a commercial nuclear power plant. The CPSES environmental monitoring program collects broadleaf vegetation samples as per the Nuclear Regulatory Commission (NRC). Broadleaf trees are scarce in the area because of local climate, soils, and geology. The dominate tree is an evergreen juniper. Few broadleaves are available during winter for sampling. This study compared the environmental {sup 137}C s radioactivity between broadleaf and evergreen foliage. The study`s objective was to determine if {sup 137}C s radioactivity is statistically the same in the deciduous and evergreen vegetation. Radioactivity from the same statistical population could allow the sampling program to collect evergreen (junipers) foliage. Broadleaf and evergreen tree leaf samples were collected on and off the CPSES area. Gamma-ray spectrometry was performed on the samples to measure {sup 137}Cs radioactivity. The means of the {sup 137}Cs concentrations in broadleaf and evergreen foliage samples were found to be statistically the same and therefore from the same population. This study`s conclusion is that evergreen leaves from juniper trees can be used to supplement and/or substitute for the broadleaf samples currently collected. This change in foliage collection, if approved by the NRC, would allow the CPSES to better satisfy its environmental sampling regulatory requirements.

  17. [Diversity, relative abundance and activity patterns of medium and large mammals in a tropical deciduous forest in the Isthmus of Tehuantepec, Oaxaca, Mexico].

    PubMed

    Cortés-Marcial, Malinalli; Briones-Salas, Miguel

    2014-12-01

    The use of camera traps and mammal track search are complementary methods to monitoring species of which is not well documented their natural history, as in the case of medium and large mammals. To ensure its conservation and good management, it is necessary to generate information about the structure of the community and their populations. The objective of the present study was to estimate the diversity, relative abundance and activity patterns of medium and large mammals in a tropical deciduous forest located in the Isthmus of Tehuantepec, Oaxaca, Mexico. Samplings were conducted in three month intervals, from September 2011 to May 2013. We used photographic-sampling and track search, two complementary sampling methods. For photographic-sampling, 12 camera traps were placed covering an area of 60 km2, while for the tracks search a monthly tour of four line-transect surveys of three kilometers length each was undertaken. We obtained a total of 344 pictures with 5292 trap-days total sampling effort; in addition, 187 track records in a total of 144 km. With both methods we registered 21 species of mammals, in 13 families and seven orders, and five species resulted in new records to the area. The diversity index of Shannon-Wiener obtained with the method of tracks was H' = 2.41, while the most abundant species were Urocyon cinereoargen- teus (IAR = 0.23) and Pecari tajacu (IAR = 0.20). By the method of trap the most abundant species were P. tajacu (IAR = 2.62) and Nasua narica (IAR = 1.28). In terms of patterns of activity P. tajacu, N. narica and Odocoileus virginianus were primarily diurnal species; Canis latrans and Leopardus pardalis did not show preference for any schedule in particular, and Didelphis virginiana and Dasypus novemcinctus preferred to have nocturnal activity. This information can be of help to the creation of programs of management and conservation of mam- mals of medium and large in the Isthmus of Tehuantepec, Oaxaca, México. PMID:25720178

  18. Hygroscopic properties of newly formed ultrafine particles at an urban site surrounded by deciduous forest (Sapporo, northern Japan) during the summer of 2011

    NASA Astrophysics Data System (ADS)

    Jung, J.; Kawamura, K.

    2014-07-01

    To investigate the hygroscopic properties of ultrafine particles during new particle formation events, the hygroscopic growth factors of size-segregated atmospheric particles were measured at an urban site in Sapporo, northern Japan, during the summer of 2011. The hygroscopic growth factor at 85 % relative humidity [g(85%)] of freshly formed nucleation mode particles was 1.11 to 1.28 (average: 1.16 ± 0.06) at a dry particle diameter (Dp) centered on 20 nm, which is equivalent to 1.17 to 1.35 (1.23 ± 0.06) at a dry Dp centered on 100 nm after considering the Kelvin effect. These values are comparable with those of secondary organic aerosols, suggesting that low-volatility organic vapors are important to the burst of nucleation mode particles. The equivalent g(85%) at a dry Dp of 100 nm for nucleated particles that have grown to Aitken mode sizes (1.24 to 1.34; average: 1.30 ± 0.04) were slightly higher than those of newly formed nucleation mode particles, suggesting that the growth of freshly formed nucleation mode particles to the Aitken mode size can be subjected to condensation of not only low-volatility organic vapors, but also water-soluble inorganic species. Based on this result, and previous measurement of radiocarbon in aerosols, we suggest that the burst of nucleation mode particles and their subsequent growth were highly affected by biogenic organic emissions at this measurement site, which is surrounded by deciduous forest. Gradual increases in mode diameter after the burst of nucleation mode particles were observed under southerly wind conditions, with a dominant contribution of intermediately hygroscopic particles. However, sharp increases in mode diameter were observed when the wind direction shifted to northwesterly or northeasterly, with a sharp increase in the highly hygroscopic particle fraction of the Aitken mode particles, indicating that the hygroscopic growth factor of newly formed particles is perturbed by the local winds that deliver

  19. A comparison of {sup 137}Cs radioactivity in localized evergreen and deciduous plant species

    SciTech Connect

    Rangel, R.C.

    1996-05-01

    A vegetation study at the Comanche Peak Steam Electric Station (CPSES) near Glen Rose, Texas was conducted in 1991 and 1992. The CPSES is a commercial nuclear power plant owned and operated by Texas Utilities Electric of Dallas, Texas. The US Nuclear Regulatory Commission (USNRC) requires the CPSES to routinely sample broadleaf vegetation in place of milk samples. Few commercial dairies exist in the vicinity. Broadleaf tree species are scarce because the climate and local limestone geology have produced a dry rolling hill topography. An evergreen juniper is the dominant tree species. Few broadleaves during the winter season have hindered year-round sampling. This study compares the environmental {sup 137}Cs concentrations between broadleaf and evergreen foliage at CPSES. Soil {sup 137}Cs concentrations from each vegetation location were also compared to the foliage {sup 137}Cs concentrations. The study`s objective was to determine if the deciduous and evergreen vegetation {sup 137}Cs concentrations are statistically the same.

  20. AmeriFlux CA-TPD Ontario - Turkey Point Mature Deciduous

    SciTech Connect

    Arain, M. Altaf

    2016-01-01

    This is the AmeriFlux version of the carbon flux data for the site CA-TPD Ontario - Turkey Point Mature Deciduous. Site Description - The forest is approximately 90 years old. Naturally regenerated on sandy terrain and abandoned agricultural land. Predominantly hardwood species with a few scattered conifers. Site has been managed (thinned) in the past. It has a high biodiversity with 573 tree and plant species, 102 bird species, 23 mamal species and 22 reptile and amphibian species (SWALSREP Report, 1999). The dominant tree species is white oak (Quercus alba), with other scattered broadleaf Carolinian species including sugar and red maple (Acer saccharum, A. rubrum), American beech (Fagus grandifolia), black and red oak (Q. velutina, Q. rubra) and white ash (Fraxinus americana) . There are also scattered conifers, mostly white and red pine (Pinus strobes, P. resinosa), comprising about 5% of the trees. Average tree height is 25.7 m with a stand density of 504 ± 18 trees per hectare. Average tree diameter at breast height is 22.3 cm and basal area is 0.06 m2 or approximately 29 square meters per hectare.

  1. Carbon emissions and sequestration in forests: Case studies from seven developing countries. Volume 4: Mexico: Draft

    SciTech Connect

    Makundi, W.; Sathaye, J.; Cerutti, O.M.; Ordonez, M.J.; Minjarez, R.D.

    1992-08-01

    Estimates of carbon emissions from deforestation in Mexico are derived for the year 1985 and for two contrasting scenarios in 2025. Carbon emissions are calculated through an in-depth review of the existing information on forest cover deforestation mtes and area affected by forest fires as well as on forests` carbon-related biological characteristics. The analysis covers both tropical -- evergreen and deciduous -- and temperate -- coniferous and broadleaf -- closed forests. Emissions from the forest sector are also compared to those from energy and industry. Different policy options for promoting the sustainable management of forest resources in the country are discussed. The analysis indicates that approximately 804,000 hectares per year of closed forests suffered from major perturbations in the mid 1980`s in Mexico, leading to an annual deforestation mte of 668,000 hectares. Seventy five percent of total deforestation is concentrated in tropical forests. The resulting annual carbon balance is estimated in 53.4 million tons per year, and the net committed emissions in 45.5 million tons or 41% and 38%, respectively, of the country`s total for 1985--87. The annual carbon balance from the forest sector in 2025 is expected to decline to 16.5 million tons in the low emissions scenario and to 22.9 million tons in the high emissions scenario. Because of the large uncertainties in some of the primary sources of information, the stated figures should be taken as preliminary estimates.

  2. Carbon emissions and sequestration in forests: Case studies from seven developing countries

    SciTech Connect

    Makundi, W.; Sathaye, J. ); Cerutti, O.M.; Ordonez, M.J.; Minjarez, R.D. Centro de Ecologia)

    1992-08-01

    Estimates of carbon emissions from deforestation in Mexico are derived for the year 1985 and for two contrasting scenarios in 2025. Carbon emissions are calculated through an in-depth review of the existing information on forest cover deforestation mtes and area affected by forest fires as well as on forests' carbon-related biological characteristics. The analysis covers both tropical -- evergreen and deciduous -- and temperate -- coniferous and broadleaf -- closed forests. Emissions from the forest sector are also compared to those from energy and industry. Different policy options for promoting the sustainable management of forest resources in the country are discussed. The analysis indicates that approximately 804,000 hectares per year of closed forests suffered from major perturbations in the mid 1980's in Mexico, leading to an annual deforestation mte of 668,000 hectares. Seventy five percent of total deforestation is concentrated in tropical forests. The resulting annual carbon balance is estimated in 53.4 million tons per year, and the net committed emissions in 45.5 million tons or 41% and 38%, respectively, of the country's total for 1985--87. The annual carbon balance from the forest sector in 2025 is expected to decline to 16.5 million tons in the low emissions scenario and to 22.9 million tons in the high emissions scenario. Because of the large uncertainties in some of the primary sources of information, the stated figures should be taken as preliminary estimates.

  3. Optimization of forest age-dependent light-use efficiency and its implications on climate-vegetation interactions in china

    NASA Astrophysics Data System (ADS)

    Li, Z.; Zhou, T.

    2015-04-01

    Forest's net primary productivity (NPP) is a key index in studying interactions of climate and vegetation, and accurate prediction of NPP is essential to understand the forests' response to climate change. The magnitude and trends of forest NPP not only depend on climate factors (e.g., temperature and precipitation), but also on the succession stages (i.e., forest stand age). Although forest stand age plays a significant role on NPP, it is usually ignored by remote sensing-based models. In this study, we used remote sensing data and meteorological data to estimate forest NPP in China based on CASA model, and then employed field observations to inversely estimate the parameter of maximum light-use efficiency (ɛmax) of forests in different stand ages. We further developed functions to describe the relationship between maximum light-use efficiency (ɛmax) and forest stand age, and estimated forest age-dependent NPP based on these functions. The results showed that ɛmax has changed according to forest types and the forest stand age. For deciduous broadleaf forest, the average ɛmax of young, middle-aged and mature forest are 0.68, 0.65 and 0.60 gC MJ-1. For evergreen broadleaf forest, the average ɛmax of young, middle-aged and mature forests are 1.05, 1.01 and 0.99 gC MJ-1. For evergreen needleleaf forest, the average ɛmax of young, middle-aged and mature forests are 0.72, 0.57 and 0.52 gC MJ-1.The NPP of young and middle-aged forests were underestimated based on a constant ɛmax. Young forests and middle-aged forests had higher ɛmax, and they were more sensitive to trends and fluctuations of climate change, so they led to greater annual fluctuations of NPP. These findings confirm the importance of considering forest stand age to the estimation of NPP and they are significant to study the response of forests to climate change.

  4. Fatty acid profiles of great tit ( Parus major) eggs differ between urban and rural habitats, but not between coniferous and deciduous forests

    NASA Astrophysics Data System (ADS)

    Toledo, Alejandra; Andersson, Martin N.; Wang, Hong-Lei; Salmón, Pablo; Watson, Hannah; Burdge, Graham C.; Isaksson, Caroline

    2016-08-01

    Early-life nutrition is an important determinant of both short- and long-term performance and fitness. The avian embryo develops within an enclosed package of nutrients, of which fatty acids (FA) are essential for many aspects of development. The FA composition of yolk depends on maternal nutrition and condition prior to egg formation, which may be affected by the external environment. To test if maternal environment affects yolk FA composition, we investigated whether the FA composition of great tit ( Parus major) egg yolks differed between urban and rural habitats, and between deciduous and coniferous habitats. The results reveal differences in FA composition between eggs laid in urban and rural habitats, but not between eggs from the coniferous and deciduous habitats. To a large extent, this difference likely reflects dietary differences associated with urban habitats rather than dominating vegetation type. Specifically, urban yolks contained lower proportions of both ω-3 and ω-6 polyunsaturated FAs (PUFA), which are important for chick development. We also found a positive association between the proportion of saturated fatty acids and laying date, and a negative association between the proportion of ω-6 PUFA and clutch size. Given that urbanization is expanding rapidly, future studies should investigate whether factors such as anthropogenic food in the urban environment underlie these differences and whether they impair chick development.

  5. Fatty acid profiles of great tit (Parus major) eggs differ between urban and rural habitats, but not between coniferous and deciduous forests.

    PubMed

    Toledo, Alejandra; Andersson, Martin N; Wang, Hong-Lei; Salmón, Pablo; Watson, Hannah; Burdge, Graham C; Isaksson, Caroline

    2016-08-01

    Early-life nutrition is an important determinant of both short- and long-term performance and fitness. The avian embryo develops within an enclosed package of nutrients, of which fatty acids (FA) are essential for many aspects of development. The FA composition of yolk depends on maternal nutrition and condition prior to egg formation, which may be affected by the external environment. To test if maternal environment affects yolk FA composition, we investigated whether the FA composition of great tit (Parus major) egg yolks differed between urban and rural habitats, and between deciduous and coniferous habitats. The results reveal differences in FA composition between eggs laid in urban and rural habitats, but not between eggs from the coniferous and deciduous habitats. To a large extent, this difference likely reflects dietary differences associated with urban habitats rather than dominating vegetation type. Specifically, urban yolks contained lower proportions of both ω-3 and ω-6 polyunsaturated FAs (PUFA), which are important for chick development. We also found a positive association between the proportion of saturated fatty acids and laying date, and a negative association between the proportion of ω-6 PUFA and clutch size. Given that urbanization is expanding rapidly, future studies should investigate whether factors such as anthropogenic food in the urban environment underlie these differences and whether they impair chick development. PMID:27300022

  6. High sensitivity of broadleaf trees to water availability in northeastern United States

    NASA Astrophysics Data System (ADS)

    Levesque, Mathieu; Andreu-Hayles, Laia; Pederson, Neil

    2016-04-01

    Broadleaf dominated forests of eastern US cover more than one million km2 and provide ecosystem services to millions of people. High species diversity and a varied sensitivity to drought make it uncertain whether these forests will be carbon sinks or sources under climate change. Ongoing climate change, increased in atmospheric CO2 concentration (ca) and strong reductions in acidic depositions are expected to alter growth and gas exchange of trees, and ultimately forest productivity. Still, the magnitude of these effects is unclear. A better comprehension of the species-specific responses to environmental changes will better inform models and managers on the vulnerability and resiliency of these forests. Here, we combined tree-ring width data with δ13C and δ18O measurements to investigate growth and physiological responses of red oak (Quercus rubra L.) and tulip poplar (Liriodendron tulipifera L.) in northeastern US to changes in water availability, ca and acidic depositions for the period 1950-2014. Based on structural equation modeling approaches, we found that summer water availability (June-August) is the main environmental variable driving growth, water-use efficiency and δ18O of broadleaf trees whereas ca and acidic depositions have little effects. This high sensitivity to moisture availability was also supported by the very strong correlations found between summer vapor pressure deficit (VPD) and tree-ring δ13C (r = 0.67 and 0.71), and δ18O series (r = 0.62 and 0.72), for red oak and tulip poplar, respectively. In contrast, tree-ring width was less sensitive to summer VPD (r = ‑0.44 and‑0.31). Since the mid 1980s, pluvial conditions occurring in northeastern US have increased stomatal conductance, carbon uptake, and growth of both species. Further, the strong spatial field correlations found between the tree-ring δ13C and δ18O and summer VPD indicate a greater sensitivity of eastern US broadleaf forests to moisture availability than previously

  7. From Leaf Synthesis to Senescence: n-Alkyl Lipid Abundance and D/H Composition Among Plant Species in a Temperate Deciduous Forest at Brown's Lake Bog, Ohio, USA

    NASA Astrophysics Data System (ADS)

    Freimuth, E. J.; Diefendorf, A. F.; Lowell, T. V.

    2014-12-01

    The hydrogen isotope composition (D/H, δD) of terrestrial plant leaf waxes is a promising paleohydrology proxy because meteoric water (e.g., precipitation) is the primary hydrogen source for wax synthesis. However, secondary environmental and biological factors modify the net apparent fractionation between precipitation δD and leaf wax δD, limiting quantitative reconstruction of paleohydrology. These secondary factors include soil evaporation, leaf transpiration, biosynthetic fractionation, and the seasonal timing of lipid synthesis. Here, we investigate the influence of each of these factors on n-alkyl lipid δD in five dominant deciduous angiosperm tree species as well as shrubs, ferns and grasses in the watershed surrounding Brown's Lake Bog, Ohio, USA. We quantified n-alkane and n-alkanoic acid concentrations and δD in replicate individuals of each species at weekly to monthly intervals from March to October 2014 to assess inter- and intraspecific isotope variability throughout the growing season. We present soil, xylem and leaf water δD from each individual, and precipitation and atmospheric water vapor δD throughout the season to directly examine the relationship between source water and lipid isotope composition. These data allow us to assess the relative influence of soil evaporation and leaf transpiration among plant types, within species, and along a soil moisture gradient throughout the catchment. We use leaf water δD to approximate biosynthetic fractionation for each individual and test whether this is a species-specific and seasonal constant, and to evaluate variation among plant types with identical growth conditions. Our high frequency sampling approach provides new insights into the seasonal timing of n-alkane and n-alkanoic acid synthesis and subsequent fluctuations in concentration and δD in a temperate deciduous forest. These results will advance understanding of the magnitude and timing of secondary influences on the modern leaf wax

  8. Late Cretaceous- Cenozoic history of deciduousness and the terminal Cretaceous event.

    USGS Publications Warehouse

    Wolfe, J.A.

    1987-01-01

    Deciduousness in mesic, broad-leaved plants occurred in disturbed, middle-latitude environments during the Late Cretaceous. Only in polar environments in the Late Cretaceous was the deciduous element dominant, although of low diversity. The terminal Cretaceous event resulted in wide-spread selection for plants of deciduous habit and diversification of deciduous taxa, thus leaving a lasting imprint on Northern Hemisphere vegetation. Various environmental factors have played important roles in subsequent diversification of mesic, broad-leaved deciduous taxa and in origination and decline of broad-leaved deciduous forests. Low diversity and rarity of mesic deciduous plants in the post-Cretaceous of the Southern Hemisphere indicate that the inferred 'impact winter' of the terminal Cretaceous event had little effect on Southern Hemisphere vegetation and climate. -Author

  9. Modeling nonstructural carbohydrate reserve dynamics in forest trees

    NASA Astrophysics Data System (ADS)

    Richardson, Andrew; Keenan, Trevor; Carbone, Mariah; Pederson, Neil

    2013-04-01

    Understanding the factors influencing the availability of nonstructural carbohydrate (NSC) reserves is essential for predicting the resilience of forests to climate change and environmental stress. However, carbon allocation processes remain poorly understood and many models either ignore NSC reserves, or use simple and untested representations of NSC allocation and pool dynamics. Using model-data fusion techniques, we combined a parsimonious model of forest ecosystem carbon cycling with novel field sampling and laboratory analyses of NSCs. Simulations were conducted for an evergreen conifer forest and a deciduous broadleaf forest in New England. We used radiocarbon methods based on the 14C "bomb spike" to estimate the age of NSC reserves, and used this to constrain the mean residence time of modeled NSCs. We used additional data, including tower-measured fluxes of CO2, soil and biomass carbon stocks, woody biomass increment, and leaf area index and litterfall, to further constrain the model's parameters and initial conditions. Incorporation of fast- and slow-cycling NSC pools improved the ability of the model to reproduce the measured interannual variability in woody biomass increment. We show how model performance varies according to model structure and total pool size, and we use novel diagnostic criteria, based on autocorrelation statistics of annual biomass growth, to evaluate the model's ability to correctly represent lags and memory effects.

  10. Retrieval of seasonal dynamics of forest understory reflectance from semi-arid to boreal forests using MODIS BRDF data

    NASA Astrophysics Data System (ADS)

    Pisek, Jan; Chen, Jing; Kobayashi, Hideki; Rautiainen, Miina; Schaepman, Michael; Karnieli, Arnon; Sprintsin, Michael; Ryu, Youngryel; Nikopensius, Maris; Raabe, Kairi

    2016-04-01

    Ground vegetation (understory) provides an essential contribution to the whole-stand reflectance signal in many boreal, sub-boreal, and temperate forests. Accurate knowledge about forest understory reflectance is urgently needed in various forest reflectance modelling efforts. However, systematic collections of understory reflectance data covering different sites and ecosystems are almost missing. Measurement of understory reflectance is a real challenge because of an extremely high variability of irradiance at the forest floor, weak signal in some parts of the spectrum, spectral separability issues of over- and understory and its variable nature. Understory can consist of several sub-layers (regenerated tree, shrub, grasses or dwarf shrub, mosses, lichens, litter, bare soil), it has spatially-temporally variable species composition and ground coverage. Additional challenges are introduced by patchiness of ground vegetation, ground surface roughness, and understory-overstory relations. Due to this variability, remote sensing might be the only means to provide consistent data at spatially relevant scales. In this presentation, we report on retrieving seasonal courses of understory Normalized Difference Vegetation Index (NDVI) from multi-angular MODIS BRDF/Albedo data. We compared satellite-based seasonal courses of understory NDVI against an extended collection of different types of forest sites with available in-situ understory reflectance measurements. These sites are distributed along a wide latitudinal gradient on the Northern hemisphere: a sparse and dense black spruce forests in Alaska and Canada, a northern European boreal forest in Finland, hemiboreal needleleaf and deciduous stands in Estonia, a mixed temperate forest in Switzerland, a cool temperate deciduous broadleaf forest in Korea, and a semi-arid pine plantation in Israel. Our results indicated the retrieval method performs well particularly over open forests of different types. We also demonstrated

  11. Species specific temporal patterns of throughfall and stemflow in deciduous and coniferous forests with implications for unsaturated zone and groundwater recharge processes

    NASA Astrophysics Data System (ADS)

    Dreibrodt, Janek; Hopp, Luisa; Germer, Sonja; Morgner, Markus; Güntner, Andreas; Blume, Theresa

    2015-04-01

    The extent of rainfall redistribution by forest canopies and resulting spatial patterns vary for different tree species and can play an important role for soil moisture distribution and subsequently for groundwater recharge. A thorough understanding of these relationships will improve our ability to predict future impacts of climate and forest structural changes on the water balance of forest stands. Therefore we quantified the fractions of throughfall and stemflow per gross rainfall for different forest types and for different meteorological conditions and rainfall characteristics. Throughfall was continuously measured at 7 sites with different dominant tree species and ages: young and old beech, young oak, and young and old pine. Within 2000m²-plots situated in the Müritz-Nationalpark (north-eastern Germany), trough-based throughfall monitoring systems with a total collecting area of 6.6m² per site, and soil moisture, leaf wetness and sapflow sensors were installed. Stemflow was measured for 5-10 trees per site with a temporal resolution of 1min. Canopy structure is likely to have a major influence on the throughfall distribution. Therefore, the forest structure was characterized by a detailed mapping of tree species, stem positions and stem diameters. Seasonal variations of leaf coverage were monitored by ground-based leaf-area index (LAI) measurements. Evaporation from the canopy is the sum of evaporation during rainfall events and of precipitation stored in the canopy that is evaporated after rainfall ceased. We estimated the storage capacity of the canopy based on the cumulative precipitation between the onset of rainfall and the onset of throughfall. The influence of rainfall intensity and leaf wetness before the onset of rainfall events on canopy storage was also assessed. The data set was used to parameterize and run the soil hydrological model HYDRUS-2D at various spatial scales to assess the effect of stemflow and throughfall patterns on the dynamics

  12. Estimation of Aboveground Biomass Change for Tropical Deciduous Forest in Bago Yoma, Myanmar between year 2000 and 2014 using Landsat Images and Ground Measurements

    NASA Astrophysics Data System (ADS)

    Kim, H. S.; Wynn, K. Z.; Ryu, Y.

    2015-12-01

    Even with recently increased awareness of the environmental conservation, the degradation of tropical forests are still one of the major sources of global carbon emission. Especially in Myanmar, the pressure to develop natural forest is growing rapidly after the change from socialism to capitalism in 2010. As the initial step of the forest conservation, the aboveground biomass(AGB) of South Zarmani Reserved Forest in Bago Yoma region were estimated using Landsat 8 OLI after the evaluation with 100 sample plot measurements. Multiple linear regression (MLR) model of band values and their principal component analysis (PCA) model were developed to estimate the AGB using the spectral reflectance from Landsat images and elevation as the input variables. The MLR model had r2 = 0.43, RMSE = 60.2 tons/ha, relative RMSE = 70.1%, Bias = -9.1 tons/ha, Bias (%) = -10.6%, and p < 0.0001, while the PCA model showed r2 = 0.45, RMSE = 55.1 tons/ha, relative RMSE = 64.1%, Bias = -8.3 tons/ha, Bias (%) = -9.7%, and p < 0.0001. The AGB maps of the study area were generated based on both MLR and PCA models. The estimated mean AGB values were 74.74±22.3 tons/ha and 73.04±17.6 tons/ha and the total AGB of the study area are about 5.7 and 5.6 million tons from MLR and PCA, respectively. Then, Landsat 7 ETM+ image acquired on 2000 was also used to compare the changing of AGB between year 2000 and 2014. The estimated mean AGB value generated from the Landsat 7 ETM+ image was 78.9±16.9 tons/ha, which is substantially decreased about 7.5% compared to year 2014. The reduction of AGB increased with closeness to village, however AGB in distant areas showed steady increases. In conclusion, we were able to generate solid regression models from Landsat 8 OLI image after ground truth and two regression models gave us very similar AGB estimation (less than 2%) of the study area. We were also able to estimate the changing of AGB from year 2000 to 2014 of South Zarmani Reserved Forest, Bago Yoma

  13. Joint assimilation of eddy covariance flux measurements and FAPAR products over temperate forests within a process-oriented biosphere model

    NASA Astrophysics Data System (ADS)

    Bacour, C.; Peylin, P.; MacBean, N.; Rayner, P. J.; Delage, F.; Chevallier, F.; Weiss, M.; Demarty, J.; Santaren, D.; Baret, F.; Berveiller, D.; Dufrêne, E.; Prunet, P.

    2015-09-01

    We investigate the benefits of assimilating in situ and satellite data of the fraction of photosynthetically active radiation (FAPAR) relative to eddy covariance flux measurements for the optimization of parameters of the ORCHIDEE (Organizing Carbon and Hydrology in Dynamic Ecosystem) biosphere model. We focus on model parameters related to carbon fixation, respiration, and phenology. The study relies on two sites—Fontainebleau (deciduous broadleaf forest) and Puechabon (Mediterranean broadleaf evergreen forest)—where measurements of net carbon exchange (NEE) and latent heat (LE) fluxes are available at the same time as FAPAR products derived from ground measurements or derived from spaceborne observations at high (SPOT (Satellite Pour l'Observation de la Terre)) and medium (MERIS (MEdium Resolution Imaging Spectrometer)) spatial resolutions. We compare the different FAPAR products, analyze their consistency with the in situ fluxes, and then evaluate the potential benefits of jointly assimilating flux and FAPAR data. The assimilation of FAPAR data leads to a degradation of the model-data agreement with respect to NEE at the two sites. It is caused by the change in leaf area required to fit the magnitude of the various FAPAR products. Assimilating daily NEE and LE fluxes, however, has a marginal impact on the simulated FAPAR. The results suggest that the main advantage of including FAPAR data is the ability to constrain the timing of leaf onset and senescence for deciduous ecosystems, which is best achieved by normalizing FAPAR time series. The joint assimilation of flux and FAPAR data leads to a model-data improvement across all variables similar to when each data stream is used independently, corresponding, however, to different and likely improved parameter values.

  14. Regional assessment of boreal forest productivity using an ecological process model and remote sensing parameter maps.

    PubMed

    Kimball, J. S.; Keyser, A. R.; Running, S. W.; Saatchi, S. S.

    2000-06-01

    An ecological process model (BIOME-BGC) was used to assess boreal forest regional net primary production (NPP) and response to short-term, year-to-year weather fluctuations based on spatially explicit, land cover and biomass maps derived by radar remote sensing, as well as soil, terrain and daily weather information. Simulations were conducted at a 30-m spatial resolution, over a 1205 km(2) portion of the BOREAS Southern Study Area of central Saskatchewan, Canada, over a 3-year period (1994-1996). Simulations of NPP for the study region were spatially and temporally complex, averaging 2.2 (+/- 0.6), 1.8 (+/- 0.5) and 1.7 (+/- 0.5) Mg C ha(-1) year(-1) for 1994, 1995 and 1996, respectively. Spatial variability of NPP was strongly controlled by the amount of aboveground biomass, particularly photosynthetic leaf area, whereas biophysical differences between broadleaf deciduous and evergreen coniferous vegetation were of secondary importance. Simulations of NPP were strongly sensitive to year-to-year variations in seasonal weather patterns, which influenced the timing of spring thaw and deciduous bud-burst. Reductions in annual NPP of approximately 17 and 22% for 1995 and 1996, respectively, were attributed to 3- and 5-week delays in spring thaw relative to 1994. Boreal forest stands with greater proportions of deciduous vegetation were more sensitive to the timing of spring thaw than evergreen coniferous stands. Similar relationships were found by comparing simulated snow depth records with 10-year records of aboveground NPP measurements obtained from biomass harvest plots within the BOREAS region. These results highlight the importance of sub-grid scale land cover complexity in controlling boreal forest regional productivity, the dynamic response of the biome to short-term interannual climate variations, and the potential implications of climate change and other large-scale disturbances. PMID:12651512

  15. Atmospheric deposition and corresponding variability of throughfall and stemflow chemistry across temporal scales in a mid-Atlantic broadleaved deciduous forest

    NASA Astrophysics Data System (ADS)

    Levia, D. F.; van Stan, J. T.; Siegert, C. M.; Inamdar, S. P.; Mitchell, M. J.; Mage, S. M.; McHale, P.

    2010-12-01

    Atmospheric deposition is acknowledged to be an important process in the biogeochemical cycling of forests, yet no single study is known that has examined both throughfall and stemflow chemistry in relation to atmospheric deposition across time scales, from within discrete events to season. This research partitions stemflow and throughfall solute fluxes (K+, Na+, Mg2+, Ca2+, Cl-, NO3-, SO42-) from two tree species with disparate canopy structures into their leaching and dry deposition washoff components to examine differences within and among individual rain events. Seasonal-scale leaching and washoff dynamics are investigated utilizing event-based chemical enrichment and depletion ratios. Intrastorm leaching percentages generally increase as throughfall pathways are initiated and expand for base cations, yet decrease for dominant anions across species. All intrastorm Fagus grandifolia Ehrh. (American beech) stemflow solute fluxes started with high dry deposition percentages then shifted toward increased leachate contributions. Liriodendron tulipifera L. (yellow poplar) was much more inconsistent, with dry deposition percentages of anions generally increasing, Na+ and Mg2+ dry deposition proportions decreasing (with the exception of the last two samples attributed to the initiation of new flowpaths), and K+ and Ca2+ leaching remaining more or less stable throughout an event. Generally, the stemflow washoff component from smooth-barked F. grandifolia was greater than the rough-barked, more plagiophile L. tulipifera at the interstorm scale, whereas L. tulipifera generated larger stemflow leached percentages. These findings: (1) underscore the essential role of new flowpath initiation, expansion, and maturation on a tree’s surface to solute enrichment and transport to the forest floor as a canopy wets-up and reaches saturation; and (2) indicate that the temporal scale of analysis of canopy-derived fluxes can improve our understanding of the effect of variable time

  16. Aggregated and complementary: symmetric proliferation, overyielding, and mass effects explain fine-root biomass in soil patches in a diverse temperate deciduous forest landscape.

    PubMed

    Valverde-Barrantes, Oscar J; Smemo, Kurt A; Feinstein, Larry M; Kershner, Mark W; Blackwood, Christopher B

    2015-01-01

    Few studies describe root distributions at the species level in diverse forests, although belowground species interactions and traits are often assumed to affect fine-root biomass (FRB). We used molecular barcoding to study how FRB of trees relates to soil characteristics, species identity, root diversity, and root traits, and how these relationships are affected by proximity to ecotones in a temperate forest landscape. We found that soil patch root biomass increased in response to soil resources across all species, and there was little belowground vertical or horizontal spatial segregation among species. Root traits and species relative abundance did not explain significant variation in FRB after correcting for soil fertility. A positive relationship between phylogenetic diversity and FRB indicated significant belowground overyielding attributable to local root diversity. Finally, variation in FRB explained by soil fertility and diversity was reduced near ecotones, but only because of a reduction in biomass in periodically anoxic areas. These results suggest that symmetric responses to soil properties are coupled with complementary species traits and interactions to explain variation in FRB among soil patches. In addition, landscape-level dispersal among habitats and across ecotones helps explain variation in the strength of these relationships in complex landscapes. PMID:25441303

  17. Passive Microwave and Optical Indices-Based Approaches for Estimating Surface Conductance in Forest Ecosystems

    NASA Astrophysics Data System (ADS)

    Barraza Bernadas, V.; Restrepo-Coupe, N.; Huete, A. R.; Grings, F. M.; Van Gorsel, E.

    2014-12-01

    The ability to monitor evapotranspiration (ET) from land surface is relevant for applications requiring spatially-resolved estimates of moisture availability over large areas. ET estimations from remote sensing data are generally based on parameterizations, such as canopy conductance(Gs) using optical vegetation indices. However, optical data presents some limitations related to the low temporal resolution and cloud contamination. Although characterized by coarser spatial resolutions, passive microwave sensors can be useful since they present shorter revisit times and are less affected by clouds and aerosols. In particular, microwave indices are known to be sensitive to vegetation moisture during growing season for forest ecosystems. In this work, we evaluate the performance of passive microwave frequency index (FI) and/or optical vegetation indices (VI) to retrieve ET over different forests under the Penman-Monteith (PM) method. Model results were validated in five FLUXNET sites over USA and Australia over three land covert type including deciduous broadleaf forest (DBF), evergreen needle leaf (ENF) and broadleaf forest (EDF). A subset of Gs values were then regressed against VIs, FI and a combination of FI and VI, and used to parameterize the PM equation for retrievals of ET (PM-Gs). The optical indices calculated from MODIS products were: NDVI, NDWI, and EVI. FI was calculated from AMSR-E passive microwave system. EVI and FI correlated well with Gs (coefficient of determination (R2) >0.5, root mean square error (RMSE)< 45 mm/s for EVI; and R2>0.5, RMSE < 47 mm/s for FI) for DBF. In general optical VI presents similar R2, but less RMSE. For evergreen forests, we found lower or poor relationships between vegetation indices and Gs. Finally, in terms of RMSE the coupled model (FI and EVI) resulted in a lower RMSE of 4-9% compared to independent relations (EVI-Gs and FI-Gs). Interestingly, these three models (PM-Gs) explained 80% of the variance of ET (RSME < 16 W/m2

  18. An improved approach for remotely sensing water stress impacts on forest C uptake.

    PubMed

    Sims, Daniel A; Brzostek, Edward R; Rahman, Abdullah F; Dragoni, Danilo; Phillips, Richard P

    2014-09-01

    Given that forests represent the primary terrestrial sink for atmospheric CO2 , projections of future carbon (C) storage hinge on forest responses to climate variation. Models of gross primary production (GPP) responses to water stress are commonly based on remotely sensed changes in canopy 'greenness' (e.g., normalized difference vegetation index; NDVI). However, many forests have low spectral sensitivity to water stress (SSWS) - defined here as drought-induced decline in GPP without a change in greenness. Current satellite-derived estimates of GPP use a vapor pressure deficit (VPD) scalar to account for the low SWSS of forests, but fail to capture their responses to water stress. Our objectives were to characterize differences in SSWS among forested and nonforested ecosystems, and to develop an improved framework for predicting the impacts of water stress on GPP in forests with low SSWS. First, we paired two independent drought indices with NDVI data for the conterminous US from 2000 to 2011, and examined the relationship between water stress and NDVI. We found that forests had lower SSWS than nonforests regardless of drought index or duration. We then compared satellite-derived estimates of GPP with eddy-covariance observations of GPP in two deciduous broadleaf forests with low SSWS: the Missouri Ozark (MO) and Morgan Monroe State Forest (MMSF) AmeriFlux sites. Model estimates of GPP that used VPD scalars were poorly correlated with observations of GPP at MO (r(2) = 0.09) and MMSF (r(2) = 0.38). When we included the NDVI responses to water stress of adjacent ecosystems with high SSWS into a model based solely on temperature and greenness, we substantially improved predictions of GPP at MO (r(2) = 0.83) and for a severe drought year at the MMSF (r(2) = 0.82). Collectively, our results suggest that large-scale estimates of GPP that capture variation in SSWS among ecosystems could improve predictions of C uptake by forests under drought. PMID:24464936

  19. Directional scattering properties of a winter deciduous hardwood canopy

    NASA Technical Reports Server (NTRS)

    Kimes, Daniel S.; Newcomb, W. Wayne

    1987-01-01

    The unique directional scattering properties of a deciduous hardwood forest without leaves during the winter period was measured in a visible and near-infrared band. A radiative transfer model was used to explore the scattering properties of such a forest. The reflectance distributions look similar to sparse homogeneous vegetation canopies. The overall reflectance distribution is a combination of the extreme azimuthal scattering behavior of tree limbs and the more typical scattering behavior of understory litter.

  20. Is digital cover photography a viable method for measuring leaf index for phenological research in closed forest ecosystems?

    NASA Astrophysics Data System (ADS)

    Felts, E. S.; Sonnentag, O.; Ryu, Y.; Macfarlane, C.; Hufkens, K.; Keenan, T. F.; Friedl, M. A.; Richardson, A. D.

    2011-12-01

    The use of the LAI-2000 plant canopy analyzer as instrument for calculating plant area index (PAI), and ultimately leaf area index (LAI), based on hemispherical gap-fraction measurements has been established through past studies. Ideally, these measurements are taken under diffuse light, which restricts their application to overcast conditions or short time windows during dusk and dawn. A promising and less restrictive alternative is digital cover photography (DCP), which provides estimates of crown porosity (φ), and foliage (ff) and crown cover fractions (fc). From these, PAI can be calculated, which can then be corrected for the influence of woody canopy elements to obtain LAI. The method has been developed and tested in Eucalyptus forests and oak-savanna woodland, i.e. in open ecosystems where enough light can penetrate the canopy for sufficient scene illumination. This research seeks to explore the viability of DCP as a method of obtaining PAI and LAI for phenological research in closed forest ecosystems such as temperate broadleaf deciduous forests, where limited scene illumination especially under fully developed canopies and the seasonally changing influence of woody canopy elements to φ, ff and fc might pose methodological challenges. To test the performance of DCP under these conditions, weekly imaging of 33 long-term incremental biomass plots at a temperate broadleaf-deciduous-dominated forest (Harvard Forest) was undertaken with a digital single-lens reflex camera (Pentax K100D). To examine the role of changing scene illumination at different canopy development stages, the images were acquired in RAW format to allow maximum control over image exposure in the post-processing. Using a range of different exposure settings, DCP-based PAI estimates were then compared to PAI estimates obtained from gap-fraction measurements made with the LAI-2000 instrument (recomputed using only the first 7° ring) at the same plots, and with canopy greenness obtained with

  1. Beyond leaf color: Comparing camera-based phenological metrics with leaf biochemical, biophysical, and spectral properties throughout the growing season of a temperate deciduous forest

    NASA Astrophysics Data System (ADS)

    Yang, Xi; Tang, Jianwu; Mustard, John F.

    2014-03-01

    Plant phenology, a sensitive indicator of climate change, influences vegetation-atmosphere interactions by changing the carbon and water cycles from local to global scales. Camera-based phenological observations of the color changes of the vegetation canopy throughout the growing season have become popular in recent years. However, the linkages between camera phenological metrics and leaf biochemical, biophysical, and spectral properties are elusive. We measured key leaf properties including chlorophyll concentration and leaf reflectance on a weekly basis from June to November 2011 in a white oak forest on the island of Martha's Vineyard, Massachusetts, USA. Concurrently, we used a digital camera to automatically acquire daily pictures of the tree canopies. We found that there was a mismatch between the camera-based phenological metric for the canopy greenness (green chromatic coordinate, gcc) and the total chlorophyll and carotenoids concentration and leaf mass per area during late spring/early summer. The seasonal peak of gcc is approximately 20 days earlier than the peak of the total chlorophyll concentration. During the fall, both canopy and leaf redness were significantly correlated with the vegetation index for anthocyanin concentration, opening a new window to quantify vegetation senescence remotely. Satellite- and camera-based vegetation indices agreed well, suggesting that camera-based observations can be used as the ground validation for satellites. Using the high-temporal resolution dataset of leaf biochemical, biophysical, and spectral properties, our results show the strengths and potential uncertainties to use canopy color as the proxy of ecosystem functioning.

  2. Space Radar Image of Harvard Forest

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This is a radar image of the area surrounding the Harvard Forest in north-central Massachusetts that has been operated as a ecological research facility by Harvard University since 1907. At the center of the image is the Quabbin Reservoir, and the Connecticut River is at the lower left of the image. The Harvard Forest itself is just above the reservoir. Researchers are comparing the naturally occurring physical disturbances in the forest and the recent and projected chemical disturbances and their effects on the forest ecosystem. Agricultural land appears dark blue/purple, along with low shrub vegetation and some wetlands. Urban development is bright pink; the yellow to green tints are conifer-dominated vegetation with the pitch pine sand plain at the middle left edge of the image appearing very distinctive. The green tint may indicate pure pine plantation stands, and deciduous broadleaf trees appear gray/pink with perhaps wetter sites being pinker. This image was acquired by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour. SIR-C/X-SAR, a joint mission of the German, Italian and the United States space agencies, is part of NASA's Mission to Planet Earth. The image is centered at 42.50 degrees North latitude and 72.33 degrees West longitude and covers an area of 53 kilometers 63 by kilometers (33 miles by 39 miles). The colors in the image are assigned to different frequencies and polarizations of the radar as follows: red is L-band horizontally transmitted and horizontally received; green is L-band horizontally transmitted and vertically received; and blue is C-band horizontally transmitted and horizontally received.

  3. The Five-Year Fate of a 15N Tracer in a Mixed Deciduous Forest: Retention, Redistribution, and Differences by Mycorrhizal Association

    NASA Astrophysics Data System (ADS)

    Goodale, C. L.

    2015-12-01

    The impact of nitrogen deposition on forest ecosystems depends in large part on its fate: uptake by trees can stimulate growth, while gaseous or leaching losses contribute to air and water pollution and represent the loss of a limiting nutrient. Past tracer studies have shown that soils dominate the short-term fate of added 15N, but its longer-term term fate remains uncertain. This study examined how much 15N tracer moved plant or soil pools or was lost over 5-6 years. In 2007, a 15N tracer (0.21 kg/ha as 99% enriched 15N-KNO3) was added to 0.25 ha mixed hardwood forest in central NY. All of the tracer was recovered in the days after its addition, but recovery fell to 78% by the end of this year (25% surface litter, 48% 0-10 cm soil, 5% roots). One year later, recovery in these pools fell (to 51%), with losses from surface litter (-11%) and the 0-10 cm soils (-15%), including losses from the "heavy" soil fraction. Additional tracer moved to other plant pools (+5%) and to deeper soil (+13%; up to 30 cm), for a total recovery of 69% of the added tracer. Between years 1 and 5-6, only total tracer recovery decreased by only 1.4%. Recovery decreased in foliage (-0.2%), all roots (-3.5%), and surface litter (-9.8%), while increasing in woody biomass (+0.9%), 0-10 cm soil (+8.9%), and deep soil (+2.3%; up to 50 cm). Tracer recovery in live and dead plant N pools (11%) did not change, as 3% moved from roots into aboveground plant tissues and 3% moved from live plant pools into leaf litter; these results imply no net transfer of 15N from soil to plants during this period. Over all 5-6 years, only 1.6% of the tracer moved into bark or wood, a small but important sink because of its high C:N ratio; however, roughly one-third of this total was in wood formed prior to the start of the tracer addition. Tree species differed in their recovery of 15N: the six species with ectomycorrhizal associations showed more enrichment than the four species with arbuscular mycorrhizae. It is

  4. The influence of tree species composition on the storage and mobility of semivolatile organic compounds in forest soils.

    PubMed

    Komprdová, Klára; Komprda, Jiří; Menšík, Ladislav; Vaňková, Lenka; Kulhavý, Jiří; Nizzetto, Luca

    2016-05-15

    Soil contamination with PCBs and PAHs in adjacent forest plots, characterized by a distinct composition in tree species (spruce only, mixed and beech only), was analyzed to investigate the influence of ecosystem type on contaminant mobility in soil under very similar climate and exposure conditions. Physical-chemical properties and contaminant concentrations in litter (L), organic (F, H) and mineral (A, B) soil horizons were analyzed. Contaminant distribution in the soil core varied both in relation to forest type and contaminant group/properties. Contaminant mobility in soil was assessed by examining the ratios of total organic carbon (TOC)-standardized concentrations across soil horizons (Enrichment factors, EFTOC) and the relationship between EFTOC and the octanol-water equilibrium partitioning coefficient (KOW). Contaminant distribution appeared to be highly unsteady, with pedogenic/biogeochemical drivers controlling contaminant mobility in organic layers and leaching controlling accumulation in mineral layers. Lighter PCBs displayed higher mobility in all forest types primarily controlled by leaching and, to a minor extent, diffusion. Pedogenic processes controlling the formation of soil horizons were found to be crucial drivers of PAHs and heavier PCBs distribution. All contaminants appeared to be more mobile in the soil of the broadleaved plot, followed by mixed canopy and spruce forest. Increasing proportion of deciduous broadleaf species in the forest can thus lead to faster degradation or the faster leaching of PAHs and PCBs. The composition of humic substances was found to be a better descriptor of contaminant concentration than TOC. PMID:26938316

  5. The Effects of Fine-scale Soil Moisture and Canopy Heterogeneities on Energy and Soil Water Fluxes in a Temperate Mixed Deciduous Forest

    NASA Astrophysics Data System (ADS)

    He, L.; Ivanov, V. Y.; Bohrer, G.; Maurer, K.; Vogel, C. S.; Moghaddam, M.

    2011-12-01

    Vegetation is heterogeneous at different scales, influencing spatially variable energy and water exchanges between land-surface and atmosphere. Current land surface parameterizations of large-scale models consider spatial variability at a scale of a few kilometers and treat vegetation cover as aggregated patches with uniform properties. However, the coupling mechanisms between fine-scale soil moisture, vegetation, and energy fluxes such as evapotranspiration are strongly nonlinear; the aggregation of surface variations may produce biased energy fluxes. This study aims to improve the understanding of the scale impact in atmosphere-biosphere-hydrosphere interactions, which affects predictive capabilities of land surface models. The study uses a high-resolution, physically-based ecohydrological model tRIBS + VEGGIE as a data integration tool to upscale the heterogeneity of canopy distribution resolved at a few meters to the watershed scale. The study was carried out for a spatially heterogeneous, temperate mixed forest environment of Northern Michigan located near the University of Michigan Biological Station (UMBS). Energy and soil water dynamics were simulated at the tree-canopy resolution in the horizontal plane for a small domain (~2 sq. km) located within a footprint of the AmeriFlux tower. A variety of observational data were used to constrain and confirm the model, including a 3-m profile continuous soil moisture dataset and energy flux data (measured at the AmeriFlux tower footprint). A scenario with a spatially uniform canopy, corresponding to the commonly used 'big-leaf' scheme in land surface parameterizations was used to infer the effects of coarse-scale averaging. To gain insights on how heterogeneous canopy and soil moisture interact and contribute to the domain-averaged transpiration, several scenarios of tree-scale leaf area and soil moisture spatial variability were designed. Specifically, for the same mean states, the scenarios of variability of

  6. Extreme warm temperatures alter forest phenology and productivity in Europe.

    PubMed

    Crabbe, Richard A; Dash, Jadu; Rodriguez-Galiano, Victor F; Janous, Dalibor; Pavelka, Marian; Marek, Michal V

    2016-09-01

    Recent climate warming has shifted the timing of spring and autumn vegetation phenological events in the temperate and boreal forest ecosystems of Europe. In many areas spring phenological events start earlier and autumn events switch between earlier and later onset. Consequently, the length of growing season in mid and high latitudes of European forest is extended. However, the lagged effects (i.e. the impact of a warm spring or autumn on the subsequent phenological events) on vegetation phenology and productivity are less explored. In this study, we have (1) characterised extreme warm spring and extreme warm autumn events in Europe during 2003-2011, and (2) investigated if direct impact on forest phenology and productivity due to a specific warm event translated to a lagged effect in subsequent phenological events. We found that warmer events in spring occurred extensively in high latitude Europe producing a significant earlier onset of greening (OG) in broadleaf deciduous forest (BLDF) and mixed forest (MF). However, this earlier OG did not show any significant lagged effects on autumnal senescence. Needleleaf evergreen forest (NLEF), BLDF and MF showed a significantly delayed end of senescence (EOS) as a result of extreme warm autumn events; and in the following year's spring phenological events, OG started significantly earlier. Extreme warm spring events directly led to significant (p=0.0189) increases in the productivity of BLDF. In order to have a complete understanding of ecosystems response to warm temperature during key phenological events, particularly autumn events, the lagged effect on the next growing season should be considered. PMID:27152990

  7. Different responses to shade of evergreen and deciduous oak seedlings and the effect of acorn size

    NASA Astrophysics Data System (ADS)

    Ke, Guo; Werger, Marinus J. A.

    1999-11-01

    An evergreen oak species, Cyclobalanopsis multinervis, and a deciduous oak species, Quercus aliena var. acuteserrata were grown from acorns under two light levels (full sunlight and shade at about 18 % of full sunlight, simulating the light intensities in forest clearings and gaps, respectively) for one growing season. Three hypotheses were tested: (i) the deciduous species grows faster than the evergreen species in forest gaps and clearings; (ii) the deciduous species responds more strongly in terms of growth and morphology to variation in light climate than the evergreen species; and (iii) seedling size is positively correlated to acorn size. The results showed: (i) at both light levels, the deciduous seedlings gained significantly more growth in biomass and height than the evergreen seedlings; (ii) both species produced significantly more biomass in full sunlight than in shade, without showing any significant difference in height between treatments. Increase in light intensity improved the growth of the deciduous seedlings more strongly; (iii) at a similar age, the deciduous seedlings showed a greater response in leaf morphology and biomass allocation to variation in light levels, but when compared at a similar size, biomass allocation patterns did not differ significantly between species; (iv) bigger acorns tended to produce larger seedlings, larger leaf sizes and more leaf area, between and within species. These differences demonstrate that the deciduous species is gap-dependent and has the advantage over the evergreen species in forest gaps and clearings.

  8. Windthrow and salvage logging in an old-growth hemlock-northern hardwoods forest

    USGS Publications Warehouse

    Lang, K.D.; Schulte, L.A.; Guntenspergen, G.R.

    2009-01-01

    Although the initial response to salvage (also known as, post-disturbance or sanitary) logging is known to vary among system components, little is known about longer term forest recovery. We examine forest overstory, understory, soil, and microtopographic response 25 years after a 1977 severe wind disturbance on the Flambeau River State Forest in Wisconsin, USA, a portion of which was salvage logged. Within this former old-growth hemlock-northern hardwoods forest, tree dominance has shifted from Eastern hemlock (Tsuga canadensis) to broad-leaf deciduous species (Ulmus americana, Acer saccharum, Tilia americana, Populus tremuloides, and Betula alleghaniensis) in both the salvaged and unsalvaged areas. While the biological legacies of pre-disturbance seedlings, saplings, and mature trees were initially more abundant in the unsalvaged area, regeneration through root suckers and stump sprouts was common in both areas. After 25 years, tree basal area, sapling density, shrub layer density, and seedling cover had converged between unsalvaged and salvaged areas. In contrast, understory herb communities differed between salvaged and unsalvaged forest, with salvaged forest containing significantly higher understory herb richness and cover, and greater dominance of species benefiting from disturbance, especially Solidago species. Soil bulk density, pH, organic carbon content, and organic nitrogen content were also significantly higher in the salvaged area. The structural legacy of tip-up microtopography remains more pronounced in the unsalvaged area, with significantly taller tip-up mounds and deeper pits. Mosses and some forest herbs, including Athyrium filix-femina and Hydrophyllum virginianum, showed strong positive responses to this tip-up microrelief, highlighting the importance of these structural legacies for understory biodiversity. In sum, although the pathways of recovery differed, this forest appeared to be as resilient to the compound disturbances of windthrow

  9. The Impact of Diffuse Sunlight and Shortwave Dimming on Canopy Light-use Efficiency and net Carbon Exchange in 3 Forest Biomes.

    NASA Astrophysics Data System (ADS)

    Alton, P.; North, P.; Los, S.

    2006-05-01

    The latter half of the 20th century has seen a 5-10% fall in mean global insolation with reductions of up to 20% regionally (Stanhill & Cohen 2001). Anthropogenic aerosols, by their propensity to increase the optical depth of clouds, are cited as the major factor in this trend (Liepert 2002). By evaluating observed carbon flow, we estimate the impact of reduced downwelling shortwave radiation (SW) on 3 forest biomes (sparse Boreal needleleaf, temperate deciduous broadleaf and dense tropical broadleaf). We are careful to account for the increased proportion of diffuse sky radiation that accompanies obscuration by cloud (Roderick et al 2001). We find that canopy light-use efficiency (LUE) is enhanced at all 3 study sites when diffuse rather than direct sunlight predominates. The increase spans 6-33%. Intepretation with the land-surface model JULES, modified to take account of sunfleck penetration, indicates that increased sharing of the radiation-load across the foliage is the primary factor responsible for this LUE-enhancement. The increase in LUE, however, is insufficient to offset the reduction in GPP associated with attenuated SW. Greatest sensitivity is exhibited by the Boreal site, Zotino, where net ecosystem exchange (NEE) falls by 12±6% for a reduction of 20% in SW. (Part of this work has just appeared in JGR (110, D23209) and was accorded very favourable reviews.)

  10. Influence of spring and autumn phenological transitions on forest ecosystem productivity

    PubMed Central

    Richardson, Andrew D.; Andy Black, T.; Ciais, Philippe; Delbart, Nicolas; Friedl, Mark A.; Gobron, Nadine; Hollinger, David Y.; Kutsch, Werner L.; Longdoz, Bernard; Luyssaert, Sebastiaan; Migliavacca, Mirco; Montagnani, Leonardo; William Munger, J.; Moors, Eddy; Piao, Shilong; Rebmann, Corinna; Reichstein, Markus; Saigusa, Nobuko; Tomelleri, Enrico; Vargas, Rodrigo; Varlagin, Andrej

    2010-01-01

    We use eddy covariance measurements of net ecosystem productivity (NEP) from 21 FLUXNET sites (153 site-years of data) to investigate relationships between phenology and productivity (in terms of both NEP and gross ecosystem photosynthesis, GEP) in temperate and boreal forests. Results are used to evaluate the plausibility of four different conceptual models. Phenological indicators were derived from the eddy covariance time series, and from remote sensing and models. We examine spatial patterns (across sites) and temporal patterns (across years); an important conclusion is that it is likely that neither of these accurately represents how productivity will respond to future phenological shifts resulting from ongoing climate change. In spring and autumn, increased GEP resulting from an ‘extra’ day tends to be offset by concurrent, but smaller, increases in ecosystem respiration, and thus the effect on NEP is still positive. Spring productivity anomalies appear to have carry-over effects that translate to productivity anomalies in the following autumn, but it is not clear that these result directly from phenological anomalies. Finally, the productivity of evergreen needleleaf forests is less sensitive to phenology than is productivity of deciduous broadleaf forests. This has implications for how climate change may drive shifts in competition within mixed-species stands. PMID:20819815

  11. DRY DEPOSITION OF POLLUTANTS TO FORESTS

    EPA Science Inventory

    We report on the results of an extensive field campaign to measure dry deposition of ozone and sulfur dioxide to a sample of forest types in the United States. Measurements were made for full growing seasons over a deciduous forest in Pennsylvania and a mixed deciduous-conifer...

  12. Effects of fire on regional evapotranspiration in the central Canadian boreal forest

    SciTech Connect

    Bond-Lamberty, Benjamin; Peckham, Scott D.; Gower, Stith T.; Ewers, Brent

    2009-04-08

    Changes in fire regimes are driving the carbon balance of much of the North American boreal forest, but few studies have examined fire-driven changes in evapotranspiration (ET) at a regional scale. This study used a version of the Biome-BGC process model with dynamic and competing vegetation types, and explicit spatial representation of a large (106 km2) region, to simulate the effects of wildfire on ET and its components from 1948 to 2005 by comparing the fire dynamics of the 1948-1967 period with those of 1968-2005. Simulated ET averaged, over the entire temporal and spatial modeling domain, 323 mm yr-1; simulation results indicated that changes in fire in recent decades decreased regional ET by 1.4% over the entire simulation, and by 3.9% in the last ten years (1996-2005). Conifers dominated the transpiration (EC) flux (120 mm yr-1) but decreased by 18% relative to deciduous broadleaf trees in the last part of the 20th century, when increased fire resulted in increased soil evaporation, lower canopy evaporation, lower EC and a younger and more deciduous forest. Well- and poorly-drained areas had similar rates of evaporation from the canopy and soil, but EC was twice as high in the well-drained areas. Mosses comprised a significant part of the evaporative flux to the atmosphere (22 mm yr-1). Modeled annual ET was correlated with net primary production, but not with temperature or precipitation; ET and its components were consistent with previous field and modeling studies. Wildfire is thus driving significant changes in hydrological processes, changes that may control the future carbon balance of the boreal forest.

  13. Decidual Control of Trophoblast Invasion.

    PubMed

    Sharma, Shipra; Godbole, Geeta; Modi, Deepak

    2016-03-01

    At the time of implantation, the trophoblast cells of the embryo adhere and then invade into the maternal endometrium and eventually establish placentation. The endometrium at the same time undergoes decidualization, which is essential for successful pregnancy. While the NK cells of the decidua have been implicated to play a key role in trophoblast invasion, few evidence are now available to demonstrate a pro-invasive property of decidual stromal cells. Secretions from decidualized endometrial stromal cells promote invasion of primary trophoblasts and model cell lines by activating proteases and altering expression of adhesion-related molecules. The decidual secretions contain high amounts of pro-invasive factors that include IL-1β, IL-5, IL-6, IL-7, IL-8, IL-9, IL-13, IL-15, Eotaxin CCL11, IP-10 and RANTES, and anti-invasive factors IL-10, IL-12 and VEGF. It appears that these decidual factors promote invasion by regulating the protease pathways and integrin expression utilizing the STAT pathways in the trophoblast cells. At the same time the decidua also seem to secrete some anti-invasive factors that are antagonist to the matrix metalloproteinases and/or are activators of tissue inhibitors of metalloproteinases. This might be essential to neutralize the effects of the invasion-promoting factors and restrain overinvasion. It is tempting to propose that during the course of pregnancy, the decidua must balance the production of these pro and anti-invasive molecules and such harmonizing production would allow a timely and regulated invasion. PMID:26755153

  14. Observed and modeled ecosystem isoprene fluxes from an oak-dominated temperate forest and the influence of drought stress

    SciTech Connect

    Potosnak, M.; LeStourgeon, Lauren; Pallardy, Stephen G.; Hosman, Kevin P.; Gu, Lianghong; Karl, Thomas; Geron, Chris; Guenther, Alex B.

    2014-02-19

    Ecosystem fluxes of isoprene emission were measured during the majority of the 2011 growing season at the University of Missouri's Baskett Wildlife Research and Education Area in centralMissouri, USA (38.7° N, 92.2° W). This broadleaf deciduous forest is typical of forests common in theOzarks region of the central United States. The goal of the isoprene flux measurements was to test ourunderstanding of the controls on isoprene emission from the hourly to the seasonal timescale using a state-of-the-art emission model, MEGAN (Model of Emissions of Gases and Aerosols from Nature). Isoprene emission rates were very high from the forest with a maximum of 50.9 mg m-2 hr-1 (208 nmol m-2 s-1), which to our knowledge exceeds all other reports of canopy-scale isoprene emission. The fluxes showed a clear dependence on the previous temperature and light regimes which was successfully captured by the existing algorithms in MEGAN. During a period of drought, MEGAN was unable to reproduce the time-dependent response of isoprene emission to water stress. Overall, the performance of MEGAN was robust and could explain 87% of the observed variance in the measured fluxes, but the response of isoprene emission to drought stress is a major source of uncertainty.

  15. Land surface phenology, hydrology and CO2 fluxes of forests and grasslands in Northern Eurasia

    NASA Astrophysics Data System (ADS)

    Xiao, X.; Li, C.; Kurbatova, J.; Varlagin, A.; Zhang, J.; Wu, J.; Wu, W.; Biradar, C.; Chen, J.

    2008-12-01

    Land surface phenology (LSP) is a key indicator of ecosystem dynamics under a changing environment. Changes in phenology of plants affect the carbon cycle, water cycle, climate through photosynthesis and evapotranspiration. We have combined satellite observations, CO2 eddy flux tower sites and process-based biogeochemical model to improve our understanding of the effect of land surface phenology and hydrology on gross primary production (GPP), ecosystem respiration and net ecosystem exchange of CO2 (NEE) from a variety of ecosystem types. In this paper, we will present case studies from two spruce forest sites (wet spruce forest and dry spruce forest) in Russia, a deciduous broadleaf forest site and a grassland site in Northern China. Among the three vegetation indices (Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI) and Land Surface Water Index (LSWI), both LSWI and EVI agreed well with the photosynthetically active period (as defined by estimated GPP data from CO2 eddy flux tower sites) than NDVI does. The Vegetation Photosynthesis Model (VPM), which uses EVI and LSWI data as input, provides improved prediction of GPP for various types of terrestrial ecosystems. NEE is the difference between GPP and ecosystem respiration. Simulations of processed-based DNDC model for two spruce forests (wet and dry spruce forests) suggested that ecosystem respiration (and consequently NEE) fluxes are highly sensitive to water table depth at the sites. Because Northern Eurasia has a large area of wetlands and underwent significant climate change, potential change in water table due to hydrological processes could have significant implication to the carbon fluxes and carbon balance (carbon sink or source) in the region.

  16. Forest Dynamics and Their Phenological Response to Climate Warming in the Khingan Mountains, Northeastern China

    PubMed Central

    Cai, Hongyan; Zhang, Shuwen; Yang, Xiaohuan

    2012-01-01

    The Khingan Mountain region, the most important and typical natural foci of tick-borne encephalitis (TBE) in China, is the largest and northernmost forest area and the one more sensitive to climate change. Taking this region as the study area, we investigated the spatio-temporal dynamics of deciduous broadleaf forest (DBF) and its phenology changes in relation to climate change and elevation. Based on MODIS Enhanced Vegetation Index (EVI) time series over the period of 2001 to 2009, the start-of-season (SOS), length-of-season (LOS) and another two vegetation variables (seasonal amplitude (SA) and integrated EVI (SI)) were derived. Over the past decade, the DBF in Khingan Mountains has generally degraded and over 65% of DBF has experienced negative SA and SI trends. Earlier trends in SOS and longer trends in LOS for DBF were observed, and these trends were mainly caused by climate warming. In addition, results from our analysis also indicated that the effects of temperature on DBF phenology were elevation dependent. The magnitude of advancement in SOS and extension in LOS with temperature increase significantly increased along a raising elevation gradient. PMID:23202825

  17. New flux based dose-response relationships for ozone for European forest tree species.

    PubMed

    Büker, P; Feng, Z; Uddling, J; Briolat, A; Alonso, R; Braun, S; Elvira, S; Gerosa, G; Karlsson, P E; Le Thiec, D; Marzuoli, R; Mills, G; Oksanen, E; Wieser, G; Wilkinson, M; Emberson, L D

    2015-11-01

    To derive O3 dose-response relationships (DRR) for five European forest trees species and broadleaf deciduous and needleleaf tree plant functional types (PFTs), phytotoxic O3 doses (PODy) were related to biomass reductions. PODy was calculated using a stomatal flux model with a range of cut-off thresholds (y) indicative of varying detoxification capacities. Linear regression analysis showed that DRR for PFT and individual tree species differed in their robustness. A simplified parameterisation of the flux model was tested and showed that for most non-Mediterranean tree species, this simplified model led to similarly robust DRR as compared to a species- and climate region-specific parameterisation. Experimentally induced soil water stress was not found to substantially reduce PODy, mainly due to the short duration of soil water stress periods. This study validates the stomatal O3 flux concept and represents a step forward in predicting O3 damage to forests in a spatially and temporally varying climate. PMID:26164201

  18. A review and synthesis of monoterpene speciation from forests in the United States

    NASA Astrophysics Data System (ADS)

    Geron, Chris; Rasmussen, Rei; Arnts, Robert R.; Guenther, Alex

    The monoterpene composition (emission and tissue internal concentration) of major forest tree species in the United States is discussed. Of the 14 most commonly occurring compounds ( α-pinene, β-pinene, Δ 3-carene, d-limonene, camphene, myrcene, α-terpinene, β-phellandrene, sabinene, ρ-cymene, ocimene, α-thujene, terpinolene, and γ-terpinene), the first six are usually found to be most abundant. Expected regional variability based on the monoterpene composition fingerprints and corresponding tree species distribution and abundance is examined. In the southeast, α-pinene and β-pinene seem to dominate monoterpene emissions, while in the northern forests emissions are distributed more evenly among the six major compounds. In some parts of western forests, β-pinene and Δ 3-carene can be more abundant than α-pinene. Among the other eight compounds, β-phellandrene and sabinene occasionally are significant percentages of expected local monoterpene emissions. Ocimene and ρ-cymene are estimated to be more common in regions dominated by deciduous broadleaf forests, although total emission rates are generally lower for these forests relative to those dominated by conifers. These percentages are compared with monoterpene composition measured in ambient air at various sites. Estimated monoterpene emission composition based on local forest species composition agrees fairly well with ambient measurements for the six major compounds. The past assumption that α-pinene composes approximately 50% of total monoterpene emissions appears reasonable for many areas, except for possibly the northern coniferous forests and some areas in the west dominated by true firs, spruce, and western pines (lodgepole and ponderosa pines). The oxygenated monoterpenes such as camphor, bornyl acetate, and cineole often compose high percentages of the monoterpenes within plant tissues, but are much less abundant in emission samples. Even after adjusting for lower vapor pressures of these

  19. Reconstructing a 40-year record of forest disturbance in Russia from contemporary satellite data

    NASA Astrophysics Data System (ADS)

    Loboda, T. V.; Chen, D.; Hight-Harf, C.

    2012-12-01

    types. The reconstruction method limits the disturbance mapping to the latest disturbance time thus making it impossible to develop estimates of the extent of repeated disturbances outside of the data available since 2001. The analysis of the regional MODIS burned area product shows that between 2001 and 2011 over 31 million ha of Russian forests burned. More than 7% of those experienced repeated burning once, and almost 1% burned 3 times or more. Although the majority (over 61%) of burned forest is found within deciduous needleleaf forest, deciduous broadleaf forests are more prone to repeated burning, with nearly 22% of burns in these forests mapped 2 or more times since 2001. The combination of extended record for forests disturbance and the detailed analysis of disturbance within the recent decade represents an improved view of stand age distribution and forest type in support of carbon and climate modeling activities.

  20. The response of the water fluxes of the boreal forest region at the Volga's source area to climatic and land-use changes

    NASA Astrophysics Data System (ADS)

    Oltchev, A.; Cermak, J.; Gurtz, J.; Tishenko, A.; Kiely, G.; Nadezhdina, N.; Zappa, M.; Lebedeva, N.; Vitvar, T.; Albertson, J. D.; Tatarinov, F.; Tishenko, D.; Nadezhdin, V.; Kozlov, B.; Ibrom, A.; Vygodskaya, N.; Gravenhorst, G.

    The project “Volgaforest” was focused on a study of the water budget of the forested Upper Volga catchment in Russia in order to describe: the terrestrial water balance of the Upper Volga catchment as a function of external factors, such as climate and land-use, and the response of forest ecosystems to these external factors. Future changes of water budget of the Upper Volga catchment area were estimated from: past and present dynamics of the atmospheric, water and forest conditions, different climatic scenarios and SVAT (Soil-Vegetation-Atmosphere Transfer) and hydrological models. Analysis of past climatological and hydrological data showed a large atmospheric and hydrological variability of the Upper Volga catchment. During the last 50-60 years the mean annual air temperature increased by 1.2 °C, and annual precipitation increased by 140 mm. However, no significant trend of annual runoff during the last 20 years could be found. Air temperature and precipitation changes were significant during winter and spring but very small in summer. Coniferous and mixed coniferous-broadleaf forests cover at present about 72% of the catchment area. During the last 30 years the area of natural coniferous forests (spruce, pine) decreased from 8.4% to 7% and the area of mixed forests increased from 52% to 59% of the total land area. Results of field measurements at a forest site showed a large variability of energy and water fluxes during the entire year. Transpiration of the boreal forest ecosystem measured using a sap flow method during the dry summer 1999 was limited by very dry soil water conditions, especially for spruce trees, and during the rainy summer 2000 probably by lack of oxygen in the rooting zone. Transpiration was about 10-20% larger for broadleaf trees (birch, aspen) than for spruce trees. Model estimations of possible changes in the hydrological regime of the Upper Volga catchment area for climatic scenarios suggest changes of evapotranspiration, surface

  1. How did climate drying reduce ecosystem carbon storage in the forest-steppe ecotone? A case study in Inner Mongolia, China.

    PubMed

    Zhang, Yuke; Liu, Hongyan

    2010-07-01

    The projected recession of forests in the forest-steppe ecotone under projected climate drying would restrict the carbon sink function of terrestrial ecosystems. Previous studies have shown that the forest-steppe ecotone in the southeastern Inner Mongolia Plateau originally resulted from climate drying and vegetation shifts during the mid- to late-Holocene, but the interrelated processes of changing soil carbon storage and vegetation and soil shifts remain unclear. A total of 44 forest soil profiles and 40 steppe soil profiles were excavated to determine soil carbon storage in deciduous broadleaf forests (DBF), coniferous forests (CF) and steppe (ST) in this area. Carbon density was estimated to be 106.51 t/hm(2) (DBF), 73.20 t/hm(2) (CF), and 28.14 t/hm(2) (ST) for these ecosystems. Soil organic carbon (SOC) content was negatively correlated with sand content (R = -0.879, P < 0.01, n = 42), and positively correlated with silt (R = 0.881, P < 0.01, n = 42) and clay (R = 0.858, P < 0.01, n = 42) content. Consistent trends between fractions of coarse sand and a proxy index of relative aridity in sediment sequences from two palaeo-lakes further imply that climate drying reduced SOC through coarsening of the soil texture in the forest-steppe ecotone. Changes in carbon storage caused by climate drying can be divided into two stages: (1) carbon storage of the ecosystem was reduced to 68.7%, mostly by soil coarsening when DBF were replaced by CF at approximately 5,900 (14)C years before present (BP); and (2) carbon storage was reduced to 26.4%, mostly by vegetation shifts when CF were replaced by ST at approximately 2,900 (14)C years BP. PMID:20174958

  2. ABOVEGROUND BIOMASS DISTRIBUTION OF US EASTERN HARDWOOD FORESTS AND THE USE OF LARGE TREES AS AN INDICATOR OF FOREST DEVELOPMENT

    EPA Science Inventory

    Past clearing and harvesting of the deciduous hardwood forests of eastern USA released large amount of carbon dioxide into the atmosphere, but through recovery and regrowth these forests are now accumulating atmospheric carbon (C). This study examined quantities and distribution ...

  3. Interspecific vs intraspecific patterns in leaf nitrogen of forest trees across nitrogen availability gradients.

    PubMed

    Dybzinski, Ray; Farrior, Caroline E; Ollinger, Scott; Pacala, Stephen W

    2013-10-01

    Leaf nitrogen content (δ) coordinates with total canopy N and leaf area index (LAI) to maximize whole-crown carbon (C) gain, but the constraints and contributions of within-species plasticity to this phenomenon are poorly understood. Here, we introduce a game theoretic, physiologically based community model of height-structured competition between late-successional tree species. Species are constrained by an increasing, but saturating, relationship between photosynthesis and leaf N per unit leaf area. Higher saturating rates carry higher fixed costs. For a given whole-crown N content, a C gain-maximizing compromise exists between δ and LAI. With greater whole-crown N, both δ and LAI increase within species. However, a shift in community composition caused by reduced understory light at high soil N availability (which competitively favors species with low leaf costs and consequent low optimal δ) counteracts the within-species response, such that community-level δ changes little with soil N availability. These model predictions provide a new explanation for the changes in leaf N per mass observed in data from three dominant broadleaf species in temperate deciduous forests of New England. Attempts to understand large-scale patterns in vegetation often omit competitive interactions and intraspecific plasticity, but here both are essential to an understanding of ecosystem-level patterns. PMID:23738827

  4. Spatial and temporal variability of soil CO2 efflux in southeastern forests

    NASA Astrophysics Data System (ADS)

    Oishi, A. C.; Palmroth, S.; Butnor, J. R.; Johnsen, K.; Oren, R.

    2011-12-01

    The combination of biotic and abiotic factors that contribute to soil CO2 efflux can lead to large variability across spatial and temporal scales. This variability can result in uncertainty in respiration estimates; however, it can also provide insight into the primary processes affecting CO2 emissions from soil. In order to quantify the magnitude and identify the sources of variability in soil CO2 efflux across spatial and temporal scales, we deployed several automated, multi-chamber sampling systems in forest stands in the southeastern U.S. We measured fluxes from a medium-age loblolly pine stand for 10 years (2001-2010), which spanned two severe droughts and one very wet year. During this time period, we also operated three systems in additional plots within the pine stand for 5 years, one system in an adjacent mixed-species broadleaf deciduous stand for 4 years, and one system in a nearby mature loblolly pine stand for 2 years. The high frequency of measurements (~2 hours per chamber) allows us to examine diurnal trends and precipitation responses while longevity of this study provides information on interannual variability and effects of stand age. Additionally, we quantify spatial variability at the scale of plot-level (1-10 m), stand-level (~100 m), and regionally (1-50 km) to examine the effects of local heterogeneity, species composition, and soil type. Chamber-based measurements are compared with leaf litter fall, trenched plot data, and eddy covariance measurements.

  5. Land-use Change and Biophysical Accounting in Forest Carbon Projects

    NASA Astrophysics Data System (ADS)

    Jackson, R. B.

    2014-12-01

    Biological carbon sequestration by reforestation and afforestation is being promoted as an opportunity to help mitigate global warming and climate change. The scientific basis to support such forestry activities is shifting to include many biophysical dimensions beyond carbon storage. In this talk I address two questions: 1) Where can forests help slow the buildup of greenhouse gases in the atmosphere while also providing beneficial biophysical feedbacks? and (2) How many extra resources, including water and nutrients, may be needed to achieve this carbon storage and climate benefit? By comparing the biophysical forcings and climatic impact of vegetation replacement across North America using satellite-derived albedo, land surface temperature (LST), and evapotranspiration (ET) between adjacent vegetation types, we show that a carbon-centric accounting is, in most cases, insufficient for climate mitigation policies. Where afforestation or reforestation occurs, deciduous broadleaf trees are likely to produce stronger cooling benefits than evergreen needleleaf trees provide in temperate ecosystems. Our analyses also suggest that forestry activities will have the most climatic benefits at locations where background albedo prior to landscape change is low, snow cover is minimal, cloud cover is high, and soil water availability is ample.

  6. Broadcast application of vinegar for broadleaf weed control in spring-transplanted onions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vinegar (acetic acid) is a non-selective contact herbicide used in organic crop production. Research was conducted to determine if vinegar could be successfully applied over the top of onion plants to control broadleaf weeds. The experiment included 6 weed control treatments (2 application volumes...

  7. Evaluation of imazosulfuron for yellow nutsedge (cyperus esculentus) and broadleaf weed control in potato

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field studies were conducted in 2007 and 2008 near Nyssa, OR, Pasco, and Paterson, WA to evaluate yellow nutsedge and broadleaf weed control and potato tolerance to imazosulfuron. No injury symptoms from imazosulfuron were evident on potato at Nyssa whereas in Washington studies, imazosulfuron cause...

  8. Sulfur nutrition of deciduous trees

    NASA Astrophysics Data System (ADS)

    Herschbach, Cornelia; Rennenberg, Heinz

    2001-01-01

    Sulfur in its reduced form (-II) is an essential nutrient for growth and development, but is mainly available to plants in its oxidised form as sulfate. Deciduous trees take up sulfate by the roots from the soil solution and reduce sulfate to sulfide via assimilatory sulfate reduction in both roots and leaves. For reduction in the leaves, sulfate is loaded into the xylem and transported to the shoot. The surplus of sulfate not reduced in the chloroplast or stored in the vacuole and the surplus of reduced S not used for protein synthesis in the leaves is loaded into the phloem and transported back to the roots. Along the transport path, sulfate and glutathione (GSH) is unloaded from the phloem for storage in xylem and phloem parenchyma as well as in pit and ray cells. Re-mobilised S from storage tissues is loaded into the xylem during spring, but a phloem to xylem exchange does not appear to exist later in the season. As a consequence, a cycling pool of S was only found during the change of the seasons. The sulfate:glutathione ratio in the phloem seems to be involved in the regulation of S nutrition. This picture of S nutrition is discussed in relation to the different growth patterns of deciduous trees from the temperate climate zone, i.e. (1) terminated, (2) periodic and (3) indeterminate growth patterns, and in relation to environmental changes.

  9. Carbon dynamics of mature and regrowth tropical forests derived from a pantropical database (TropForC-db).

    PubMed

    Anderson-Teixeira, Kristina J; Wang, Maria M H; McGarvey, Jennifer C; LeBauer, David S

    2016-05-01

    Tropical forests play a critical role in the global carbon (C) cycle, storing ~45% of terrestrial C and constituting the largest component of the terrestrial C sink. Despite their central importance to the global C cycle, their ecosystem-level C cycles are not as well-characterized as those of extra-tropical forests, and knowledge gaps hamper efforts to quantify C budgets across the tropics and to model tropical forest-climate interactions. To advance understanding of C dynamics of pantropical forests, we compiled a new database, the Tropical Forest C database (TropForC-db), which contains data on ground-based measurements of ecosystem-level C stocks and annual fluxes along with disturbance history. This database currently contains 3568 records from 845 plots in 178 geographically distinct areas, making it the largest and most comprehensive database of its type. Using TropForC-db, we characterized C stocks and fluxes for young, intermediate-aged, and mature forests. Relative to existing C budgets of extra-tropical forests, mature tropical broadleaf evergreen forests had substantially higher gross primary productivity (GPP) and ecosystem respiration (Reco), their autotropic respiration (Ra) consumed a larger proportion (~67%) of GPP, and their woody stem growth (ANPPstem) represented a smaller proportion of net primary productivity (NPP, ~32%) or GPP (~9%). In regrowth stands, aboveground biomass increased rapidly during the first 20 years following stand-clearing disturbance, with slower accumulation following agriculture and in deciduous forests, and continued to accumulate at a slower pace in forests aged 20-100 years. Most other C stocks likewise increased with stand age, while potential to describe age trends in C fluxes was generally data-limited. We expect that TropForC-db will prove useful for model evaluation and for quantifying the contribution of forests to the global C cycle. The database version associated with this publication is archived in Dryad (DOI

  10. Simulating Carbon cycle and phenology in complex forests using a multi-layer process based ecosystem model; evaluation and use of 3D-CMCC-Forest Ecosystem Model in a deciduous and an evergreen neighboring forests, within the area of Brasschaat (Be)

    NASA Astrophysics Data System (ADS)

    Marconi, S.; Collalti, A.; Santini, M.; Valentini, R.

    2013-12-01

    3D-CMCC-Forest Ecosystem Model is a process based model formerly developed for complex forest ecosystems to estimate growth, water and carbon cycles, phenology and competition processes on a daily/monthly time scale. The Model integrates some characteristics of the functional-structural tree models with the robustness of the light use efficiency approach. It treats different heights, ages and species as discrete classes, in competition for light (vertical structure) and space (horizontal structure). The present work evaluates the results of the recently developed daily version of 3D-CMCC-FEM for two neighboring different even aged and mono specific study cases. The former is a heterogeneous Pedunculate oak forest (Quercus robur L. ), the latter a more homogeneous Scot pine forest (Pinus sylvestris L.). The multi-layer approach has been evaluated against a series of simplified versions to determine whether the improved model complexity in canopy structure definition increases its predictive ability. Results show that a more complex structure (three height layers) should be preferable to simulate heterogeneous scenarios (Pedunculate oak stand), where heights distribution within the canopy justify the distinction in dominant, dominated and sub-dominated layers. On the contrary, it seems that using a multi-layer approach for more homogeneous stands (Scot pine stand) may be disadvantageous. Forcing the structure of an homogeneous stand to a multi-layer approach may in fact increase sources of uncertainty. On the other hand forcing complex forests to a mono layer simplified model, may cause an increase in mortality and a reduction in average DBH and Height. Compared with measured CO2 flux data, model results show good ability in estimating carbon sequestration trends, on both a monthly/seasonal and daily time scales. Moreover the model simulates quite well leaf phenology and the combined effects of the two different forest stands on CO2 fluxes.

  11. Infrasonic wind noise under a deciduous tree canopy.

    PubMed

    Webster, Jeremy; Raspet, Richard

    2015-05-01

    In a recent paper, the infrasonic wind noise measured at the floor of a pine forest was predicted from the measured wind velocity spectrum and profile within and above the trees [Raspet and Webster, J. Acoust. Soc. Am. 137, 651-659 (2015)]. This research studies the measured and predicted wind noise under a deciduous forest with and without leaves. A calculation of the turbulence-shear interaction pressures above the canopy predicts the low frequency peak in the wind noise spectrum. The calculated turbulence-turbulence interaction pressure due to the turbulence field near the ground predicts the measured wind noise spectrum in the higher frequency region. The low frequency peak displays little dependence on whether the trees have leaves or not. The high frequency contribution with leaves is approximately an order of magnitude smaller than the contribution without leaves. Wind noise levels with leaves are very similar to the wind noise levels in the pine forest. The calculated turbulence-shear contribution from the wind within the canopy is shown to be negligible in comparison to the turbulence-turbulence contribution in both cases. In addition, the effect of taller forests and smaller roughness lengths than those of the test forest on the turbulence-shear interaction is simulated based on measured meteorological parameters. PMID:25994698

  12. Modeling nonstructural carbohydrate reserve dynamics in forest trees

    NASA Astrophysics Data System (ADS)

    Richardson, A. D.; Keenan, T. F.; Carbone, M. S.; Czimczik, C. I.; Hollinger, D. Y.; Murakami, P.; Schaberg, P.; Xu, X.

    2012-12-01

    Understanding the factors influencing the availability of nonstructural carbohydrate (NSC) reserves is essential for predicting the resilience of forests to climate change and environmental stress. However, carbon allocation processes remain poorly understood and many models either ignore NSC reserves, or use simple and untested representations of NSC allocation and pool dynamics. Using model-data fusion techniques, we combined a parsimonious model of forest ecosystem carbon cycling with novel field sampling and laboratory analyses of NSCs. Simulations were conducted for an evergreen conifer forest and a deciduous broadleaf forest in New England. We used radiocarbon methods based on the 14C "bomb spike" to estimate the age of NSC reserves, and used this to constrain the mean residence time of modeled NSCs. We used additional data, including tower-measured fluxes of CO2, soil and biomass carbon stocks, woody biomass increment, and leaf area index and litterfall, to further constrain the model's parameters and initial conditions. Three years of field measurements indicate that stemwood NSCs are highly dynamic on seasonal time scales. The modeled seasonal dynamics conform to expectations (accumulated in the growing season, depleted in the dormant season) but are inconsistent with the observational data (total stemwood NSC concentrations higher in March than November, lower in August than June). We interpret this contradiction to suggest that stemwood concentrations provide an incomplete picture of the whole-tree NSC budget. A two-pool model structure that accounted for both "fast" (active pool, MRT ≈1 y) and "slow" (passive pool, MRT ≥ 20 y) cycling reserves (1) gives reasonable estimates of the size and MRT of the total NSC pool; (2) greatly improves model predictions of interannual variability in woody biomass increment, compared to zero- or one-pool structures used in the majority of existing models; (3) provides a mechanism by which observations of a one

  13. LASER ALTIMETER CANOPY HEIGHT PROFILES: METHODS AND VALIDATION FOR CLOSED-CANOPY, BROADLEAF FORESTS. (R828309)

    EPA Science Inventory

    Abstract

    Waveform-recording laser altimeter observations of vegetated landscapes provide a time-resolved measure of laser pulse backscatter energy from canopy surfaces and the underlying ground. Airborne laser altimeter waveform data was acquired using the Scanning Lid...

  14. Estimating aboveground biomass for broadleaf woody plants and young conifers in Sierra Nevada, California forests.

    USGS Publications Warehouse

    McGinnis, Thomas W.; Shook, Christine D.; Keeley, Jon E.

    2010-01-01

    Quantification of biomass is fundamental to a wide range of research and natural resource management goals. An accurate estimation of plant biomass is essential to predict potential fire behavior, calculate carbon sequestration for global climate change research, assess critical wildlife habitat, and so forth. Reliable allometric equations from simple field measurements are necessary for efficient evaluation of plant biomass. However, allometric equations are not available for many common woody plant taxa in the Sierra Nevada. In this report, we present more than 200 regression equations for the Sierra Nevada western slope that relate crown diameter, plant height, crown volume, stem diameter, and both crown diameter and height to the dry weight of foliage, branches, and entire aboveground biomass. Destructive sampling methods resulted in regression equations that accurately predict biomass from one or two simple, nondestructive field measurements. The tables presented here will allow researchers and natural resource managers to easily choose the best equations to fit their biomass assessment needs.

  15. Estimating aboveground biomass for broadleaf woody plants and young conifers in Sierra Nevada, California, forests

    USGS Publications Warehouse

    McGinnis, T.W.; Shook, C.D.; Keeley, J.E.

    2010-01-01

    Quantification of biomass is fundamental to a wide range of research and natural resource management goals. An accurate estimation of plant biomass is essential to predict potential fire behavior, calculate carbon sequestration for global climate change research, assess critical wildlife habitat, and so forth. Reliable allometric equations from simple field measurements are necessary for efficient evaluation of plant biomass. However, allometric equations are not available for many common woody plant taxa in the Sierra Nevada. In this report, we present more than 200 regression equations for the Sierra Nevada western slope that relate crown diameter, plant height, crown volume, stem diameter, and both crown diameter and height to the dry weight of foliage, branches, and entire aboveground biomass. Destructive sampling methods resulted in regression equations that accurately predict biomass from one or two simple, nondestructive field measurements. The tables presented here will allow researchers and natural resource managers to easily choose the best equations to fit their biomass assessment needs.

  16. Remote sensing-based predictors improve distribution models of rare, early successional and broadleaf tree species in Utah

    PubMed Central

    ZIMMERMANN, N E; EDWARDS, T C; MOISEN, G G; FRESCINO, T S; BLACKARD, J A

    2007-01-01

    Compared to bioclimatic variables, remote sensing predictors are rarely used for predictive species modelling. When used, the predictors represent typically habitat classifications or filters rather than gradual spectral, surface or biophysical properties. Consequently, the full potential of remotely sensed predictors for modelling the spatial distribution of species remains unexplored. Here we analysed the partial contributions of remotely sensed and climatic predictor sets to explain and predict the distribution of 19 tree species in Utah. We also tested how these partial contributions were related to characteristics such as successional types or species traits. We developed two spatial predictor sets of remotely sensed and topo-climatic variables to explain the distribution of tree species. We used variation partitioning techniques applied to generalized linear models to explore the combined and partial predictive powers of the two predictor sets. Non-parametric tests were used to explore the relationships between the partial model contributions of both predictor sets and species characteristics. More than 60% of the variation explained by the models represented contributions by one of the two partial predictor sets alone, with topo-climatic variables outperforming the remotely sensed predictors. However, the partial models derived from only remotely sensed predictors still provided high model accuracies, indicating a significant correlation between climate and remote sensing variables. The overall accuracy of the models was high, but small sample sizes had a strong effect on cross-validated accuracies for rare species. Models of early successional and broadleaf species benefited significantly more from adding remotely sensed predictors than did late seral and needleleaf species. The core-satellite species types differed significantly with respect to overall model accuracies. Models of satellite and urban species, both with low prevalence, benefited more from

  17. Remote sensing-based predictors improve distribution models of rare, early successional and broadleaf tree species in Utah

    USGS Publications Warehouse

    Zimmermann, N.E.; Edwards, T.C., Jr.; Moisen, G.G.; Frescino, T.S.; Blackard, J.A.

    2007-01-01

    1. Compared to bioclimatic variables, remote sensing predictors are rarely used for predictive species modelling. When used, the predictors represent typically habitat classifications or filters rather than gradual spectral, surface or biophysical properties. Consequently, the full potential of remotely sensed predictors for modelling the spatial distribution of species remains unexplored. Here we analysed the partial contributions of remotely sensed and climatic predictor sets to explain and predict the distribution of 19 tree species in Utah. We also tested how these partial contributions were related to characteristics such as successional types or species traits. 2. We developed two spatial predictor sets of remotely sensed and topo-climatic variables to explain the distribution of tree species. We used variation partitioning techniques applied to generalized linear models to explore the combined and partial predictive powers of the two predictor sets. Non-parametric tests were used to explore the relationships between the partial model contributions of both predictor sets and species characteristics. 3. More than 60% of the variation explained by the models represented contributions by one of the two partial predictor sets alone, with topo-climatic variables outperforming the remotely sensed predictors. However, the partial models derived from only remotely sensed predictors still provided high model accuracies, indicating a significant correlation between climate and remote sensing variables. The overall accuracy of the models was high, but small sample sizes had a strong effect on cross-validated accuracies for rare species. 4. Models of early successional and broadleaf species benefited significantly more from adding remotely sensed predictors than did late seral and needleleaf species. The core-satellite species types differed significantly with respect to overall model accuracies. Models of satellite and urban species, both with low prevalence, benefited

  18. OZONE AND SULFUR DIOXIDE DRY DEPOSITION TO FORESTS: OBSERVATIONS AND MODEL EVALUATION

    EPA Science Inventory

    Fluxes and deposition velocities of O3 and SO2 were measured over both a deciduous and a mixed coniferous-deciduous forest for full growing seasons. Fluxes and deposition velocities of O3 were measured over a coniferous forest for a month. Mean deposition velocities of 0.35 t...

  19. AmeriFlux US-WCr Willow Creek

    SciTech Connect

    Desai, Ankur

    2016-01-01

    This is the AmeriFlux version of the carbon flux data for the site US-WCr Willow Creek. Site Description - Upland decduous broadleaf forest. Mainly sugar maple, also basswood. Uniform stand atop a very modest hill. Clearcut approximately 80 years ago. Chosen to be representative of the upland deciduous broadleaf forests within the WLEF tall tower flux footprint. It appears to be more heavily forested and more productive than most of the upland deciduous broadleaf forests in the WLEF flux footprint (see publications for more details). It is also important that SE winds are screened from the flux data (see Cook et al, 2004 for details). Propane generator power.

  20. Soil organic matter quantity and quality shape microbial community compositions of subtropical broadleaved forests.

    PubMed

    Ding, Junjun; Zhang, Yuguang; Wang, Mengmeng; Sun, Xin; Cong, Jing; Deng, Ye; Lu, Hui; Yuan, Tong; Van Nostrand, Joy D; Li, Diqiang; Zhou, Jizhong; Yang, Yunfeng

    2015-10-01

    As two major forest types in the subtropics, broadleaved evergreen and broadleaved deciduous forests have long interested ecologists. However, little is known about their belowground ecosystems despite their ecological importance in driving biogeochemical cycling. Here, we used Illumina MiSeq sequencing targeting 16S rRNA gene and a microarray named GeoChip targeting functional genes to analyse microbial communities in broadleaved evergreen and deciduous forest soils of Shennongjia Mountain of Central China, a region known as 'The Oriental Botanic Garden' for its extraordinarily rich biodiversity. We observed higher plant diversity and relatively richer nutrients in the broadleaved evergreen forest than the deciduous forest. In odds to our expectation that plant communities shaped soil microbial communities, we found that soil organic matter quantity and quality, but not plant community parameters, were the best predictors of microbial communities. Actinobacteria, a copiotrophic phylum, was more abundant in the broadleaved evergreen forest, while Verrucomicrobia, an oligotrophic phylum, was more abundant in the broadleaved deciduous forest. The density of the correlation network of microbial OTUs was higher in the broadleaved deciduous forest but its modularity was smaller, reflecting lower resistance to environment changes. In addition, keystone OTUs of the broadleaved deciduous forest were mainly oligotrophic. Microbial functional genes associated with recalcitrant carbon degradation were also more abundant in the broadleaved deciduous forests, resulting in low accumulation of organic matters. Collectively, these findings revealed the important role of soil organic matter in shaping microbial taxonomic and functional traits. PMID:26363284

  1. Interaction of ice storms and management practices on current carbon sequestration in forests with potential mitigation under future CO2 atmosphere

    NASA Astrophysics Data System (ADS)

    McCarthy, Heather R.; Oren, Ram; Kim, Hyun-Seok; Johnsen, Kurt H.; Maier, Chris; Pritchard, Seth G.; Davis, Micheal A.

    2006-08-01

    Ice storms are disturbance events with potential impacts on carbon sequestration. Common forest management practices, such as fertilization and thinning, can change wood and stand properties and thus may change vulnerability to ice storm damage. At the same time, increasing atmospheric CO2 levels may also influence ice storm vulnerability. Here we show that a nonintensively managed pine plantation experienced a ˜250 g C m-2 reduction in living biomass during a single storm, equivalent to ˜30% of the annual net ecosystem carbon exchange of this ecosystem. Drawing on weather and damage survey data from the entire storm cell, the amount of C transferred from the living to the dead biomass pool (26.5 ± 3.3 Tg C), 85% of which will decompose within 25 years, was equivalent to ˜10% of the estimated annual sequestration in conterminous U.S. forests. Conifer trees were more than twice as likely to be killed as leafless deciduous broadleaf trees. In the Duke Forest case study, nitrogen fertilization had no effect on storm-induced carbon transfer from the living to detrital pool while thinning increased carbon transfer threefold. Elevated CO2 (administered with the free-air CO2 enrichment (FACE) system) reduced the storm-induced carbon transfer to a third. Because of the lesser leaf area reduction, plots growing under elevated CO2 also exhibited a smaller reduction in biomass production the following year. These results suggest that forests may suffer less damage during each ice storm event of similar severity in a future with higher atmospheric CO2.

  2. Canopy wetness patterns in a Mediterranean deciduous stand

    NASA Astrophysics Data System (ADS)

    Llorens, P.; Domingo, F.; Garcia-Estringana, P.; Muzylo, A.; Gallart, F.

    2014-05-01

    This study provides detailed information on the canopy drying process subsequent to rainfall events in a Mediterranean deciduous stand. Since this is a study of a deciduous forest (Quercus pubescens Willd.), it has been possible to assess the differences in canopy structure as well as in meteorological conditions between seasons. Results show clear seasonal differences in wetness duration during the drying phase after rainfall, with longer wetness duration in the leafed period (8 h) than in the leafless one (4 h). There is better canopy ventilation in the leafless season, increasing canopy boundary layer conductance. However, there is a wind shelter effect in the leafed season, which entails low turbulence transfer within the canopy. Likewise, canopies remain wet longer at night in both seasons, but the differences in wetness duration between day and night are greater in the leafless season. Finally, the results indicate that the methods commonly used to separate rainfall events give an erroneous indication of the real canopy drying duration. This leads to inaccuracy in the number and duration of rainfall events and, thus, in their properties (such as rainfall depth and intensity) and represents a challenge to rainfall interception models.

  3. Atmospheric deposition in coniferous and deciduous tree stands in Poland

    NASA Astrophysics Data System (ADS)

    Kowalska, Anna; Astel, Aleksander; Boczoń, Andrzej; Polkowska, Żaneta

    2016-05-01

    The objective of this study was to assess the transformation of precipitation in terms of quantity and chemical composition following contact with the crown layer in tree stands with varied species composition, to investigate the effect of four predominant forest-forming species (pine, spruce, beech, and oak) on the amount and composition of precipitation reaching forest soils, and to determine the sources of pollution in atmospheric precipitation in forest areas in Poland. The amount and chemical composition (pH, electric conductivity, alkalinity, and chloride, nitrate, sulfate, phosphate, ammonium, calcium, magnesium, sodium, potassium, iron aluminum, manganese, zinc, copper, total nitrogen, and dissolved organic carbon contents) of atmospheric (bulk, BP) and throughfall (TF) precipitation were studied from January to December 2010 on twelve forest monitoring plots representative of Polish conditions. The study results provided the basis for the determination of the fluxes of pollutants in the forest areas of Poland and allowed the comparison of such fluxes with values provided in the literature for European forest areas. The transformation of precipitation in the canopy was compared for different tree stands. The fluxes of substances in an open field and under canopy were influenced by the location of the plot, including the regional meteorological conditions (precipitation amounts), vicinity of the sea (effect of marine aerosols), and local level of anthropogenic pollution. Differences between the plots were higher in TF than in BP. The impact of the vegetation cover on the chemical composition of precipitation depended on the region of the country and dominant species in a given tree stand. Coniferous species tended to cause acidification of precipitation, whereas deciduous species increased the pH of TF. Pine and oak stands enriched precipitation with components that leached from the canopy (potassium, manganese, magnesium) to a higher degree than spruce and

  4. Decidual Cell Polyploidization Necessitates Mitochondrial Activity

    PubMed Central

    Ma, Xinghong; Gao, Fei; Rusie, Allison; Hemingway, Jennifer; Ostmann, Alicia B.; Sroga, Julie M.; Jegga, Anil G.; Das, Sanjoy K.

    2011-01-01

    Cellular polyploidy has been widely reported in nature, yet its developmental mechanism and function remain poorly understood. In the present study, to better define the aspects of decidual cell polyploidy, we isolated pure polyploid and non-polyploid decidual cell populations from the in vivo decidual bed. Three independent RNA pools prepared for each population were then subjected to the Affymetrix gene chip analysis for the whole mouse genome transcripts. Our data revealed up-regulation of 1015 genes and down-regulation of 1207 genes in the polyploid populations, as compared to the non-polyploid group. Comparative RT-PCR and in situ hybridization results indeed confirmed differential expressional regulation of several genes between the two populations. Based on functional enrichment analyses, up-regulated polyploidy genes appeared to implicate several functions, which primarily include cell/nuclear division, ATP binding, metabolic process, and mitochondrial activity, whereas that of down-regulated genes primarily included apoptosis and immune processes. Further analyses of genes that are related to mitochondria and bi-nucleation showed differential and regional expression within the decidual bed, consistent with the pattern of polyploidy. Consistently, studies revealed a marked induction of mitochondrial mass and ATP production in polyploid cells. The inhibition of mitochondrial activity by various pharmacological inhibitors, as well as by gene-specific targeting using siRNA-mediated technology showed a dramatic attenuation of polyploidy and bi-nucleation development during in vitro stromal cell decidualization, suggesting mitochondria play a major role in positive regulation of decidual cell polyploidization. Collectively, analyses of unique polyploidy markers and molecular signaling networks may be useful to further characterize functional aspects of decidual cell polyploidy at the site of implantation. PMID:22046353

  5. Relationship between the Decomposition Process of Coarse Woody Debris and Fungal Community Structure as Detected by High-Throughput Sequencing in a Deciduous Broad-Leaved Forest in Japan

    PubMed Central

    Yamashita, Satoshi; Masuya, Hayato; Abe, Shin; Masaki, Takashi; Okabe, Kimiko

    2015-01-01

    We examined the relationship between the community structure of wood-decaying fungi, detected by high-throughput sequencing, and the decomposition rate using 13 years of data from a forest dynamics plot. For molecular analysis and wood density measurements, drill dust samples were collected from logs and stumps of Fagus and Quercus in the plot. Regression using a negative exponential model between wood density and time since death revealed that the decomposition rate of Fagus was greater than that of Quercus. The residual between the expected value obtained from the regression curve and the observed wood density was used as a decomposition rate index. Principal component analysis showed that the fungal community compositions of both Fagus and Quercus changed with time since death. Principal component analysis axis scores were used as an index of fungal community composition. A structural equation model for each wood genus was used to assess the effect of fungal community structure traits on the decomposition rate and how the fungal community structure was determined by the traits of coarse woody debris. Results of the structural equation model suggested that the decomposition rate of Fagus was affected by two fungal community composition components: one that was affected by time since death and another that was not affected by the traits of coarse woody debris. In contrast, the decomposition rate of Quercus was not affected by coarse woody debris traits or fungal community structure. These findings suggest that, in the case of Fagus coarse woody debris, the fungal community structure is related to the decomposition process of its host substrate. Because fungal community structure is affected partly by the decay stage and wood density of its substrate, these factors influence each other. Further research on interactive effects is needed to improve our understanding of the relationship between fungal community structure and the woody debris decomposition process

  6. An ancient forest suggests a new view of Antarctica's past

    SciTech Connect

    Not Available

    1993-03-01

    Solid evidence that 200 million years ago Antarctica was warm enough to support a rapidly growing deciduous forest has been uncovered in the central Transantarctic Mountains. Like existing forest in high latitude regions, this forest was adapted to 24 hours of light during the growing season and 24 hours of darkness during the winter. However, unlike these boreal forest, the Mount Achernar forest was most likely deciduous, a theory supported by the presence of Glossopteris leaves and other data. This discovery emphasizes the importance of including biological input into climate models to accurately describe the range of past climates.

  7. The Forest, Part 4: Late Summer and Fall

    ERIC Educational Resources Information Center

    Johnson, Elfriede Nemetz

    1973-01-01

    Briefly describes the ecology of a deciduous forest, and suggests activities for observing and appreciating the changes that occur during the Fall. Simple experiments relating to mosses and lichens are outlined. (JR)

  8. Innate immunity, decidual cells, and preeclampsia.

    PubMed

    Yeh, Chang-Ching; Chao, Kuan-Chong; Huang, S Joseph

    2013-04-01

    Preeclampsia (PE) manifested by hypertension and proteinuria complicates 3% to 8% of pregnancies and is a leading cause of fetal-maternal morbidity and mortality worldwide. It may lead to intrauterine growth restriction, preterm delivery, and long-term sequelae in women and fetuses, and consequently cause socioeconomic burden to the affected families and society as a whole. Balanced immune responses are required for the maintenance of successful pregnancy. Although not a focus of most studies, decidual cells, the major resident cell type at the fetal-maternal interface, have been shown to modulate the local immune balance by interacting with other cell types, such as bone marrow derived-immune cells, endothelial cells, and invading extravillous trophoblasts. Accumulating evidence suggests that an imbalanced innate immunity, facilitated by decidual cells, plays an important role in the pathogenesis of PE. Thus, this review will discuss the role of innate immunity and the potential contribution of decidual cells in the pathogenesis of PE. PMID:22814099

  9. Polycomb repressive complex 1 controls uterine decidualization

    PubMed Central

    Bian, Fenghua; Gao, Fei; Kartashov, Andrey V.; Jegga, Anil G.; Barski, Artem; Das, Sanjoy K.

    2016-01-01

    Uterine stromal cell decidualization is an essential part of the reproductive process. Decidual tissue development requires a highly regulated control of the extracellular tissue remodeling; however the mechanism of this regulation remains unknown. Through systematic expression studies, we detected that Cbx4/2, Rybp, and Ring1B [components of polycomb repressive complex 1 (PRC1)] are predominantly utilized in antimesometrial decidualization with polyploidy. Immunofluorescence analyses revealed that PRC1 members are co-localized with its functional histone modifier H2AK119ub1 (mono ubiquitination of histone-H2A at lysine-119) in polyploid cell. A potent small-molecule inhibitor of Ring1A/B E3-ubiquitin ligase or siRNA-mediated suppression of Cbx4 caused inhibition of H2AK119ub1, in conjunction with perturbation of decidualization and polyploidy development, suggesting a role for Cbx4/Ring1B-containing PRC1 in these processes. Analyses of genetic signatures by RNA-seq studies showed that the inhibition of PRC1 function affects 238 genes (154 up and 84 down) during decidualization. Functional enrichment analyses identified that about 38% genes primarily involved in extracellular processes are specifically targeted by PRC1. Furthermore, ~15% of upregulated genes exhibited a significant overlap with the upregulated Bmp2 null-induced genes in mice. Overall, Cbx4/Ring1B-containing PRC1 controls decidualization via regulation of extracellular gene remodeling functions and sheds new insights into underlying molecular mechanism(s) through transcriptional repression regulation. PMID:27181215

  10. Polycomb repressive complex 1 controls uterine decidualization.

    PubMed

    Bian, Fenghua; Gao, Fei; Kartashov, Andrey V; Jegga, Anil G; Barski, Artem; Das, Sanjoy K

    2016-01-01

    Uterine stromal cell decidualization is an essential part of the reproductive process. Decidual tissue development requires a highly regulated control of the extracellular tissue remodeling; however the mechanism of this regulation remains unknown. Through systematic expression studies, we detected that Cbx4/2, Rybp, and Ring1B [components of polycomb repressive complex 1 (PRC1)] are predominantly utilized in antimesometrial decidualization with polyploidy. Immunofluorescence analyses revealed that PRC1 members are co-localized with its functional histone modifier H2AK119ub1 (mono ubiquitination of histone-H2A at lysine-119) in polyploid cell. A potent small-molecule inhibitor of Ring1A/B E3-ubiquitin ligase or siRNA-mediated suppression of Cbx4 caused inhibition of H2AK119ub1, in conjunction with perturbation of decidualization and polyploidy development, suggesting a role for Cbx4/Ring1B-containing PRC1 in these processes. Analyses of genetic signatures by RNA-seq studies showed that the inhibition of PRC1 function affects 238 genes (154 up and 84 down) during decidualization. Functional enrichment analyses identified that about 38% genes primarily involved in extracellular processes are specifically targeted by PRC1. Furthermore, ~15% of upregulated genes exhibited a significant overlap with the upregulated Bmp2 null-induced genes in mice. Overall, Cbx4/Ring1B-containing PRC1 controls decidualization via regulation of extracellular gene remodeling functions and sheds new insights into underlying molecular mechanism(s) through transcriptional repression regulation. PMID:27181215

  11. Leaf economics of evergreen and deciduous tree species along an elevational gradient in a subtropical mountain

    PubMed Central

    Bai, Kundong; He, Chengxin; Wan, Xianchong; Jiang, Debing

    2015-01-01

    The ecophysiological mechanisms underlying the pattern of bimodal elevational distribution of evergreen tree species remain incompletely understood. Here we used leaf economics spectrum (LES) theory to explain such patterns. We measured leaf economic traits and constructed an LES for the co-existing 19 evergreen and 15 deciduous species growing in evergreen broad-leaved forest at low elevation, beech-mixed forest at middle elevation and hemlock-mixed forest at high elevation in Mao'er Mountain, Guangxi, Southern China (25°50′N, 110°49′E). Leaf economic traits presented low but significant phylogenetic signal, suggesting trait similarity between closely related species. After considering the effects of phylogenetic history, deciduous species in general showed a more acquisitive leaf strategy with a higher ratio of leaf water to dry mass, higher leaf nitrogen and phosphorous contents, higher photosynthetic and respiratory rates and greater photosynthetic nitrogen-use efficiency. In contrast, evergreen species exhibited a more conservative leaf strategy with higher leaf mass per area, greater construction costs and longer leaf life span. With the elevation-induced decreases of temperature and soil fertility, both evergreen and deciduous species showed greater resource conservation, suggesting the increasing importance of environmental filtering to community assembly with increasing elevation. We found close inter-specific correlations between leaf economic traits, suggesting that there are strong genetic constraints limiting the independent evolution of LES traits. Phylogenetic signal increased with decreasing evolutionary rate across leaf economic traits, suggesting that genetic constraints are important for the process of trait evolution. We found a significantly positive relationship between primary axis species score (PASS) distance and phylogenetic distance across species pairs and an increasing average PASS distance between evergreen and deciduous species

  12. Leaf economics of evergreen and deciduous tree species along an elevational gradient in a subtropical mountain.

    PubMed

    Bai, Kundong; He, Chengxin; Wan, Xianchong; Jiang, Debing

    2015-01-01

    The ecophysiological mechanisms underlying the pattern of bimodal elevational distribution of evergreen tree species remain incompletely understood. Here we used leaf economics spectrum (LES) theory to explain such patterns. We measured leaf economic traits and constructed an LES for the co-existing 19 evergreen and 15 deciduous species growing in evergreen broad-leaved forest at low elevation, beech-mixed forest at middle elevation and hemlock-mixed forest at high elevation in Mao'er Mountain, Guangxi, Southern China (25°50'N, 110°49'E). Leaf economic traits presented low but significant phylogenetic signal, suggesting trait similarity between closely related species. After considering the effects of phylogenetic history, deciduous species in general showed a more acquisitive leaf strategy with a higher ratio of leaf water to dry mass, higher leaf nitrogen and phosphorous contents, higher photosynthetic and respiratory rates and greater photosynthetic nitrogen-use efficiency. In contrast, evergreen species exhibited a more conservative leaf strategy with higher leaf mass per area, greater construction costs and longer leaf life span. With the elevation-induced decreases of temperature and soil fertility, both evergreen and deciduous species showed greater resource conservation, suggesting the increasing importance of environmental filtering to community assembly with increasing elevation. We found close inter-specific correlations between leaf economic traits, suggesting that there are strong genetic constraints limiting the independent evolution of LES traits. Phylogenetic signal increased with decreasing evolutionary rate across leaf economic traits, suggesting that genetic constraints are important for the process of trait evolution. We found a significantly positive relationship between primary axis species score (PASS) distance and phylogenetic distance across species pairs and an increasing average PASS distance between evergreen and deciduous species with

  13. 29 CFR 780.1015 - Other forest products.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... means any plant of the forest and includes, of course, deciduous plants as well. ... 29 Labor 3 2012-07-01 2012-07-01 false Other forest products. 780.1015 Section 780.1015 Labor... Provisions Under Section 13(d) Requirements for Exemption § 780.1015 Other forest products. The...

  14. 29 CFR 780.1015 - Other forest products.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... means any plant of the forest and includes, of course, deciduous plants as well. ... 29 Labor 3 2014-07-01 2014-07-01 false Other forest products. 780.1015 Section 780.1015 Labor... Provisions Under Section 13(d) Requirements for Exemption § 780.1015 Other forest products. The...

  15. 29 CFR 780.1015 - Other forest products.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... means any plant of the forest and includes, of course, deciduous plants as well. ... 29 Labor 3 2011-07-01 2011-07-01 false Other forest products. 780.1015 Section 780.1015 Labor... Provisions Under Section 13(d) Requirements for Exemption § 780.1015 Other forest products. The...

  16. 29 CFR 780.1015 - Other forest products.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... means any plant of the forest and includes, of course, deciduous plants as well. ... 29 Labor 3 2010-07-01 2010-07-01 false Other forest products. 780.1015 Section 780.1015 Labor... Provisions Under Section 13(d) Requirements for Exemption § 780.1015 Other forest products. The...

  17. 29 CFR 780.1015 - Other forest products.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... means any plant of the forest and includes, of course, deciduous plants as well. ... 29 Labor 3 2013-07-01 2013-07-01 false Other forest products. 780.1015 Section 780.1015 Labor... Provisions Under Section 13(d) Requirements for Exemption § 780.1015 Other forest products. The...

  18. Ectopic decidual reaction mimicking inguinal lymphoma on ultrasound

    PubMed Central

    Prangsgaard, T; Lorentzen, T

    2014-01-01

    Ectopic decidual reaction has been described in various intraperitoneal locations. We present a case of unusual ectopic decidual reaction in the groin mimicking inguinal lymphoma on ultrasound in a pregnant woman. This case contributes evidence illustrating the variability of the clinical presentation of ectopic decidual reaction.

  19. Insect management in deciduous orchard ecosystems: Habitat manipulation

    NASA Astrophysics Data System (ADS)

    Tedders, W. L.

    1983-01-01

    Current literature pertaining to habitat manipulation of deciduous fruit and nut orchards for pest control is reviewed. The hypothesis of pesticide-induced pest problems in deciduous orchards as well as the changing pest population dynamics of deciduous orchards is discussed An experimental habitat manipulation program for pecans, utilizing vetch cover crops to enhance lady beetle populations for pecan aphid control is presented

  20. Forest in My Neighborhood: An Exercise Using Aerial Photos to Engage Students in Forest Ecology & Land Use History

    ERIC Educational Resources Information Center

    Matlack, Glenn R.; McEwan, Ryan W.

    2008-01-01

    Human activity has profoundly altered the deciduous forest of the eastern United States. Modern forest is a patchwork of stands of varying ages, sizes, and shapes reflecting a complex history of land use. Much modern forest is nestled in and around human communities, and faces the threat of imminent clearance for residential and commercial…

  1. Pre-Dispersal Seed Predation in a Species-Rich Forest Community: Patterns and the Interplay with Determinants.

    PubMed

    Xu, Yue; Shen, Zehao; Li, Daoxin; Guo, Qinfeng

    2015-01-01

    Pre-dispersal seed predation (PDSP) is commonly observed in woody plants, and recognized as a driver of seed production variability that is critical for successful regeneration. Earlier studies on PDSP and its determinants were mostly species specific, with community-level PDSP rarely estimated; and the interactions between the temporal variability of seed production and PDSP remain elusive. In this study, the community seed rain of woody plants in a mixed evergreen-deciduous broadleaf forest was monitored for seven years. We examined predation on collected seeds and analyzed the determinants of PDSP. PDSP was recorded in 17 out of 44 woody plant species, and three-quarters of PDSP was due to insect predators. Annual seed production varied substantially at community level, reversely linked with the temporal variation of PDSP rate. The PDSP rate was biased regarding fruit types, and being significantly correlated with seed mass when using phylogenetic independent contrasts (PICs) or without taking into account phylogenetic relations, especially for nuts. PDSP rate was also negatively correlated with seed density, showing a threshold-related predator satiation effect. The community-level PDSP rate was primarily determined by tree height, fruit type, and interannual variation of seed production and seed mass. Our analysis revealed a causal link between seed production and the dynamics of PDSP rate at the community level. The predator satiation effect was primarily contributed by the dominant species, whereas the rare species seemed to apply a distinct "hide-and-seek" strategy to control the risk of PDSP. The mechanistic difference of seed production between the common and rare species can shed new light on species coexistence and community assembly. Long-term monitoring of both seed rain and seed predation is required for understanding the ecological and evolutionary implications of species regeneration strategies in a species-rich forest community. PMID:26575270

  2. Pre-Dispersal Seed Predation in a Species-Rich Forest Community: Patterns and the Interplay with Determinants

    PubMed Central

    Xu, Yue; Shen, Zehao; Li, Daoxin; Guo, Qinfeng

    2015-01-01

    Pre-dispersal seed predation (PDSP) is commonly observed in woody plants, and recognized as a driver of seed production variability that is critical for successful regeneration. Earlier studies on PDSP and its determinants were mostly species specific, with community-level PDSP rarely estimated; and the interactions between the temporal variability of seed production and PDSP remain elusive. In this study, the community seed rain of woody plants in a mixed evergreen-deciduous broadleaf forest was monitored for seven years. We examined predation on collected seeds and analyzed the determinants of PDSP. PDSP was recorded in 17 out of 44 woody plant species, and three-quarters of PDSP was due to insect predators. Annual seed production varied substantially at community level, reversely linked with the temporal variation of PDSP rate. The PDSP rate was biased regarding fruit types, and being significantly correlated with seed mass when using phylogenetic independent contrasts (PICs) or without taking into account phylogenetic relations, especially for nuts. PDSP rate was also negatively correlated with seed density, showing a threshold-related predator satiation effect. The community-level PDSP rate was primarily determined by tree height, fruit type, and interannual variation of seed production and seed mass. Our analysis revealed a causal link between seed production and the dynamics of PDSP rate at the community level. The predator satiation effect was primarily contributed by the dominant species, whereas the rare species seemed to apply a distinct “hide-and-seek” strategy to control the risk of PDSP. The mechanistic difference of seed production between the common and rare species can shed new light on species coexistence and community assembly. Long-term monitoring of both seed rain and seed predation is required for understanding the ecological and evolutionary implications of species regeneration strategies in a species-rich forest community. PMID:26575270

  3. Deposition of SOCs in forests

    SciTech Connect

    Horstmann, M.; McLachlan, M.S.

    1995-12-31

    The bulk deposition, wet-only deposition, dry-only deposition and ambient air concentrations of PCDD/Fs, PCBs and PAHs were measured in an 80 year old spruce forest, an 80 year old mixed deciduous (beech and oak) forest, and in an adjacent clearing over a period of 1--2 years. The deposition of the less volatile compounds that are primarily particle bound in the atmosphere was similar at both sites. These compounds were deposited primarily through wet deposition, as shown by the measurements in the clearing. In contrast, the deposition of the more volatile compounds was much higher at the forest sites than in the clearing. For instance, the annual deposition of Cl{sub 4}DF was 5 times higher in the spruce forest and 8 times higher in the deciduous forest. The excess deposition in the deciduous forest was almost completely due to the leaf fall in October--December, while about half of the excess deposition in the spruce forest was the result of needle fall. A further, as yet unexplained deposition mechanism accounted for the remainder of the flux in the spruce forest. Other studies have shown that more volatile SOCs are deposited to vegetation primarily through dry gaseous deposition. Hence, while forests have little influence on the deposition of less volatile compounds like the higher chlorinated PCDD/Fs and the 5--6 ring PAHs, dry deposition to leaves/needles and their subsequent falling to the forest floor make forest soils an extremely important sink for more volatile SOC.

  4. Estimating canopy fuel parameters for Atlantic Coastal Plain forest types.

    SciTech Connect

    Parresol, Bernard, R.

    2007-01-15

    Abstract It is necessary to quantify forest canopy characteristics to assess crown fire hazard, prioritize treatment areas, and design treatments to reduce crown fire potential. A number of fire behavior models such as FARSITE, FIRETEC, and NEXUS require as input four particular canopy fuel parameters: 1) canopy cover, 2) stand height, 3) crown base height, and 4) canopy bulk density. These canopy characteristics must be mapped across the landscape at high spatial resolution to accurately simulate crown fire. Currently no models exist to forecast these four canopy parameters for forests of the Atlantic Coastal Plain, a region that supports millions of acres of loblolly, longleaf, and slash pine forests as well as pine-broadleaf forests and mixed species broadleaf forests. Many forest cover types are recognized, too many to efficiently model. For expediency, forests of the Savannah River Site are categorized as belonging to 1 of 7 broad forest type groups, based on composition: 1) loblolly pine, 2) longleaf pine, 3) slash pine, 4) pine-hardwood, 5) hardwood-pine, 6) hardwoods, and 7) cypress-tupelo. These 7 broad forest types typify forests of the Atlantic Coastal Plain region, from Maryland to Florida.

  5. The effect of broadleaf woodland on aluminium speciation in stream water in an acid-sensitive area in the UK.

    PubMed

    Ryan, Jennifer L; Lynam, Philippa; Heal, Kate V; Palmer, Sheila M

    2012-11-15

    Acidification can result in the mobilisation and release of toxic inorganic monomeric aluminium (Al) species from soils into aquatic ecosystems. Although it is well-established that conifer trees enhance acidic atmospheric deposition and exacerbate soil and water acidification, the effect of broad-leaved woodland on soil and water acidification is less clear. This study investigated the effect of broadleaf woodland cover on the acid-base chemistry and Al species present in stream water, and processes controlling these in the acid-sensitive area around Loch Katrine, in the central Highlands, Scotland, UK, where broadleaf woodland expansion is occurring. A nested sampling approach was used to identify 22 stream sampling locations, in sub-catchments of 3.2-61 ha area and 0-45% broadleaf woodland cover. In addition, soils sampled from 68 locations were analysed to assess the influence of: (i) broadleaf woodland cover on soil characteristics and (ii) soil characteristics on stream water chemistry. Stream water pH was negatively correlated with sub-catchment % woodland cover, indicating that woodland cover is enhancing stream water acidification. Concentrations of all stream water Al species (monomeric total, organic and inorganic) were positively correlated with % woodland cover, although not significantly, but were below levels that are toxic to fish. Soil depth, O horizon depth and soil chemistry, particularly of the A horizon, appeared to be the dominant controls on stream water chemistry rather than woodland cover. There were significant differences in soil acid-base chemistry, with significantly lower O horizon pH and A horizon base saturation and higher A horizon exchangeable Al in the wooded catchments compared to the control. This is evidence that the mobile anion effect is already occurring in the study catchments and suggests that stream water acidification arising from broadleaf woodland expansion could occur, especially where tree density is high and acid

  6. Two Unique Human Decidual Macrophage Populations

    PubMed Central

    Houser, Brandy L.; Tilburgs, Tamara; Hill, Jonathan; Nicotra, Matthew L.; Strominger, Jack L.

    2013-01-01

    Several important events occur at the maternal–fetal interface, including generation of maternal–fetal tolerance, remodeling of the uterine smooth muscle and its spiral arteries and glands, and placental construction. Fetal-derived extravillous trophoblasts come in direct contact with maternal decidual leukocytes. Macrophages represent ~20% of the leukocytes at this interface. In this study, two distinct subsets of CD14+ decidual macrophages (dMϕs) are found to be present in first-trimester decidual tissue, CD11cHI and CD11cLO. Gene expression analysis by RNA microarray revealed that 379 probes were differentially expressed between these two populations. Analysis of the two subsets revealed several clusters of coregulated genes that suggest distinct functions for these subsets in tissue remodeling, growth, and development. CD11cHI dMϕs express genes associated with lipid metabolism and inflammation, whereas CD11cLO dMϕs express genes associated with extracellular matrix formation, muscle regulation, and tissue growth. The CD11cHI dMϕs also differ from CD11cLO dMϕs in their ability to process protein Ag and are likely to be the major APCs in the decidua. Moreover, these populations each secrete both proinflammatory and anti-inflammatory cytokines that may contribute to the balance that establishes fetal–maternal tolerance. Thus, they do not fit the conventional M1/M2 categorization. PMID:21257965

  7. Forest canopy effects on the estimation of soil moisture at L-Band

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Truck-based measurements of brightness temperature at Lband over small deciduous stands located in Maryland were made in 2006 and 2007. Ground truth data related to forest stands and the ground were also collected. The deciduous trees were modeled by the Distorted Born Approximation (DBA) in conjunc...

  8. Estimating Chemical Exchange between Atmospheric Deposition and Forest Canopy in Guizhou, China.

    PubMed

    Li, Wei; Gao, Fang; Liao, Xueqin

    2013-01-01

    To evaluate the effects of atmospheric deposition on forest ecosystems, wet-only precipitation and throughfall samples were collected in two forest types (Masson pine [ Lamb.] forests and mixed conifer and broadleaf forests) in the Longli forest in the Guizhou province of southwestern China for a period of 21 successive months from April 2007 to December 2008. The pH and chemical components of precipitation and throughfall were analyzed. In addition, the canopy budget model was applied to distinguish between in-canopy and atmospheric sources of chemical compounds. Canopy leaching and total potentially acidifying deposition fluxes were calculated. The results showed that the average pH and the concentration of ions in throughfall were higher than those in precipitation, with the exception of the NH concentration. Dry deposition of S and N accumulated more in Masson pine forests than in mixed conifer and broadleaf forests. Canopy leaching was the most significant source of base cations in forest throughfall, which was higher in the mixed forests than in the coniferous forests. Anions in throughfall deposition in Masson pine forests exceeded those in the mixed forests. Higher total potentially acidifying deposition fluxes reflected the more effective amounts of acid delivered to Masson pine forests compared with mixed conifer and broadleaf forests. In addition, acid deposition induced the leaching and loss of nutrient ions such as Mg, K, and Ca. Although the trees of the studied areas have not shown any symptoms of cation loss, a potentially harmful influence was engendered by atmospheric deposition in the two forest types in the Longli area. PMID:23673825

  9. Conifer-Derived Monoterpenes and Forest Walking

    PubMed Central

    Sumitomo, Kazuhiro; Akutsu, Hiroaki; Fukuyama, Syusei; Minoshima, Akiho; Kukita, Shin; Yamamura, Yuji; Sato, Yoshiaki; Hayasaka, Taiki; Osanai, Shinobu; Funakoshi, Hiroshi; Hasebe, Naoyuki; Nakamura, Masao

    2015-01-01

    Conifer and broadleaf trees emit volatile organic compounds in the summer. The major components of these emissions are volatile monoterpenes. Using solid phase microextraction fiber as the adsorbant, monoterpenes were successfully detected and identified in forest air samples. Gas chromatography/mass chromatogram of monoterpenes in the atmosphere of a conifer forest and that of serum from subjects who were walking in a forest were found to be similar each other. The amounts of α-pinene in the subjects became several folds higher after forest walking. The results indicate that monoterpenes in the atmosphere of conifer forests are transferred to and accumulate in subjects by inhalation while they are exposed to this type of environment. PMID:26819913

  10. Discrimination of Deciduous Tree Species from Time Series of Unmanned Aerial System Imagery

    PubMed Central

    Lisein, Jonathan; Michez, Adrien; Claessens, Hugues; Lejeune, Philippe

    2015-01-01

    Technology advances can revolutionize Precision Forestry by providing accurate and fine forest information at tree level. This paper addresses the question of how and particularly when Unmanned Aerial System (UAS) should be used in order to efficiently discriminate deciduous tree species. The goal of this research is to determine when is the best time window to achieve an optimal species discrimination. A time series of high resolution UAS imagery was collected to cover the growing season from leaf flush to leaf fall. Full benefit was taken of the temporal resolution of UAS acquisition, one of the most promising features of small drones. The disparity in forest tree phenology is at the maximum during early spring and late autumn. But the phenology state that optimized the classification result is the one that minimizes the spectral variation within tree species groups and, at the same time, maximizes the phenologic differences between species. Sunlit tree crowns (5 deciduous species groups) were classified using a Random Forest approach for monotemporal, two-date and three-date combinations. The end of leaf flushing was the most efficient single-date time window. Multitemporal datasets definitely improve the overall classification accuracy. But single-date high resolution orthophotomosaics, acquired on optimal time-windows, result in a very good classification accuracy (overall out of bag error of 16%). PMID:26600422

  11. Discrimination of Deciduous Tree Species from Time Series of Unmanned Aerial System Imagery.

    PubMed

    Lisein, Jonathan; Michez, Adrien; Claessens, Hugues; Lejeune, Philippe

    2015-01-01

    Technology advances can revolutionize Precision Forestry by providing accurate and fine forest information at tree level. This paper addresses the question of how and particularly when Unmanned Aerial System (UAS) should be used in order to efficiently discriminate deciduous tree species. The goal of this research is to determine when is the best time window to achieve an optimal species discrimination. A time series of high resolution UAS imagery was collected to cover the growing season from leaf flush to leaf fall. Full benefit was taken of the temporal resolution of UAS acquisition, one of the most promising features of small drones. The disparity in forest tree phenology is at the maximum during early spring and late autumn. But the phenology state that optimized the classification result is the one that minimizes the spectral variation within tree species groups and, at the same time, maximizes the phenologic differences between species. Sunlit tree crowns (5 deciduous species groups) were classified using a Random Forest approach for monotemporal, two-date and three-date combinations. The end of leaf flushing was the most efficient single-date time window. Multitemporal datasets definitely improve the overall classification accuracy. But single-date high resolution orthophotomosaics, acquired on optimal time-windows, result in a very good classification accuracy (overall out of bag error of 16%). PMID:26600422

  12. How environmental conditions affect canopy leaf-level photosynthesis in four deciduous tree species

    SciTech Connect

    Bassow, S.L.; Bazzaz, F.A.

    1998-12-01

    Species composition of temperate forests vary with successional age and seems likely to change in response to significant global climate change. Because photosynthesis rates in co-occurring tree species can differ in their sensitivity to environmental conditions, these changes in species composition are likely to alter the carbon dynamics of temperate forests. To help improve their understanding of such atmosphere-biosphere interactions, the authors explored changes in leaf-level photosynthesis in a 60--70 yr old temperate mixed-deciduous forest in Petersham, Massachusetts (USA). Diurnally and seasonally varying environmental conditions differentially influenced in situ leaf-level photosynthesis rates in the canopies of four mature temperate deciduous tree species: red oak (Quercus rubra), red maple (Acer rubrum), white birch (Betula papyrifera), and yellow birch (Betula alleghaniensis). The authors measured in situ photosynthesis at two heights within the canopies through a diurnal time course on 7 d over two growing seasons. They simultaneously measured a suite of environmental conditions surrounding the leaf at the time of each measurement. The authors used path analysis to examine the influence of environmental factors on in situ photosynthesis in the tree canopies.

  13. Remote sensing-based estimation of annual soil respiration at two contrasting forest sites

    NASA Astrophysics Data System (ADS)

    Huang, Ni; Gu, Lianhong; Black, T. Andrew; Wang, Li; Niu, Zheng

    2015-11-01

    Soil respiration (Rs), an important component of the global carbon cycle, can be estimated using remotely sensed data, but the accuracy of this technique has not been thoroughly investigated. In this study, we proposed a methodology for the remote estimation of annual Rs at two contrasting FLUXNET forest sites (a deciduous broadleaf forest and an evergreen needleleaf forest). A version of the Akaike's information criterion was used to select the best model from a range of models for annual Rs estimation based on the remotely sensed data products from the Moderate Resolution Imaging Spectroradiometer and root-zone soil moisture product derived from assimilation of the NASA Advanced Microwave Scanning Radiometer soil moisture products and a two-layer Palmer water balance model. We found that the Arrhenius-type function based on nighttime land surface temperature (LST-night) was the best model by comprehensively considering the model explanatory power and model complexity at the Missouri Ozark and BC-Campbell River 1949 Douglas-fir sites. In addition, a multicollinearity problem among LST-night, root-zone soil moisture, and plant photosynthesis factor was effectively avoided by selecting the LST-night-driven model. Cross validation showed that temporal variation in Rs was captured by the LST-night-driven model with a mean absolute error below 1 µmol CO2 m-2 s-1 at both forest sites. An obvious overestimation that occurred in 2005 and 2007 at the Missouri Ozark site reduced the evaluation accuracy of cross validation because of summer drought. However, no significant difference was found between the Arrhenius-type function driven by LST-night and the function considering LST-night and root-zone soil moisture. This finding indicated that the contribution of soil moisture to Rs was relatively small at our multiyear data set. To predict intersite Rs, maximum leaf area index (LAImax) was used as an upscaling factor to calibrate the site-specific reference respiration

  14. Ecology of Missouri Forests. Instructional Unit. Conservation Education Series.

    ERIC Educational Resources Information Center

    Jackson, Jim

    This unit is designed to help science, social studies, vocational agriculture, and other teachers incorporate forest ecology concepts into their subject matter. The unit includes: (1) topic outline; (2) unit objectives; (3) background information on climate and soils, levels of a deciduous forest, age classes, food and energy relationships, forest…

  15. EVALUATION OF FOREST CANOPY MODELS FOR ESTIMATING ISOPRENE EMISSIONS

    EPA Science Inventory

    During the summer of 1992, isoprene emissions were measured in a mixed deciduous forest near Oak Ridge, Tennessee. Measurements were aimed at the experimental scale-up of emissions from the leaf level to the forest canopy to the mixed layer. Results from the scale-up study are co...

  16. Subtropical Forest Biomass Estimation Using Airborne LiDAR and Hyperspectral Data

    NASA Astrophysics Data System (ADS)

    Pang, Yong; Li, Zengyuan

    2016-06-01

    Forests have complex vertical structure and spatial mosaic pattern. Subtropical forest ecosystem consists of vast vegetation species and these species are always in a dynamic succession stages. It is very challenging to characterize the complexity of subtropical forest ecosystem. In this paper, CAF's (The Chinese Academy of Forestry) LiCHy (LiDAR, CCD and Hyperspectral) Airborne Observation System was used to collect waveform Lidar and hyperspectral data in Puer forest region, Yunnan province in the Southwest of China. The study site contains typical subtropical species of coniferous forest, evergreen broadleaf forest, and some other mixed forests. The hypersectral images were orthorectified and corrected into surface reflectance with support of Lidar DTM product. The fusion of Lidar and hyperspectral can classify dominate forest types. The lidar metrics improved the classification accuracy. Then forest biomass estimation was carried out for each dominate forest types using waveform Lidar data, which get improved than single Lidar data source.

  17. Forest statistics for Michigan`s northern lower peninsula unit, 1993. Forest Service research bulletin

    SciTech Connect

    Leatherberry, E.C.

    1994-10-30

    Michigan`s Northern Lower Peninsula Unit (fig. 1) is comprised of 33 counties. This region of the State is rich with resources that support a network of social, economic, and ecological processes that are forest dependent. The forest resource of the Unit presently supports an industry that operates on a sustaining basis. In 1990 nearly half of Michigan`s saw-log production--297 million board feet--was harvest in the Unit. The forests of the Northern Lower Peninsula are vital to the region. The forest contains a variety of both deciduous and coniferous forest species, which results in regionally unique ecosystems that contribute to biodiversity.

  18. Quantifying the effects of harvesting on carbon fluxes and stocks in northern temperate forests

    NASA Astrophysics Data System (ADS)

    Wang, W.; Xiao, J.; Ollinger, S. V.; Desai, A. R.; Chen, J.; Noormets, A.

    2014-12-01

    Harvest disturbance has substantial impacts on forest carbon (C) fluxes and stocks. The quantification of these effects is essential for the better understanding of forest C dynamics and informing forest management in the context of global change. We used a process-based forest ecosystem model, PnET-CN, to evaluate how, and by what mechanisms, clear-cuts alter ecosystem C fluxes, aboveground C stocks (AGC), and leaf area index (LAI) in northern temperate forests. We compared C fluxes and stocks predicted by the model and observed at two chronosequences of eddy covariance flux sites for deciduous broadleaf forests (DBF) and evergreen needleleaf forests (ENF) in the Upper Midwest region of northern Wisconsin and Michigan, USA. The average normalized root mean square error (NRMSE) and the Willmott index of agreement (d) for carbon fluxes, LAI, and AGC in the two chronosequences were 20% and 0.90, respectively. Simulated gross primary productivity (GPP) increased with stand age, reaching a maximum (1200-1500 g C m-2 yr-1) at 11-30 years of age, and leveled off thereafter (900-1000 g C m-2 yr-1). Simulated ecosystem respiration (ER) for both plant functional types (PFTs) was initially as high as 700-1000 g C m-2 yr-1 in the first or second year after harvesting, decreased with age (400-800 g C m-2 yr-1) before canopy closure at 10-25 years of age, and increased to 800-900 g C m-2 yr-1 with stand development after canopy recovery. Simulated net ecosystem productivity (NEP) for both PFTs was initially negative, with net C losses of 400-700 g C m-2 yr-1 for 6-17 years after clear-cuts, reaching peak values of 400-600 g C m-2 yr-1 at 14-29 years of age, and eventually stabilizing in mature forests (> 60 years old), with a weak C sink (100-200 g C m-2 yr-1). The decline of NEP with age was caused by the relative flattening of GPP and gradual increase of ER. ENF recovered more slowly from a net C source to a net sink, and lost more C than DBF. This suggests that in general

  19. Vegetation turnover and nitrogen feedback drive temperate forest carbon sequestration in response to elevated CO[2]. A multi-model structural analysis

    NASA Astrophysics Data System (ADS)

    Walker, A. P.; Zaehle, S.; Medlyn, B. E.; De Kauwe, M. G.; Asao, S.; Hickler, T.; Lomas, M. R.; Pak, B. C.; Parton, W. J.; Quegan, S.; Ricciuto, D. M.; Wang, Y.; Warlind, D.; Norby, R. J.

    2013-12-01

    Predicting forest carbon (C) sequestration requires understanding the processes leading to rates of biomass C accrual (net primary productivity; NPP) and loss (turnover). In temperate forest ecosystems, experiments and models have shown that feedback via progressive nitrogen limitation (PNL) is a key driver of NPP responses to elevated CO[2]. In this analysis we show that while still important, PNL may not be as severe a constraint on NPP as indicated by some studies and that the response of turnover to elevated CO[2] could be as important, especially in the near to medium term. Seven terrestrial ecosystem and biosphere models that couple C and N cycles with varying assumptions and complexity were used to simulate responses over 300 years to a step change in CO[2] to 550 ppmv. Simulations were run for the evergreen needleleaf Duke forest and the deciduous broadleaf Oak Ridge forest FACE experiments. Whether or not a model simulated PNL under elevated CO[2] depended on model structure and the timescale of observation. Avoiding PNL depended on mechanisms that reduced ecosystem N losses. The two key assumptions that reduced N losses were whether plant N uptake was based on plant N demand and whether ecosystem N losses (volatisation and leaching) were dependent on the concentration of N in the soil solution. Assumptions on allocation and turnover resulted in very different responses of turnover to elevated CO[2], which had profound implications for C sequestration. For example, at equilibrium CABLE2.0 predicted an increase in vegetation C sequestration despite decreased NPP, while O-CN predicted much less vegetation C sequestration than would be expected from predicted NPP increases alone. Generally elevated CO[2] favoured a shift in C partitioning towards longer lived wood biomass, which increased vegetation turnover and enhanced C sequestration. Enhanced wood partitioning was overlaid by increases or decreases in self-thinning depended on whether self-thinning was

  20. Water cycle observations in forest watersheds of Cambodia

    NASA Astrophysics Data System (ADS)

    Shimizu, A.; Tamai, K.; Kabeya, N.; Shimizu, T.; Iida, S. I.

    2015-12-01

    The Lower Mekong River flows through Cambodia, where forests cover ~60% of the country and are believed to have a marked effect on the water cycle. These tropical seasonal forests in the Cambodian flat lands are very precious in the Indochinese Peninsula as few forests of this type remain. However, few hydrological observations have been conducted in these areas. In Cambodia, deciduous and evergreen forests make up 42% and 33% of the total forest area, respectively. We established experimental watersheds both in deciduous and evergreen forests containing meteorological observation towers in Cambodia and collected various observational data since 2003 (O'Krieng, deciduous forest watershed including a 30-m-high observation tower, 2,245 km2; Stung Chinit, evergreen forest watershed including a 60-m-high observation tower, 3,700 km2 including three small watersheds). The basic data from these sites included various kinds of information related to the composition of vegetation, soil characteristics, etc. Hydrologic data was collected and linked to the above data; the main hydrologic research results follow. The water budget for each watershed was determined using an observational rainfall and runoff dataset. The evapotranspiration rate in an evergreen forest was obtained using various observational methods including the Bowen energy-balance ratio and the bandpass eddy covariance method. The annual evapotranspiration of evergreen forests, estimated using the Bowen energy-balance ratio method and water balance, was about 1100-1200 mm, corresponding to 70-80% of annual rainfall. While considering the importance of the presence of evergreen forest, we conducted sap flow measurements to analyze the transpiration process that maintains water uptake through root systems that reach to depths exceeding 8 m. Characteristics of the evaporation from the forest floor that form an important element of the evaporation system were estimated in both evergreen and deciduous forests.

  1. Lead levels among various deciduous tooth types

    SciTech Connect

    Rabinowitz, M.B. National Taiwan Univ., Taipei ); Bellinger, D.; Leviton, A. ); Jungder Wang )

    1991-10-01

    The amount of lead in deciduous teeth has been used extensively as a marker for infant lead exposure and body burden. However, the pattern of lead abundances among the various tooth positions in a child's mouth appears to be non-uniform. Taken together these findings show an apparently inconsistent pattern among the tooth types. These comparisons are complicated by different research groups using different portions of the tooth. This issue is of significance to those who wish to compare the lead burden of children but have available teeth from different positions from the various children. By examining a large number of teeth from two different populations, the authors hope to explore the more universal aspects of any variability among tooth types.

  2. Ecophysiological and biochemical strategies of response to ozone in Mediterranean evergreen broadleaf species

    NASA Astrophysics Data System (ADS)

    Nali, C.; Paoletti, E.; Marabottini, R.; Della Rocca, G.; Lorenzini, G.; Paolacci, A. R.; Ciaffi, M.; Badiani, M.

    Three Mediterranean shrubs, Phillyrea latifolia L. (phillyrea), Arbutus unedo L. (strawberry tree), and Laurus nobilis L. (laurel), differing in their morphological and ecological response to water shortage, were exposed for 90 days to 0 or 110 ppb of ozone (O 3), 5 h each day. This yielded an accumulated exposure over of a threshold of 40 ppb (AOT40) of 31.5 ppm h over the 3 months experiment. These species showed differing responses to O 3: laurel and phillyrea developed foliar chlorotic mottles on the adaxial surface of leaves, whereas strawberry tree leaves showed reddish interveinal stipple-like necrotic lesions. In all cases, however, foliar injury did not exceed 8% of the sampled leaf area. At the end of the exposure period, O 3-induced stomatal limitation caused significant decreases of net photosynthesis in strawberry tree and laurel, but not in phillyrea. The relative water content of the leaves was significantly decreased by O 3, especially in laurel and strawberry tree, suggesting the occurrence of drought stress. Electrical conductivity of leachates from foliar discs increased in response to the treatment, much more strongly in laurel and in strawberry tree than in phillyrea, suggesting an O 3-dependent alteration of the membrane retention capacity. At the end of the experimental period, the activity of superoxide dismutase and the content of reduced glutathione, but not that of reduced ascorbate, were significantly increased in the ozonated leaves of strawberry tree and phillyrea, but not in laurel. The evergreen broadleaves studied here maybe relatively tolerant to realistic O 3 levels, at least in terms of visible injury and gas exchange. Such tolerance might overlap with their level of tolerance to drought stress. High constitutive levels, and/or O 3-induced increases in antioxidants, might contribute to O 3 tolerance in these Mediterranean evergreen broadleaf species.

  3. Decidual-secreted factors alter invasive trophoblast membrane and secreted proteins implying a role for decidual cell regulation of placentation.

    PubMed

    Menkhorst, Ellen Melaleuca; Lane, Natalie; Winship, Amy Louise; Li, Priscilla; Yap, Joanne; Meehan, Katie; Rainczuk, Adam; Stephens, Andrew; Dimitriadis, Evdokia

    2012-01-01

    Inadequate or inappropriate implantation and placentation during the establishment of human pregnancy is thought to lead to first trimester miscarriage, placental insufficiency and other obstetric complications. To create the placental blood supply, specialized cells, the 'extravillous trophoblast' (EVT) invade through the differentiated uterine endometrium (the decidua) to engraft and remodel uterine spiral arteries. We hypothesized that decidual factors would regulate EVT function by altering the production of EVT membrane and secreted factors. We used a proteomics approach to identify EVT membrane and secreted proteins regulated by decidual cell factors. Human endometrial stromal cells were decidualized in vitro by treatment with estradiol (10(-8) M), medroxyprogesterone acetate (10(-7) M) and cAMP (0.5 mM) for 14 days. Conditioned media (CM) was collected on day 2 (non-decidualized CM) and 14 (decidualized CM) of treatment. Isolated primary EVT cultured on Matrigel™ were treated with media control, non-decidualized or decidualized CM for 16 h. EVT CM was fractionated for proteins <30 kDa using size-exclusion affinity nanoparticles (SEAN) before trypsin digestion and HPLC-MS/MS. 43 proteins produced by EVT were identified; 14 not previously known to be expressed in the placenta and 12 which had previously been associated with diseases of pregnancy including preeclampsia. Profilin 1, lysosome associated membrane glycoprotein 1 (LAMP1), dipeptidyl peptidase 1 (DPP1/cathepsin C) and annexin A2 expression by interstitial EVT in vivo was validated by immunhistochemistry. Decidual CM regulation in vitro was validated by western blotting: decidualized CM upregulated profilin 1 in EVT CM and non-decidualized CM upregulated annexin A2 in EVT CM and pro-DPP1 in EVT cell lysate. Here, non-decidualized factors induced protease expression by EVT suggesting that non-decidualized factors may induce a pro-inflammatory cascade. Preeclampsia is a pro-inflammatory condition

  4. Decidual-Secreted Factors Alter Invasive Trophoblast Membrane and Secreted Proteins Implying a Role for Decidual Cell Regulation of Placentation

    PubMed Central

    Menkhorst, Ellen Melaleuca; Lane, Natalie; Winship, Amy Louise; Li, Priscilla; Yap, Joanne; Meehan, Katie; Rainczuk, Adam; Stephens, Andrew; Dimitriadis, Evdokia

    2012-01-01

    Inadequate or inappropriate implantation and placentation during the establishment of human pregnancy is thought to lead to first trimester miscarriage, placental insufficiency and other obstetric complications. To create the placental blood supply, specialized cells, the ‘extravillous trophoblast’ (EVT) invade through the differentiated uterine endometrium (the decidua) to engraft and remodel uterine spiral arteries. We hypothesized that decidual factors would regulate EVT function by altering the production of EVT membrane and secreted factors. We used a proteomics approach to identify EVT membrane and secreted proteins regulated by decidual cell factors. Human endometrial stromal cells were decidualized in vitro by treatment with estradiol (10−8 M), medroxyprogesterone acetate (10−7 M) and cAMP (0.5 mM) for 14 days. Conditioned media (CM) was collected on day 2 (non-decidualized CM) and 14 (decidualized CM) of treatment. Isolated primary EVT cultured on Matrigel™ were treated with media control, non-decidualized or decidualized CM for 16 h. EVT CM was fractionated for proteins <30 kDa using size-exclusion affinity nanoparticles (SEAN) before trypsin digestion and HPLC-MS/MS. 43 proteins produced by EVT were identified; 14 not previously known to be expressed in the placenta and 12 which had previously been associated with diseases of pregnancy including preeclampsia. Profilin 1, lysosome associated membrane glycoprotein 1 (LAMP1), dipeptidyl peptidase 1 (DPP1/cathepsin C) and annexin A2 expression by interstitial EVT in vivo was validated by immunhistochemistry. Decidual CM regulation in vitro was validated by western blotting: decidualized CM upregulated profilin 1 in EVT CM and non-decidualized CM upregulated annexin A2 in EVT CM and pro-DPP1 in EVT cell lysate. Here, non-decidualized factors induced protease expression by EVT suggesting that non-decidualized factors may induce a pro-inflammatory cascade. Preeclampsia is a pro-inflammatory condition

  5. EFFECTS OF SULFURIC ACID RAIN ON MAJOR CATION AND SULFATE CONCENTRATIONS OF WATER PERCOLATING THROUGH TWO MODEL HARDWOOD FORESTS

    EPA Science Inventory

    Acid precipitation falls on vast areas of forested land, including most of the eastern deciduous forest of the United States. Forest productivity, ground-water quality, and surface waters might all be affected. To document and quantify ecosystem response to the onset of acid prec...

  6. Spontaneous decidualization in pseudopregnant rats with vitamin E deficiency.

    PubMed

    Lang, Nan; Wu, Bin; He, Bin; Wang, Lili; Wang, Jiedong

    2016-05-13

    Successful implantation of an embryo requires adequate depth of invasion in the endometrium, which depends upon decidualization. The aim of the present study was to elucidate why humans experience spontaneous decidualization and menstruation while most other mammals do not. We established a spontaneous decidualization model in pseudopregnant rats with vitamin E deficiency (VED) to investigate mechanisms associated with spontaneous decidualization. Vaginal smears were used to monitor bleeding while vitamin E levels were analyzed with a commercial vitamin E assay kit. Trypan blue staining was used to observe the implantation site at 5.5 days post-coitum (dpc). Uterine morphology, estradiol (E2) and progesterone levels, and the anti-oxidation system were evaluated at 5.5, 7.5, and 9.5 dpc. The proportion of rats in the VED group exhibiting endometrial bleeding gradually increased (5.9%, 32.3%, and 50%) over three consecutive cycles of pseudopregnancy. Vitamin E levels in the VED group were markedly lower compared to the control group in both the plasma and uterus, while the level of vitamin E in the liver did not differ between the control and VED groups. Spontaneous decidualization in the VED group was validated by histological examination and immunohistochemistry. At 5.5 dpc, the mean serum E2 level in the VED group was more than twice that of the control group. The mean total anti-oxidizing capability, catalase level, and glutathione peroxidase activity were significantly reduced in the decidualized portion of the VED group compared to controls, while the malondialdehyde level was also significantly higher in the decidualized portion of the VED group. We hypothesize that the E2 surge at 5.5 dpc and increasing levels of reactive oxygen species are responsible for spontaneous decidualization in VED rats. PMID:27033606