Science.gov

Sample records for broadleaf deciduous forest

  1. Leaf domatia and foliar mite abundance in broadleaf deciduous forest of north Asia.

    PubMed

    O'Dowd, D; Pemberton, R

    1998-01-01

    Plant morphology may be shaped, in part, by the third trophic level. Leaf domatia, minute enclosures usually in vein axils on the leaf underside, may provide the basis for protective mutualism between plants and mites. Domatia are particularly frequent among species of trees, shrubs, and vines in the temperate broadleaf deciduous forests in north Asia where they may be important in determining the distribution and abundance of mites in the forest canopy. In lowland and montane broadleaf deciduous forests at Kwangn;akung and Chumbongsan in Korea, we found that approximately half of all woody species in all forest strata, including many dominant trees, have leaf domatia. Pooling across 24 plant species at the two sites, mites occupied a mode of 60% (range 20-100%) of domatia and used them for shelter, egg-laying, and development. On average, 70% of all active mites and 85% of mite eggs on leaves were found in domatia; over three-quarters of these were potentially beneficial to their hosts. Further, mite abundance and reproduction (expressed as the proportion of mites at the egg stage) were significantly greater on leaves of species with domatia than those without domatia in both forests. Effects of domatia on mite abundance were significant only for predaceous and fungivorous mite taxa; herbivore numbers did not differ significantly between leaves of species with and without domatia. Comparable patterns in broadleaf deciduous forest in North America and other biogeographic regions suggest that the effect of leaf domatia on foliar mite abundance is general. These results are consistent with several predictions of mutualism between plants and mites, and indicate that protective mutualisms may be frequent in the temperate zone.

  2. 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.

  3. 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.

  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. Use of digital webcam images to track spring green-up in a deciduous broadleaf forest.

    PubMed

    Richardson, Andrew D; Jenkins, Julian P; Braswell, Bobby H; Hollinger, David Y; Ollinger, Scott V; Smith, Marie-Louise

    2007-05-01

    Understanding relationships between canopy structure and the seasonal dynamics of photosynthetic uptake of CO(2) by forest canopies requires improved knowledge of canopy phenology at eddy covariance flux tower sites. We investigated whether digital webcam images could be used to monitor the trajectory of spring green-up in a deciduous northern hardwood forest. A standard, commercially available webcam was mounted at the top of the eddy covariance tower at the Bartlett AmeriFlux site. Images were collected each day around midday. Red, green, and blue color channel brightness data for a 640 x 100-pixel region-of-interest were extracted from each image. We evaluated the green-up signal extracted from webcam images against changes in the fraction of incident photosynthetically active radiation that is absorbed by the canopy (f (APAR)), a broadband normalized difference vegetation index (NDVI), and the light-saturated rate of canopy photosynthesis (A(max)), inferred from eddy flux measurements. The relative brightness of the green channel (green %) was relatively stable through the winter months. A steady rising trend in green % began around day 120 and continued through day 160, at which point a stable plateau was reached. The relative brightness of the blue channel (blue %) also responded to spring green-up, although there was more day-to-day variation in the signal because blue % was more sensitive to changes in the quality (spectral distribution) of incident radiation. Seasonal changes in blue % were most similar to those in f (APAR) and broadband NDVI, whereas changes in green % proceeded more slowly, and were drawn out over a longer period of time. Changes in A(max) lagged green-up by at least a week. We conclude that webcams offer an inexpensive means by which phenological changes in the canopy state can be quantified. A network of cameras could offer a novel opportunity to implement a regional or national phenology monitoring program.

  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. 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

  9. Separating overstory and understory leaf area indices for global needleleaf and deciduous broadleaf forests by fusion of MODIS and MISR data

    NASA Astrophysics Data System (ADS)

    Liu, Yang; Liu, Ronggao; Pisek, Jan; Chen, Jing M.

    2017-03-01

    Forest overstory and understory layers differ in carbon and water cycle regimes and phenology, as well as ecosystem functions. Separate retrievals of leaf area index (LAI) for these two layers would help to improve modeling forest biogeochemical cycles, evaluating forest ecosystem functions and also remote sensing of forest canopies by inversion of canopy reflectance models. In this paper, overstory and understory LAI values were estimated separately for global needleleaf and deciduous broadleaf forests by fusing MISR and MODIS observations. Monthly forest understory LAI was retrieved from the forest understory reflectivity estimated using MISR data. After correcting for the background contribution using monthly mean forest understory reflectivities, the forest overstory LAI was estimated from MODIS observations. The results demonstrate that the largest extent of forest understory vegetation is present in the boreal forest zones at northern latitudes. Significant seasonal variations occur for understory vegetation in these zones with LAI values up to 2-3 from June to August. The mean proportion of understory LAI to total LAI is greater than 30 %. Higher understory LAI values are found in needleleaf forests (with a mean value of 1.06 for evergreen needleleaf forests and 1.04 for deciduous needleleaf forests) than in deciduous broadleaf forests (0.96) due to the more clumped foliage and easier penetration of light to the forest floor in needleleaf forests. Spatially and seasonally variable forest understory reflectivity helps to account for the effects of the forest background on LAI retrieval while compared with constant forest background. The retrieved forest overstory and understory LAI values were compared with an existing dataset for larch forests in eastern Siberia (40-75° N, 45-180° E). The retrieved overstory and understory LAI is close to that of the existing dataset, with an absolute error of 0.02 (0.06), relative error of 1.3 % (14.3 %) and RMSE of 0

  10. 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

  11. Evaluation of deciduous broadleaf forests mountain using satellite data using neural network method near Caspian Sea in North of Iran.

    PubMed

    Hashemi, Seyed A

    2016-01-01

    During the recent decades, deciduous forests have been molested by human intervention. Easy access, abundance and diversity of valuable forest products have led to increased population density, creating new residential areas and deforestation activities. Revealing changes is one of the fundamental methods in management and assessment of natural resources. This study is evaluated changes in forests area of 2013 using satellite images. In order to mapping the forest extent condition 2013, images of the mentioned years were digitized and geo-referenced by using the ground control points and the maps of mapping organization. After selecting the best set of band using the Bhattacharya distance index, the image classification was performed by using artificial neural network algorithm. Classification by neural network method 2013 in showed that it has a high overall accuracy equal to 95.96%.

  12. 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.

  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. Seasonal ozone uptake by a warm-temperate mixed deciduous and evergreen broadleaf forest in western Japan estimated by the Penman-Monteith approach combined with a photosynthesis-dependent stomatal model.

    PubMed

    Kitao, Mitsutoshi; Komatsu, Masabumi; Hoshika, Yasutomo; Yazaki, Kenichi; Yoshimura, Kenichi; Fujii, Saori; Miyama, Takafumi; Kominami, Yuji

    2014-01-01

    Canopy-level stomatal conductance over a warm-temperate mixed deciduous and evergreen broadleaf forest in Japan was estimated by the Penman-Monteith approach, as compensated by a semi-empirical photosynthesis-dependent stomatal model, where photosynthesis, relative humidity, and CO2 concentration were assumed to regulate stomatal conductance. This approach, using eddy covariance data and routine meteorological observations at a flux tower site, permits the continuous estimation of canopy-level O3 uptake, even when the Penman-Monteith approach is unavailable (i.e. in case of direct evaporation from soil or wet leaves). Distortion was observed between the AOT40 exposure index and O3 uptake through stomata, as AOT40 peaked in April, but with O3 uptake occurring in July. Thus, leaf pre-maturation in the predominant deciduous broadleaf tree species (Quercus serrata) might suppress O3 uptake in springtime, even when the highest O3 concentrations were observed.

  15. Effects of seasonal and interannual variations in leaf photosynthesis and canopy leaf area index on gross primary production of a cool-temperate deciduous broadleaf forest in Takayama, Japan.

    PubMed

    Muraoka, Hiroyuki; Saigusa, Nobuko; Nasahara, Kenlo N; Noda, Hibiki; Yoshino, Jun; Saitoh, Taku M; Nagai, Shin; Murayama, Shohei; Koizumi, Hiroshi

    2010-07-01

    Revealing the seasonal and interannual variations in forest canopy photosynthesis is a critical issue in understanding the ecological mechanisms underlying the dynamics of carbon dioxide exchange between the atmosphere and deciduous forests. This study examined the effects of temporal variations of canopy leaf area index (LAI) and leaf photosynthetic capacity [the maximum velocity of carboxylation (V (cmax))] on gross primary production (GPP) of a cool-temperate deciduous broadleaf forest for 5 years in Takayama AsiaFlux site, central Japan. We made two estimations to examine the effects of canopy properties on GPP; one is to incorporate the in situ observation of V (cmax) and LAI throughout the growing season, and another considers seasonality of LAI but constantly high V (cmax). The simulations indicated that variation in V (cmax) and LAI, especially in the leaf expansion period, had remarkable effects on GPP, and if V (cmax) was assumed constant GPP will be overestimated by 15%. Monthly examination of air temperature, radiation, LAI and GPP suggested that spring temperature could affect canopy phenology, and also that GPP in summer was determined mainly by incoming radiation. However, the consequences among these factors responsible for interannual changes of GPP are not straightforward since leaf expansion and senescence patterns and summer meteorological conditions influence GPP independently. This simulation based on in situ ecophysiological research suggests the importance of intensive consideration and understanding of the phenology of leaf photosynthetic capacity and LAI to analyze and predict carbon fixation in forest ecosystems.

  16. Inversely estimating the vertical profile of the soil CO2 production rate in a deciduous broadleaf forest using a particle filtering method.

    PubMed

    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.

  17. 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

  18. Mercury in leaf litter in typical suburban and urban broadleaf forests in China.

    PubMed

    Niu, Zhenchuan; Zhang, Xiaoshan; Wang, Zhangwei; Ci, Zhijia

    2011-01-01

    To study the role of leaf litter in the mercury (Hg) cycle in suburban broadleaf forests and the distribution of Hg in urban forests, we collected leaf litter and soil from suburban evergreen and deciduous broadleaf forests and from urban forests in Beijing. The Hg concentrations in leaf litter from the suburban forests varied from 8.3 to 205.0 ng/g, with an average (avg) of (49.7 +/- 36.9) ng/g. The average Hg concentration in evergreen broadleaf forest leaf litter (50.8 + 39.4) ng/g was higher than that in deciduous broadleaf forest leaf litter (25.8 +/- 10.1) ng/g. The estimated Hg fluxes of leaf litter in suburban evergreen and deciduous broadleaf forests were 179.0 and 83.7 mg/(ha x yr), respectively. The Hg concentration in organic horizons (O horizons) ((263.1 +/- 237.2) ng/g) was higher than that in eluvial horizons (A horizons) ((83.9 +/- 52.0) ng/g). These results indicated that leaf litterfall plays an important role in transporting atmospheric mercury to soil in suburban forests. For urban forests in Beijing, the Hg concentrations in leaf litter ranged from 8.8-119.0 (avg 28.1 +/- 16.6) ng/g, with higher concentrations at urban sites than at suburban sites for each tree. The Hg concentrations in surface soil in Beijing were 32.0-25300.0 ng/g and increased from suburban sites to urban sites, with the highest value from Jingshan (JS) Park at the centre of Beijing. Therefore, the distribution of Hg in Beijing urban forests appeared to be strongly influenced by anthropogenic activities.

  19. Midday stomatal conductance is more related to stem rather than leaf water status in subtropical deciduous and evergreen broadleaf trees.

    PubMed

    Zhang, Yong-Jiang; Meinzer, Frederick C; Qi, Jin-Hua; Goldstein, Guillermo; Cao, Kun-Fang

    2013-01-01

    Midday depressions in stomatal conductance (g(s) ) and photosynthesis are common in plants. The aim of this study was to understand the hydraulic determinants of midday g(s) , the coordination between leaf and stem hydraulics and whether regulation of midday g(s) differed between deciduous and evergreen broadleaf tree species in a subtropical cloud forest of Southwest (SW) China. We investigated leaf and stem hydraulics, midday leaf and stem water potentials, as well as midday g(s) of co-occurring deciduous and evergreen tree species. Midday g(s) was correlated positively with midday stem water potential across both groups of species, but not with midday leaf water potential. Species with higher stem hydraulic conductivity and greater daily reliance on stem hydraulic capacitance were able to maintain higher stem water potential and higher g(s) at midday. Deciduous species exhibited significantly higher stem hydraulic conductivity, greater reliance on stem capacitance, higher stem water potential and g(s) at midday than evergreen species. Our results suggest that midday g(s) is more associated with midday stem than with leaf water status, and that the functional significance of stomatal regulation in these broadleaf tree species is probably for preventing stem xylem dysfunction.

  20. 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

  1. 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

  2. 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

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

    PubMed

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

    2010-12-01

    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

  4. 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

  5. Responses of leaf structure and photosynthetic properties to intra-canopy light gradients: a common garden test with four broadleaf deciduous angiosperm and seven evergreen conifer tree species.

    PubMed

    Wyka, Tomasz P; Oleksyn, J; Zytkowiak, R; Karolewski, P; Jagodziński, A M; Reich, P B

    2012-09-01

    Spectra of leaf traits in northern temperate forest canopies reflect major differences in leaf longevity between evergreen conifers and deciduous broadleaf angiosperms, as well as plastic modifications caused by within-crown shading. We investigated (1) whether long-lived conifer leaves exhibit similar intra-canopy plasticity as short-lived broadleaves, and (2) whether global interspecific relationships between photosynthesis, nitrogen, and leaf structure identified for sun leaves adequately describe leaves differentiated in response to light gradients. We studied structural and photosynthetic properties of intra-tree sun and shade foliage in adult trees of seven conifer and four broadleaf angiosperm species in a common garden in Poland. Shade leaves exhibited lower leaf mass-per-area (LMA) than sun leaves; however, the relative difference was smaller in conifers than in broadleaves. In broadleaves, LMA was correlated with lamina thickness and tissue density, while in conifers, it was correlated with thickness but not density. In broadleaves, but not in conifers, reduction of lamina thickness was correlated with a thinner palisade layer. The more conservative adjustment of conifer leaves could result from a combination of phylogenetic constraints, contrasting leaf anatomies and shoot geometries, but also from functional requirements of long-lived foliage. Mass-based nitrogen concentration (N(mass)) was similar between sun and shade leaves, and was lower in conifers than in deciduous broadleaved species. Given this, the smaller LMA in shade corresponded with a lower area-based N concentration (N(area)). In evergreen conifers, LMA and N(area) were less powerful predictors of area-based photosynthetic rate (A (max(area))) in comparison with deciduous broadleaved angiosperms. Multiple regression for sun and shade leaves showed that, in each group, A (max(mass)) was related to N(mass) but not to LMA, whereas LMA became a significant codeterminant of A (max(mass)) in

  6. 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.

  7. Edge effects enhance carbon uptake and its vulnerability to climate change in temperate broadleaf forests.

    PubMed

    Reinmann, Andrew B; Hutyra, Lucy R

    2017-01-03

    Forest fragmentation is a ubiquitous, ongoing global phenomenon with profound impacts on the growing conditions of the world's remaining forest. The temperate broadleaf forest makes a large contribution to the global terrestrial carbon sink but is also the most heavily fragmented forest biome in the world. We use field measurements and geospatial analyses to characterize carbon dynamics in temperate broadleaf forest fragments. We show that forest growth and biomass increase by 89 ± 17% and 64 ± 12%, respectively, from the forest interior to edge, but ecosystem edge enhancements are not currently captured by models or approaches to quantifying regional C balance. To the extent that the findings from our research represent the forest of southern New England in the United States, we provide a preliminary estimate that edge growth enhancement could increase estimates of the region's carbon uptake and storage by 13 ± 3% and 10 ± 1%, respectively. However, we also find that forest growth near the edge declines three times faster than that in the interior in response to heat stress during the growing season. Using climate projections, we show that future heat stress could reduce the forest edge growth enhancement by one-third by the end of the century. These findings contrast studies of edge effects in the world's other major forest biomes and indicate that the strength of the temperate broadleaf forest carbon sink and its capacity to mitigate anthropogenic carbon emissions may be stronger, but also more sensitive to climate change than previous estimates suggest.

  8. Winning and losing tree species of reassembly in Minnesota's mixed and broadleaf forests.

    PubMed

    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.

  9. 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

  10. 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

  11. Edge effects enhance carbon uptake and its vulnerability to climate change in temperate broadleaf forests

    PubMed Central

    Reinmann, Andrew B.; Hutyra, Lucy R.

    2017-01-01

    Forest fragmentation is a ubiquitous, ongoing global phenomenon with profound impacts on the growing conditions of the world’s remaining forest. The temperate broadleaf forest makes a large contribution to the global terrestrial carbon sink but is also the most heavily fragmented forest biome in the world. We use field measurements and geospatial analyses to characterize carbon dynamics in temperate broadleaf forest fragments. We show that forest growth and biomass increase by 89 ± 17% and 64 ± 12%, respectively, from the forest interior to edge, but ecosystem edge enhancements are not currently captured by models or approaches to quantifying regional C balance. To the extent that the findings from our research represent the forest of southern New England in the United States, we provide a preliminary estimate that edge growth enhancement could increase estimates of the region’s carbon uptake and storage by 13 ± 3% and 10 ± 1%, respectively. However, we also find that forest growth near the edge declines three times faster than that in the interior in response to heat stress during the growing season. Using climate projections, we show that future heat stress could reduce the forest edge growth enhancement by one-third by the end of the century. These findings contrast studies of edge effects in the world’s other major forest biomes and indicate that the strength of the temperate broadleaf forest carbon sink and its capacity to mitigate anthropogenic carbon emissions may be stronger, but also more sensitive to climate change than previous estimates suggest. PMID:27994137

  12. 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.

  13. 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

  14. 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.

  15. Microscale Pressure Fluctuations Within a Deciduous Forest

    NASA Astrophysics Data System (ADS)

    Sigmon, John Thomas

    Attempts to evaluate sources of errors in estimates of fluxes from forested surfaces have been thwarted by the lack of an accurate description of the nature of air flow within forest canopies. An important property of any boundary layer flow is the occurrence of pressure fluctuations at the boundary and within the flow. This study was designed to provide an understanding of the microscale pressure fluctuations within a forest canopy and the relationship between these fluctuations and the air flow within and above the forest canopy. Pressure fluctuations were measured using a method similar to that developed by J. A. Elliott in 1972. Measurements were taken at the ground and above a deciduous forest canopy. Time series, spectra, and cross-correlations were calculated under different canopy conditions, and relationships between surface pressure fluctuations and mean windspeeds were determined. Turbulent pressure fluctuations at the forest floor did not contain the higher frequencies found over smooth terrain and were continuously occurring at frequencies greater than 0.5 Hz. Somewhat higher frequencies and larger amplitudes occurred in the pressure fluctuations above the canopy after leaf emergence than at the surface. Horizontal length scales many times larger than the average spacing of the overstory trees were predominant. While both leaf emergence of flow-through from an adjacent field had an effect on the mean windspeed profiles, only the flow-through conditions had an effect on the relationship of mean windspeed above the canopy to pressure fluctuation variance at the surface. Pressure fluctuations at the surface appeared coupled at all times to those above the canopy and were directly related to windspeed above the canopy. Pressure eddies were advected downwind at speeds approximating the mean windspeed 6-8 meters above the canopy. Shapes of the pressure spectra were affected slightly by changes in windspeed, and comparisons of spectra above and below the

  16. 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.

  17. [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.

  18. 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

  19. 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

  20. [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⁺.

  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. Species coexistence in temperate, mixed deciduous forests.

    PubMed

    Nakashizuka, T

    2001-04-01

    The response of tree life-history traits to community profiles (horizontal and vertical heterogeneity, disturbances and biotic interactions) determines community assembly rules, which are currently a hot issue in community ecology. Important mechanisms of coexistence differ throughout the developing stages of tree life history. Many processes of niche partitioning and tradeoffs that potentially enable tree coexistence have been reported to be present in temperate forests, although some of these life-history traits are either correlated with each other or are not independent. Not all of the proposed mechanisms explain coexistence equally well; some could predominate in determining the community organization of forest communities. Population studies need to concentrate more on the component species of a target community to detect the ecological assembly rule. These approaches can also address how chance factors contribute to the composition of temperate tree communities, which might be less dependent on chance than are tropical ones.

  3. [Spatial heterogeneity of soil organic carbon and total nitrogen in a monsoon evergreen broadleaf forest in Dinghushan, Guangdong, China].

    PubMed

    Zhang, Ya-Ru; Ouyang, Xu; Chu, Guo-Wei; Zhang, Qian-Mei; Liu, Shi-Zhong; Zhang, De-Qiang; Li, Yue-Lin

    2014-01-01

    Geostatistical techniques were used to quantify the spatial heterogeneity of soil organic carbon and total nitrogen of one monsoon evergreen broadleaf forest area in Dinghushan, Guangdong, China. The results demonstrated that a significant spatial autocorrelation existed between soil organic carbon and total nitrogen contents in the Dinghushan monsoon evergreen broadleaf forest, such that 93.6% and 53.7% of their total spatial heterogeneity originated from their spatial autocorrelation. This observation agreed with a traditional statistics analysis showing a significant linear correlation between soil organic carbon and total nitrogen, and also their spatial autocorrelation existed at a landscape level. The best fit from an exponential model showed that soil organic carbon had high degree of spatial heterogeneity at a scale of 17.4 m.

  4. 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.

  5. 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

  6. 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).

  7. Multiresolution quantification of deciduousness in West-Central African forests

    NASA Astrophysics Data System (ADS)

    Viennois, G.; Barbier, N.; Fabre, I.; Couteron, P.

    2013-11-01

    The characterization of leaf phenology in tropical forests is of major importance for forest typology as well as to improve our understanding of earth-atmosphere-climate interactions or biogeochemical cycles. The availability of satellite optical data with a high temporal resolution has permitted the identification of unexpected phenological cycles, particularly over the Amazon region. A primary issue in these studies is the relationship between the optical reflectance of pixels of 1 km or more in size and ground information of limited spatial extent. In this paper, we demonstrate that optical data with high to very-high spatial resolution can help bridge this scale gap by providing snapshots of the canopy that allow discernment of the leaf-phenological stage of trees and the proportions of leaved crowns within the canopy. We also propose applications for broad-scale forest characterization and mapping in West-Central Africa over an area of 141 000 km2. Eleven years of the Moderate Resolution Imaging Spectroradiometer (MODIS) Enhanced Vegetation Index (EVI) data were averaged over the wet and dry seasons to provide a data set of optimal radiometric quality at a spatial resolution of 250 m. Sample areas covered at a very-high (GeoEye) and high (SPOT-5) spatial resolution were used to identify forest types and to quantify the proportion of leaved trees in the canopy. The dry-season EVI was positively correlated with the proportion of leaved trees in the canopy. This relationship allowed the conversion of EVI into canopy deciduousness at the regional level. On this basis, ecologically important forest types could be mapped, including young secondary, open Marantaceae, Gilbertiodendron dewevrei and swamp forests. We show that in West-Central African forests, a large share of the variability in canopy reflectance, as captured by the EVI, is due to variation in the proportion of leaved trees in the upper canopy, thereby opening new perspectives for biodiversity and

  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.

  9. Forest carbon uptake in North America's aging temperate deciduous forests: A data-theory-model mismatch?

    NASA Astrophysics Data System (ADS)

    Gough, C. M.; Curtis, P.; Bond-Lamberty, B. P.; Hardiman, B. S.; Scheuermann, C. M.; Nave, L. E.; Nadelhoffer, K. J.

    2015-12-01

    Century-old temperate deciduous forests in the US upper Midwest and Northeast power much of North America's terrestrial carbon sink, but these forests' carbon uptake capacity is expected to soon decline. But will this really happen? We marshal empirical data and ecological theory to show that declines in carbon uptake are not imminent in regrown temperate deciduous forests during coming decades, despite long-held assumptions and modeling results that predict declining carbon uptake during middle stages of ecosystem development. Age and production data for temperate deciduous forests, synthesized from published literature, do not provide evidence for declining net primary and ecosystem production (NPP and NEP, respectively) within the age-range most regional forests will occupy over the next half-century. Ecological theory suggests a mechanism for sustained carbon uptake in the region's aging forests in which high-frequency, low-severity disturbances maintain NPP and NEP by increasing ecosystem complexity. This theoretical model is supported by observations from the Forest Accelerated Succession Experiment in Michigan, USA, but such mechanisms sustaining production in old forests are not broadly represented in ecosystem models. Ecosystems experiencing low-frequency, high-severity disturbances that simplify ecosystem complexity do exhibit declining production during middle stages of succession, but we suggest that such scenarios have exerted a disproportionate influence on prevailing modeling and ecological assumptions regarding age-related declines in forest production. We conclude that there is wide ecological space for forests to sustain high rates of carbon uptake during middle stages of ecosystem development, and that advancing mechanistic understanding of long-term forest carbon cycle dynamics is essential to modeling the continent's future carbon sink strength.

  10. Multiresolution quantification of deciduousness in West Central African forests

    NASA Astrophysics Data System (ADS)

    Viennois, G.; Barbier, N.; Fabre, I.; Couteron, P.

    2013-04-01

    The characterization of leaf phenology in tropical forests is of major importance and improves our understanding of earth-atmosphere-climate interactions. The availability of satellite optical data with a high temporal resolution has permitted the identification of unexpected phenological cycles, particularly over the Amazon region. A primary issue in these studies is the relationship between the optical reflectance of pixels of 1 km or more in size and ground information of limited spatial extent. In this paper, we demonstrate that optical data with high to very-high spatial resolution can help bridge this scale gap by providing snapshots of the canopy that allow discernment of the leaf-phenological stage of trees and the proportions of leaved crowns within the canopy. We also propose applications for broad-scale forest characterization and mapping in West Central Africa over an area of 141 000 km2. Eleven years of the Moderate Resolution Imaging Spectroradiometer (MODIS) Enhanced Vegetation Index (EVI) data were averaged over the wet and dry seasons to provide a dataset of optimal radiometric quality at a spatial resolution of 250 m. Sample areas covered at a very-high (GeoEye) and high (SPOT-5) spatial resolution were used to identify forest types and to quantify the proportion of leaved trees in the canopy. The dry season EVI was positively correlated with the proportion of leaved trees in the canopy. This relationship allowed the conversion of EVI into canopy deciduousness at the regional level. On this basis, ecologically important forest types could be mapped, including young secondary, open Marantaceae, Gilbertiodendron dewevrei and swamp forests. We show that in west central African forests, a large share of the variability in canopy reflectance, as captured by the EVI, is due to variation in the proportion of leaved trees in the upper canopy, thereby opening new perspectives for biodiversity and carbon-cycle applications.

  11. 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.

  12. Ultrafine particle number fluxes over and in a deciduous forest

    NASA Astrophysics Data System (ADS)

    Pryor, S. C.; Barthelmie, R. J.; Larsen, S. E.; Sørensen, L. L.

    2017-01-01

    Ultrafine particles (UFP, particles with diameters (Dp) < 100 nm) play a key role in climate forcing; thus, there is interest in improved understanding of atmosphere-surface exchange of these particles. Long-term flux measurements from a deciduous forest in the Midwestern USA (taken during December 2012 to May 2014) show that although a substantial fraction of the data period indicates upward fluxes of UFP, on average, the forest is a net sink for UFP during both leaf-active and leaf-off periods. The overall mean above-canopy UFP number flux computed from this large data set is -4.90 × 106 m-2 s-1 which re-emphasizes the importance of these ecosystems to UFP removal from the atmosphere. Although there remain major challenges to accurate estimation of the UFP number flux and in drawing inferences regarding the actual surface exchange from measurements taken above the canopy, the above the canopy mean flux is shown to be downward throughout the day (except at 23.00) with largest-magnitude fluxes during the middle of the day. On average, nearly three quarters of the total UFP capture by this ecosystem occurs at the canopy. This fraction increases to 78% during the leaf-active period, but the over-storey remains dominant over the subcanopy even during the leaf-off period.

  13. Interannual variability in ozone removal by a temperate deciduous forest

    NASA Astrophysics Data System (ADS)

    Clifton, O. E.; Fiore, A. M.; Munger, J. W.; Malyshev, S.; Horowitz, L. W.; Shevliakova, E.; Paulot, F.; Murray, L. T.; Griffin, K. L.

    2017-01-01

    The ozone (O3) dry depositional sink and its contribution to observed variability in tropospheric O3 are both poorly understood. Distinguishing O3 uptake through plant stomata versus other pathways is relevant for quantifying the O3 influence on carbon and water cycles. We use a decade of O3, carbon, and energy eddy covariance (EC) fluxes at Harvard Forest to investigate interannual variability (IAV) in O3 deposition velocities (vd,O3). In each month, monthly mean vd,O3 for the highest year is twice that for the lowest. Two independent stomatal conductance estimates, based on either water vapor EC or gross primary productivity, vary little from year to year relative to canopy conductance. We conclude that nonstomatal deposition controls the substantial observed IAV in summertime vd,O3 during the 1990s over this deciduous forest. The absence of obvious relationships between meteorology and vd,O3 implies a need for additional long-term, high-quality measurements and further investigation of nonstomatal mechanisms.

  14. 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.

  15. Does selective logging change ground-dwelling beetle assemblages in a subtropical broad-leafed forest of China?

    PubMed

    Yu, Xiao-Dong; Liu, Chong-Ling; Lü, Liang; Bearer, Scott L; Luo, Tian-Hong; Zhou, Hong-Zhang

    2017-04-01

    Selective logging with natural regeneration is advocated as a near-to-nature strategy and has been implemented in many forested systems during the last decades. However, the efficiency of such practices for the maintenance of forest species are poorly understood. We compared the species richness, abundance and composition of ground-dwelling beetles between selectively logged and unlogged forests to evaluate the possible effects of selective logging in a subtropical broad-leafed forest in southeastern China. Using pitfall traps, beetles were sampled in two naturally regenerating stands after clearcuts (ca. 50 years old, stem-exclusion stage: selectively logged 20 years ago) and two mature stands (> 80 years old, understory re-initiation stage: selectively logged 50 years ago) during 2009 and 2010. Overall, selective logging had no significant effects on total beetle richness and abundance, but saproxylic species group and some abundant forest species significantly decreased in abundance in selectively logged plots compared with unlogged plots in mature stands. Beetle assemblages showed significant differences between selectively logged and unlogged plots in mature stands. Some environmental characteristics associated with selective logging (e.g., logging strategy, stand age, and cover of shrub and moss layers) were the most important variables explaining beetle assemblage structure. Our results conclude that selective logging has no significant impacts on overall richness and abundance of ground-dwelling beetles. However, the negative effects of selective logging on saproxylic species group and some unlogged forest specialists highlight the need for large intact forested areas for sustaining the existence of forest specialist beetles.

  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.

  17. 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)...

  18. Within-canopy sampling of global irradiance to describe downwelling light distribution and infer canopy stratification in a broadleaf forest.

    PubMed

    Giuliani, Rita; Brown, Kim J

    2008-09-01

    A broadleaf mixed forest diversified through partial tree thinning was studied to identify expedient sampling and data analysis procedures to capture the heterogeneous within-canopy downward distribution of instantaneous global photosynthetic photon flux (PPF); to extract foliage structural properties from the acquired light values; and to compute statistics descriptive of the within-canopy light and leaf layer distributions. We sampled PPF at 1-m intervals along vertical gradients using a helium-filled balloon as a platform for a light sensor. A random method was used to identify the forest floor locations for the within-canopy balloon ascents. About 400 PPF measurements were recorded per vertical transect. For each PPF value, we computed, by inversion of the Monsi-Saeki model, the number of leaf strata cumulated along the sunbeam direction from the position where the light was measured. Variability in PPF and leaf layer at different vegetation scales was computed by non-parametric statistics. The methods were evaluated as appropriate for intra-canopy PPF sampling, particularly in an undisturbed canopy. The minimum number of vertical PPF profiles required to capture the within-canopy PPF variability was 9-10 (equivalent to about 4000 measurements). The reliability and sensitivity of the inversion of the Monsi-Saeki method were sufficient to capture the canopy structural differences between undisturbed and partially thinned forests. The proposed PPF canopy sampling and data analysis procedures provide a fast, reliable and inexpensive way to characterize tree crown structure, and to predict plant growth and forest dynamics and could be applied whenever vegetation absorbed radiation is a main driving force for forest canopy processes. The experimental light attenuation data and the extracted canopy leaf layer numbers could serve to corroborate canopy mechanistic models of radiative transfer and net primary production.

  19. Forest-to-pasture conversion influences on soil organic carbon dynamics in a tropical deciduous forest.

    PubMed

    García-Oliva, Felipe; Casar, Isabel; Morales, Pedro; Maass, José M

    1994-09-01

    On a global basis, nearly 42% of tropical land area is classified as tropical deciduous forest (TDF) (Murphy and Lugo 1986). Currently, this ecosystem has very high deforestation rates; and its conversion to cattle pasture may result in losses of soil organic matter, decreases in soil fertility, and increases in CO2 flux to the atmosphere. The soil organic matter turnover rate in a TDF after pasture conversion was estimated in Mexico by determining natural abundances of(13)C. Changes in these values would be induced by vegetation changes from the C3 (forest) to the C4 (pasture) photosynthetic pathway. The rate of loss of remnant forest-soil organic matter (fSOM) was 2.9 t ha(-1) year(-1) in 7-year-old pasture and decreased to 0.66 t ha(-1) year(-1) by year 11. For up to 3 years, net fSOM level increased in pastures; this increment can be attributed to decomposition of remnant forest roots. The sand-associated SOM fraction was the most and the silt-associated fraction the least depleted. TDF conversion to pasture results in extremely high rates of loss of remnant fSOM that are higher than any reported for any tropical forest.

  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. 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.

  2. 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.

  3. Nutrient translocation in the outer canopy and understory of an eastern deciduous forest

    SciTech Connect

    Luxmoore, R.J.; Grizzard, T.; Strand, R.H.

    1981-09-01

    The translocation of nutrients into and out of outer canopy leaves of ten eastern deciduous forest species was calculated from the temporal patterns of foliar nutrient pools sampled through a growing season. The calculations accounted for average chemical leaching effects due to rainfall. There were no significant differences in translocation rate between species within the evergreen, understory, or overstory-deciduous tree groups. Evergreen species had lower translocation rates than deciduous trees. Translocation rates into leaves of deciduous species showed a very rapid increase during spring; however, by late May, foliar phosphorus was being translocated at a slow rate back to stems. A similar trend was established for nitrogen by mid-June. An internal storage pool is suggested as the major source of foliar nitrogen during the spring flush since a simulation of nitrogen uptake from soil could only account for one-fourth of the quantity of nitrogen transported to leaves by the end of May. Simulation further showed that trace levels of soluble nitrogen (0.01 ppm) in soil were sufficient to supply a deciduous forest with an estimated nitrogen uptake of 100 kg N ha/sup -1/ year/sup -1/.

  4. 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.

  5. 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

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

    PubMed

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

    2015-11-03

    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.

  7. 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.

  8. Sampling design and required sample size for evaluating contamination levels of (137)Cs in Japanese fir needles in a mixed deciduous forest stand in Fukushima, Japan.

    PubMed

    Oba, Yurika; Yamada, Toshihiro

    2017-05-01

    We estimated the sample size (the number of samples) required to evaluate the concentration of radiocesium ((137)Cs) in Japanese fir (Abies firma Sieb. & Zucc.), 5 years after the outbreak of the Fukushima Daiichi Nuclear Power Plant accident. We investigated the spatial structure of the contamination levels in this species growing in a mixed deciduous broadleaf and evergreen coniferous forest stand. We sampled 40 saplings with a tree height of 150 cm-250 cm in a Fukushima forest community. The results showed that: (1) there was no correlation between the (137)Cs concentration in needles and soil, and (2) the difference in the spatial distribution pattern of (137)Cs concentration between needles and soil suggest that the contribution of root uptake to (137)Cs in new needles of this species may be minor in the 5 years after the radionuclides were released into the atmosphere. The concentration of (137)Cs in needles showed a strong positive spatial autocorrelation in the distance class from 0 to 2.5 m, suggesting that the statistical analysis of data should consider spatial autocorrelation in the case of an assessment of the radioactive contamination of forest trees. According to our sample size analysis, a sample size of seven trees was required to determine the mean contamination level within an error in the means of no more than 10%. This required sample size may be feasible for most sites.

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

    DOE PAGES

    Gu, Lianhong; Huang, Ni; Black, T. Andrew; ...

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

    DOE PAGES

    Young-Robertson, Jessica M.; Bolton, W. Robert; Bhatt, Uma S.; ...

    2016-07-12

    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 Yukonmore » 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. Furthermore, 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.« less

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

    SciTech Connect

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

    2016-07-12

    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. Furthermore, 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.

  12. 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.

  13. 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

    2016-07-12

    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.

  14. 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

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

    USGS Publications Warehouse

    Young, Jessica; Bolton, W. Robert; Bhatt, Uma; Cristobal, 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.

  16. 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

  17. Herbivory among habitats on the Neotropical tree Cnidoscolus quercifolius Pohl. in a seasonally deciduous forest.

    PubMed

    Coelho, M S; Belmiro, M S; Santos, J C; Fernandes, G W

    2012-08-01

    Our goal was to identify herbivory patterns from two insect guilds associated with Cnidoscolus quercifolius in a tropical deciduous forest in northeastern Brazil. We sampled four different habitats: (1) forest edge, (2) mesic (near to the perennial water source), (3) forest interior and (4) rupestrian fields. Habitat edge had lower leaf damage than rupestrian, mesic and forest interior habitats. Nevertheless, abundance of galls at the edge habitat was higher than at mesic, forest interior and/or rupestrian habitats. There was no difference in gall mortality by natural enemies among the four habitats sampled, demonstrating the absence of any influence of top-down controls related to abundance of galls. Trophic relationships were not related to the patterns of distribution among habitats of two insect herbivorous guilds associated with C. quercifolius. Our results demonstrated that environmental heterogeneity of dry forests can significantly alter important ecological interactions and experimental studies are needed to better understand the mechanisms responsible for differences in herbivory among habitats.

  18. Enhancement of understory productivity by asynchronous phenology with overstory competitors in a temperate deciduous forest.

    PubMed

    Jolly, William M; Nemani, Ramakrishna; Running, Steven W

    2004-09-01

    Some saplings and shrubs growing in the understory of temperate deciduous forests extend their periods of leaf display beyond that of the overstory, resulting in periods when understory radiation, and hence productivity, are not limited by the overstory canopy. To assess the importance of the duration of leaf display on the productivity of understory and overstory trees of deciduous forests in the north eastern United States, we applied the simulation model, BIOME-BGC with climate data for Hubbard Brook Experimental Forest, New Hampshire, USA and mean ecophysiological data for species of deciduous, temperate forests. Extension of the overstory leaf display period increased overstory leaf area index (LAI) by only 3 to 4% and productivity by only 2 to 4%. In contrast, extending the growing season of the understory relative to the overstory by one week in both spring and fall, increased understory LAI by 35% and productivity by 32%. A 2-week extension of the growing period in both spring and fall increased understory LAI by 53% and productivity by 55%.

  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.

  20. Variation in throughfall deposition across a deciduous beech (Fagus sylvatica L.) forest edge in Flanders.

    PubMed

    Devlaeminck, Rebecca; De Schrijver, An; Hermy, Martin

    2005-01-20

    Throughfall deposition and canopy exchange of acidifying and eutrophying compounds and major base cations were studied by means of throughfall analysis in a deciduous beech (Fagus sylvatica L.) forest edge in Belgium over a period of 1 year. Throughfall fluxes of Cl(-), NH(4)(+) and Na(+) were significantly elevated at the forest edge compared to the forest interior. As no edge effect on throughfall water volume could be detected, the observed edge enhancement effects were mainly due to dry deposition and canopy exchange patterns. Indeed, there was an elevated dry deposition of Cl(-), Na(+), K(+), Ca(2+) and Mg(2+) up to 50 m from the field/forest border. Within the forest, throughfall and dry deposition of SO(4)(2-) were highly variable and no significant differences were observed between the forest edge and the forest interior. Leaching of K(+) and Ca(2+) was reduced in the forest edge up to a distance of 30 m from the border. The measured nitrogen and acidic depositions far exceeded the current Flemish critical loads with respect to the protection of biodiversity in forests, especially at the forest edge. This points to an urgent need for controlling emissions as well as the need to consider the elevated deposition load in forest edges when calculating the critical loads in forests.

  1. Ecohydrologic implications of differences in throughfall between hemlock and deciduous forest plots, West Whately, MA

    NASA Astrophysics Data System (ADS)

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

    2009-12-01

    Invasive pests, especially in conjunction with climate change, have the potential to transform the species composition of many forests. In the northeastern United States, the hemlock woolly adelgid poses a significant threat to eastern hemlock (Tsuga Canadensis), a tree known for its ecological role more than its timber value. To begin to assess the effect on the water cycle of converting hemlock to deciduous forest, we carried out a throughfall investigation in West Whately, MA during the summer of 2009. From 3 June to 25 July, we measured the volume and chemistry of throughfall in two forest plots: one dominated by hemlock (LAI = 5.6) and one comprising a variety of deciduous species (LAI = 4.7), including many saplings and sub-canopy trees. Over the period of the study, rainfall totaled 311 mm and throughfall amounted to 276 mm (89%) in the deciduous plot and 242 mm (78%) in the hemlock stand. When compared to open precipitation, throughfall from both plots showed significantly higher levels of acid neutralizing capacity, pH, and concentrations of K+, Ca2+, and Mg2+. On an event-by-event basis, the fraction of precipitation that shows up as throughfall increases with amount, and representing interception as a constant depth, Δ, provides a reasonable fit (Δdeciduous = 2.5 mm, R2 = 0.99; Δhemlock = 5 mm, R2 = 0.96). Analysis of variance and time-stability plots indicate a strong persistent effect of collector position on throughfall depth, leading to potential efficiencies in measurement strategies. In both stands, the spatial variability of throughfall depths is higher for lower intensity events, and the coefficient of variation has a value around 30% for larger events. The skewness of throughfall depths among collectors within the hemlock plot is generally small. Throughfall depths are positively skewed in the deciduous plot, and one collector consistently received throughfall equal to twice the incident rainfall. Should hemlock stands be eliminated and

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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...

  7. Disturbance, complexity, and succession of net ecosystem production in North America’s temperate deciduous forests

    SciTech Connect

    Gough, Christopher; Curtis, Peter; Hardiman, Brady; Scheuermann, Cynthia; Bond-Lamberty, Benjamin

    2016-06-29

    Century-old forests in the U.S. upper Midwest and Northeast power much of North Amer- ica’s terrestrial carbon (C) sink, but these forests’ production and C sequestration capacity are expected to soon decline as fast-growing early successional species die and are replaced by slower growing late successional species. But will this really happen? Here we marshal empirical data and ecological theory to argue that substantial declines in net ecosystem production (NEP) owing to reduced forest growth, or net primary production (NPP), are not imminent in regrown temperate deciduous forests over the next several decades. Forest age and production data for temperate deciduous forests, synthesized from published literature, suggest slight declines in NEP and increasing or stable NPP during middle successional stages. We revisit long-held hypotheses by EP Odum and others that suggest low-severity, high-frequency disturbances occurring in the region’s aging forests will, against intuition, maintain NEP at higher-than- expected rates by increasing ecosystem complexity, sustaining or enhancing NPP to a level that largely o sets rising C losses as heterotrophic respiration increases. This theoretical model is also supported by biological evidence and observations from the Forest Accelerated Succession Experiment in Michigan, USA. Ecosystems that experience high-severity disturbances that simplify ecosystem complexity can exhibit substantial declines in production during middle stages of succession. However, observations from these ecosystems have exerted a disproportionate in uence on assumptions regarding the trajectory and magnitude of age-related declines in forest production. We conclude that there is a wide ecological space for forests to maintain NPP and, in doing so, lessens the declines in NEP, with signi cant implications for the future of the North American carbon sink. Our intellectual frameworks for understanding forest C cycle dynamics and resilience need to

  8. Seasonal variation of temperature response of respiration in invasive Berberis thunbergii (Japanese barberry) and two co-occurring native understory shrubs in a northeastern US deciduous forest.

    PubMed

    Xu, Cheng-Yuan; Schuster, W S F; Griffin, Kevin L

    2007-10-01

    In the understory of a closed forest, plant growth is limited by light availability, and early leafing is proposed to be an important mechanism of plant invasion by providing a spring C "subsidy" when high light is available. However, studies on respiration, another important process determining plant net C gain, are rare in understory invasive plants. In this study, leaf properties and the temperature response of leaf respiration were compared between invasive Berberis thunbergii, an early leafing understory shrub, and two native shrubs, Kalmia latifolia, a broadleaf evergreen and Vaccinium corymbosum, a late-leafing deciduous species, in an oak-dominated deciduous forest. The seasonal trend of the basal respiration rates (R(0)) and the temperature response coefficient (E(0)), were different among the three shrubs and species-specific negative correlations were observed between R(0) and E(0). All three shrubs showed significant correlation between respiration rate on an area basis (20 degrees C) and leaf N on an area basis. The relationship was attributed to the variation of both leaf N on a mass basis and leaf mass per area (LMA) in B. thunbergii, but to LMA only in K. latifolia and V. corymbosum. After modeling leaf respiration throughout 2004, B. thunbergii displayed much higher annual leaf respiration (mass based) than the two native shrubs, indicating a higher cost per unit of biomass investment. Thus, respiratory properties alone were not likely to lead to C balance advantage of B. thunbergii. Future studies on whole plant C budgets and leaf construction cost are needed to address the C balance advantage in early leafing understory shrubs like B. thunbergii.

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

    SciTech Connect

    Stitt, Caroline R.

    2013-09-16

    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 a unique radiocarbon (14C) tracer. Results from the dark incubation of organic and mineral soils are heavily influenced by site characteristics when incubated at optimal microbial activity temperature. Sites with considerable differences in temperature, texture, and location differ in carbon source attribution, indicating that site characteristics play a role in soil respiration.

  10. Vegetation recovery on closed paths in temperate deciduous forests.

    PubMed

    Roovers, Pieter; Bossuyt, Beatrijs; Gulinck, Hubert; Hermy, Martin

    2005-02-01

    The objective of this study was to evaluate vegetation recovery on footpaths in woodland that have been closed for access for 6 years. A vegetation survey was conducted in four mesophile forests, in transects perpendicular to the trail. Analyses concentrated on the direction and rate of the recovery process. Vegetation on trail sides in these ecosystems recovered substantially. Non-metric multidimensional scaling based upon species composition separated the four sample locations and each cluster contained representatives of the three major trail zones: path centre, transition and undisturbed zones. Analysis of distribution of life forms, plant strategies and seedbank longevity indices showed no differences between trail zones. This indicates that vegetation on the path centre is likely to recover towards the plant composition of the undisturbed zone. Ellenberg values indicate that environmental variation is not related to former path structures, as significant variability was only observed between the forest sites. Furthermore, the analysis concentrated on characteristics of species relevant to the recovery process.

  11. 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.

  12. Resource partitioning by evergreen and deciduous species in a tropical dry forest.

    PubMed

    Álvarez-Yépiz, Juan C; Búrquez, Alberto; Martínez-Yrízar, Angelina; Teece, Mark; Yépez, Enrico A; Dovciak, Martin

    2017-02-01

    Niche differentiation can lead to coexistence of plant species by partitioning limiting resources. Light partitioning promotes niche differentiation in tropical humid forests, but it is unclear how niche partitioning occurs in tropical dry forests where both light and soil resources can be limiting. We studied the adult niche of four dominant evergreen (cycad, palm) and drought-deciduous (legume, oak) species co-occurring along environmental gradients. We analyzed light intensity and soil fertility effects on key functional traits related to plant carbon and water economy, how these traits determine species' functional strategies, and how these strategies relate to relative species abundance and spatial patterns. Light intensity was negatively associated with a key trait linked to plant water economy (leaf δ (13) C, a proxy for long-term water-use efficiency-WUE), while soil fertility was negatively associated with a key trait for plant carbon economy (LNC, leaf nitrogen content). Evergreens were highly sclerophyllous and displayed an efficient water economy but poor carbon economy, in agreement with a conservative resource-use strategy (i.e., high WUE but low LNC, photosynthetic rates and stature). Conversely, deciduous species, with an efficient carbon economy but poor water economy, exhibited an exploitative resource-use strategy (i.e., high LNC, photosynthetic rates and stature, but low WUE). Evergreen and deciduous species segregated spatially, particularly at fine-scales, as expected for species with different resource-use strategies. The efficient water economy of evergreens was related to their higher relative abundance, suggesting a functional advantage against drought-deciduous species in water-limited environments within seasonally dry tropical forests.

  13. 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

  14. 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.

  15. Identification, distribution, and quantification of biominerals in a deciduous forest.

    PubMed

    Krieger, C; Calvaruso, C; Morlot, C; Uroz, S; Salsi, L; Turpault, M-P

    2017-03-01

    Biomineralization is a common process in most vascular plants, but poorly investigated for trees. Although the presence of calcium oxalate and silica accumulation has been reported for some tree species, the chemical composition, abundance, and quantification of biominerals remain poorly documented. However, biominerals may play important physiological and structural roles in trees, especially in forest ecosystems, which are characterized by nutrient-poor soils. In this context, our study aimed at investigating the morphology, distribution, and relative abundance of biominerals in the different vegetative compartments (foliage, branch, trunk, and root) of Fagus sylvatica L. and Acer pseudoplatanus L. using a combination of scanning electron microscopy and tomography analyses. Biomineral crystallochemistry was assessed by X-ray diffraction and energy-dispersive X-ray analyses, while calcium, silicon, and oxalic acid were quantified in the compartments and at the forest scale. Our analyses revealed that biominerals occurred as crystals or coating layers mostly in bark and leaves and were identified as opal, whewellite, and complex biominerals. In both tree species, opal was mostly found in the external tissues of trunk, branch, and leaves, but also in the roots of beech. In the stand, opal represents around 170 kg/ha. Whewellite was found to suit to conductive tissues (i.e., axial phloem parenchyma, vascular bundles, vessel element) in all investigated compartments of the two tree species. The shape of whewellite was prismatic and druses in beech, and almost all described shapes were seen in sycamore maple. Notably, the amount of whewellite was strongly correlated with the total calcium in all investigated compartments whatever the tree species is, suggesting a biologic control of whewellite precipitation. The amount of whewellite in the aboveground biomass of Montiers forest was more important than that of opal and was around 1170 kg/ha. Therefore, biominerals

  16. Changes of ndvi across vertical canopy layers in temperate deciduous forest during a litterfall period

    NASA Astrophysics Data System (ADS)

    Kim, J. M.; Ryu, Y.

    2015-12-01

    Normalized Difference Vegetation Index (NDVI) is a key variable indicating changes in vegetation dynamics and carbon flux. Previous studies have paid little attention to the changes in NDVI during litterfall period. In this study, we report the changes of NDVI across vertical canopy layers in a temperate deciduous forest during a litterfall period. To monitor changes in canopy structure, functions, and spectral properties during the litterfall period, we combined automatic observations of NDVI derived from LED-spectral sensors and LAI derived from digital cover photography installed at multiple canopy layer depths. Furthermore, we collected hyperspectral optical properties of leaves across multiple canopy layers and hyperspectral reflectance of forest background using ASD-FieldSpec. We found that NDVI in forest floor became greater than the NDVI measured from the top of canopy during the litterfall period. We discuss what satellite-derived NDVI exactly sees during the litterfall period, which will be useful to better understand forest autumn phenology at large scales.

  17. Nitrogen Deposition to and Cycling in a Deciduous Forest

    DOE PAGES

    Pryor, Sara C.; Barthelmie, Rebecca J.; Carreiro, Margaret; ...

    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

  18. 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.

  19. 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.

  20. Mollusc grazing limits growth and early development of the old forest lichen Lobaria pulmonaria in broadleaved deciduous forests.

    PubMed

    Asplund, Johan; Gauslaa, Yngvar

    2008-02-01

    THIS STUDY AIMS: (1) to quantify mollusc grazing on juvenile and mature thalli of the foliose epiphytic lichen Lobaria pulmonaria, and (2) to test the hypothesis inferring a herbivore defensive role of lichen depsidones in forests with indigenous populations of lichen-feeding molluscs. Lichens were transplanted in shaded and less shaded positions in each of two calcareous broadleaved deciduous forests, one poor in lichens, one with a rich Lobarion community. Preventing the access of molluscs significantly reduced the loss of juvenile L. pulmonaria, particularly in the naturally lichen-poor forest. Molluscs also severely grazed mature thalli in the lichen-poor forest, especially thalli placed under the more shading canopies. Furthermore, reducing the natural concentration of depsidones by pre-rinsing with acetone increased subsequent grazing significantly, showing that lichen depsidones function as herbivore defence in natural habitats. Our results suggest that mollusc grazing may play important roles in shaping the epiphytic vegetation in calcareous deciduous forests, and that recently established juvenile L. pulmonaria thalli seem to be particularly vulnerable.

  1. 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.

  2. 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

    2015-05-06

    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.

  3. 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

  4. 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

  5. Extended leaf phenology and the autumn niche in deciduous forest invasions.

    PubMed

    Fridley, Jason D

    2012-05-17

    The phenology of growth in temperate deciduous forests, including the timing of leaf emergence and senescence, has strong control over ecosystem properties such as productivity and nutrient cycling, and has an important role in the carbon economy of understory plants. Extended leaf phenology, whereby understory species assimilate carbon in early spring before canopy closure or in late autumn after canopy fall, has been identified as a key feature of many forest species invasions, but it remains unclear whether there are systematic differences in the growth phenology of native and invasive forest species or whether invaders are more responsive to warming trends that have lengthened the duration of spring or autumn growth. Here, in a 3-year monitoring study of 43 native and 30 non-native shrub and liana species common to deciduous forests in the eastern United States, I show that extended autumn leaf phenology is a common attribute of eastern US forest invasions, where non-native species are extending the autumn growing season by an average of 4 weeks compared with natives. In contrast, there was no consistent evidence that non-natives as a group show earlier spring growth phenology, and non-natives were not better able to track interannual variation in spring temperatures. Seasonal leaf production and photosynthetic data suggest that most non-native species capture a significant proportion of their annual carbon assimilate after canopy leaf fall, a behaviour that was virtually absent in natives and consistent across five phylogenetic groups. Pronounced differences in how native and non-native understory species use pre- and post-canopy environments suggest eastern US invaders are driving a seasonal redistribution of forest productivity that may rival climate change in its impact on forest processes.

  6. 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.

  7. [Effects of simulated nitrogen deposition on soil respiration in northern subtropical deciduous broad-leaved forest].

    PubMed

    Hu, Zheng-hua; Li, Han-mao; Yang, Yan-ping; Chen, Shu-tao; Li, Cen-zi; Shen, Shuang-he

    2010-08-01

    To investigate the effects of elevated nitrogen deposition on forest soil respiration, a simulated nitrogen deposition field experiment was conducted in northern subtropical deciduous broad-leave forest from April 2008 to April 2009. Nitrogen treatments included the control (no N addition, CK), low-N [50 kg x (hm2 x a)(-1), T(L)], medium-N [100 kg x (hm2 x a)(-1), T(M)], and high-N [150 kg x (hm2 x a)(-1), T(H)]. The respiration rates were measured by a static chamber-gas chromatograph method. Results showed that nitrogen deposition did not change the seasonal and daily variation patterns of soil respiration. Compared to the control, T(L), T(M) and T(H) treatments reduced soil annual average respiration rates by 8.51%, 9.74% and 11.24%, respectively. Meanwhile, T(L), T(M) and T(H) treatments decreased daily average soil respiration rates by 4.42%, 11.09% and 12.17%, respectively. Significant relationship was found between soil respiration rate and soil temperature. The Q10 (temperature sensitivity coefficients) for soil respiration of CK, T(L), T(M), and T(H) treatments were 2.53, 3.22, 2.64 and 2.92, respectively. Our findings suggested that nitrogen deposition reduced soil respiration, and increased soil respiration temperature sensitivity in northern subtropical deciduous broad-leave forest.

  8. 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.

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

    PubMed

    Migliavacca, Mirco; Reichstein, Markus; Richardson, Andrew D; Mahecha, Miguel D; Cremonese, Edoardo; Delpierre, Nicolas; Galvagno, Marta; Law, Beverly E; Wohlfahrt, Georg; Black, T Andrew; Carvalhais, Nuno; Ceccherini, Guido; Chen, Jiquan; Gobron, Nadine; Koffi, Ernest; Munger, J William; Perez-Priego, Oscar; Robustelli, Monica; Tomelleri, Enrico; Cescatti, Alessandro

    2015-01-01

    Understanding the environmental and biotic drivers of respiration at the ecosystem level is a prerequisite to further improve scenarios of the global carbon cycle. In this study we investigated the relevance of physiological phenology, defined as seasonal changes in plant physiological properties, for explaining the temporal dynamics of ecosystem respiration (RECO) in deciduous forests. Previous studies showed that empirical RECO models can be substantially improved by considering the biotic dependency of RECO on the short-term productivity (e.g., daily gross primary production, GPP) in addition to the well-known environmental controls of temperature and water availability. Here, we use a model-data integration approach to investigate the added value of physiological phenology, represented by the first temporal derivative of GPP, or alternatively of the fraction of absorbed photosynthetically active radiation, for modeling RECO at 19 deciduous broadleaved forests in the FLUXNET La Thuile database. The new data-oriented semiempirical model leads to an 8% decrease in root mean square error (RMSE) and a 6% increase in the modeling efficiency (EF) of modeled RECO when compared to a version of the model that does not consider the physiological phenology. The reduction of the model-observation bias occurred mainly at the monthly time scale, and in spring and summer, while a smaller reduction was observed at the annual time scale. The proposed approach did not improve the model performance at several sites, and we identified as potential causes the plant canopy heterogeneity and the use of air temperature as a driver of ecosystem respiration instead of soil temperature. However, in the majority of sites the model-error remained unchanged regardless of the driving temperature. Overall, our results point toward the potential for improving current approaches for modeling RECO in deciduous forests by including the phenological cycle of the canopy.

  10. 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.

  11. 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

  12. Spatial pulses of water inputs in deciduous and hemlock forest stands

    NASA Astrophysics Data System (ADS)

    Guswa, A. J.; Mussehl, M.; Pecht, A.; Spence, C.

    2010-12-01

    Trees intercept and redistribute precipitation in time and space. While spatial patterns of throughfall are challenging to link to plant and canopy characteristics, many studies have shown that the spatial patterns persist through time. This persistence leads to wet and dry spots under the trees, creating spatial pulses of moisture that can affect infiltration, transpiration, and biogeochemical processes. In the northeast, the invasive hemlock woolly adelgid poses a significant threat to eastern hemlock (Tsuga canadensis), and replacement of hemlock forests by other species, such as birch, maple, and oak, has the potential to alter throughfall patterns and hydrologic processes. During the summers of 2009 and 2010, we measured throughfall in both hemlock and deciduous plots to assess its spatial distribution and temporal persistence. From 3 June to 25 July 2009, we measured throughfall in one hemlock and one deciduous plot over fourteen events with rainfall totaling 311 mm. From 8 June through 28 July 2010, we measured throughfall in the same two plots plus an additional hemlock stand and a young black birch stand, and rainfall totaled 148 mm over eight events. Averaged over space and time, throughfall was 81% of open precipitation in the hemlock stands, 88% in the mixed deciduous stand, and 100% in the young black birch stand. On an event basis, spatial coefficients of variation are similar among the stands and range from 11% to 49% for rain events greater than 5 mm. With the exception of very light events, coefficients of variation are insensitive to precipitation amount. Spatial patterns of throughfall persist through time, and seasonal coefficients of variation range from 13% to 33%. All stands indicate localized concentrations of water inputs, and there were individual collectors in the deciduous stands that regularly received more than twice the stand-average throughfall.

  13. 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

  14. [NDVI difference rate recognition model of deciduous broad-leaved forest based on HJ-CCD remote sensing data].

    PubMed

    Wang, Yan; Tian, Qing-Jiu; Huang, Yan; Wei, Hong-Wei

    2013-04-01

    The present paper takes Chuzhou in Anhui Province as the research area, and deciduous broad-leaved forest as the research object. Then it constructs the recognition model about deciduous broad-leaved forest was constructed using NDVI difference rate between leaf expansion and flowering and fruit-bearing, and the model was applied to HJ-CCD remote sensing image on April 1, 2012 and May 4, 2012. At last, the spatial distribution map of deciduous broad-leaved forest was extracted effectively, and the results of extraction were verified and evaluated. The result shows the validity of NDVI difference rate extraction method proposed in this paper and also verifies the applicability of using HJ-CCD data for vegetation classification and recognition.

  15. Foliage shedding in deciduous forests lifts up long-distance seed dispersal by wind.

    PubMed

    Nathan, Ran; Katul, Gabriel G

    2005-06-07

    Seed terminal velocity and release height are recognized as key biotic determinants of long-distance dispersal (LDD) of seeds by wind. Yet, potential determinants at the ecosystem level, such as seasonal dynamics in foliage density characterizing many deciduous forests, have received much less attention. We integrated detailed field observations and experiments with a mechanistic wind dispersal model to assess how seasonal variation in foliage density, estimated by leaf-area index (LAI), affects LDD in deciduous forests. We found that the model, previously shown to accurately predict seed dispersal by wind, also reliably describes the effects of LAI variation on wind statistics for a wide range of canopy types. Sparser canopies are characterized by more organized vertical eddy motion that promotes LDD by uplifting seeds to higher elevations where winds are stronger. Yet, sparser canopies are also characterized by reduced mean windspeed aloft. We showed that former effect more than compensates for the latter, i.e., conditions of low LAI are favorable for LDD. This may account for the tendency of many temperate tree species to restrict seed release to either early spring or late fall, when LAI is relatively low. Sensitivity analysis reveals that the typical seasonal variation in LAI can be more important to LDD of seeds by wind than the natural variation in seed terminal velocity. Because our model accurately describes the effects of LAI variation for distinctly different sites, species, and life forms, we suggest that its results reflect a general association between LDD and foliage density dynamics.

  16. 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.

  17. 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.

  18. 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

  19. Comparison of Characteristic of Water Balance between Evergreen Coniferous and Deciduous Broad-leaved Forests

    NASA Astrophysics Data System (ADS)

    Hisada, Shigeta; Senge, Masateru; Ito, Kengo; Maruyama, Toshisuke

    Hydrological observation was carried out at two basins occupied mainly by evergreen coniferous forest of Chamaecyparis obtusa and deciduous broad-leaved forest of Quercus crispula in order to clarify the influences of different forest type on water balance. The analysis of short-time period water-budget method showed that the evapotranspiration of coniferous forest was more than broad-leaved one. By calculating transpiration from Priestley-Taylor equation, intercepted evaporation was separated from evapotranspiration. The result of comparison of intercepted evaporation between two basin was that intercepted evaporation of coniferous basin was more than that of broad-leaved basin. From separating total runoff into direct and base flow components; it was shown that there was no difference in direct runoff of two basins, so the differences of total runoff of two basins were caused due to the difference of base flow. From the above analysis of water balance components, it is clarified that the different forest type influences the amount of intercepted evaporation and base flow.

  20. Foliar d13C within a temperate deciduous forest: spatial, temporal, and species sources of variation

    SciTech Connect

    Garten Jr, Charles T; TaylorJr, G. E.

    1992-04-01

    Foliar {sup 13}C-abundance ({delta}{sup 13}C) was analyzed in the dominant trees of a temperate deciduous forest in east Tennessee (Walker Branch Watershed) to investigate the variation in foliar {delta}{sup 13}C as a function of time (within-year and between years), space (canopy height, watershed topography and habitat) and species (deciduous and coniferous taxa). Various hypotheses were tested by analyzing (i) samples collected from the field during the growing season and (ii) foliar tissues maintained in an archived collection. The {delta}{sup 13}C-value for leaves from the tops of trees was 2 to 3%. more positive than for leaves sampled at lower heights in the canopy. Quercus prinus leaves sampled just prior to autumn leaf fall had significantly more negative {delta}{sup 13}C-values than those sampled during midsummer. On the more xeric ridges, needles of Pinus spp. had more positive {delta}{sup 13}C-values than leaves from deciduous species. Foliar {delta}{sup 13}C-values differed significantly as a function of topography. Deciduous leaves from xeric sites (ridges and slopes) had more positive {delta}{sup 13}C-values than those from mesic (riparian and cove) environments. On the more xeric sites, foliar {delta}{sup 13}C was significantly more positive in 1988 (a dry year) relative to that in 1989 (a year with above-normal precipitation). In contrast, leaf {delta}{sup 13}C in trees from mesic valley bottoms did not differ significantly among years with disparate precipitation. Patterns in foliar {delta}{sup 13}C indicated a higher ratio of net CO{sub 2} assimilation to transpiration (A/E) for trees in more xeric versus mesic habitats, and for trees in xeric habitats during years of drought versus years of normal precipitation. However, A/E (units of mmol CO{sub 2} fixed/mol H{sub 2}O transpired) calculated on the basis of {delta}{sup 13}C-values for leaves from the more xeric sites was higher in a wet year (6.6 {+-} 1.2) versus a dry year (3.4 {+-} 0.4). This

  1. 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.

  2. 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.

  3. Two new species of Pasipha Ogren & Kawakatsu (Platyhelminthes: Continenticola) from areas of deciduous forest in southern Brazil.

    PubMed

    Amaral, Silvana Vargas Do; Leal-Zanchet, Ana Maria

    2016-09-29

    Two new species of Geoplaninae from southern Brazil are described herein. The new species, belonging to the genus Pasipha Ogren & Kawakatsu, 1990, can be distinguished from each other and from their congeners by colour pattern and characteristics of the copulatory apparatus, especially regarding the female organs and prostatic vesicle. Both new species seem to be endemic to areas covered by deciduous forest.

  4. Winter photosynthesis by saplings of evergreen broad-leaved trees in a deciduous temperate forest.

    PubMed

    Miyazawa, Yoshiyuki; Kikuzawa, Kihachiro

    2005-03-01

    * Here we investigated photosynthetic traits of evergreen species under a deciduous canopy in a temperate forest and revealed the importance of CO2 assimilation during winter for annual CO2 assimilation. * Saplings were shaded by the canopy trees from spring through to autumn, but were less shaded during the winter months. Photosynthetic rates at light saturation (Aarea) were lower during winter than during the growing season. Aarea was higher in Camellia, Ilex and Photinia than in Castanopsis, Cleyera and Quercus during the winter, but differed little during summer and autumn. * Estimated daily CO2 assimilation (Aday) was higher during the winter than during the growing season in Camellia, Ilex and Photinia but was higher than that during the growing season only at the beginning and end of winter in Castanopsis, Cleyera and Quercus. Aday was higher in Camellia, Ilex and Photinia than in Castanopsis, Cleyera and Quercus but differed little among them during the growing season. * These results reveal the importance of winter CO2 assimilation for the growth of Camellia, Ilex and Photinia. Furthermore, differences in annual CO2 assimilation among species are strongly modified by species-specific photosynthetic traits during the winter under deciduous canopy trees.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. 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

  13. 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

  14. 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.

  15. [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.

  16. Canopy structure and vertical patterns of photosynthesis and related leaf traits in a deciduous forest.

    PubMed

    Ellsworth, D S; Reich, P B

    1993-11-01

    Canopy structure and light interception were measured in an 18-m tall, closed canopy deciduous forest of sugar maple (Acer saccharum) in southwestern Wisconsin, USA, and related to leaf structural characteristics, N content, and leaf photosynthetic capacity. Light attenuation in the forest occurred primarily in the upper and middle portions of the canopy. Forest stand leaf area index (LAI) and its distribution with respect to canopy height were estimated from canopy transmittance values independently verified with a combined leaf litterfall and point-intersect method. Leaf mass, N and A max per unit area (LMA, N/area and A max/area, respectively) all decreased continuously by over two-fold from the upper to lower canopy, and these traits were strongly correlated with cumulative leaf area above the leaf position in the canopy. In contrast, neither N concentration nor A max per unit mass varied significantly in relation to the vertical canopy gradient. Since leaf N concentration showed no consistent pattern with respect to canopy position, the observed vertical pattern in N/area is a direct consequence of vertical variation of LMA. N/area and LMA were strongly correlated with A max/area among different canopy positions (r(2)=0.81 and r(2)=0.66, respectively), indicating that vertical variation in area-based photosynthetic capacity can also be attributed to variation in LMA. A model of whole-canopy photosynthesis was used to show that observed or hypothetical canopy mass distributions toward higher LMA (and hence higher N/area) in the upper portions of the canopy tended to increase integrated daily canopy photosynthesis over other LMA distribution patterns. Empirical relationships between leaf and canopy-level characteristics may help resolve problems associated with scaling gas exchange measurements made at the leaf level to the individual tree crown and forest canopy-level.

  17. 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

  18. 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

  19. 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.

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

    DOE PAGES

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

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

    SciTech Connect

    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 were 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.

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

    PubMed

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

    2015-04-28

    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.

  3. 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.

  4. Volatile organic compound emission rates from mixed deciduous and coniferous forests in Northern Wisconsin, USA

    NASA Astrophysics Data System (ADS)

    Isebrands, J. G.; Guenther, A. B.; Harley, P.; Helmig, D.; Klinger, L.; Vierling, L.; Zimmerman, P.; Geron, C.

    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 regions of the world to understand regional and global impacts and to implement possible mitigation strategies. The mixed deciduous and coniferous forests of northern Wisconsin, USA, were predicted to have significant VOC emission rates because they are comprised of many genera (i.e. Picea, Populus, Quercus, Salix) known to be high VOC emitters. In July 1993, a study was conducted on the Chequamegon National Forest near Rhinelander, WI, to identify and quantify VOC emitted from major trees, shrubs, and understory herbs in the mixed northern forests of this region. Emission rates were measured at various scales - at the leaf level with cuvettes, the branch level with branch enclosures, the canopy level with a tower based system, and the landscape level with a tethered balloon air sampling system. Area-average emission rates were estimated by scaling, using biomass densities and species composition along transects representative of the study site. Isoprene (C 5H 8) was the primary VOC emitted, although significant quantities of monoterpenes (C 10H 16) were also emitted. The highest emission rates of isoprene (at 30°C and photosynthetically active radiation of 1000 μmol m -2 s -1) were from northern red oak ( Quercus rubra, >110 μg(C) g -1 h -1); aspen ( Populus tremuloides, >77); willow ( Salix spp., >54); and black spruce ( Picea mariana, >10). Emission rates of hybrid poplar clones ranged from 40 to 90 μg(C) g -1 h -1 at 25°C; those of Picea provenances were generally <10, and emission rates of a hybrid between North American and European spruces were intermediate to parental rates. More than 30 species of plants were surveyed from the sites, including several from previously unstudied

  5. 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.

  6. 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.

  7. 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

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

    PubMed

    Pyritz, Lennart W; Büntge, Anna B S; Herzog, Sebastian K; Kessler, Michael

    2010-10-01

    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.

  9. 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

  10. Phenological changes in morphological, physiological and optical properties of single-leaves in canopy trees of a cool-temperate deciduous forest in Japan

    NASA Astrophysics Data System (ADS)

    Noda, H. M.; Muraoka, H.

    2013-12-01

    Phenology of forest canopy has been focused in carbon cycle studies, but still we need further understandings on its ecophysiological dynamics, to link them to the ecosystem function. For example, combined analysis of yearly NEP (net ecosystem production) by eddy covariance and NPP (net primary production) by biometric measurements in a cool-temperate deciduous broadleaf forest in Japan showed that the interannual variability of NEP is mostly explained by the NPP in tree biomass, rather than those by NPP in foliage nor heterotrophyic respiration (Ohtsuka et al. 2009; Glob. Chan. Ecol.). This result suggests the possible influence of interannual variations in either the length of growing season, phenology and the yearly maximum of leaf photosynthetic capacity, which largely affects GPP (gross primary production). In present study, in order to reveal the phenological pattern and its interannual variation of the leaf ecophysiological properties, leaf mass per area (LMA), chlorophyll contents and photosynthetic traits (Vcmax and Jmax) were measured for dominant canopy tree species Quercus crispla and Betula ermanii in Takayama site (AsiaFlux, JaLTER) for nine years during 2003 and 2012. In addition, to link such ecophysiological traits to the remote sensing of canopy dynamics, the optical properties (reflectance and transmittance spectra) of single leaf were also measured in spring (early June), summer (mid August) and autumn (October) in 2010 and 2012. Leaf budbreak occurred in mid to late May, after two to three weeks of snowmelt, and the photosynthetic capacity increased gradually in Quercus crispla but quickly in Betula ermanii. Seasonal developmental rate, the timing of leaf photosynthetic maturation and its maximum values varied year by year. Photosynthetic capacity was largely correlated with chlorophyll contents throughout the growing season. From spring to summer, i.e., in developing period, both chlorophyll content and LMA increased almost in parallel

  11. Effects of forest age on soil autotrophic and heterotrophic respiration differ between evergreen and deciduous forests.

    PubMed

    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.

  12. Evaluating remote sensing of deciduous forest phenology at multiple spatial scales using PhenoCam imagery

    NASA Astrophysics Data System (ADS)

    Klosterman, S. T.; Hufkens, K.; Gray, J. M.; Melaas, E.; Sonnentag, O.; Lavine, I.; Mitchell, L.; Norman, R.; Friedl, M. A.; Richardson, A. D.

    2014-08-01

    Plant phenology regulates ecosystem services at local and global scales and is a sensitive indicator of global change. Estimates of phenophase transition dates, such as the start of spring or end of fall, can be derived from sensor-based time series, but must be interpreted in terms of biologically relevant events. We use the PhenoCam archive of digital repeat photography to implement a consistent protocol for visual assessment of canopy phenology at 13 temperate deciduous forest sites throughout eastern North America, and to perform digital image analysis for time-series-based estimation of phenophase transition dates. We then compare these results to remote sensing metrics of phenophase transition dates derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) and Advanced Very High Resolution Radiometer (AVHRR) sensors. We present a new type of curve fit that uses a generalized sigmoid function to estimate phenology dates, and we quantify the statistical uncertainty of phenophase transition dates estimated using this method. Results show that the generalized sigmoid provides estimates of dates with less statistical uncertainty than other curve-fitting methods. Additionally, we find that dates derived from analysis of high-frequency PhenoCam imagery have smaller uncertainties than satellite remote sensing metrics of phenology, and that dates derived from the remotely sensed enhanced vegetation index (EVI) have smaller uncertainty than those derived from the normalized difference vegetation index (NDVI). Near-surface time-series estimates for the start of spring are found to closely match estimates derived from visual assessment of leaf-out, as well as satellite remote-sensing-derived estimates of the start of spring. However late spring and fall phenology metrics exhibit larger differences between near-surface and remote scales. Differences in late spring phenology between near-surface and remote scales are found to correlate with a landscape metric

  13. Evaluating remote sensing of deciduous forest phenology at multiple spatial scales using PhenoCam imagery

    NASA Astrophysics Data System (ADS)

    Klosterman, S. T.; Hufkens, K.; Gray, J. M.; Melaas, E.; Sonnentag, O.; Lavine, I.; Mitchell, L.; Norman, R.; Friedl, M. A.; Richardson, A. D.

    2014-02-01

    Plant phenology regulates ecosystem services at local and global scales and is a sensitive indicator of global change. Estimates of phenophase transition dates, such as the start of spring or end of autumn, can be derived from sensor-based time series data at the near-surface and remote scales, but must be interpreted in terms of biologically relevant events. We use the PhenoCam archive of digital repeat photography to implement a consistent protocol for visual assessment of canopy phenology at 13 temperate deciduous forest sites throughout eastern North America, as well as to perform digital image analysis for time series-based estimates of phenology dates. We then compare these near-surface results to remote sensing metrics of phenology at the landscape scale, derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) and Advanced Very High Resolution Radiometer (AVHRR) sensors. We present a new type of curve fit, using a generalized sigmoid, to estimate phenology dates. We quantify the statistical uncertainty of phenophase transition dates estimated using this method and show that the generalized sigmoid results in less statistical uncertainty than other curve-fitting methods. Additionally, we find that dates derived from analysis of high-frequency PhenoCam imagery have smaller uncertainties than remote sensing metrics of phenology, and that dates derived from the remotely-sensed enhanced vegetation index (EVI) have smaller uncertainty than those derived from the normalized difference vegetation index (NDVI). Near-surface time series estimates for the start of spring are found to closely match visual assessment of leaf out, as well as remote sensing-derived estimates of the start of spring. However late spring and autumn phenology exhibit larger differences between near-surface and remote scales. Differences in late spring phenology between near-surface and remote scales are found to correlate with a landscape metric of deciduous forest cover. These

  14. Quantifying the amount of root-derived carbon retained in soil at 4 temperate deciduous forests

    NASA Astrophysics Data System (ADS)

    Matamala, R.; Jastrow, J. D.; McFarlane, K. J.; Guilderson, T. P.; Hanson, P. J.

    2013-12-01

    Soil organic matter (SOM) represents the largest reservoir of carbon (C) in terrestrial ecosystems. The contributions of root-litter sources to SOM are high but they are not well understood. In this study, our objectives were to quantify the transfer of root-derived materials into soil and to study how climate and edaphic factors affect root decomposition and root-derived C retention in soils. We established 14C-enriched root-litter manipulations at four sites representing the climatic extent of Eastern deciduous forest. These sites span a range of soil types and mean annual temperature and precipitation. We followed root decomposition and incorporation of root-derived C into soil for four years. Our results show that root mass in root decomposition bags decreased over time; the average percent root mass decomposed in Y1 was 27% of the initial mass, 42% in Y2 and 56% in Y3. Data for Y4 will also be available at the poster. Root decay constants were significantly affected by climate and edaphic factors. Soils in root incubation bags showed 14C enrichment after only one month, suggesting that root C was quickly transferred to SOM, perhaps mostly as microbial residues. After the first month, soil 14C enrichment exhibited cyclic dynamics that varied by site, which were likely related to site differences in microbial activity and edaphic factors affecting SOM stabilization. After 3 years, the average root-derived C retained in the soil varied depending on site and ranged from 5% to 25% of total root decomposition inputs. The two sites with the highest soil C concentrations were also the sites that retained the most root-derived C, at about 23% of the total inputs. At the warmest site, root retention was slightly lower than at the colder sites, but higher than the colder site with sandy soils, which only retained about 4% of the root decomposition C inputs. Data from Y4 will be available at the poster. Overall, we found that retention of root-derived materials accounted

  15. 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

  16. 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.

  17. Land Surface Temperature estimation using ENVISAT AATSR Data -A study over tropical deciduous forest region.

    NASA Astrophysics Data System (ADS)

    Kvs, Badarinath

    Seasonal vegetation characteristics and other related phenological parameters can be better studies by Combined analysis of reflective and thermal data recorded by coarse resolution and high repetitive satellites. ENVISAT Advanced Along Track Scanning Radiometer (AATSR) data for different seasons from January 04 to April 04 has been analyzed to derive the Normal-ized Difference Vegetation Index (NDVI) and Surface Temperature (ST) images for the forest regions of Nagarjunasagar Srisailam Tiger Reserve (NSTR), India. Temporal variation of NDVI and ST reflected the phenology of the forest area. A negative relationship was observed be-tween the NDVI and ST over all the vegetation types and the proportion of vegetation cover seemed to has bearing on the ST. Scatter plots for NDVI and ST drawn for winter season showed a good separability of land use/land cover types of the study area. AATSR operates in channels with band centers at 0.555, 0.659, 0.858,1.61,3.70,10.85 and 12m. NDVI estimated from AATSR has been taken as a parameter for estimating surface emissivity and algorithm based on nadir and forward scans of brightness temperature in 12m has been used for esti-mating surface temperature. The surface temperature(ST) showed an inverse relation with a maximum for less vegetated areas and minimum from high vegetated areas. NDVI and surface temperature are inversely related and different land use / land cover categories can be segre-gated depending on the date of satellite pass in the TS vs. NDVI relation. Combination of spectral vegetation indices and thermal infrared measurements forms a useful tool in studying the land-atmospheric interactions. The proportion of vegetation cover at pixel level plays an important role in observing surface temperature variations over forest regions. The relation between NDVI and ST depends on vegetation phenology and thus on the availability of mois-ture in forest regions. The study area comprises mostly of deciduous type of forest

  18. The effects of gap size on some microclimate variables during late summer and autumn in a temperate broadleaved deciduous forest.

    PubMed

    Abd Latif, Zulkiflee; Blackburn, George Alan

    2010-03-01

    The creation of gaps can strongly influence forest regeneration and habitat diversity within forest ecosystems. However, the precise characteristics of such effects depend, to a large extent, upon the way in which gaps modify microclimate and soil water content. Hence, the aim of this study was to understand the effects of gap creation and variations in gap size on forest microclimate and soil water content. The study site, in North West England, was a mixed temperate broadleaved deciduous forest dominated by mature sessile oak (Quercus petraea), beech (Fagus sylvatica) and ash (Fraxinus excelsior) with some representatives of sycamore (Acer pseudoplatanus). Solar radiation (I), air temperature (T(A)), soil temperature (T(S)), relative humidity (h), wind speed (v) and soil water content (Psi) were measured at four natural treefall gaps created after a severe storm in 2006 and adjacent sub-canopy sites. I, T(A), T(S), and Psi increased significantly with gap size; h was consistently lower in gaps than the sub-canopy but did not vary with gap size, while the variability of v could not be explained by the presence or size of gaps. There were systematic diurnal patterns in all microclimate variables in response to gaps, but no such patterns existed for Psi. These results further our understanding of the abiotic and consequent biotic responses to gaps in broadleaved deciduous forests created by natural treefalls, and provide a useful basis for evaluating the implications of forest management practices.

  19. 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).

  20. [Dynamics of soil inorganic nitrogen in middle mountain moist evergreen broadleaf forest under different disturbance intensities in Ailao Mountain].

    PubMed

    Li, Guicai; Han, Xingguo; Huang, Jianhui; Wamg, Changyao

    2003-08-01

    The effects of three different intensities of disturbance on soil NH4(+)-N and NO3(-).N contents were studied in three community types (primary Lithocarpus xylocarpus forest, secondary oak forest, and tea plantation, which represent three different intensities of disturbance). The results showed that the contents of inorganic nitrogen in soil (0-15 cm) of three community types had marked differences. Soil organic matter and total nitrogen decreased, while C/N ratio increased, with the increasing intensity of the disturbance. Simultaneously, the potential lose of NO3(-)-N increased. It suggested that the disturbance was not in favor of the retainment of soil fertility and the positive development of community succession. The soil organic matter, total nitrogen and C/N ratio were basically same at different spatial sites in same community, while the NO3(-)-N contents were obvious difference. This implied that soil NO3(-)-N content was less stable than NH4(+)-N. In addition, NH4(+)-N was the major component of the soil inorganic nitrogen, accounted for 95.5%-99.3% of the total content of soil inorganic nitrogen.

  1. 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.

  2. [Characteristics of dominant tree species stem sap flow and their relationships with environmental factors in a mixed conifer-broadleaf forest in Dinghushan, Guangdong Province of South China].

    PubMed

    Huang, De-Wei; Zhang, De-Qiang; Zhou, Guo-Yi; Liu, Shi-Zhong; Otieno, Dennis; Li, Yue-Lin

    2012-05-01

    By the method of Granier' s thermal dissipation probe, the stem sap flow density of four dominant tree species (Pinus massoniana, Castanopsis chinensis, Schima superba, and Machilus kwangtungensis) in a mixed conifer-broadleaf forest in Dinghushan Reserve of South China was continuously measured in the dry season (November) and wet season (July) in 2010, and the environmental factors including air temperature, relative humidity, and photosynthetically active radiation (PAR) were measured synchronically, aimed to study the characteristics of the stem sap flow of the tree species in response to environmental factors. During the dry and wet seasons, the diurnal changes of the stem sap flow velocity of the tree species all presented a typical single-peak curve, with high values in the daytime and low values in the nighttime. The average and maximum sap flow velocities and the daily sap flow flux of broad-leaved trees (C. chinensis, S. superba, and M. kwangtungensis) were significantly higher than those of coniferous tree (P. massoniana), and the maximum sap flow velocity of P. massoniana, C. valueschinensis, S. superba, and M. kwangtungensis was 29.48, 38.54, 51.67 and 58.32 g H2O x m(-2) x s(-1), respectively. A time lag was observed between the sap flow velocity and the diurnal variations of PAR, vapor pressure deficiency, and air temperature, and there existed significant positive correlations between the sap flow velocity and the three environmental factors. The PAR in wet season and the air temperature in dry season were the leading factors affecting the stem sap flow velocity of the dominant tree species.

  3. 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.

  4. Intraspecific sequence variation of chloroplast DNA among the component species of deciduous broad-leaved forests in Japan.

    PubMed

    Iwasaki, Takaya; Aoki, Kyoko; Seo, Akihiro; Murakami, Noriaki

    2006-09-01

    To select appropriate plant materials for a phylogeography of deciduous broad-leaved forests in Japan, we surveyed intraspecific chloroplast DNA variation in 34 species found in these forests. A relatively large number of intraspecific cpDNA variations were detected in ten species: Carpinus japonica (nucleotide diversity pi=0.00083), C. laxiflora (pi=0.00221), Magnolia obovata (pi=0.00134), Lindera triloba (pi=0.00255), L. obtusiloba (pi=0.00289), Pourthiaea villosa var. leavis (pi=0.00263), Acer japonicum (pi=0.00170), A. micranthum (pi=0.00237), Euonymus oxyphyllus (pi=0.00322) and Styrax obassia (pi=0.00100).

  5. Soil fluxes of carbon dioxide, nitrous oxide, and methane at a productive temperate deciduous forest

    SciTech Connect

    Bowden, R.D.; Rullo, G.; Stevens, G.R.; Steudler, P.A.

    2000-02-01

    The authors measured CO{sub 2}, N{sub 2}O, and CH{sub 4} fluxes between soils and the atmosphere in ambient and N-addition plots at a productive black cherry-sugar maple forest in northwest Pennsylvania to examine the link between N-cycling and trace gas fluxes. Fluxes were estimated using in-situ chambers. Net annual N mineralization was 121.0 kg N ha{sup {minus}1}yr{sup {minus}1}, and net nitrification was 85.8 kg N ha{sup {minus}1}yr{sup {minus}1}, or 71% of net mineralization. Carbon dioxide efflux and CH{sub 4} uptake were among the highest rates reported for temperate deciduous forests. Emissions of N{sub 2}O were within the range of rates reported elsewhere, including locations with lower rates of N-cycling. A short-term study (May-Oct.) showed that N fertilization reduced both CO{sub 2} emissions and CH{sub 4} uptake. N{sub 2}O effluxes in fertilized plots were not different from control plots. The relatively high rate of soil respiration corresponded to a high rate of N-cycling; however, N{sub 2}O emissions were not necessarily result in large emissions of N{sub 2}O. Concurrent rapid rates of N-cycling and high rates of CH{sub 4} uptake did not support the hypothesis that N-cycling rates directly control CH{sub 4} uptake. Links between N-cycling and CH{sub 4} oxidation are complex; the influence of N-cycling on flux rates must consider not only the rate of cycling, but also the disposition of N-cycling products, and the factors that influence rates of N dynamics.

  6. 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.

  7. 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

  8. 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.

  9. 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

  10. Seasonal variability of multiple leaf traits captured by leaf spectroscopy at two temperate deciduous forests

    DOE PAGES

    Yang, Xi; Tang, Jianwu; Mustard, John F.; ...

    2016-04-02

    Understanding the temporal patterns of leaf traits is critical in determining the seasonality and magnitude of terrestrial carbon, water, and energy fluxes. However, we lack robust and efficient ways to monitor the temporal dynamics of leaf traits. Here we assessed the potential of leaf spectroscopy to predict and monitor leaf traits across their entire life cycle at different forest sites and light environments (sunlit vs. shaded) using a weekly sampled dataset across the entire growing season at two temperate deciduous forests. In addition, the dataset includes field measured leaf-level directional-hemispherical reflectance/transmittance together with seven important leaf traits [total chlorophyll (chlorophyllmore » a and b), carotenoids, mass-based nitrogen concentration (Nmass), mass-based carbon concentration (Cmass), and leaf mass per area (LMA)]. All leaf traits varied significantly throughout the growing season, and displayed trait-specific temporal patterns. We used a Partial Least Square Regression (PLSR) modeling approach to estimate leaf traits from spectra, and found that PLSR was able to capture the variability across time, sites, and light environments of all leaf traits investigated (R2 = 0.6–0.8 for temporal variability; R2 = 0.3–0.7 for cross-site variability; R2 = 0.4–0.8 for variability from light environments). We also tested alternative field sampling designs and found that for most leaf traits, biweekly leaf sampling throughout the growing season enabled accurate characterization of the seasonal patterns. Compared with the estimation of foliar pigments, the performance of Nmass, Cmass and LMA PLSR models improved more significantly with sampling frequency. Our results demonstrate that leaf spectra-trait relationships vary with time, and thus tracking the seasonality of leaf traits requires statistical models calibrated with data sampled throughout the growing season. In conclusion, our results have broad implications for future

  11. 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

  12. Plant Litter to Mineral Soil Sinks: Tracking Carbon Flux into Soil Sinks in Temperate Broadleaf Forests in the Eastern US with Radiocarbon

    NASA Astrophysics Data System (ADS)

    McFarlane, K. J.; Hanson, P. J.; Matamala, R.; Porras, R. C.; Torn, M. S.

    2011-12-01

    In 2007, a multiyear study was initiated to characterize the rate of C flux from litter sources to mineral soil sinks in four Eastern deciduous forests spanning a range of climatic and soil conditions. The Enriched Background Isotope Study focusing on AmeriFlux Sites (EBIS-AmeriFlux) provides quantitative data on the rate of C flux from litter to soil sinks using unique radiocarbon-enriched materials. Radiocarbon-enriched leaf and root litter and humus have been deployed under at the University of Michigan Biological Station (MI-UMBS), Bartlett Forest (NH-BF), Harvard Forest (MA-HF), and Baskett Research and Education Area in the Missouri Ozarks (MO-OZ). In addition to investigating rates of C transfer from litter to bulk O horizon sand mineral soil, we used density fractionation to separate bulk mineral soil into three pools of varying stability. These fractions are being used to identify which soil organic matter pools incorporate C from the experimental sources and determine pool-specific transfer rates. We will present results from the first two years of enriched-leaf and -humus applications and first year of enriched-root decomposition experiments. Preliminary results show that little humus-C was incorporated into soil over 2 years, but that by the second year after enriched-litter applications began new litter C had been transferred to mineral soil at MO-OZ and MI-UMBS. After 1 year, root-derived 14C label was detected in all three soil-density fractions isolated from the MO-OZ, but not in fractions from NH-BF. These data allow for the calculation of annual transfer rates for carbon from plant litter sources to mineral soil sinks.

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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

  18. 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.

  19. 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

  20. 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

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

    PubMed

    Jacob, Mascha; Viedenz, Karin; Polle, Andrea; Thomas, Frank M

    2010-12-01

    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 Acer platanoides) 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.

  2. 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.

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

    PubMed

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

    2015-03-01

    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.

  4. 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

  5. Seasonal variability of multiple leaf traits captured by leaf spectroscopy at two temperate deciduous forests

    SciTech Connect

    Yang, Xi; Tang, Jianwu; Mustard, John F.; Wu, Jin; Zhao, Kaiguang; Serbin, Shawn; Lee, Jung-Eun

    2016-04-02

    Understanding the temporal patterns of leaf traits is critical in determining the seasonality and magnitude of terrestrial carbon, water, and energy fluxes. However, we lack robust and efficient ways to monitor the temporal dynamics of leaf traits. Here we assessed the potential of leaf spectroscopy to predict and monitor leaf traits across their entire life cycle at different forest sites and light environments (sunlit vs. shaded) using a weekly sampled dataset across the entire growing season at two temperate deciduous forests. In addition, the dataset includes field measured leaf-level directional-hemispherical reflectance/transmittance together with seven important leaf traits [total chlorophyll (chlorophyll a and b), carotenoids, mass-based nitrogen concentration (Nmass), mass-based carbon concentration (Cmass), and leaf mass per area (LMA)]. All leaf traits varied significantly throughout the growing season, and displayed trait-specific temporal patterns. We used a Partial Least Square Regression (PLSR) modeling approach to estimate leaf traits from spectra, and found that PLSR was able to capture the variability across time, sites, and light environments of all leaf traits investigated (R2 = 0.6–0.8 for temporal variability; R2 = 0.3–0.7 for cross-site variability; R2 = 0.4–0.8 for variability from light environments). We also tested alternative field sampling designs and found that for most leaf traits, biweekly leaf sampling throughout the growing season enabled accurate characterization of the seasonal patterns. Compared with the estimation of foliar pigments, the performance of Nmass, Cmass and LMA PLSR models improved more significantly with sampling frequency. Our results demonstrate that leaf spectra-trait relationships vary with time, and thus tracking the seasonality of leaf traits requires statistical models calibrated with data sampled throughout the growing season

  6. 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.

  7. Do deer and raccoons defecate in the right place? Fitness consequences of vertebrate seed dispersal for a deciduous forest herb.

    PubMed

    Niederhauser, Eric C; Matlack, Glenn R

    2017-03-01

    Precision of seed placement in a heterogeneous environment is often assumed to select for the evolution of animal-mediated dispersal systems, but this hypothesis has rarely been tested in a multivariate sense. We quantify the microsite fitness benefits of dispersal by white-tailed deer (Odocoileus virginianus) and raccoons (Procyon lotor) for mayapple (Podophyllum peltatum), a shade-tolerant perennial herb, in deciduous forests of southeastern Ohio, USA. Micro-environmental variables were recorded at dung-deposition microsites, at rooting points of mayapple shoots, and at random (control) points in the forest. Fitness was assessed as the degree of overlap in ordinations of microsites by environmental variables. Mayapple occupied a broad sector (56%) of environment space corresponding to low and mid-slope positions, ravines, and proximity to trees. Deer and raccoon defecation placed dung in 71-74 and 86-95% of environment space, respectively, reaching mayapple microsites in 57-60 and 53-54% of cases. Deer placed dung in mayapple environment space 7-9% more often than predicted by random distribution, and raccoons placed dung in mayapple space 0-5% more often, consistent with only a modest degree of directed dispersal. Thus, the precision hypothesis is only weakly supported. The greatest fitness benefit of vertebrate dispersal appears to be the broad distribution of seeds, thereby increasing the probability of randomly reaching a suitable microsite. Imprecise dispersal suggests that secondary mechanisms of seed movement need to be explored in deciduous forest communities.

  8. A robust approach for tree segmentation in deciduous forests using small-footprint airborne LiDAR data

    NASA Astrophysics Data System (ADS)

    Hamraz, Hamid; Contreras, Marco A.; Zhang, Jun

    2016-10-01

    This paper presents a non-parametric approach for segmenting trees from airborne LiDAR data in deciduous forests. Based on the LiDAR point cloud, the approach collects crown information such as steepness and height on-the-fly to delineate crown boundaries, and most importantly, does not require a priori assumptions of crown shape and size. The approach segments trees iteratively starting from the tallest within a given area to the smallest until all trees have been segmented. To evaluate its performance, the approach was applied to the University of Kentucky Robinson Forest, a deciduous closed-canopy forest with complex terrain and vegetation conditions. The approach identified 94% of dominant and co-dominant trees with a false detection rate of 13%. About 62% of intermediate, overtopped, and dead trees were also detected with a false detection rate of 15%. The overall segmentation accuracy was 77%. Correlations of the segmentation scores of the proposed approach with local terrain and stand metrics was not significant, which is likely an indication of the robustness of the approach as results are not sensitive to the differences in terrain and stand structures.

  9. Differential winter stemflow generation under contrasting storm conditions in a southern New England broad-leaved deciduous forest

    NASA Astrophysics Data System (ADS)

    Levia, Delphis F., Jr.

    2004-04-01

    Despite the importance of stemflow as a hydroecological process, differential winter stemflow generation among and within precipitation types (e.g. snow, rain-to-snow) is poorly understood. The purpose of the present study is to understand winter stemflow generation better under contrasting meteorological conditions in a leafless deciduous forest. It is hypothesized that stemflow volume and production, expressed as a funnelling ratio, will differ significantly among and within precipitation event types. Acceptance of this hypothesis would mean that intra-event meteorological conditions have a significant and discernible effect on stemflow production in deciduous forests, differentially affecting soil moisture, groundwater recharge, soil solution chemistry, and nutrient cycling. Stemflow volumes generated from seven canopy trees were monitored in a leafless deciduous forest of southern New England on a precipitation event basis over two successive winter seasons. Stemflow volume was found to differ significantly among different and same-type precipitation events. A rain event that occurred on 8 December 1998 and snow-to-rain event on 18 January 1999 were of similar duration, magnitude, and intensity, yet produced stemflow volumes that differed by a factor of 4. For two snow-to-rain events, stemflow volumes differed by a factor of 11. Stemflow production even varies widely within a discrete precipitation event as a function of meteorological conditions. Significant differential stemflow yield under contrasting storm conditions obviates generalizations concerning stemflow production as a function of precipitation event type and necessitates a deeper, process-level understanding of winter stemflow generation before modelling exercises are undertaken.

  10. Carbon exchange and quantum efficiency of ecosystem carbon storage in mature deciduous and old-growth coniferous forest in central New England in 2001

    NASA Astrophysics Data System (ADS)

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

    2002-12-01

    Carbon storage in forests of the northeastern U.S. and adjacent Canada may be a significant carbon sink, as forests and soils in this region have recovered after agricultural abandonment in the 19th century. Data collected during the 1990's showed that an area of 70 to 100 year old deciduous forest on abandoned farmland in central Massachusetts stored an average of 2.0 Mg C/ha/yr in trees and soil. During 2001 we measured carbon exchange and environmental parameters (above-canopy air temperature, atmospheric humidity, photosynthetically active radiation (PAR) and soil temperature) in both the 70-100 year old deciduous forest and in a nearby eastern hemlock (Tsuga canadensis L.)-dominated forest with trees up to 220 years old that was never cleared for agricultural use. The deciduous forest stored more than 4 Mg C/ ha in 2001, far higher than in any previous year since measurements started in 1991. Highest monthly deciduous forest carbon storage (1.8 - 1.9 Mg ha-1 month-1) occurred in July and August. The hemlock forest stored about 3 Mg C/ha, with peak storage in April and May (0.8 - 0.9Mg C ha-1 month-1), and little or no C storage during August. The differences in carbon storage between the two forests were related to differences in quantum use efficiency. Quantum efficiency of ecosystem carbon storage in the foliated deciduous forest averaged about 0.16 g C /mol PAR and was insensitive to temperature after leaf maturation. In contrast, the average hemlock forest quantum efficiency declined from about 0.10 g C /mol PAR at daily average above-canopy air temperature (T{a}{v}{g}) = 5 oC to zero quantum efficiency (no net carbon storage) at T{a}{v}{g} = 23 oC. Optimum temperatures for carbon storage in the hemlock forest occurred in April. Differences between the two forests are likely due primarily to a higher maximum photosynthetic rate and a more positive temperature response of leaf-level photosynthesis in red oak (the dominant deciduous species) as compared with

  11. Species differences in stomatal control of water loss at the canopy scale in a mature bottomland deciduous forest

    NASA Astrophysics Data System (ADS)

    Pataki, D. E.; Oren, R.

    2003-12-01

    In order to evaluate factors controlling transpiration of six common eastern deciduous species in North America, a model describing responses of canopy stomatal conductance ( GS) to net radiation ( RN), vapor pressure deficit ( D) and relative extractable soil water (REW) was parameterized from sap flux data. Sap flux was measured in 24 mature trees consisting of the species Carya tomentosa, Quercus alba, Q. rubra, Fraxinus americana, Liriodendron tulipifera, and Liquidambar styraciflua in a bottomland oak-hickory forest in the Duke Forest, NC. Species differences in model coefficients were found during the 1997 growing season. All species showed a reduction in GS with increasing D. RN influenced GS in the overstory shade intolerant L. styraciflua to a larger extent than the other species measured. In addition, despite a severe drought during the study period, only L. tulipifera showed a decline in GS with decreasing REW. The primary effect of the drought for the other species appeared to be early autumn leaf senescence and abscission. As a result, despite the drought in this bottomland forest accustomed to ample water supply, maximum daily transpiration (1.6 mm) and growing season transpiration (264 mm) were similar to a nearby upland forest measured during a year of above average precipitation. These results may aid in assessing differences in water use and the ability of bottomland deciduous species to tolerate alterations in the frequency or amount of precipitation. Results also suggest little variation in water use among forests of similar composition and structure growing in different positions in the landscape and subjected to large interannual variation in water supply.

  12. Phylogeographical patterns of a generalist acorn weevil: insight into the biogeographical history of broadleaved deciduous and evergreen forests

    PubMed Central

    Aoki, Kyoko; Kato, Makoto; Murakami, Noriaki

    2009-01-01

    Background Climatic changes during glacial periods have had a major influence on the recent evolutionary history of living organisms, even in temperate forests on islands, where the land was not covered with ice sheets. We investigated the phylogeographical patterns of the weevil Curculio sikkimensis (Curculionidae), a generalist seed predator of Fagaceae plants living in both deciduous oak and evergreen forests of Japan. Its genetic structure was compared to that of another host-specific seed predator, C. hilgendorfi, inhabiting only evergreen forests. Results We examined 921 bp of mitochondrial DNA for 115 individuals collected from 33 populations of C. sikkimensis from 11 plant species of three genera, Quercus, Lithocarpus, and Castanopsis. An analysis of molecular variance revealed that a large proportion (almost 50%, P < 0.001) of the total genetic variance could be explained by differences between two geographical regions, the southwestern and northeastern parts of the main islands of Japan. In contrast, no significant genetic differentiation of the weevil was observed among vegetation types of their utilized host plant species. The phylogeographical patterns of the generalist and the host-specific seed predator exhibited a congruent genetic boundary in the Chugoku-Shikoku region. Conclusion Our results suggest that geology and historical environment have contributed to shaping the present genetic structure of C. sikkimensis. The geographical patterns of genetic differentiation in the Chugoku-Shikoku region observed in the two types of Fagaceae-associated Curculio in this study have also been observed in several plant species growing in warm and cool temperate zones of Japan. The occurrence of this common pattern suggests that deciduous oak and evergreen forests of Japan survived together, or adjacent to each other, in small refugia during glacial ages, in the southwestern and northeastern parts of the main islands, although these two types of forests are

  13. 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.

  14. 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

  15. 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.

  16. Deposition velocity of PM2.5 in the winter and spring above deciduous and coniferous forests in Beijing, China.

    PubMed

    Sun, Fengbin; Yin, Zhe; Lun, Xiaoxiu; Zhao, Yang; Li, Renna; Shi, Fangtian; Yu, Xinxiao

    2014-01-01

    To estimate the deposition effect of PM2.5 (particle matter with aerodynamic diameter <2.5 µm) in forests in northern China, we used the gradient method to measure the deposition velocity of PM2.5 during the winter and spring above a deciduous forest in Olympic Forest Park and above a coniferous forest in Jiufeng National Forest Park. Six aerosol samplers were placed on two towers at each site at heights of 9, 12 and 15 m above the ground surface. The sample filters were exchanged every four hours at 6∶00 AM, 10∶00 AM, 2∶00 PM, 6∶00 PM, 10∶00 PM, and 2∶00 AM. The daytime and nighttime deposition velocities in Jiufeng Park and Olympic Park were compared in this study. The February deposition velocities in Jiufeng Park were 1.2±1.3 and 0.7±0.7 cm s-1 during the day and night, respectively. The May deposition velocities in Olympic Park were 0.9±0.8 and 0.4±0.5 cm s-1 during the day and night, respectively. The May deposition velocities in Jiufeng Park were 1.1±1.2 and 0.6±0.5 cm s-1 during the day and night, respectively. The deposition velocities above Jiufeng National Forest Park were higher than those above Olympic Forest Park. The measured values were smaller than the simulated values obtained by the Ruijgrok et al. (1997) and Wesely et al. (1985) models. However, the reproducibility of the Ruijgrok et al. (1997) model was better than that of the Wesely et al. (1985) model. The Hicks et al. (1977) model was used to analyze additional forest parameters to calculate the PM2.5 deposition, which could better reflect the role of the forest in PM2.5 deposition.

  17. Temporal Dynamics of Oxygen Isotope Compositions of Soil and Canopy CO2 Fluxes in a Temperate Deciduous Forest

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    The stable isotopomer of CO2, C18OO, is a valuable tracer and have been used to study the CO2 exchange in different spatial scales. The objectives of this study were: to quantify the magnitude of isotopic desiquilibrium (Deq) in a temperate deciduous forest throughout the growing season, and to determine the sensitivity of Deq to CO2 hydration efficiency. In this study, C18OO and H218O composition of the air were measured quasi-continuously and simultaneously above a temperate deciduous forest using tunable diode laser trace gas analyzers. In addition, detailed measurements of H218O composition of ecosystem water pools were performed throughout the experimental period. These field measurements were used with existing formulations to estimate the C18OO of soil (δR) and canopy (δR) CO2 fluxes. Values of δA also showed large day to day variation in our site. The dynamics of δR was mainly driven by changes in soil water isotope composition, caused by precipitation events. The magnitude of Deq was variable throughout the season and very sensitive to the extent of the CO2 hydration in the canopy. In this ecosystem, for most of the growing season, the magnitude of Deq was inversely proportional to θeq. This can be explained by the very negative δR signal in our ecosystem.

  18. Modeling the impact of disturbances on the carbon cycle of a mixed-deciduous forest in the upper Midwest

    NASA Astrophysics Data System (ADS)

    Frasson, R.; Bohrer, G.; Medvigy, D.; Ivanov, V. Y.; Vogel, C.; Curtis, P.

    2013-12-01

    Disturbances, either natural or anthropogenic, impact the carbon and water cycles. Therefore, understanding their immediate effect, as well as how fluxes evolve while forests recover from disturbances is essential to carbon and water cycle modeling. Our study area is located in northern Michigan and encompasses the mixed-deciduous forest surrounding the University of Michigan Biological Station (UMBS). The two AmeriFlux affiliated towers operated by the UMBS, one with an undisturbed footprint and a second overlooking the Forest Accelerated Succession ExperimenT (FASET) site, a 39 ha area where all aspen (Populus spp.) and birch (Betula papyrifera) trees were girdled, provides the supporting data for our study. We used the Ecosystem Demography model version 2 (ED2) to run three scenarios: a control (undisturbed) case, a homogeneous disturbance (dist-1) where 30% of the leaf area was removed regardless of functional type, and a FASET like disturbance (dist-2) where all early successional trees, which occupy 30% of leaf area, were removed. We parameterized ED2 using observations of monthly and yearly net ecosystem exchange (NEE), latent, and sensible heat fluxes from the undisturbed site (UMBS-AmeriFlux) from pre-disturbance years. We force the model using meteorological data recorded by the flux towers and evaluate the output of the three cases against NEE, latent, and sensible heat fluxes measured at the UMBS-AmeriFlux site (undisturbed case) and against the FASET tower (cases dist-1 and dist-2) after the disturbance occurred. Our results indicate that in such a case of an intermediate disturbance the results of the disturbance are defendant on the functional type that was affected. As a result of this study, we expect to improve the understanding of the role disturbances and the subsequent recovery on carbon and water fluxes of broadleaved deciduous forests.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 137Cs vertical migration in a deciduous forest soil following the Fukushima Dai-ichi Nuclear Power Plant accident.

    PubMed

    Nakanishi, Takahiro; Matsunaga, Takeshi; Koarashi, Jun; Atarashi-Andoh, Mariko

    2014-02-01

    The large amount of (137)Cs deposited on the forest floor because of the Fukushima Dai-ichi Nuclear Power Plant accident represents a major potential long-term source for mobile (137)Cs. To investigate (137)Cs mobility in forest soils, we investigated the vertical migration of (137)Cs through seepage water, using a lysimetric method. The study was conducted in a deciduous forest soil over a period spanning 2 month to 2 y after the Fukushima nuclear accident. Our observations demonstrated that the major part of (137)Cs in the litter layer moved into the mineral soil within one year after the accident. On the other hand, the topsoil prevented migration of (137)Cs, and only 2% of (137)Cs in the leachate from litter and humus layer penetrated below a 10 cm depth. The annual migration below a 10 cm depth accounted for 0.1% of the total (137)Cs inventory. Therefore, the migration of (137)Cs by seepage water comprised only a very small part of the total (137)Cs inventory in the mineral soil, which was undetectable from the vertical distribution of (137)Cs in the soil profile. In the present and immediate future, most of the (137)Cs deposited on the forest floor will probably remain in the topsoil successively, although a small but certain amount of bioavailable (137)Cs exists in forest surface soil.

  4. 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.

  5. Water use by a warm-temperate deciduous forest under the influence of the Asian monsoon: contributions of the overstory and understory to forest water use.

    PubMed

    Jung, Eun-Young; Otieno, Dennis; Kwon, Hyojung; Lee, Bora; Lim, Jong-Hwan; Kim, Joon; Tenhunen, John

    2013-09-01

    The warm temperate deciduous forests in Asia have a relatively dense understory, hence, it is imperative that we understand the dynamics of transpiration in both the overstory (E O) and understory (E U) of forest stands under the influence of the Asian monsoon in order to improve the accuracy of forest water use budgeting and to identify key factors controlling forest water use under climate change. In this study, E O and E U of a temperate deciduous forest stand located in South Korea were measured during the growing season of 2008 using sap flow methods. The objectives of this study were (1) to quantify the total transpiration of the forest stand, i.e., overstory and understory, (2) to determine their relative contribution to ecosystem evapotranspiration (E eco), and (3) to identify factors controlling the transpiration of each layer. E O and E U were 174 and 22 mm, respectively. Total transpiration accounted for 55 % of the total E eco, revealing the importance of unaccounted contributions to E eco (i.e., soil evaporation and wet canopy evaporation). During the monsoon period, there was a strong reduction in the total transpiration, likely because of reductions in photosynthetic active radiation, vapor pressure deficit and plant area index. The ratio of E U to E O declined during the same period, indicating an effect of monsoon on the partitioning of E eco in its two components. The seasonal pattern of E O was synchronized with the overstory canopy development, which equally had a strong regulatory influence on E U.

  6. 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

  7. 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

  8. Effects of structural complexity on within-canopy light environments and leaf traits in a northern mixed deciduous forest.

    PubMed

    Fotis, Alexander T; Curtis, Peter S

    2017-01-18

    Canopy structure influences forest productivity through its effects on the distribution of radiation and the light-induced changes in leaf physiological traits. Due to the difficulty of accessing and measuring forest canopies, few field-based studies have quantitatively linked these divergent scales of canopy functioning. The objective of our study was to investigate how canopy structure affects light profiles within a forest canopy and whether leaves of mature trees adjust morphologically and biochemically to the light environments characteristic of canopies with different structural complexity. We used a combination of light detection and ranging (LiDAR) data and hemispherical photographs to quantify canopy structure and light environments, respectively, and a telescoping pole to sample leaves. Leaf mass per area (LMA), nitrogen on an area basis (Narea) and chlorophyll on a mass basis (Chlmass) were measured in red maple (Acer rubrum), american beech (Fagus grandifolia), white pine (Pinus strobus), and northern red oak (Quercus rubra) at different heights in plots with similar leaf area index but contrasting canopy complexity (rugosity). We found that more complex canopies had greater porosity and reduced light variability in the midcanopy while total light interception was unchanged relative to less complex canopies. Leaf phenotypes of F. grandifolia, Q. rubra and P strobus were more sun-acclimated in the midstory of structurally complex canopies while leaf phenotypes of A. rubrum were more shade-acclimated (lower LMA) in the upper canopy of more complex stands, despite no differences in total light interception. Broadleaf species showed further differences in acclimation with increased Narea and reduced Chlmass in leaves with higher LMA, while P. strobus showed no change in Narea and Chlmass with higher LMA. Our results provide new insight on how light distribution and leaf acclimation in mature trees might be altered when natural and anthropogenic disturbances

  9. 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.

  10. 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.

  11. 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.

  12. The rhizospheric microbial community structure and diversity of deciduous and evergreen forests in Taihu Lake area, China.

    PubMed

    Wei, Zhiwen; Hu, Xiaolong; Li, Xunhang; Zhang, Yanzhou; Jiang, Leichun; Li, Jing; Guan, Zhengbing; Cai, Yujie; Liao, Xiangru

    2017-01-01

    Soil bacteria are important drivers of biogeochemical cycles and participate in many nutrient transformations in the soil. Meanwhile, bacterial diversity and community composition are related to soil physic-chemical properties and vegetation factors. However, how the soil and vegetation factors affect the diversity and community composition of bacteria is poorly understood, especially for bacteria associated with evergreen and deciduous trees in subtropical forest ecosystems. In the present paper, the microbial communities of rhizospheric soils associated with different types of trees were analyzed by Illumina MiSeq sequencing the V3-V4 region of the 16S rRNA gene. A total of 121,219 effective 16S rRNA gene sequences were obtained, which were classified into 29 bacterial phyla and 2 archaeal phyla. The dominant phyla across all samples (>5% of good-quality sequences in each sample) were Proteobacteria, Acidobacteria, Firmicutes and Bacteroidetes. The bacterial community composition and diversity were largely affected by both soil pH and tree species. The soil pH was the key factor influencing bacterial diversity, with lower pH associated with less diverse communities. Meanwhile, the contents of NO3- were higher in evergreen tree soils than those associated with deciduous trees, while less NH4+ than those associated with deciduous trees, leading to a lower pH and indirectly influencing the diversity and composition of the bacteria. The co-occurrence patterns were assessed by network analysis. A total of 415 pairs of significant and robust correlations (co-occurrence and negative) were identified from 89 genera. Sixteen hubs of co-occurrence patterns, mainly under the phyla Acidobacteria, Proteobacteria, Firmicutes and Bacteroidetes, may play important roles in sustaining the stability of the rhizospheric microbial communities. In general, our results suggested that local environmental conditions and soil pH were important in shaping the bacterial community of the

  13. 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.

  14. Long-term effects of climate change on carbon storage and tree species composition in a dry deciduous forest.

    PubMed

    Fekete, István; Lajtha, Kate; Kotroczó, Zsolt; Várbíró, Gábor; Varga, Csaba; Tóth, János Attila; Demeter, Ibolya; Veperdi, Gábor; Berki, Imre

    2017-02-21

    Forest vegetation and soils have been suggested as potentially important sinks for carbon (C) with appropriate management and thus are implicated as effective tools in stabilizing climate even with increasing anthropogenic release of CO2 . Drought, however, which is often predicted to increase in models of future climate change, may limit net primary productio (NPP) of dry forest types, with unknown effects on soil C storage. We studied C dynamics of a deciduous temperate forest of Hungary that has been subject to significant decreases in precipitation and increases in temperature in recent decades. We resampled plots that were established in 1972 and repeated the full C inventory by analyzing more than 4 decades of data on the number of living trees, biomass of trees and shrubs, and soil C content. Our analyses show that the decline in number and biomass of oaks started around the end of the 1970s with a 71% reduction in the number of sessile oak stems by 2014. Projected growth in this forest, based on the yield table's data for Hungary, was 4.6 kg C/m(2) . Although new species emerged, this new growth and small increases in oak biomass resulted in only 1.9 kg C/m(2) increase over 41 years. The death of oaks increased inputs of coarse woody debris to the surface of the soil, much of which is still identifiable, and caused an increase of 15.5%, or 2.6 kg C/m(2) , in the top 1 m of soil. Stability of this fresh organic matter input to surface soil is unknown, but is likely to be low based on the results of a colocated woody litter decomposition study. The effects of a warmer and drier climate on the C balance of forests in this region will be felt for decades to come as woody litter inputs decay, and forest growth remains impeded.

  15. 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...

  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. Characterization factors for land use impacts on biodiversity in life cycle assessment based on direct measures of plant species richness in European farmland in the 'Temperate Broadleaf and Mixed Forest' biome.

    PubMed

    Knudsen, Marie Trydeman; Hermansen, John E; Cederberg, Christel; Herzog, Felix; Vale, Jim; Jeanneret, Philippe; Sarthou, Jean-Pierre; Friedel, Jürgen K; Balázs, Katalin; Fjellstad, Wendy; Kainz, Max; Wolfrum, Sebastian; Dennis, Peter

    2017-02-15

    Life Cycle Assessment (LCA) is a widely used tool to assess environmental sustainability of products. The LCA should optimally cover the most important environmental impact categories such as climate change, eutrophication and biodiversity. However, impacts on biodiversity are seldom included in LCAs due to methodological limitations and lack of appropriate characterization factors. When assessing organic agricultural products the omission of biodiversity in LCA is problematic, because organic systems are characterized by higher species richness at field level compared to the conventional systems. Thus, there is a need for characterization factors to estimate land use impacts on biodiversity in life cycle assessment that are able to distinguish between organic and conventional agricultural land use that can be used to supplement and validate the few currently suggested characterization factors. Based on a unique dataset derived from field recording of plant species diversity in farmland across six European countries, the present study provides new midpoint occupation Characterization Factors (CF) expressing the Potentially Disappeared Fraction (PDF) to estimate land use impacts on biodiversity in the 'Temperate Broadleaf and Mixed Forest' biome in Europe. The method is based on calculation of plant species on randomly selected test sites in the biome and enables the calculation of characterization factors that are sensitive to particular types of management. While species richness differs between countries, the calculated CFs are able to distinguish between different land use types (pastures (monocotyledons or mixed), arable land and hedges) and management practices (organic or conventional production systems) across countries. The new occupation CFs can be used to supplement or validate the few current CF's and can be applied in LCAs of agricultural products to assess land use impacts on species richness in the 'Temperate Broadleaf and Mixed Forest' biome.

  18. 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.

  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. 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.

  1. Genetic structure and breeding system of a rare understory herb, Dysosma versipellis (Berberidaceae), from temperate deciduous forests in China.

    PubMed

    Guan, Bi-Cai; Fu, Cheng-Xing; Qiu, Ying-Xiong; Zhou, Shi-Liang; Comes, Hans Peter

    2010-01-01

    To evaluate the role of Quaternary refugial isolation in allopatric (incipient) speciation of East Asian temperate forest biotas, we analyzed amplified fragment length polymorphisms (AFLPs) and the breeding system in Dysosma versipellis. The study revealed that D. versipellis is mostly self-incompatible, genetically highly subdivided and depauperate at the population level (e.g., Φ(ST) = 0.572/H(E) = 0.083), and characterized by a low pollen-to-seed migration ratio (r ≈ 4.0). The latter outcome likely reflects limited pollen flow in a low-seed disperser whose hypothesized "sapromyophilous" flowers undergo scarce, inefficient, and likely specialized cross-pollination by small Anoplodera beetles, rather than carrion flies as assumed previously. In consequence, fruit set in D. versipellis was strongly pollen-limited. Our AFLP data support the hypothesis of a long-standing cessation of gene flow between western and central eastern populations, consistent with previous chloroplast DNA data. This phylogeographic pattern supports the role of the Sichuan Basin as a floristic boundary separating the Sino-Himalayan vs. Sino-Japanese Forest subkingdoms. Our genetic data of D. versipellis also imply that temperate deciduous forest elements to the west and the east of this basin responded differently to Quaternary climate change, which may have triggered or is leading to allopatric (incipient) speciation.

  2. 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.

  3. On the limits and capability of modeling water, energy and carbon fluxes in deciduous forest exposed to elevated CO2

    NASA Astrophysics Data System (ADS)

    Fatichi, Simone; Leuzinger, Sebastian

    2013-04-01

    Understanding future patterns of carbon cycle is strongly connected to forest behavior in an atmosphere with increasing CO2. Observations in mature, steady-state forests are logistically challenging and difficult to upscale, therefore most of our experimental knowledge is derived from results obtained for young trees or homogenous stands. A combination of numerical modeling and observations can complement our knowledge on the behavior of heterogeneous forests where the leaf-level photosynthetic response to elevated CO2 typically does not translate into a proportional increase in plant growth. We compare data from a free air CO2 enrichment (FACE) experiment in a mature deciduous forest in Switzerland with realizations from a state-of-the-art ecohydrological model (Tethys-Chloris). Model realizations compare favorably with field observations of photosynthesis, stomatal conductance, sap flow, leaf and fruit litter, and stem growth. The model captures the observed CO2-induced difference in transpiration and its sensitivity to atmospheric demand, as well as qualitative changes in soil moisture. The simulated differences between CO2 scenarios for both the carbon and water balance are generally less than 10% and fall within the uncertainty of experimental observations. Simulated allocation to stem growth is c. 50 gC yr-1 m-2 higher in the modeled CO2 scenario, which is within the uncertainty of stand upscaled observations. These results demonstrate that while ecohydrological models can be used to reliably simulate multi-year energy, water, and carbon fluxes, evaluating the modeled carbon allocation remains critical. Simplified and rather empirical carbon allocation rules used in the model cannot be confirmed or rejected given the current accuracy of field measurements. Despite such uncertainties we conclude that, taken together both modeling and experimental results, for this type of forest, ecosystem responses to elevated CO2 in terms of energy and water fluxes are

  4. 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.

  5. 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...

  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. Using eddy covariance, remote sensing, and in situ observations to improve models of springtime phenology in temperate deciduous forests

    NASA Astrophysics Data System (ADS)

    Melaas, Eli Kellen

    Phenological events in temperate 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 and photoperiod, although the exact nature and magnitude of these controls is poorly understood. In this dissertation, I use in situ and remotely sensed observations of phenology in combination with surface meteorological data and measurements of biosphere-atmosphere carbon exchanges to improve understanding and develop models of canopy phenology in temperate forest ecosystems. In the first element of this research I use surface air temperatures and eddy covariance measurements of carbon dioxide fluxes to evaluate and refine widely used approaches for predicting the onset of photosynthesis in spring that account for geographic variation in thermal and photoperiod constraints on phenology. Results from this analysis show that the refined models predict the onset of spring photosynthetic activity with significantly higher accuracy than existing models. A key challenge in developing and testing these models, however, is lack of adequate data sets that characterize phenology over large areas at multi-decadal time scales. To address this need, I develop a new method for estimating long-term average and interannual dynamics in the phenology of temperate forests using time series of Landsat TM/ETM+ images. Results show that estimated spring and autumn transition dates agree closely with in-situ measurements and that Landsat-derived estimates for the start and end of the growing season in Southern New England varied by as much as 4 weeks over the 30-year record of Landsat images. In the final element of this dissertation, I use meteorological data, species composition maps, satellite remote sensing, and ground observations to develop models of springtime leaf onset in temperate deciduous forests that account for geographic differences in how forest

  8. Evidence of formation of submicrometer water-soluble organic aerosols at a deciduous forest site in northern Japan in summer

    NASA Astrophysics Data System (ADS)

    Miyazaki, Yuzo; Jung, Jinsang; Fu, Pingqing; Mizoguchi, Yasuko; Yamanoi, Katsumi; Kawamura, Kimitaka

    2012-10-01

    Semicontinuous measurements of submicrometer water-soluble organic aerosols and particle size distributions were conducted at a deciduous forest site in northern Japan in August 2010. Increases in particle number concentration were frequently observed in daytime, accompanied by an increase in the concentrations of water-soluble organic carbon (WSOC). We found that daily averaged WSOC concentrations positively correlated with gross primary production of CO2 by the forest ecosystem (r2 = 0.63) and ambient temperature during daytime. These relations suggest that the formation of WSOC is closely linked to photosynthetic activity by the forest ecosystem, which depends on both temperature and solar radiation. Off-line chemical analysis of samples of particles with aerodynamic diameter smaller than 1 μm collected during a 2 day event of elevated WSOC levels suggests that photochemical aging of both α- andβ-pinene and isoprene oxidation products contributes to the particle growth and the WSOC mass. Organic tracers of primary biological aerosol particles (PBAPs) showed distinct diurnal variations with a maximum around noontime, also indicating that higher temperature and light intensity induce emissions of PBAPs. However, their contribution to the submicrometer WSOC mass was likely insignificant. During the day, the concentrations of 3-methyl-1,2,3-butanetricarboxylic acid (3-MBTCA) showed a strong dependence on temperature, and the ratios of WSOC to particle volume concentration increased with an increase in the concentration ratios of 3-MBTCA to pinonic acid (PA). This result supports a previous proposal that the 3-MBTCA/PA ratios in submicrometer particles can be a useful tracer for chemical aging of biogenic secondary organic aerosol from forest vegetation.

  9. Interannual variability in the extent and intensity of tropical dry forest deciduousness in the Mexican Yucatan (2000-2016): Drivers and Links to Regional Atmospheric Conditions

    NASA Astrophysics Data System (ADS)

    Cuba, Nicholas Joseph

    The dry topical forests of the southern Yucatan Peninsula experience multiple natural and anthropogenic disturbances, as well as substantial interannual climate variability that can result in stark interannual differences in vegetation phenology. Dry season deciduousness is a typical response to limit tree water loss during prolonged periods of hot and dry conditions, and this behavior has both direct implications for ecosystem functioning, and the potential to indicate climate conditions when observed using remotely-sensed data. The first research paper of this dissertation advances methods to assess the accuracy of remotely-sensed measurements of canopy conditions using in-situ observations. Linear regression models show the highest correlation (R2 = 0.751) between in-situ canopy gap fraction and Landsat NDWISWIR2. MODIS time series NDWISWIR2 are created for the period March 2000-February 2011, and exhibit stronger correlation with time series of TRMM precipitation data than do MODIS EVI time series (R2= 0.48 vs. R2 = 0.43 in deciduous forest areas). The second paper examines differences between the deciduous phenology of young forest stands and older forest stands. Land-cover maps are overlaid to determine whether forested areas are greater than or less than 22 years old in 2010, and metrics related to deciduous phenology are derived from MODIS EVI2 time series in three years, 2008 to 2011. Statistical tests that compare matched pairs of young (12-22 years) and older (>22 years) forest stand age class samples are used to detect significant differences in metrics related to the intensity and timing of deciduousness. In all three years, younger forests exhibit significantly more intense deciduousness, measured as total seasonal change of EVI2 normalized by annual maximum EVI2 (p<0.001), and exhibit larger EVI2 declines at successive 32-day periods during dry season months (p<0.02), than nearby older forests that are assumed to share similar environmental

  10. Relationships between canopy greenness and CO2 dynamics of a Mediterranean deciduous forest assessed with webcam imagery and MODIS vegetation indices

    NASA Astrophysics Data System (ADS)

    Balzarolo, M.; Papale, D.; Richardson, A. D.

    2009-04-01

    Phenological observations of foliar development and senescence are needed to understand the relationship between canopy properties and seasonal productivity dynamics (e.g., carbon uptake) of terrestrial ecosystems. Traditional phenological ground observations based on a visual observation of different vegetation growth phases (from first leaf opening, to first leaf flowering, full bloom until senescence) are laborious and typically limited to observations on just a few individual subjects. On the contrary, remote sensing techniques appear to offer the potential for assessing long-term variability in primary productivity at a global scale (Field et al., 1993). Recent studies have shown that biochemical and biophysical canopy properties can be measured with a quantifiable uncertainty that can be incorporated in the land-biosphere models (Ustin et al., 2004a; Ollinger et al 2008). Canopy greenness can be quantified by the use of vegetation indices (VIs) as, for example, Normalized Difference Vegetation Index (NDVI, Rouse et al., 1974; Deering, 1978), but a disadvantage of this approach is that there are uncertainties associated with these indices (due to the spatial and temporal resolution of the data), and the interpretation of a specific VI value, in the context of on-the-ground phenology, is not clear. Improved ground-based datasets are needed to validate and improve remotely-sensed phenological indices. Continuous monitoring of vegetation canopies with digital webcams (Richardson et al. 2007) may offer a direct link between phenological changes in canopy state and what is "seen" by satellite sensors. The general objective of this study is to analyze the relationship between biosphere-atmosphere CO2 exchange (measured by eddy covariance) and phenological canopy status, or greenness, of a Mediterranean deciduous broadleaf forest in central Italy (Roccarespampani, 42°24' N, 11°55' E). Canopy greenness is quantify using two different approaches: from digital webcam

  11. Above- and belowground controls on water use by trees of different wood types in an eastern US deciduous forest.

    PubMed

    Meinzer, Frederick C; Woodruff, David R; Eissenstat, David M; Lin, Henry S; Adams, Thomas S; McCulloh, Katherine A

    2013-04-01

    Stomata control tree transpiration by sensing and integrating environmental signals originating in the atmosphere and soil, and co-occurring species may differ in inherent stomatal sensitivity to these above- and belowground signals and in the types of signals to which they respond. Stomatal responsiveness to environmental signals is likely to differ across species having different types of wood (e.g., ring-porous, diffuse-porous and coniferous) because each wood type differs in the structure, size and spatial distribution of its xylem conduits as well as in the scaling of hydraulic properties with stem diameter. The objective of this study was to evaluate the impact of variation in soil water availability and atmospheric evaporative demand on stomatal regulation of transpiration in seven co-occurring temperate deciduous forest species representing three wood types. We measured whole-tree sap flux and soil and atmospheric variables in a mixed deciduous forest in central Pennsylvania over the course of a growing season characterized by severe drought and large fluctuations in atmospheric vapor pressure deficit (D). The relative sensitivity of sap flux to soil drying was ∼2.2-2.3 times greater in the diffuse-porous and coniferous species than in the ring-porous species. Stomata of the ring-porous oaks were only about half as responsive to increased D as those of trees of the other two wood types. These differences in responsiveness to changes in the below- and aboveground environment implied that regulation of leaf water potential in the ring-porous oaks was less stringent than that in the diffuse-porous angiosperms or the conifers. The results suggest that increases in the frequency or intensity of summer droughts in the study region could have multiple consequences for forest function, including altered successional time courses or climax species composition and cumulative effects on whole-tree architecture, resulting in a structural and physiological legacy that

  12. 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

  13. Catchment-scale distribution of radiocesium air dose rate in a mountainous deciduous forest and its relation to topography.

    PubMed

    Atarashi-Andoh, Mariko; Koarashi, Jun; Takeuchi, Erina; Tsuduki, Katsunori; Nishimura, Syusaku; Matsunaga, Takeshi

    2015-09-01

    A large number of air dose rate measurements were collected by walking through a mountainous area with a small gamma-ray survey system, KURAMA-II. The data were used to map the air dose rate of a mountainous deciduous forest that received radiocesium from the Fukushima Dai-ichi Nuclear Power Plant accident. Measurements were conducted in a small stream catchment (0.6 km(2) in area) in August and September 2013, and the relationship between air dose rates and the mountainous topography was examined. Air dose rates increased with elevation, indicating that more radiocesium was deposited on ridges, and suggesting that it had remained there for 2.5 y with no significant downslope migration by soil erosion or water drainage. Orientation in relation to the dominant winds when the radioactive plume flowed to the catchment also strongly affected the air dose rates. Based on our continuous measurements using the KURAMA-II, we describe the variation in air dose rates in a mountainous forest area and suggest that it is important to consider topography when determining sampling points and resolution to assess the spatial variability of dose rates and contaminant deposition.

  14. Variability in Carbon Stable Isotope Ratio of Heterotrophic Soil Respiration in a Deciduous Needle-leaf Forest

    NASA Astrophysics Data System (ADS)

    Takahashi, Y.; Liang, N.; Machida, T.; Fujinuma, Y.; Inoue, G.

    2005-12-01

    We investigated spatial and temporal variability in the carbon stable isotope ratio (δ13C) of heterotrophic soil respiration in a deciduous Japanese needle-leaf forest for 3 years. We used high-precision isotope measurement coupled with a sampling system optimized for soil respiration to capture this variability under natural conditions. The limitations of chamber-based measurements combined with spatial variation created a representation error that prevented precise estimates of flux-weighted mean δ13C, but we could nonetheless characterize the δ13C variations intrinsic to heterotrophic respiration. In the absence of root respiration, δ13C exhibited significant seasonal variation, with a greater range than in previous models. In a root-exclusion plot, δ13C was lowest at high temperatures but showed a different seasonal course from that of CO2 efflux. A simple model explained the seasonal variation in δ13C using interpool differences in δ13C of decomposed organic matter, in the temperature dependence of decomposition rates, and in the seasonal changes in pool size. The characteristic seasonality of δ13C appears to be associated with the properties of the forest, including litterfall patterns.

  15. Impact of Hydraulic Redistribution on Present and Future Vegetation Competition in Tropical Dry Forest

    NASA Astrophysics Data System (ADS)

    Wang, G.; Mei, R.; Alo, C. A.

    2009-12-01

    Hydraulic redistribution (HR) is generally considered to increase plant water availability thus buffer plants against seasonal drought. This study uses the NCAR CLM3-DGVM to investigate the long-term impact of HR on tropical vegetation composition and how that influence vegetation resonse to climate changes, using as example the Amazon region. HR is found to increase the percentage of tropical broadleaf drought deciduous trees at the expense of tropical broadleaf evergreen trees. While HR increases the long-term mean of dry season transpiration, it reduces dry season transpiration in extremely dry years when the HR-induced acceleration of moisture depletion leaves less water available later in the dry season. Such negative hydrological impact of HR can lead to extremely low or negative NPP later in the dry season that limits the growth of trees that are not in dry-season senescence, i.e., evergreen trees. As a result, HR leads to a shift in vegetation competition, favoring tropical broadleaf drought deciduous trees at the expense of tropical broadleaf evergreen trees. Projected future climate changes are expected to cause a gradual shift of vegetation in tropical forest towards more drought deciduous trees. Hydraulic redistribution enhances or accelerate the projected future vegetation response, due primarily to the increased frequency of extreme droughts in the projected future climate.

  16. Large-scale carbon stock assessment of woody vegetation in tropical dry deciduous forest of Sathanur reserve forest, Eastern Ghats, India.

    PubMed

    Gandhi, Durai Sanjay; Sundarapandian, Somaiah

    2017-04-01

    Tropical dry forests are one of the most widely distributed ecosystems in tropics, which remain neglected in research, especially in the Eastern Ghats. Therefore, the present study was aimed to quantify the carbon storage in woody vegetation (trees and lianas) on large scale (30, 1 ha plots) in the dry deciduous forest of Sathanur reserve forest of Eastern Ghats. Biomass of adult (≥10 cm DBH) trees was estimated by species-specific allometric equations using diameter and wood density of species whereas in juvenile tree population and lianas, their respective general allometric equations were used to estimate the biomass. The fractional value 0.4453 was used to convert dry biomass into carbon in woody vegetation of tropical dry forest. The mean aboveground biomass value of juvenile tree population was 1.86 Mg/ha. The aboveground biomass of adult trees ranged from 64.81 to 624.96 Mg/ha with a mean of 245.90 Mg/ha. The mean aboveground biomass value of lianas was 7.98 Mg/ha. The total biomass of woody vegetation (adult trees + juvenile population of trees + lianas) ranged from 85.02 to 723.46 Mg/ha, with a mean value of 295.04 Mg/ha. Total carbon accumulated in woody vegetation in tropical dry deciduous forest ranged from 37.86 to 322.16 Mg/ha with a mean value of 131.38 Mg/ha. Adult trees accumulated 94.81% of woody biomass carbon followed by lianas (3.99%) and juvenile population of trees (1.20%). Albizia amara has the greatest biomass and carbon stock (58.31%) among trees except for two plots (24 and 25) where Chloroxylon swietenia contributed more to biomass and carbon stock. Similarly, Albizia amara (52.4%) showed greater carbon storage in juvenile population of trees followed by Chloroxylon swietenia (21.9%). Pterolobium hexapetalum (38.86%) showed a greater accumulation of carbon in liana species followed by Combretum albidum (33.04%). Even though, all the study plots are located within 10 km radius, they show a significant spatial variation among

  17. How vertical patterns in leaf traits shift seasonally and the implications for modeling canopy photosynthesis in a temperate deciduous forest.

    PubMed

    Coble, Adam P; VanderWall, Brittany; Mau, Alida; Cavaleri, Molly A

    2016-09-01

    Leaf functional traits are used in modeling forest canopy photosynthesis (Ac) due to strong correlations between photosynthetic capacity, leaf mass per area (LMA) and leaf nitrogen per area (Narea). Vertical distributions of these traits may change over time in temperate deciduous forests as a result of acclimation to light, which may result in seasonal changes in Ac To assess both spatial and temporal variations in key traits, we measured vertical profiles of Narea and LMA from leaf expansion through leaf senescence in a sugar maple (Acer saccharum Marshall) forest. To investigate mechanisms behind coordinated changes in leaf morphology and function, we also measured vertical variation in leaf carbon isotope composition (δ(13)C), predawn turgor pressure, leaf water potential and osmotic potential. Finally, we assessed potential biases in Ac estimations by parameterizing models with and without vertical and seasonal Narea variations following leaf expansion. Our data are consistent with the hypothesis that hydrostatic constraints on leaf morphology drive the vertical increase in LMA with height early in the growing season; however, LMA in the upper canopy continued to increase over time during light acclimation, indicating that light is primarily driving gradients in LMA later in the growing season. Models with no seasonal variation in Narea overestimated Ac by up to 11% early in the growing season, while models with no vertical variation in Narea overestimated Ac by up to 60% throughout the season. According to the multilayer model, the upper 25% of leaf area contributed to over 50% of Ac, but when gradients of intercellular CO2, as estimated from δ(13)C, were accounted for, the upper 25% of leaf area contributed to 26% of total Ac Our results suggest that ignoring vertical variation of key traits can lead to considerable overestimation of Ac.

  18. 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

  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. Climatic and Edaphic Effects on the Turnover and Composition of Mineral-Associated Soil Organic Matter in Temperate Deciduous Forests

    NASA Astrophysics Data System (ADS)

    Jastrow, J. D.; Calderon, F. J.; McFarlane, K. J.; Porras, R. C.; Torn, M. S.; Guilderson, T. P.; Hanson, P. J.

    2013-12-01

    Soil organic matter (SOM) is the largest reservoir of carbon (C) in terrestrial ecosystems. But, efforts to predict future changes in soil C stocks are challenged by our incomplete understanding of how soil C pools stabilized by different mechanisms will respond to changing climatic conditions and other environmental forcing factors. One approach to quantifying soil C pools of differing stability is to physically fractionate SOM into (1) a free light fraction representing an unprotected C pool, (2) an occluded light fraction characterizing a pool physically protected within aggregates, and (3) a mineral-associated dense fraction approximating a pool stabilized by organomineral interactions. Although the two light fractions are generally considered to be relatively homogenous pools, any assumption that the dense fraction represents a homogenous pool is problematic. To explore the potential for reducing the heterogeneity within the dense fraction, we isolated acid-hydrolyzable and acid-resistant C pools from the dense fraction at four sites representing a range of soil types and the climatic extent of Eastern deciduous forest. Soils were collected from before and after 14C-enriched leaf-litter manipulations at each site. Across all sites, 50-75% of the C in the dense fraction was acid-hydrolyzable, and the mean turnover time of C in this fraction was 1-2 orders of magnitude faster (~35-350 y) than that of the acid-resistant fraction (~300-1500 y). Remarkably, in some cases leaf-derived 14C accounted for up to about 5% of the C in one or both dense fraction pools after only 2 years, demonstrating the existence of a very rapid turnover component within both pools at some sites. Characterization of these mineral-associated C pools by mid-infrared spectroscopy showed variations in C chemistry across sites and site differences in the types of C isolated by hydrolysis. Taken together, these results demonstrate considerable differences within the Eastern deciduous forest in

  1. Linking canopy phenology to the seasonality of biosphere-atmosphere interactions in a temperate deciduous forest (Invited)

    NASA Astrophysics Data System (ADS)

    Richardson, A. D.; Toomey, M. P.; Aubrecht, D.; Sonnentag, O.; Ryu, Y.; Hilker, T.

    2013-12-01

    Phenology - the annual rhythm of canopy development and senescence - is a key control on the seasonality of surface-atmosphere fluxes of CO2, water, and energy. Phenology is also a highly sensitive indicator of the biological impacts of climate change. In many biomes, there is strong evidence of trends towards earlier spring onset, and later autumn senescence, over the last four decades. These shifts in phenology may play an imprortant role in mitigating - or amplifying - feedbacks between terrestrial ecosystems and the climate system. To better understand relationships between canopy structure and function in a temperate deciduous forest, we installed a wide array of radiometric instruments and imaging sensors near the top of a 40-m high tower at Harvard Forest beginning in 2011. Our data set includes: - incoming and outgoing visible (including incoming direct and diffuse components), shortwave, and longwave radiation; - narrowband (five visible and three near-infrared channels) canopy reflectance; - leaf area index (LAI, from continuous below-canopy digital cover photography), fraction of absorbed photosynthetically active radiation (fAPAR, from above- and below-canopy quantum sensors), normalized difference vegetation index (NDVI, from broad- and narrow-band radiometric sensors), and photochemical reflectance index (PRI, from narrow-band radiometric sensors); - visible and near-infrared PhenoCam (http://phenocam.sr.unh.edu) canopy imagery; - multi-angular narrowband hyperspectral canopy reflectance (AMSPEC, in 2012); and - beginning in 2013, hyperspectral and thermal canopy imagery. Together with eddy covariance measurements of CO2 and water fluxes from the Harvard Forest AmeriFlux site, located in similar forest about 1 km to the east, on-the-ground visual observations of phenology, and continuous stem diameter measurements with automated band dendrometers, these data provide an unusually detailed view of phenological processes at scales from leaves to trees to

  2. 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.

  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.

  4. 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...

  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. 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.

  7. Frugivory and seed dispersal of Solanum granuloso-leprosum Dunal (Solanaceae) by birds in deciduous seasonal forest.

    PubMed

    Jacomassa, F A F

    2016-01-01

    The goal of this study was to identify which bird species consume Solanum granuloso-leprosum fruits and disperse its seeds. 60 hours of focal observations were carried out between April and May 2006 on the edge of a deciduous forest fragment in the Uruguay River region, Rio Grande do Sul state, Brazil. Ten species were observed in total removing 443 fruits. Saltator similis removed 61.8% of the fruits, followed by Tangara sayaca (17.1%), Pipraeidea bonariensis (11.7%), and T. preciosa (6.8%), while the remaining six species accounted for only 2.5% of the fruits removed. Most fruit removal occurred early in the day or mid-afternoon. The most common feeding behaviors were picking (60.7%), followed by stalling (23%) and hovering (16%). Birds flew more than 10 m from the fruit plant in 62% of the removal events. All bird species observed here may be considered potential dispersers of S. granuloso-leprosum, as they moved the seeds away from the mother plant where strong competition and predation are likely to occur. Results also suggest that S. granuloso-leprosum may be useful in ecological restoration programs.

  8. Quantitative linking of dominant environmental drivers and fluxes with vertical CO2 fluxes of eight deciduous forests

    NASA Astrophysics Data System (ADS)

    Ishtiaq, K. S.; Abdul-Aziz, O.

    2013-12-01

    We used a simple, systematic approach to analyze observational data (level 2; 30 minutes interval) and quantitatively link the dominant ecosystem-scale environmental drivers/fluxes with the canopy level vertical CO2 exchanges in eight U.S. deciduous forests of AmeriFLUX Network. Principal Component Analysis (PCA) and Factor Analysis (FA) were applied to identify data groupings and determine comparative rankings of participatory variables. Explanatory, normalized multiple linear regression models were developed to extract the statistically significant, relatively uncorrelated predictors and their relative weights on CO2 flux dynamics. Radiation components (Net radiation and photosynthetically active radiation) along with the ecosystem heat fluxes (sensible and latent heat) were the most dominant predictors, whereas temperature related variables (air temperature, soil temperature and vapor pressure deficit) moderately effected carbon flux exchanges. Velocity constituents (wind speed and friction velocity) were less explanatory in capturing the variances of small (30 min) temporal scale carbon flux exchanges. Radiation and heat flux components were around 3 to 5 times stronger than temperature variables and 8 to16 times stronger than velocity components for all the study sites. Developed models exhibited acceptable performance in explaining vertical carbon flux exchanges (coefficient of determination, R2: 0.57-0.80; and ratio of root mean square error (RMSE) to observations' standard deviation, RSR: 0.43-0.66). Invariant patterns and groupings of different predictors and their relative weights highlight the prospect of developing spatio-temporally robust models for predicting terrestrial carbon fluxes under a changing climate and environment.

  9. The role of dung beetles as a secondary seed disperser after dispersal by frugivore mammals in a temperate deciduous forest

    NASA Astrophysics Data System (ADS)

    Koike, Shinsuke; Morimoto, Hideto; Kozakai, Chinatsu; Arimoto, Isao; Soga, Masashi; Yamazaki, Koji; Koganezawa, Masaaki

    2012-05-01

    We studied the effects of dung beetles on the fates of endozoochorous seeds of five species (Prunus jamasakura, Prunus verecunda, Prunus grayana, Swida controversa, and Vitis coignetiae) in a temperate deciduous forest in Japan during 2004-2006. In field experiments using dung of the Asiatic black bear (Ursus thibetanus), we investigated the depths that dung beetles (Onthophagus atripennis, Onthophagus lenzii, and Phelotrupes auratus) buried seeds (4.8-6.8 mm diameter) and plastic markers (2 or 5 mm diameter), the levels of predation on buried and unburied seeds, and germination rates of seeds buried to different depths. All three species buried the 2-mm markers, but only P. auratus buried the seeds and 5-mm markers. There were seasonal differences in mean seed burial rates (range, 27-51%) and depths (range, 1-27 mm). Significantly more seeds were buried in June, July, and September than in August or October, and the mean burial depth was significantly deeper in June and July. Most seeds and markers were buried to a 3-6 cm depth. Germination of seeds that were positioned at depths of 1-4 cm was significantly greater than that of seeds left on the surface or buried at greater depths. Buried seeds were less likely to disappear than seeds at the surface, which may reflect differential predation. These results suggested that dung beetles, especially P. auratus, acted as a secondary seed disperser that affected the survival and distribution of seeds dispersed by a frugivore.

  10. 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

  11. 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

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

    PubMed

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

    2016-09-12

    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.

  13. Water Vapor Storage Change in the Canopy-Air Space of a Tall Deciduous Forest

    NASA Astrophysics Data System (ADS)

    Wade, C.; Dragoni, D.; Schmid, H.

    2005-05-01

    The ability of weather and climate models to predict humidity, cloud formation and precipitation critically depends on the exchange of water vapor between vegetation and the atmosphere. The canopy air-space in tall forests is deep enough to act as a buffer volume that is depleted at times of well developed turbulent mixing, and gets recharged in conditions of poor mixing. Recent studies have attributed biases in modeled vapor exchange to the misrepresentation or neglect of this mechanism. At the Morgan-Monroe State Forest AmeriFlux site (Indiana, USA), water vapor exchange and the vapor storage change in the canopy air-space has been observed for the last six years. The objective of this work is to calculate vapor storage change fluxes in the canopy air-space from time increments of concentration profiles from data collected in 2003. We relate vapor storage change fluxes to measured environmental forcing quanitites, such as net radiation, ambient vapor pressure deficit, dew-point temperature depression, stability, and friction velocity to interpret the observed seasonal and daily patterns. Also, changes in water vapor storage rates are compared with measured latent heat fluxes to determine how the total forest-atmosphere vapor exchange is affected by the recharging and depletion of water vapor throughout the canopy air-space.

  14. Resource stoichiometry and the biogeochemical consequences of nitrogen deposition in a mixed deciduous forest.

    PubMed

    Midgley, Meghan G; Phillips, Richard P

    2016-12-01

    Ecosystems often show differential sensitivity to chronic nitrogen (N) deposition; hence, a critical challenge is to improve our understanding of how and why site-specific factors mediate biogeochemical responses to N enrichment. We examined the extent to which N impacts on soil carbon (C) and N dynamics depend on microbial resource stoichiometry. We added N to forest plots dominated by ectomycorrhizal (ECM) trees, which have litter and soil pools rich in organic N and relatively wide C:N ratios, and adjacent forest plots dominated by arbuscular mycorrhizal (AM) trees, which have litter and soil pools rich in inorganic N and relatively narrow C:N ratios. While microbes in both plot types exhibited fairly strict biomass homeostasis, microbes in AM- and ECM-dominated plots differed in their physiological responses to N addition. Microbes in ECM plots responded to N enrichment by decreasing their investment in N-acquisition enzymes (relative to C-acquisition enzymes) and increasing N mineralization rates (relative to C mineralization rates), suggesting that N addition alleviated microbial N demand. In contrast, heterotrophic microbial activities in AM plots were unaffected by N addition, most likely as a result of N-induced increases in net nitrification (60% increase relative to control plots) and nitrate mobilization (e.g., sixfold increases in mobilization relative to control plots). Combined, our findings suggest the stoichiometric differences between AM and ECM soils are the primary drivers of the observed responses. Plant and microbial communities characterized by wide C:N are more susceptible to N-induced changes in decomposition and soil C dynamics, whereas communities characterized by narrow C:N are more susceptible to N-induced nitrate leaching losses. Hence, the biogeochemical consequences of N deposition in temperate forests may be driven by the stoichiometry of the dominant trees and their associated microbes.

  15. 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.

  16. Invasion by the Alien Tree Prunus serotina Alters Ecosystem Functions in a Temperate Deciduous Forest.

    PubMed

    Aerts, Raf; Ewald, Michael; Nicolas, Manuel; Piat, Jérôme; Skowronek, Sandra; Lenoir, Jonathan; Hattab, Tarek; Garzón-López, Carol X; Feilhauer, Hannes; Schmidtlein, Sebastian; Rocchini, Duccio; Decocq, Guillaume; Somers, Ben; Van De Kerchove, Ruben; Denef, Karolien; Honnay, Olivier

    2017-01-01

    Alien invasive species can affect large areas, often with wide-ranging impacts on ecosystem structure, function, and services. Prunus serotina is a widespread invader of European temperate forests, where it tends to form homogeneous stands and limits recruitment of indigenous trees. We hypotesized that invasion by P. serotina would be reflected in the nutrient contents of the native species' leaves and in the respiration of invaded plots as efficient resource uptake and changes in nutrient cycling by P. serotina probably underly its aggressive invasiveness. We combined data from 48 field plots in the forest of Compiègne, France, and data from an experiment using 96 microcosms derived from those field plots. We used general linear models to separate effects of invasion by P. serotina on heterotrophic soil and litter respiration rates and on canopy foliar nutrient content from effects of soil chemical properties, litter quantity, litter species composition, and tree species composition. In invaded stands, average respiration rates were 5.6% higher for soil (without litter) and 32% higher for soil and litter combined. Compared to indigenous tree species, P. serotina exhibited higher foliar N (+24.0%), foliar P (+50.7%), and lower foliar C:N (-22.4%) and N:P (-10.1%) ratios. P. serotina affected foliar nutrient contents of co-occuring indigenous tree species leading to decreased foliar N (-8.7 %) and increased C:N ratio (+9.5%) in Fagus sylvatica, decreased foliar N:P ratio in Carpinus betulus (-13.5%) and F. sylvatica (-11.8%), and increased foliar P in Pinus sylvestris (+12.3%) in invaded vs. uninvaded stands. Our results suggest that P. serotina is changing nitrogen, phosphorus, and carbon cycles to its own advantage, hereby increasing carbon turnover via labile litter, affecting the relative nutrient contents in the overstory leaves, and potentially altering the photosynthetic capacity of the long-lived indigenous broadleaved species. Uncontrolled invasion of

  17. Invasion by the Alien Tree Prunus serotina Alters Ecosystem Functions in a Temperate Deciduous Forest

    PubMed Central

    Aerts, Raf; Ewald, Michael; Nicolas, Manuel; Piat, Jérôme; Skowronek, Sandra; Lenoir, Jonathan; Hattab, Tarek; Garzón-López, Carol X.; Feilhauer, Hannes; Schmidtlein, Sebastian; Rocchini, Duccio; Decocq, Guillaume; Somers, Ben; Van De Kerchove, Ruben; Denef, Karolien; Honnay, Olivier

    2017-01-01

    Alien invasive species can affect large areas, often with wide-ranging impacts on ecosystem structure, function, and services. Prunus serotina is a widespread invader of European temperate forests, where it tends to form homogeneous stands and limits recruitment of indigenous trees. We hypotesized that invasion by P. serotina would be reflected in the nutrient contents of the native species' leaves and in the respiration of invaded plots as efficient resource uptake and changes in nutrient cycling by P. serotina probably underly its aggressive invasiveness. We combined data from 48 field plots in the forest of Compiègne, France, and data from an experiment using 96 microcosms derived from those field plots. We used general linear models to separate effects of invasion by P. serotina on heterotrophic soil and litter respiration rates and on canopy foliar nutrient content from effects of soil chemical properties, litter quantity, litter species composition, and tree species composition. In invaded stands, average respiration rates were 5.6% higher for soil (without litter) and 32% higher for soil and litter combined. Compared to indigenous tree species, P. serotina exhibited higher foliar N (+24.0%), foliar P (+50.7%), and lower foliar C:N (−22.4%) and N:P (−10.1%) ratios. P. serotina affected foliar nutrient contents of co-occuring indigenous tree species leading to decreased foliar N (−8.7 %) and increased C:N ratio (+9.5%) in Fagus sylvatica, decreased foliar N:P ratio in Carpinus betulus (−13.5%) and F. sylvatica (−11.8%), and increased foliar P in Pinus sylvestris (+12.3%) in invaded vs. uninvaded stands. Our results suggest that P. serotina is changing nitrogen, phosphorus, and carbon cycles to its own advantage, hereby increasing carbon turnover via labile litter, affecting the relative nutrient contents in the overstory leaves, and potentially altering the photosynthetic capacity of the long-lived indigenous broadleaved species. Uncontrolled

  18. 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.

  19. 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.

  20. Fleshy fruit characteristics in a temperate deciduous forest of Japan: how unique are they?

    PubMed

    Masaki, Takashi; Takahashi, Kazuaki; Sawa, Ayako; Kado, Tomoyuki; Naoe, Shoji; Koike, Shinsuke; Shibata, Mitsue

    2012-01-01

    This study investigated the fleshy fruit characteristics of 28 woody species in a Japanese temperate forest where large sedentary seed-dispersing mammals are present. We tested whether the findings in previous studies in temperate forests of Europe and North America are universal or not. Results have suggested that fruits of all species were eaten both by birds and mammals except for four species with larger fruits, which were eaten only by mammals. A gradient was found from a syndrome characterized by small, oily, and large-seeded fruits to a syndrome characterized by large, succulent, non-oily, and small-seeded fruits. The sizes and colors of the fruits were not conspicuously different from previous findings in Europe and North America. On the other hand, nitrogen and lipids in the fleshy part did not show seasonally increasing trends, or even seasonally decreasing trends in terms of dry weight. This result, suggesting the absence of community-level adaptation of fruit traits to migratory bird dispersers, contrasted with findings in Europe and North America. Large sedentary arboreal or tree-climbing mammals may have a greater effect on the evolution of fruit-disperser relations than opportunistic migratory birds.

  1. 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.

  2. Elevated CO2 reduces sap flux in mature deciduous forest trees.

    PubMed

    Cech, Patrick G; Pepin, Steeve; Körner, Christian

    2003-10-01

    We enriched in CO2 the canopy of 14 broad-leaved trees in a species-rich, ca. 30-m-tall forest in NW Switzerland to test whether elevated CO2 reduces water use in mature forest trees. Measurements of sap flux density (JS) were made prior to CO2 enrichment (summer 2000) and throughout the first whole growing season of CO2 exposure (2001) using the constant heat-flow technique. The short-term responses of sap flux to brief (1.5-3 h) interruptions of CO2 enrichment were also examined. There were no significant a priori differences in morphological and physiological traits between trees which were later exposed to elevated CO2 (n=14) and trees later used as controls (n=19). Over the entire growing season, CO2 enrichment resulted in an average 10.7% reduction in mean daily JS across all species compared to control trees. Responses were most pronounced in Carpinus, Acer, Prunus and Tilia, smaller in Quercus and close to zero in Fagus trees. The JS of treated trees significantly increased by 7% upon transient exposure to ambient CO2 concentrations at noon. Hence, responses of the different species were, in the short term, similar in magnitude to those observed over the whole season (though opposite because of the reversed treatment). The reductions in mean JS of CO2-enriched trees were high (22%) under conditions of low evaporative demand (vapour pressure deficit, VPD <5 hPa) and small (2%) when mean daily VPD was greater than 10 hPa. During a relatively dry period, the effect of elevated CO2 on JS even appeared to be reversed. These results suggest that daily water savings by CO2-enriched trees may have accumulated to a significantly improved water status by the time when control trees were short of soil moisture. Our data indicate that the magnitude of CO2 effects on stand transpiration will depend on rainfall regimes and the relative abundance of the different species, being more pronounced under humid conditions and in stands dominated by species such as Carpinus and

  3. 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.

  4. Determinants of seed removal distance by scatter-hoarding rodents in deciduous forests.

    PubMed

    Moore, Jeffrey E; McEuen, Amy B; Swihart, Robert K; Contreras, Thomas A; Steele, Michael A

    2007-10-01

    Scatter-hoarding rodents should space food caches to maximize cache recovery rate (to minimize loss to pilferers) relative to the energetic cost of carrying food items greater distances. Optimization models of cache spacing make two predictions. First, spacing of caches should be greater for food items with greater energy content. Second, the mean distance between caches should increase with food abundance. However, the latter prediction fails to account for the effect of food abundance on the behavior of potential pilferers or on the ability of caching individuals to acquire food by means other than recovering their own caches. When considering these factors, shorter cache distances may be predicted in conditions of higher food abundance. We predicted that seed caching distances would be greater for food items of higher energy content and during lower ambient food abundance and that the effect of seed type on cache distance variation would be lower during higher food abundance. We recorded distances moved for 8636 seeds of five seed types at 15 locations in three forested sites in Pennsylvania, USA, and 29 forest fragments in Indiana, U.S.A., across five different years. Seed production was poor in three years and high in two years. Consistent with previous studies, seeds with greater energy content were moved farther than less profitable food items. Seeds were dispersed less far in seed-rich years than in seed-poor years, contrary to predictions of conventional models. Interactions were important, with seed type effects more evident in seed-poor years. These results suggest that, when food is superabundant, optimal cache distances are more strongly determined by minimizing energy cost of caching than by minimizing pilfering rates and that cache loss rates may be more strongly density-dependent in times of low seed abundance.

  5. Antioxidant content in two CAM bromeliad species as a response to seasonal light changes in a tropical dry deciduous forest.

    PubMed

    González-Salvatierra, Claudia; Luis Andrade, José; Escalante-Erosa, Fabiola; García-Sosa, Karlina; Manuel Peña-Rodríguez, Luis

    2010-07-01

    Plants have evolved photoprotective mechanisms to limit photodamage; one of these mechanisms involves the biosynthesis of antioxidant metabolites to neutralize reactive oxygen species generated when plants are exposed to excess light. However, it is known that exposure of plants to conditions of extreme water stress and high light intensity results in their enhanced susceptibility to over-excitation of photosystem II and to photooxidative stress. In this investigation we used the 2,2-diphenyl-1-picrylhydrazyl reduction assay to conduct a broad survey of the effect of water availability and light exposure conditions on the antioxidant activity of the leaf extracts of two bromeliad species showing crassulacean acid metabolism. One of these was an epiphyte, Tillandsia brachycaulos, and the other a terrestrial species, Bromelia karatas. Both species were found growing wild in the tropical dry deciduous forest of Dzibilchaltún National Park, México. The microenvironment of T. brachycaulos and B. karatas experiences significant diurnal and seasonal light variations as well as changes in temperature and water availability. The results obtained showed that, for both bromeliads, increases in antioxidant activity occurred during the dry season, as a consequence of water stress and higher light conditions. Additionally, in T. brachycaulos there was a clear correlation between high light intensity conditions and the content of anthocyanins which accumulated below the leaf epidermis. This result suggests that the role of these pigments is as photoprotective screens in the leaves. The red coloration below the leaf epidermis of B. karatas was not due to anthocyanins but to other unidentified pigments.

  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. Dynamics of canopy stomatal conductance, transpiration, and evaporation in a temperate deciduous forest, validated by carbonyl sulfide uptake

    NASA Astrophysics Data System (ADS)

    Wehr, Richard; Commane, Róisín; Munger, J. William; McManus, J. Barry; Nelson, David D.; Zahniser, Mark S.; Saleska, Scott R.; Wofsy, Steven C.

    2017-01-01

    Stomatal conductance influences both photosynthesis and transpiration, thereby coupling the carbon and water cycles and affecting surface-atmosphere energy exchange. The environmental response of stomatal conductance has been measured mainly on the leaf scale, and theoretical canopy models are relied on to upscale stomatal conductance for application in terrestrial ecosystem models and climate prediction. Here we estimate stomatal conductance and associated transpiration in a temperate deciduous forest directly on the canopy scale via two independent approaches: (i) from heat and water vapor exchange and (ii) from carbonyl sulfide (OCS) uptake. We use the eddy covariance method to measure the net ecosystem-atmosphere exchange of OCS, and we use a flux-gradient approach to separate canopy OCS uptake from soil OCS uptake. We find that the seasonal and diurnal patterns of canopy stomatal conductance obtained by the two approaches agree (to within ±6 % diurnally), validating both methods. Canopy stomatal conductance increases linearly with above-canopy light intensity (in contrast to the leaf scale, where stomatal conductance shows declining marginal increases) and otherwise depends only on the diffuse light fraction, the canopy-average leaf-to-air water vapor gradient, and the total leaf area. Based on stomatal conductance, we partition evapotranspiration (ET) and find that evaporation increases from 0 to 40 % of ET as the growing season progresses, driven primarily by rising soil temperature and secondarily by rainfall. Counterintuitively, evaporation peaks at the time of year when the soil is dry and the air is moist. Our method of ET partitioning avoids concerns about mismatched scales or measurement types because both ET and transpiration are derived from eddy covariance data. Neither of the two ecosystem models tested predicts the observed dynamics of evaporation or transpiration, indicating that ET partitioning such as that provided here is needed to further

  8. Isotopic evidence for the role of plant development on transpiration in deciduous forests of southern United States

    NASA Astrophysics Data System (ADS)

    Mora, GermáN.; Jahren, A. Hope

    2003-06-01

    We evaluated D/H ratios of soil- and plant-extracted water during the 1997 growing season to assess the influence of temperature, humidity, and rainfall on water distribution in deciduous forests. Three state parks (Chicot in Arkansas; Natchez in Mississippi, and St. Bernard in Louisiana) were identified along a 13.5-cm precipitation gradient established during the studied growing season within the Mississippi River basin. Samples were collected for isotopic determinations from five to six species at each site early (March) and late (June) in the growing season. To capture the isotopic variability in water sources, samples of rainwater, groundwater, and soil water were collected. Isotopic results for rainwater showed an average increase of 4‰ from March to June. This increase did not transfer to soil water: soil water δD values throughout the growing season showed values close to those measured for March rainwater. In contrast, leaf water showed δD values that were 15‰ to 20‰ higher in March compared to June δD values. Elevated March δD values in leaf water were observed in virtually all species at the three sites. Change in leaf water δD value during the growing season was not correlated with precipitation rate, temperature, humidity, or changes in atmospheric water vapor isotopic composition. We propose that this widespread March isotopic enrichment resulted from enhanced evaporative demand induced by accelerated plant growth early in the growing season. This suggestion implies a decoupling of environmental factors and plant response, pointing to the important role of plant developmental timing in ecosystem functioning.

  9. Dynamics of canopy stomatal conductance, transpiration, and evaporation in a temperate deciduous forest, validated by carbonyl sulfide uptake

    DOE PAGES

    Wehr, Richard; Commane, Róisín; Munger, J. William; ...

    2017-01-26

    Stomatal conductance influences both photosynthesis and transpiration, thereby coupling the carbon and water cycles and affecting surface–atmosphere energy exchange. The environmental response of stomatal conductance has been measured mainly on the leaf scale, and theoretical canopy models are relied on to upscale stomatal conductance for application in terrestrial ecosystem models and climate prediction. Here we estimate stomatal conductance and associated transpiration in a temperate deciduous forest directly on the canopy scale via two independent approaches: (i) from heat and water vapor exchange and (ii) from carbonyl sulfide (OCS) uptake. We use the eddy covariance method to measure the net ecosystem–atmosphere exchange ofmore » OCS, and we use a flux-gradient approach to separate canopy OCS uptake from soil OCS uptake. We find that the seasonal and diurnal patterns of canopy stomatal conductance obtained by the two approaches agree (to within ±6 % diurnally), validating both methods. Canopy stomatal conductance increases linearly with above-canopy light intensity (in contrast to the leaf scale, where stomatal conductance shows declining marginal increases) and otherwise depends only on the diffuse light fraction, the canopy-average leaf-to-air water vapor gradient, and the total leaf area. Based on stomatal conductance, we partition evapotranspiration (ET) and find that evaporation increases from 0 to 40 % of ET as the growing season progresses, driven primarily by rising soil temperature and secondarily by rainfall. Counterintuitively, evaporation peaks at the time of year when the soil is dry and the air is moist. Our method of ET partitioning avoids concerns about mismatched scales or measurement types because both ET and transpiration are derived from eddy covariance data. Neither of the two ecosystem models tested predicts the observed dynamics of evaporation or transpiration, indicating that ET partitioning such as that provided here is

  10. Development of a Satellite-based evapotranspiration algorithm: A case study for Two Deciduous Forest Sites

    NASA Astrophysics Data System (ADS)

    Elmasri, B.; Rahman, A. F.

    2011-12-01

    We introduce a new methodology to estimate 8-day average daily evapotranspiration (ET) using both routinely available data and the Penman-Monteith (P-M) equation. Our algorithm considers the environmental constraints on surface resistance and ET by (1) including vapor pressure deficit (VPD), incoming solar radiation, soil moisture, and temperature constraints on stomatal conductance; (2) using leaf area index (LAI) to scale from the leaf to the canopy conductance; and (3) calculating canopy resistance as a function of environmental variables such as net radiation, precipitation index, and VPD. Remote sensing data from the Moderate Resolution Spectroradiometer (MODIS) and the Advance Microwave Scanning Radiometer-EOS (AMSR-E) were used to estimate ET by using MODIS land surface temperature (LST) to estimated VPD, AMSR-E soil moisture to estimate canopy conductance, and MODIS surface emissivity and albedo to estimate shortwave and net radiation. The algorithm was evaluated using ET observations from two AmeriFlux Eddy covariance flux towers located at the Morgan Monroe State Forest (MMSF) in Indiana and the Harvard Forest (HarvF) in Massachusetts for the periods of 2003-2008. ET estimates from our algorithm was compared to the flux observations. Results indicated a root mean square error (RMSE) of the 8-day average ET of 0.57 mm for the HarvF and 0.47 mm for the MMSF. A significant correlation was found between the estimated 8-day average ET and the observed 8-day average ET with r2 of 0.84 for the HarvF and 0.88 for the MMSF. Using tower meteorological data, the r2 slightly increased to 0.90 for the MMSF. The algorithms for VPD and radiation were tested against flux observations and found a strong correlation with r2 ranging from 0.68 to 0.82. Sensitivity analysis revealed that the modeled ET predictions are highly sensitive to changes in the canopy resistance values, so accurate estimates of canopy resistance is essential for improve ET predictions. Our algorithm

  11. 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.

  12. 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.

  13. Carbon and Energy Fluxes Over two Mid-Latitude Deciduous Forests: Interannual and Latitudinal Variations

    NASA Astrophysics Data System (ADS)

    Schmid, H.; Grimmond, S.; Oliphant, A.; Su, H.; Vogel, C.; Scott, S.; Curtis, P.

    2001-12-01

    Hourly fluxes of energy, water vapor and CO2 are now available from two AmeriFlux sites in Indiana (MMSF, 39deg 10'N, 86deg 25' W, for the years 1998-2001, up to the end of the growth period) and Michigan (UMBS, 45deg 35' N, 84deg 42' W, for 1999-2001). Both sites are in extensive hardwood forests of a similar age, but the composition and diversity of tree species is quite different between the two locations. The latitudinal separation of more than 6.5 degrees causes also marked differences in the biophysical forcings of the ecosystem exchange, such as variations in growing season legth, summertime length of day, and soil thermal regimes in winter. The Indiana site was affected by a severe drought over much of summer and fall of 1999, whereas the Michigan site was only marginally affected by it. We present the seasonal carbon exchange dynamics and annual increments of net ecosystem exchange in the context of the energy and water availability and compare the results from four years of measurements in the light of these geographical and interannual variations in the ecosystem forcings.

  14. 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).

  15. 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.

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

    PubMed

    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.

  17. 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.

  18. Predicting vegetation type through physiological and environmental interactions with leaf traits: evergreen and deciduous forests in an earth system modeling framework.

    PubMed

    Weng, Ensheng; Farrior, Caroline E; Dybzinski, Ray; Pacala, Stephen W

    2016-10-26

    Earth system models are incorporating plant trait diversity into their land components to better predict vegetation dynamics in a changing climate. However, extant plant trait distributions will not allow extrapolations to novel community assemblages in future climates, which will require a mechanistic understanding of the trade-offs that determine trait diversity. In this study, we show how physiological trade-offs involving leaf mass per unit area (LMA), leaf lifespan, leaf nitrogen, and leaf respiration may explain the distribution patterns of evergreen and deciduous trees in the temperate and boreal zones based on (1) an evolutionary analysis of a simple mathematical model and (2) simulation experiments of an individual-based dynamic vegetation model (i.e., LM3-PPA). The evolutionary analysis shows that these leaf traits set up a trade-off between carbon- and nitrogen-use efficiency at the scale of individual trees and therefore determine competitively dominant leaf strategies. As soil nitrogen availability increases, the dominant leaf strategy switches from one that is high in nitrogen-use efficiency to one that is high in carbon-use efficiency or, equivalently, from high-LMA/long-lived leaves (i.e., evergreen) to low-LMA/short-lived leaves (i.e., deciduous). In a region of intermediate soil nitrogen availability, the dominant leaf strategy may be either deciduous or evergreen depending on the initial conditions of plant trait abundance (i.e., founder controlled) due to feedbacks of leaf traits on soil nitrogen mineralization through litter quality. Simulated successional patterns by LM3-PPA from the leaf physiological trade-offs are consistent with observed successional dynamics of evergreen and deciduous forests at three sites spanning the temperate to boreal zones.

  19. Spatiotemporal dynamics of Floerkea proserpinacoides (Limnanthaceae), an annual plant of the deciduous forest of eastern North America.

    PubMed

    Houle, G; McKenna, M F; Lapointe, L

    2001-04-01

    Because environmental filters are temporally and spatially heterogeneous, there often is a lack of significant relationship between the spatial patterns of successive life stages in plant populations. In this study, we determined the spatiotemporal relationships between different life stages in two populations of an annual plant of the deciduous forests of eastern North America, Floerkea proserpinacoides. Demographic surveys were done over a 4-yr period, and experiments were performed in the field and under controlled conditions to test for the effects of various environmental factors on population dynamics. There was a general lack of relationship between the spatial patterns of seed bank and seedling density, and a lack of similarity between their spatial correlograms. This was related mostly to the effects of spatially variable environmental filters operating on germination and emergence. However, environmental filters acting on plant survival were stable through time and contributed to stabilize the density and spatial patterns of the populations. Despite density-dependent presenescence mortality, spatial patterns of seedlings and mature individuals were similar and their correlograms were alike, suggesting that mortality did not fully compensate for density. Estimated fecundity was negatively correlated with population density over the study period. Although flower production started only 2-3 wk after emergence, seed maturation mostly occurred at the end of the life cycle, just before the onset of plant senescence. Yet, individual fecundity was low for an annual plant, i.e., 3.0 ± 0.5 mature seeds/plant (mean ± 1 SE). Seed predation by vertebrates was not significant. Low soil moisture had little effect on the total number of seeds germinating, although it slowed down the germination process. In quadrats where leaf litter was experimentally doubled, seedling emergence was lower than in control quadrats; in quadrats where leaf litter was completely removed

  20. AmeriFlux US-MMS Morgan Monroe State Forest

    DOE Data Explorer

    Philip, Rich [Indiana Univ., Bloomington, IN (United States); Novick, Kim [Indiana Univ., Bloomington, IN (United States)

    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.

  1. 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.

  2. 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.

  3. 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

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

    DOE PAGES

    Seco, Roger; Karl, Thomas; Guenther, Alex; ...

    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

  5. 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

  6. A metagenomics-based approach to the top-down effect on the detritivore food web: a salamanders influence on fungal communities within a deciduous forest

    PubMed Central

    Walker, Donald M; Lawrence, Brandy R; Esterline, Dakota; Graham, Sean P; Edelbrock, Michael A; Wooten, Jessica A

    2014-01-01

    The flow of energy within an ecosystem can be considered either top-down, where predators influence consumers, or bottom-up, where producers influence consumers. Plethodon cinereus (Red-backed Salamander) is a terrestrial keystone predator who feeds on invertebrates within the ecosystem. We investigated the impact of the removal of P. cinereus on the detritivore food web in an upland deciduous forest in northwest Ohio, U.S.A. A total of eight aluminum enclosures, each containing a single P. cinereus under a small log, were constructed in the deciduous forest. On Day 1 of the experiment, four salamanders were evicted from four of the eight enclosures. Organic matter and soil were collected from the center of each enclosure at Day 1 and Day 21. From each sample, DNA was extracted, fungal-specific amplification performed, and 454 pyrosequencing was used to sequence the nuclear ribosomal internal transcribed spacer (ITS2) region and partial ribosomal large subunit (LSU). Changes in overall fungal community composition or species diversity were not statistically significant between treatments. Statistically significant shifts in the most abundant taxonomic groups of fungi were documented in presence but not absence enclosures. We concluded that P. cinereus does not affect the overall composition or diversity of fungal communities, but does have an impact on specific groups of fungi. This study used a metagenomics-based approach to investigate a missing link among a keystone predator, P. cinereus, invertebrates, and fungal communities, all of which are critical in the detritivore food web. PMID:25505537

  7. A metagenomics-based approach to the top-down effect on the detritivore food web: a salamanders influence on fungal communities within a deciduous forest.

    PubMed

    Walker, Donald M; Lawrence, Brandy R; Esterline, Dakota; Graham, Sean P; Edelbrock, Michael A; Wooten, Jessica A

    2014-11-01

    The flow of energy within an ecosystem can be considered either top-down, where predators influence consumers, or bottom-up, where producers influence consumers. Plethodon cinereus (Red-backed Salamander) is a terrestrial keystone predator who feeds on invertebrates within the ecosystem. We investigated the impact of the removal of P. cinereus on the detritivore food web in an upland deciduous forest in northwest Ohio, U.S.A. A total of eight aluminum enclosures, each containing a single P. cinereus under a small log, were constructed in the deciduous forest. On Day 1 of the experiment, four salamanders were evicted from four of the eight enclosures. Organic matter and soil were collected from the center of each enclosure at Day 1 and Day 21. From each sample, DNA was extracted, fungal-specific amplification performed, and 454 pyrosequencing was used to sequence the nuclear ribosomal internal transcribed spacer (ITS2) region and partial ribosomal large subunit (LSU). Changes in overall fungal community composition or species diversity were not statistically significant between treatments. Statistically significant shifts in the most abundant taxonomic groups of fungi were documented in presence but not absence enclosures. We concluded that P. cinereus does not affect the overall composition or diversity of fungal communities, but does have an impact on specific groups of fungi. This study used a metagenomics-based approach to investigate a missing link among a keystone predator, P. cinereus, invertebrates, and fungal communities, all of which are critical in the detritivore food web.

  8. Predicting the onset of net carbon uptake by deciduous forests with soil temperature and climate data: a synthesis of FLUXNET data.

    PubMed

    Baldocchi, Dennis D; Black, T A; Curtis, P S; Falge, E; Fuentes, J D; Granier, A; Gu, L; Knohl, A; Pilegaard, K; Schmid, H P; Valentini, R; Wilson, K; Wofsy, S; Xu, L; Yamamoto, S

    2005-07-01

    We tested the hypothesis that the date of the onset of net carbon uptake by temperate deciduous forest canopies corresponds with the time when the mean daily soil temperature equals the mean annual air temperature. The hypothesis was tested using over 30 site-years of data from 12 field sites where CO(2) exchange is being measured continuously with the eddy covariance method. The sites spanned the geographic range of Europe, North America and Asia and spanned a climate space of 16 degrees C in mean annual temperature. The tested phenology rule was robust and worked well over a 75 day range of the initiation of carbon uptake, starting as early as day 88 near Ione, California to as late as day 147 near Takayama, Japan. Overall, we observed that 64% of variance in the timing when net carbon uptake started was explained by the date when soil temperature matched the mean annual air temperature. We also observed a strong correlation between mean annual air temperature and the day that a deciduous forest starts to be a carbon sink. Consequently we are able to provide a simple phenological rule that can be implemented in regional carbon balance models and be assessed with soil and temperature outputs produced by climate and weather models.

  9. A unique Middle Pleistocene beech (Fagus)-rich deciduous broad-leaved forest in the Yangtze Delta Plain, East China: Its climatic and stratigraphic implication

    NASA Astrophysics Data System (ADS)

    Shu, Jun-wu; Wang, Wei-ming

    2012-08-01

    Pollen analysis of Middle Pleistocene sediments from the Yangtze Delta Plain provides a paleoecological reconstruction and has implications for stratigraphic correlation in East China. The pollen assemblage is characterized by high values of Fagus (16.8% on average), which is unusual because Fagus is generally present only sporadically in other lowland Quaternary pollen records from the region. In addition to Fagus, the assemblage has a rich diversity of broad-leaved deciduous trees, including Quercus, Ulmus, Carpinus/Ostrya, Juglans, Betula, and Liquidambar, as well as conifers, including Pinus, Picea, Abies, Larix, and Tsuga. Thus, the pollen flora suggests a broad-leaved deciduous forest mixed with abundant conifers, which developed under cooler and more humid conditions than present. The stable pollen sequence throughout the studied section suggests a stable environment. Beech forests also characterize the Middle Pleistocene of Taiwan and Japan, and thus may be a stratigraphic indicator of the Middle Pleistocene in East Asia. The Yangtze Delta Plain may have been an important refugium for the last survival of Fagus in the lowlands.

  10. 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.

  11. Minor changes in soil organic carbon and charcoal concentrations detected in a temperate deciduous forest a year after an experimental slash-and-burn

    NASA Astrophysics Data System (ADS)

    Eckmeier, E.; Gerlach, R.; Skjemstad, J. O.; Ehrmann, O.; Schmidt, M. W. I.

    2007-06-01

    Anthropogenic fires affected the temperate deciduous forests of Central Europe over millennia. Biomass burning releases carbon to the atmosphere and produces charcoal, which potentially contributes to the stable soil carbon pools and is an important archive of environmental history. The fate of charcoal in soils of temperate deciduous forests, i.e. the processes of charcoal incorporation and transportation and the effects on soil organic matter are still not clear. We investigated the effects of slash-and-burn at a long-term experimental burning site and determined soil organic carbon and charcoal carbon concentrations as well as the soil lightness of colour (L*) in the topmost soil material (0-1, 1-2.5 and 2.5-5 cm depths) before, immediately after the fire and one year later. The main results are that (i) only a few of the charcoal particles from the forest floor were incorporated into the soil matrix, presumably by soil mixing animals. In the 0-1 cm layer, during one year, the charcoal C concentration increased only by 0.4 g kg-1 and the proportion of charcoal C to SOC concentration increased from 2.8 to 3.4%; (ii) the SOC concentrations did not show any significant differences; (iii) soil lightness decreased significantly in the topmost soil layer and correlated well with the concentrations of charcoal C (r=-0.87**) and SOC (r=-0.94**) in the samples from the 0-5 cm layer. We concluded that Holocene biomass burning could have influenced soil charcoal concentrations and soil colour.

  12. Only small changes in soil organic carbon and charcoal concentrations found one year after experimental slash-and-burn in a temperate deciduous forest

    NASA Astrophysics Data System (ADS)

    Eckmeier, E.; Gerlach, R.; Skjemstad, J. O.; Ehrmann, O.; Schmidt, M. W. I.

    2007-02-01

    Anthropogenic fires affected the temperate deciduous forests of Central Europe over millennia. Biomass burning releases carbon to the atmosphere and produces charcoal, which potentially contributes to the stable soil carbon pools and is an important archive of environmental history. The fate of charcoal in soils of temperate deciduous forests, i.e. the processes of charcoal incorporation and transportation, and the effects on soil organic matter are still not clear. In a long-term experimental burning site, we investigated the effects of slash-and-burn and determined soil organic carbon, charcoal carbon and nitrogen concentrations and the soil lightness of colour (L*) in the topmost soil material (0-1, 1-2.5 and 2.5-5 cm depths) before, immediately after the fire and one year after burning. The main results are that (i) only few charcoal particles from the forest floor were incorporated into the soil matrix by soil mixing animals. In 0-1 cm and during one year, the charcoal C concentrations increased only by 0.4 g kg-1 and the proportion of charcoal C to SOC concentrations increased from 2.8 to 3.4%; (ii) the SOC concentrations did not show any significant differences; (iii) soil lightness significantly decreased in the topmost soil layer and correlated with the concentrations of charcoal C (r=-0.87**) and SOC (r=-0.94**) in samples 0-5 cm. We concluded that the soil colour depends on the proportion of aromatic charcoal carbon in total organic matter and that Holocene burning could have influenced soil charcoal concentrations and soil colour.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. Reconstruction of the long-term fire history of an old-growth deciduous forest in Southern Québec, Canada, from charred wood in mineral soils

    NASA Astrophysics Data System (ADS)

    Talon, Brigitte; Payette, Serge; Filion, Louise; Delwaide, Ann

    2005-07-01

    Charcoal particles are widespread in terrestrial and lake environments of the northern temperate and boreal biomes where they are used to reconstruct past fire events and regimes. In this study, we used botanically identified and radiocarbon-dated charcoal macrofossils in mineral soils as a paleoecological tool to reconstruct past fire activity at the stand scale. Charcoal macrofossils buried in podzolic soils by tree uprooting were analyzed to reconstruct the long-term fire history of an old-growth deciduous forest in southern Québec. Charcoal fragments were sampled from the uppermost mineral soil horizons and identified based on anatomical characters. Spruce ( Picea spp.) fragments dominated the charcoal assemblage, along with relatively abundant wood fragments of sugar maple ( Acer saccharum) and birch ( Betula spp.), and rare fragments of pine ( Pinus cf. strobus) and white cedar ( Thuja canadensis). AMS radiocarbon dates from 16 charcoal fragments indicated that forest fires were widespread during the early Holocene, whereas no fires were recorded from the mid-Holocene to present. The paucity of charcoal data during this period, however, does not preclude that a fire event of lower severity may have occurred. At least eight forest fires occurred at the study site between 10,400 and 6300 cal yr B.P., with a dominance of burned conifer trees between 10,400 and 9000 cal yr B.P. and burned conifer and deciduous trees between 9000 and 6300 cal yr B.P. Based on the charcoal record, the climate at the study site was relatively dry during the early Holocene, and more humid from 6300 cal yr B.P. to present. However, it is also possible that the predominance of conifer trees in the charcoal record between 10,400 and 6300 cal yr B.P. created propitious conditions for fire spreading. The charcoal record supports inferences based on pollen influx data (Labelle, C., Richard, P.J.H. 1981. Végétation tardiglaciaire et postglaciaire au sud-est du Parc des Laurentides, Qu

  1. A new seasonal-deciduous spring phenology submodel in the Community Land Model 4.5: impacts on carbon and water cycling under future climate scenarios.

    PubMed

    Chen, Min; Melaas, Eli K; Gray, Josh M; Friedl, Mark A; Richardson, Andrew D

    2016-11-01

    A spring phenology model that combines photoperiod with accumulated heating and chilling to predict spring leaf-out dates is optimized using PhenoCam observations and coupled into the Community Land Model (CLM) 4.5. In head-to-head comparison (using satellite data from 2003 to 2013 for validation) for model grid cells over the Northern Hemisphere deciduous broadleaf forests (5.5 million km(2) ), we found that the revised model substantially outperformed the standard CLM seasonal-deciduous spring phenology submodel at both coarse (0.9 × 1.25°) and fine (1 km) scales. The revised model also does a better job of representing recent (decadal) phenological trends observed globally by MODIS, as well as long-term trends (1950-2014) in the PEP725 European phenology dataset. Moreover, forward model runs suggested a stronger advancement (up to 11 days) of spring leaf-out by the end of the 21st century for the revised model. Trends toward earlier advancement are predicted for deciduous forests across the whole Northern Hemisphere boreal and temperate deciduous forest region for the revised model, whereas the standard model predicts earlier leaf-out in colder regions, but later leaf-out in warmer regions, and no trend globally. The earlier spring leaf-out predicted by the revised model resulted in enhanced gross primary production (up to 0.6 Pg C yr(-1) ) and evapotranspiration (up to 24 mm yr(-1) ) when results were integrated across the study region. These results suggest that the standard seasonal-deciduous submodel in CLM should be reconsidered, otherwise substantial errors in predictions of key land-atmosphere interactions and feedbacks may result.

  2. 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.

  3. 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.

  4. Insight into the photosynthetic apparatus in evergreen and deciduous European oaks during autumn senescence using OJIP fluorescence transient analysis.

    PubMed

    Holland, V; Koller, S; Brüggemann, W

    2014-07-01

    Climate change is one of the major issues nowadays, and Mediterranean broadleaf species have been suggested to fill possible future gaps created by climate change in Central European forests. To provide a scientific-based foundation for such practical strategies, it is important to obtain a general idea about differences and similarities in the physiology of Central European and Mediterranean species. In the present study, we evaluated the onset of leaf senescence of a broad spectrum of oak species under the Central European climate in a common garden experiment. Degradation of the photosynthetic apparatus of evergreen (Quercus ilex, Q. suber), semi-evergreen (Q.×turneri, Q.×hispanica) and deciduous oaks (Q. robur, Q. cerris, Q. frainetto, Q. pubescens) was monitored as chlorophyll content and analysed chlorophyll fluorescence induction transients. In the deciduous species, a significant decline in chlorophyll content was observed during autumn/winter, with Q. pubescens showing the slowest decline. Analysis of fluorescence induction transients revealed a significant decline in quantum efficiency of the primary photochemistry and reaction centre density and later, a decrease in quantum efficiency of end acceptor reduction. Alterations in fluorescence parameters were compared to the decline in chlorophyll content, which occurred much more slowly than expected from the fluorescence data. The evergreen species showed no decline in chlorophyll content, nor different chlorophyll a fluorescence induction behaviour despite temperature falling below 0 °C. The hybrids showed intermediate behaviour between their parental evergreen and deciduous taxa.

  5. Sub-biome variability in the biophysical influence of forests on climate using the Community Earth System Model

    NASA Astrophysics Data System (ADS)

    Ahlswede, B.; Thomas, R. Q.

    2014-12-01

    Forests influence local climate through biophysical processes. It is well established that boreal forests have a warming effect by reducing albedo and tropical forests have a cooling effect due to increased evapotranspiration. However the influence of temperate forests on climate is less certain. Previous model experiments have shown the average effect of temperate forests as a whole to be a weak warming effect. However, some non-model studies that examine these effects at the sub-biome level show a latitudinal gradient of effects presumably due to differences in climate; while other studies show variation in biophysical effects due to forest type that is independent of latitude. Using the Community Earth System Model, we explore spatial variation in the direction and magnitude of the climate response to simulated deforestation in temperate forests. Our analysis focuses on the relative importance of pre-deforestation temperature, pre-deforestation precipitation, and the percentage of a grid cell occupied by needle-leaf evergreen trees as factors explaining how deforestation influences climate. We use results from deforestation simulations where forests are subdivided into temperature and precipitation clusters to develop a statistical model that predicts the change in regional air temperature, precipitation, and relative humidity based on climate. To examine the sensitivity of results to the plant-type we repeated the simulations of deforestation in the climate clusters using two pre-deforestation forest compositions: 100% needle-leaf evergreen trees (0 % broad-leaf deciduous) and 0% needle-leaf evergreen trees (100 % broad-leaf deciduous). Overall, we found that within the temperate forests warmer, wetter forests cooled climate while cooler, wetter forests warmed climate. The influence of plant-type was most pronounced in cooler regions. Our results help better understand how land-cover change in the temperate region influences climate and highlights how changes

  6. Seasonal fluctuations and temperature dependence of leaf gas exchange parameters of co-occurring evergreen and deciduous trees in a temperate broad-leaved forest.

    PubMed

    Kosugi, Yoshiko; Matsuo, Naoko

    2006-09-01

    Seasonal fluctuations in leaf gas exchange parameters were investigated in three evergreen (Quercus glauca Thunb., Cinnamomum camphora Sieb. and Castanopsis cuspidata Schottky) and one deciduous (Quercus serrata Thunb.) co-occurring, dominant tree species in a temperate broad-leaved forest. Dark respiration rate (Rn), maximum carboxylation rate (Vcmax) and stomatal coefficient (m), the ratio of stomatal conductance to net assimilation rate after adjustment to the vapor pressure deficit and internal carbon dioxide (CO2) concentration, were derived inversely from instantaneous field gas exchange data (one-point method). The normalized values of Rn and Vcmax at the reference temperature of 25 degrees C (Rn25, Vcmax25) and their temperature dependencies (Delta Ha(Rn), Delta Ha(Vcmax)) were analyzed. Parameter Vcmax25 ranged from 24.0-40.3 micromol m(-2) s(-1) and Delta Ha(Vcmax) ranged from 29.1- 67.0 kJ mol(-1). Parameter Rn25 ranged from 0.6-1.4 micromol m(-2) s(-1) and Delta Ha(Rn) ranged from 47.4-95.4 kJ mol(-1). The stomatal coefficient ranged from 7.2-8.2. For the three evergreen trees, a single set of Vcmax25 and Rn25 parameters and temperature dependence curves produced satisfactory estimates of carbon uptake throughout the year, except during the period of simultaneous leaf fall and leaf expansion, which occurs in April and May. In the deciduous oak, declines in Vcmax25 were observed after summer, along with changes in Vcmax25 and Rn25 during the leaf expansion period. In all species, variation in m during periods of leaf expansion and drought should be considered in modeling studies. We conclude that the changes in normalized gas exchange parameters during periods of leaf expansion and drought need to be considered when modeling carbon uptake of evergreen broad-leaved species.

  7. Phylogeographic analysis of a temperate-deciduous forest restricted plant (Bupleurum longiradiatum Turcz.) reveals two refuge areas in China with subsequent refugial isolation promoting speciation.

    PubMed

    Zhao, Cai; Wang, Chang-Bao; Ma, Xiang-Guang; Liang, Qian-Long; He, Xing-Jin

    2013-09-01

    This study investigates the influence of climate-induced oscillations and complicated geological conditions on the evolutionary processes responsible for species formation in presently fragmented temperate forest habitats, located in continental East Asia. In addition to this, we also investigate the heavily debated issue of whether temperate forests migrated southwards during such glacial periods or, alternatively, whether there existed refugia within north China, enabling localized survival of temperate forests within this region. In order to achieve these, we surveyed the phylogeography of Bupleurum longiradiatum Turcz. (a herbaceous plant solely confined to temperate forests) constructed from sequence variation in three chloroplast (cp) DNA fragments: trnL-trnF, psbA-trnH and rps16. Our analyses show high genetic diversity within species (h(T)=0.948) and pronounced genetic differentiation among groups (yellow and purple flowers) with a significant phylogeographical pattern (N(ST)>G(ST), P<0.05). Forty-three haplotypes were identified and clustered into two lineages (the purple-flowered lineage and the yellow-flowered lineage). Two corresponding refuge areas, one in Qinling and its adjacent regions and one in the Changbai Mountains/eastern China, were revealed across the entire distribution ranges of Bupleurum longiradiatum. These results provide evidence for the hypothesis that independent refugia were maintained across the range of temperate forests in northern China during the last glacial maximum or earlier cold periods. Bupleurum longiradiatum var. porphyranthum formed a single taxon based on molecular data. This specific formation process suggests that the historical vicariance factors, i.e. climate-induced eco-geographic isolation through the biotic displacement of temperate-deciduous forest habitats, enhanced the divergence of the yellow and purple flower lineages at different spatial-temporal scales and over glacial and interglacial periods

  8. 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.

  9. Reproductive biology of a hummingbird-pollinated Billbergia: light influence on pollinator behaviour and specificity in a Brazilian semi-deciduous forest.

    PubMed

    Pansarin, E R; de Pedro, S R M

    2016-11-01

    Ornithophily has evolved in parallel several times during evolution of angiosperms. Bird pollination is reported for 65 families, including Bromeliaceae. One of the most diverse bromeliad is Billbergia, which comprises species pollinated mainly by hummingbirds. Based on investigations on flowering phenology, morpho-anatomy, volume and concentration of nectar, pollinators and breeding system, this paper explores the reproductive biology and pollinator specificity of B. distachia in a mesophytic semi-deciduous forest of southeastern Brazil. The results have show that B. distachia is pollinated by a single species of hermit hummingbird, Phaethornis eurynome, which search for nectar produced by a septal nectary, where the secretory tissue is located above the placenta. The species is self-incompatible. The combination of pollinator specificity, due to long corolla tubes that exclude visitation of short-billed hummingbirds, complete self-incompatibility and non-territorial behaviour of pollinators, it is very important to reduce pollen loss and increase gene flow within population. Our results indicate that studies on pollination biology and reproduction are essential to understand the evolutionary history of pollination systems of plants since, at least in Billbergia, variation in the pollinator spectrum has been recorded for different habitats among Brazilian forests. Furthermore, according to our data, foraging of Phaethornis on flowers is independent of air temperature and humidity, while the main factor influencing hummingbird visitation is daylight. Considering current knowledge on climatic parameters influencing hummingbird foraging, pollination and reproductive biology of Neotropical flora and environment of the hermit hummingbird in tropical forests, new insights on plant-pollinator interaction are provided.

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. 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

  15. Effects of bark beetle outbreaks on species composition, biomass, and nutrient distribution in a mixed deciduous forest

    SciTech Connect

    Johnson, D.W.; Henderson, G.S.; Harris, W.F.

    1987-01-01

    The increment of forest biomass and nutrient content on Walker Branch Watershed, Tennessee, from 1967 to 1983 was interrupted by two bark beetle outbreaks. An outbreak of the southern pine beetle in the early 1970s and an outbreak of the hickory borer in the late 1970s, early 1980s killed a number of shortleaf pine (Pinus echinata) and hickory (Carya spp.) respectively. Yellow-poplar (Liriodendron tulipifera) growth increased over this 16-year period, especially in response to the mortality of shortleaf pine. The net result of these events was little change in total biomass but a substantial shift in species composition (from pine to yellow-poplar) in the Pine forest type over this period. No species has yet responded to the mortality of hickory. Due to the shift in species composition in the Pine type, calcium and magnesium accumulation rates in biomass increased but foliage biomass decreased over the inventory period. There was little change in foliage biomass or nutrient content in other forest types. The beetle attacks, combined with apparently natural self-thinning, caused a large increase in standing dead biomass and in nutrient return via tree fall. This increased rate of return will substantially alter forest floor nutrient content and availability, especially with regard to calcium and nitrogen.

  16. Impact of fencing on the recovery of the ground flora on heavily eroded slopes of a deciduous forest.

    PubMed

    Godefroid, Sandrine; Massant, Wim; Weyembergh, Gisele; Koedam, Nico

    2003-07-01

    This paper seeks to outline early stages in the recovery of forest ground flora on eroded slopes impacted by recreation activities and to suggest how these data might be applied in the formulation of management policies for forest recreation areas. Based on a fencing experiment in the Sonian Forest near Brussels, we investigated whether, over a 6-year period, the vegetation was able to recover after having been destroyed by recreation use. Short-term trends in overall species composition were already observable during this 6-year study. Species recovery on eroded hills was related to slope, aspect, and soil type. During the considered time scale, the proportion of hemicryptophytes and the number of ancient forest species increased significantly. A downward trend was detected for Ellenberg's nitrogen and temperature indexes and for the proportion of therophytes and pioneer plants of disturbed places. Changes in species' frequencies suggest six recovery strategies: early, late, expanding, disappearing, transient, and fluctuating species. Aside from seedling reproduction from overstory influences, Luzula sylvatica appeared to be the most resilient of the species identified in the study since this species has the highest global frequency in our sampling plots and has increased its cover during the study period. Study results indicate that (1) protection from recreation has initiated the recovery of species in the herb layer, but (2) it may take a long time before vegetation previously present in the ground flora may recover in both density and species composition.

  17. 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.

  18. Variations in transpiration rate and leaf cell turgor maintenance in saplings of deciduous broad-leaved tree species common in cool temperate forests in Japan.

    PubMed

    Saito, Takami; Tanaka, Tadashi; Tanabe, Hiromi; Matsumoto, Yoosuke; Morikawa, Yasushi

    2003-01-01

    To clarify mechanisms underlying variation in transpiration rate among deciduous broad-leaved tree species, we measured diurnal changes in stomatal conductance (gs) and leaf water potential, and calculated the maximum transpiration rate (Emax), leaf-specific hydraulic conductance (K(s-l)) and difference between the soil water potential and the daily minimum leaf water potential (Psis - Psi(l,min)). Pressure-volume (P-V) measurements were made on leaves. Saplings of eight broad-leaved tree species that are common in Japanese cool temperate forests were studied. Maximum transpiration rate varied significantly among species. There was a statistically significant difference in Psis - Psi(l,min), but not in K(s-l). Species with large Emax also had large Psis - Psi(l,min) and gs. The results of the P-V analyses showed that species with a large Psis - Psi(l,min) maintained turgor even at low leaf water potentials. The similar daily minimum leaf pressure potentials (Psip) across all eight species indicate that Psip values below this minimum are critical. Based on these results, we suggest that the leaf cell capacity for turgor maintenance strongly affects Psis - Psi(l,min) and consequently Emax via stomatal regulation.

  19. [Spatial patterns of and specific correlations between dominant tree species in a karst evergreen and deciduous broadleaved mixed forest in Mulun Karst National Nature Reserve].

    PubMed

    Han, Wen-heng; Xiang, Wu-sheng; Ye, Duo; Lü, Shi-hong; Ding, Tao; Li, Xian-kun

    2010-11-01

    In order to understand the biological characteristics and specific correlations of dominant tree species in a karst characteristic evergreen and deciduous broad-leaved mixed forest in Mulun National Nature Reserve of Guangxi, a point pattern analysis was made on the spatial distribution patterns and inter- and intraspecific correlations of four dominant species in a one-hectare plot. Among the four species, Boniodendron minius dominated in tree sublayer I, while Ligustrum japonicum, Sinosideroxylon wightianum, and Rapanea kwangsiensis dominated in tree sublayers II and III. All the four species had a clumped distribution at scale <10 m, a transition from clumped to random distribution at scale 10-25 m, and a random or regular distribution at scale >25 m. The critical scale from clumped to random distribution varied with species. No significant correlations were observed between the B. minius in sublayer I and the dominant species in sublayer II. The correlations of B. minius with the dominant species in sublayers II and III showed greater fluctuation, with significant positive correlation for L. japonicum at scale <50 m, no significant correlation for S. wightianum, and no significant correlation for R. kwangsiensis at scale <20 m but significant negative correlation at scale 20-50 m.

  20. Thelephora versatilis and Thelephora pseudoversatilis: two new cryptic species with polymorphic basidiomes inhabiting tropical deciduous and sub-perennial forests of the Mexican Pacific coast.

    PubMed

    Ramírez-López, Itzel; Villegas-Ríos, Margarita; Salas-Lizana, Rodolfo; Garibay-Orijel, Roberto; Alvarez-Manjarrez, Julieta

    2015-01-01

    Thelephora is a genus of ectomycorrhizal basidiomycetes with basidiomes of varied shape which has been poorly studied in tropical ecosystems. In this paper, we present Thelephora versatilis and Thelephora pseudoversatilis, two new species collected in the same localities of deciduous and sub-perennial tropical forests of Jalisco, Mexico. Basidiomes of both species are brownish gray to violet brown with clavarioid-mesopodal, sub-resupinate or completely resupinate growth forms. In turn, phylogenetic analyses using nrDNA ITS sequences showed that these species are not closed related, nevertheless they are part of a well-supported clade conformed by several species of Thelephora, Tomentella and some undescribed Thelephorales. Morphological segregation of these species was attained by analyzing spore and hyphae characters using a wide sample. Significant statistical differences between the new species were observed regarding spore size, spine size and context hyphae width. This work exemplifies the relevance of integrating both morphological and molecular data, as well of the use of an appropriate sample size in order to discriminate among morphological cryptic species.

  1. Effects of burial and storage on germination and seed reserves of 18 tree species in a tropical deciduous forest in Mexico.

    PubMed

    Soriano, Diana; Huante, Pilar; Gamboa-deBuen, Alicia; Orozco-Segovia, Alma

    2014-01-01

    The changes in germination and seed reserve composition that occur while seeds are stored in the laboratory or buried in the soil are important for understanding the potential and ecological longevity of seeds as well as seed-bank dynamics. Both germination and seed-bank dynamics depend on water availability. We studied 18 tree species, including those with permeable or impermeable seeds, from a tropical deciduous forest in Mexico. We measured seed germination in a growth chamber after (1) dispersal, (2) laboratory storage, (3) seed burial at two field sites and directly in the field, and (4) two rainy seasons. Lipids, nitrogen, and nonstructural carbohydrates were quantified after dispersal and after laboratory or field storage. Sixteen species were viable after three periods of laboratory storage (~3 years). Eleven species were viable after two burial periods in the field (~2 years). Nitrogen concentration decreased after storage and burial in 11 species. Species lipid concentration had a negative relationship with species water content at dispersal and after one burial period, whereas nonstructural carbohydrates showed the opposite trend. Potential and ecological longevities were similar in impermeable seeds. Most of the species studied can form persistent seed banks consisting mainly of species with impermeable seeds that can remain in the soil without degrading their viability. Germination in the field is staggered following natural precipitation pulses as a strategy to stagger seedling recruitment, which may insure against unfavorable conditions.

  2. Efficacy of Pitfall Trapping, Winkler and Berlese Extraction Methods for Measuring Ground-Dwelling Arthropods in Moist-Deciduous Forests in the Western Ghats

    PubMed Central

    Sabu, Thomas K.; Shiju, Raj T.

    2010-01-01

    The present study provides data to decide on the most appropriate method for sampling of ground-dwelling arthropods measured in a moist-deciduous forest in the Western Ghats in South India. The abundance of ground-dwelling arthropods was compared among large numbers of samples obtained using pitfall trapping, Berlese and Winkler extraction methods. Highest abundance and frequency of most of the represented taxa indicated pitfall trapping as the ideal method for sampling of ground-dwelling arthropods. However, with possible bias towards surface-active taxa, pitfall-trapping data is inappropriate for quantitative studies, and Berlese extraction is the better alternative. Berlese extraction is the better method for quantitative measurements than the other two methods, whereas pitfall trapping would be appropriate for qualitative measurements. A comparison of the Berlese and Winkler extraction data shows that in a quantitative multigroup approach, Winkler extraction was inferior to Berlese extraction because the total number of arthropods caught was the lowest; and many of the taxa that were caught from an identical sample via Berlese extraction method were not caught. Significantly a greater frequency and higher abundance of arthropods belonging to Orthoptera, Blattaria, and Diptera occurred in pitfall-trapped samples and Psocoptera and Acariformes in Berlese-extracted samples than that were obtained in the other two methods, indicating that both methods are useful, one complementing the other, eliminating a chance for possible under-representation of taxa in quantitative studies. PMID:20673122

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. Oak loss increases foliar nitrogen, δ(15)N and growth rates of Betula lenta in a northern temperate deciduous forest.

    PubMed

    Falxa-Raymond, Nancy; Patterson, Angelica E; Schuster, William S F; Griffin, Kevin L

    2012-09-01

    Oak forests dominate much of the eastern USA, but their future is uncertain due to a number of threats and widespread failure of oak regeneration. A sudden loss of oaks (Quercus spp.) could be accompanied by major changes in forest nitrogen (N) cycles with important implications for plant nutrient uptake and tree species composition. In this study, we measured the changes in N use and growth rates of black birch trees (Betula lenta L.) following oak girdling at the Black Rock Forest in southeastern New York, USA. Data were collected from nine experimental plots composed of three treatments: 100% oaks girdled (OG), 50% oaks girdled (O50) and control (C). Foliar N concentration and foliar (15)N abundance increased significantly in the oak-girdled plots relative to the control, indicating that the loss of oaks significantly altered N cycling dynamics. As mineralization and nitrification rates increase following oak loss, black birch trees increase N absorption as indicated by higher foliar N content and increased growth rates. Foliar N concentration increased by 15.5% in the O50 and 30.6% in the OG plots relative to the control, while O50 and OG plots were enriched in (15)N by 1.08‰ and 3.33‰, respectively (P < 0.0001). A 641% increase in black birch growth rates in OG plots suggests that this species is able to respond to additional N availability and/or increased light availability. The loss of oaks and subsequent increase in black birch productivity may have a lasting impact on ecosystem form and function.

  9. 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.

  10. 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

  11. 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.

  12. 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

  13. 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

    2015-05-06

    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.

  14. 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.

  15. Vegetation carbon sequestration in Chinese forests from 2010 to 2050.

    PubMed

    He, Nianpeng; Wen, Ding; Zhu, Jianxing; Tang, Xuli; Xu, Li; Zhang, Li; Hu, Huifeng; Huang, Mei; Yu, Guirui

    2017-04-01

    Forests store a large part of the terrestrial vegetation carbon (C) and have high C sequestration potential. Here, we developed a new forest C sequestration (FCS) model based on the secondary succession theory, to estimate vegetation C sequestration capacity in China's forest vegetation. The model used the field measurement data of 3161 forest plots and three future climate scenarios. The results showed that logistic equations provided a good fit for vegetation biomass with forest age in natural and planted forests. The FCS model has been verified with forest biomass data, and model uncertainty is discussed. The increment of vegetation C storage in China's forest vegetation from 2010 to 2050 was estimated as 13.92 Pg C, while the average vegetation C sequestration rate was 0.34 Pg C yr(-1) with a 95% confidence interval of 0.28-0.42 Pg C yr(-1) , which differed significantly between forest types. The largest contributor to the increment was deciduous broadleaf forest (37.8%), while the smallest was deciduous needleleaf forest (2.7%). The vegetation C sequestration rate might reach its maximum around 2020, although vegetation C storage increases continually. It is estimated that vegetation C sequestration might offset 6-8% of China's future emissions. Furthermore, there was a significant negative relationship between vegetation C sequestration rate and C emission rate in different provinces of China, suggesting that developed provinces might need to compensate for undeveloped provinces through C trade. Our findings will provide valuable guidelines to policymakers for designing afforestation strategies and forest C trade in China.

  16. 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

  17. 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.

  18. 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

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. Impacts of precipitation variability on plant species and community water stress in a temperate deciduous forest in the central US

    DOE PAGES

    Gu, Lianhong; Pallardy, Stephen G.; Hosman, Kevin P.; ...

    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

  4. Assimilating leaf area index of three typical types of subtropical forest in China from MODIS time series data based on the integrated ensemble Kalman filter and PROSAIL model

    NASA Astrophysics Data System (ADS)

    Li, Xuejian; Mao, Fangjie; Du, Huaqiang; Zhou, Guomo; Xu, Xiaojun; Han, Ning; Sun, Shaobo; Gao, Guolong; Chen, Liang

    2017-04-01

    Subtropical forest ecosystems play essential roles in the global carbon cycle and in carbon sequestration functions, which challenge the traditional understanding of the main functional areas of carbon sequestration in the temperate forests of Europe and America. The leaf area index (LAI) is an important biological parameter in the spatiotemporal simulation of the carbon cycle, and it has considerable significance in carbon cycle research. Dynamic retrieval based on remote sensing data is an important method with which to obtain large-scale high-accuracy assessments of LAI. This study developed an algorithm for assimilating LAI dynamics based on an integrated ensemble Kalman filter using MODIS LAI data, MODIS reflectance data, and canopy reflectance data modeled by PROSAIL, for three typical types of subtropical forest (Moso bamboo forest, Lei bamboo forest, and evergreen and deciduous broadleaf forest) in China during 2014-2015. There were some errors of assimilation in winter, because of the bad data quality of the MODIS product. Overall, the assimilated LAI well matched the observed LAI, with R2 of 0.82, 0.93, and 0.87, RMSE of 0.73, 0.49, and 0.42, and aBIAS of 0.50, 0.23, and 0.03 for Moso bamboo forest, Lei bamboo forest, and evergreen and deciduous broadleaf forest, respectively. The algorithm greatly decreased the uncertainty of the MODIS LAI in the growing season and it improved the accuracy of the MODIS LAI. The advantage of the algorithm is its use of biophysical parameters (e.g., measured LAI) in the LAI assimilation, which makes it possible to assimilate long-term MODIS LAI time series data, and to provide high-accuracy LAI data for the study of carbon cycle characteristics in subtropical forest ecosystems.

  5. 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.

  6. Transpiration of A Mixed Forest Stand: Field Measurements and Model Estimations

    NASA Astrophysics Data System (ADS)

    Oltchev, A.; Cermak, J.; Nadezhdina, N.; Tatarinov, F.; Gravenhorst, G.

    Transpiration of a mixed spruce-aspen-birch forest stand at the southern part of the Valday Hills in Russia was determined using sap flow measurements and SVAT mod- els. The measurements showed a significant variability of transpiration rates between different species and different trees. Under non-limited soil water conditions broadleaf trees transpired about 10-20% more than spruces trees. Deficit of available water in the upper soil layers had a more pronounced influence on water uptake of spruce than of deciduous tree species due to the shallow spruce root system. Under surplus wa- ter in the upper soil layers the transpiration rates were slightly suppressed both for spruce and for broadleaf tree species. Two one-dimensional multi-layer SVAT mod- els were applied to describe energy and water exchanges between mixed forest stand and the atmosphere. A more simplified MLOD-SVAT model uses averaged biophys- ical properties of different tree species. Estimation of forest water uptake in a more sophisticated EWE-MF model is based on separate description of water uptakes for individual tree species. Comparisons of modelling and measuring results show that under non-limited soil water conditions both modelling approaches allow to describe in a representative way the water uptake and transpiration rates. Under limited soil water conditions more sophisticated model could deduce more representatively the effect of different tree species on forest transpiration. Application of more simplified MLOD-SVAT model can result in an overestimation of daily total forest transpiration up to 50%.

  7. Chlorine-36 and chlorine concentrations within several compartments of a deciduous forest ecosystem in Meuse/Haute-Marne (France)

    NASA Astrophysics Data System (ADS)

    Pupier, Julie; Benedetti, Lucilla; Bourles, Didier; Leclerc, Elisabeth; Thiry, Yves

    2013-04-01

    Chlorine-36 is a cosmogenic nuclide mainly produced in the atmosphere by interactions between energetic particles originating from the cosmic radiations and 40Ar. Because of its long half-life (T1-2 = 3.01 105 yr) and its high mobility, chlorine-36 is a critical radionuclide concerning radioactive waste repository sites. Moreover, it has been shown that inorganic chlorine could be enriched along the trophic chain due to its high solubility and bioavailability (Ashworth and Shaw, 2006). Additionally, many studies during the last decades have established that due to chlorination process, organic chlorine may account for a large proportion of the total soil chlorine pool (more than 80 % in surface soils of temperate ecosystems. Redon et al., 2012). The aim of this study is thus to measure chlorine-36 in all the compartments of the biogeochemical cycle, to better understand its recycling in the biosphere. The study site is the experimental beech forest site of the Andra long-term monitoring and testing system (OPE*). It is located at Montiers-sur-Saulx, North-East of France and is associated to the future radioactive waste repository site of Bure. Since March 2012, rainwater above (rainfall collected from a 45 m high tower built on purpose) and below (throughfall and stemflow) the canopy, has been collected monthly, as well as soil solutions (gravitational and bound waters) at four depths (0, 10, 30, 60 cm deep). Chlorine-36 and chlorine have been measured in the rainfall samples between March and July 2012 and in water solutions collected from all compartments of the biosphere using isotope dilution mass spectrometry at the french AMS national facility ASTER located at CEREGE. The results yielded from the rainfall samples allow to study the temporal fluctuations of chlorine-36 in the atmosphere, which represents the main inflow of chlorine-36 in its biogeochemical cycle. The first results indicate a flow increase during the late spring-early summer. Santos et al

  8. 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.

  9. Post-deposition early-phase migration and retention behavior of radiocesium in a litter-mineral soil system in a Japanese deciduous forest affected by the Fukushima nuclear accident.

    PubMed

    Koarashi, Jun; Nishimura, Syusaku; Nakanishi, Takahiro; Atarashi-Andoh, Mariko; Takeuchi, Erina; Muto, Kotomi

    2016-12-01

    The fate of radiocesium ((137)Cs) derived from the Fukushima nuclear accident and associated radiation risks are largely dependent on its migration and retention behavior in the litter-soil system of Japanese forest ecosystems. However, this behavior has not been well quantified. We established field lysimeters in a Japanese deciduous broad-leaved forest soon after the Fukushima nuclear accident to continuously monitor the downward transfer of (137)Cs at three depths: the litter-mineral soil boundary and depths of 5 cm and 10 cm in the mineral soil. Observations were conducted at two sites within the forest from May 2011 to May 2015. Results revealed similar temporal and depth-wise variations in (137)Cs downward fluxes for both sites. The (137)Cs downward fluxes generally decreased year by year at all depths, indicating that (137)Cs was rapidly leached from the forest-floor litter layer and was then immobilized in the upper (0-5 cm) mineral soil layer through its interaction with clay minerals. The (137)Cs fluxes also showed seasonal variation, which was in accordance with variations in the throughfall and soil temperature at the sites. There was no detectable (137)Cs flux at a depth of 10 cm in the mineral soil in the third and fourth years after the accident. The decreased inventory of mobile (or bioavailable) (137)Cs observed during early stages after deposition indicates that the litter-soil system in the Japanese deciduous forest provides only a temporary source for (137)Cs recycling in plants.

  10. Local forest environment largely affects below-ground growth, clonal diversity and fine-scale spatial genetic structure in the temperate deciduous forest herb Paris quadrifolia.

    PubMed

    Jacquemyn, Hans; Brys, Rein; Honnay, Olivier; Hermy, Martin; Roldán-Ruiz, Isabel

    2005-12-01

    Paris quadrifolia (herb Paris) is a long-lived, clonal woodland herb that shows strong differences in local population size and shoot density along an environmental gradient of soil and light conditions. This environmentally based structuring may be mediated by differences in clonal growth and seedling recruitment through sexual reproduction. To study the interrelationship between environmental conditions and spatial patterns of clonal growth, the spatial genetic structure of four P. quadrifolia populations growing in strongly contrasting sites was determined. In the first place, plant excavations were performed in order to (i) determine differences in below-ground growth of genets, (ii) investigate connectedness of ramets and (iii) determine total genet size. Although no differences in internode length were found among sites, clones in moist sites were much smaller (genets usually consisted of 1-3 interconnected shoots, most of them flowering) than genets in dry sites, which consisted of up to 15 interconnected shoots, the majority of which were vegetative. Further, amplified fragment length polymorphism (AFLP) markers were used. Clonal diversity was higher in populations located in moist and productive ash-poplar forests compared to those found in drier and less productive mixed forest sites (G/N: 0.27 and 0.14 and Simpson's D: 0.84 and 0.75, respectively). Patterns of spatial population genetic structure under dry conditions revealed several large clones dominating the entire population, whereas in moist sites many small genets were observed. Nevertheless, strong spatial genetic structure of the genet population was observed. Our results clearly demonstrate that patterns of clonal diversity and growth form of P. quadrifolia differ among environments. Limited seedling recruitment and large clone sizes due to higher connectedness of ramets explain the low clonal diversity in dry sites. In moist sites, higher levels of clonal diversity and small clone sizes

  11. [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.

  12. Strong nitrogen retention against the pine-stands dieback by pine-wilt disease in a temperate conifer-deciduous forest in central Japan: Budget and mechanisms

    NASA Astrophysics Data System (ADS)

    Ohte, N.; Tokuchi, N.; Katsuyama, M.; Osaka, K.; Yoneda, S.; Ochiai, N.

    2013-12-01

    Decreased N uptake by tree roots and increased N supply from the litter fall that occurred with the 1992-94 pine dieback caused by pine-wilt disease brought on a threefold and 10 years increase in nitrate concentrations in streamwater and subsurface groundwater in a conifer-deciduous mixed forest catchment (Kiryu Experimental Watershed) in central Japan. The disturbance also resulted in delayed changes of input-output nitrogen balances. The objectives of this study were 1) to evaluate the controls of the hydrological processes by which NO3- concentrations increase in streamwater, 2) to clarify the impacts of soil nitrogen transformation to the streamwater chemistry. It was found that, from 1992 to 1996, seasonal peaks occurred in the stream NO3- concentrations during the rainy season (July to August). This seasonal variation corresponded directly to groundwater levels in the riparian zone near the catchment outlet, suggesting that seasonal changes in groundwater levels were the dominant factor controlling temporal variation in stream NO3- concentrations. The annual N export was 110.0 mol N ha-1 year-1 in pre-disturbance condition and 749.8 mol N ha-1 year-1 in post-disturbance, and had decreased to 37.0 mol N ha-1 year-1 in 2005. N export under dieback influence was estimated to be 3697 mol N ha-1, and N loss due to pine dieback was 2810 mol N ha-1. This was three times larger than baseline N leakage for the disturbed period. The nitrogen contribution to dieback litter inputs was 7.39 kmol ha-1, and N loss from streamwater was less than 0.2-0.75 kmol ha-1 year-1 throughout the observation period. This large discrepancy suggested there was substantial nitrogen retaining mechanisms such as microbial immobilization. Measurements of nitrogen mineralization and nitrification potential of soil using 15N pool dilution method indicated that the soil in this site has very high NH4+ immobilization potential and low nitrification potential. This was one of the evidence

  13. 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.

  14. Evaluation of three satellite-based latent heat flux algorithms over forest ecosystems using eddy covariance data.

    PubMed

    Yao, Yunjun; Zhang, Yuhu; Zhao, Shaohua; Li, Xianglan; Jia, Kun

    2015-06-01

    We have evaluated the performance of three satellite-based latent heat flux (LE) algorithms over forest ecosystems using observed data from 40 flux towers distributed across the world on all continents. These are the revised remote sensing-based Penman-Monteith LE (RRS-PM) algorithm, the modified satellite-based Priestley-Taylor LE (MS-PT) algorithm, and the semi-empirical Penman LE (UMD-SEMI) algorithm. Sensitivity analysis illustrates that both energy and vegetation terms has the highest sensitivity compared with other input variables. The validation results show that three algorithms demonstrate substantial differences in algorithm performance for estimating daily LE variations among five forest ecosystem biomes. Based on the average Nash-Sutcliffe efficiency and root-mean-squared error (RMSE), the MS-PT algorithm has high performance over both deciduous broadleaf forest (DBF) (0.81, 25.4 W/m(2)) and mixed forest (MF) (0.62, 25.3 W/m(2)) sites, the RRS-PM algorithm has high performance over evergreen broadleaf forest (EBF) (0.4, 28.1 W/m(2)) sites, and the UMD-SEMI algorithm has high performance over both deciduous needleleaf forest (DNF) (0.78, 17.1 W/m(2)) and evergreen needleleaf forest (ENF) (0.51, 28.1 W/m(2)) sites. Perhaps the lower uncertainties in the required forcing data for the MS-PT algorithm, the complicated algorithm structure for the RRS-PM algorithm, and the calibrated coefficients of the UMD-SEMI algorithm based on ground-measured data may explain these differences.

  15. Large-Scale Modeling Shows Little Impact of 20th-Century Changes in Temperature and Fire on the Central Canadian Boreal Forest

    NASA Astrophysics Data System (ADS)

    Bond-Lamberty, B.; Peckham, S.; Ahl, D. E.; Gower, S. T.

    2006-12-01

    Boreal forests are predicted to experience relatively large climate change (IPCC 2001), and the fire dynamics of this region may not be in equilibrium with the changing climate (Flannigan et al. 1998, Kasischke & Stocks 2000). Here we investigate how well a biogeochemical model can simulate observed 20^{th}-century changes in the structure and function of the boreal forest. Biome-BGC was used to simulate a 1000 km x 1000 km section (6-8% of the global boreal forest) of central Canadian forest at 1 km2 resolution. Historical climate, disturbance, and CO2 forcing data were used to drive the model; three dynamic vegetation types (evergreen needleleaf tree, broadleaf deciduous tree, and moss) were employed. Soil type, drainage, and other site conditions were represented as accurately as available data allowed. Assuming that the forest was at a carbon-neutral steady state in 1948, CO2 and disturbance frequency changes had small (<20 g C m-2 yr-1) and opposite effects on forest C balance by 2005; in particular, the C losses from more frequent fires were almost balanced by the C uptake of post-disturbance deciduous forests. Precipitation changes had the largest effects on C balance, with the overall forest shifting from being neutral to a small source of C, while interannual variability increased. Such a shift is smaller than can be measured using current biometric and eddy covariance techniques.

  16. Evaluating carbon fluxes of global forest ecosystems by using an individual tree-based model FORCCHN.

    PubMed

    Ma, Jianyong; Shugart, Herman H; Yan, Xiaodong; Cao, Cougui; Wu, Shuang; Fang, Jing

    2017-05-15

    The carbon budget of forest ecosystems, an important component of the terrestrial carbon cycle, needs to be accurately quantified and predicted by ecological models. As a preamble to apply the model to estimate global carbon uptake by forest ecosystems, we used the CO2 flux measurements from 37 forest eddy-covariance sites to examine the individual tree-based FORCCHN model's performance globally. In these initial tests, the FORCCHN model simulated gross primary production (GPP), ecosystem respiration (ER) and net ecosystem production (NEP) with correlations of 0.72, 0.70 and 0.53, respectively, across all forest biomes. The model underestimated GPP and slightly overestimated ER across most of the eddy-covariance sites. An underestimation of NEP arose primarily from the lower GPP estimates. Model performance was better in capturing both the temporal changes and magnitude of carbon fluxes in deciduous broadleaf forest than in evergreen broadleaf forest, and it performed less well for sites in Mediterranean climate. We then applied the model to estimate the carbon fluxes of forest ecosystems on global scale over 1982-2011. This application of FORCCHN gave a total GPP of 59.41±5.67 and an ER of 57.21±5.32PgCyr(-1) for global forest ecosystems during 1982-2011. The forest ecosystems over this same period contributed a large carbon storage, with total NEP being 2.20±0.64PgCyr(-1). These values are comparable to and reinforce estimates reported in other studies. This analysis highlights individual tree-based model FORCCHN could be used to evaluate carbon fluxes of forest ecosystems on global scale.

  17. 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.

  18. 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.

  19. Sensitivity of photosynthetic electron transport to photoinhibition in a temperate deciduous forest canopy: Photosystem II center openness, non-radiative energy dissipation and excess irradiance under field conditions.

    PubMed

    Niinemets U; Kull, O

    2001-08-01

    We used chlorophyll fluorescence techniques to investigate responses of Photosystem II (PSII) quantum yield to light availability in the short term (quantum flux density integrated over the measurement day, Qd) and in the long term (Qd averaged over the season, Qs) in a mixed deciduous forest comprising shade-tolerant and water-stress-sensitive Tilia cordata Mill. in the lower canopy and shade-intolerant and water-stress-resistant Populus tremula L. in the upper canopy. In both species, intrinsic efficiency of PSII in the dark-adapted state (Fv/Fm) was lower during the day than during the night, and the difference in Fv/Fm between day and night increased with increasing Qs. Although the capacity for photosynthetic electron transport increased with increasing Qs in both species, maximum quantum efficiency of PSII in the light-adapted state (alpha) decreased with increasing Qs. At a common Qs, alpha was lower in T. cordata than in P. tremula primarily because of a higher fraction of closed PSII centers, and to a smaller extent because of limited, non-radiative, excitation energy dissipation in the pigment bed in T. cordata. Across both species, photochemical quenching (qP), which measures the openness of PSII centers, varied more than fivefold, but the efficiency of excitation energy capture by open PSII centers (Fv'/Fm'), which is an estimate of non-radiative excitation energy dissipation in PSII antennae, varied by only 50%. Chlorophyll turnover rates increased with increasing irradiance, especially in T. cordata, possibly because of increased photodestruction. Diurnal measurements of PSII quantum yields (PhiPSII) indicated that, under similar environmental conditions, PhiPSII was always lower in the afternoon than in the morning, and the fraction of daily integrated photosynthetic electron transport lost because of diurnal declines in PhiPSII (Delta) increased with increasing Qd. At a common Qd, mean daily PSII center reduction state, the fraction of light in

  20. 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.

  1. Net aboveground biomass declines of four major forest types with forest ageing and climate change in western Canada's boreal forests.

    PubMed

    Chen, Han Y H; Luo, Yong

    2015-10-01

    Biomass change of the world's forests is critical to the global carbon cycle. Despite storing nearly half of global forest carbon, the boreal biome of diverse forest types and ages is a poorly understood component of the carbon cycle. Using data from 871 permanent plots in the western boreal forest of Canada, we examined net annual aboveground biomass change (ΔAGB) of four major forest types between 1958 and 2011. We found that ΔAGB was higher for deciduous broadleaf (DEC) (1.44 Mg ha(-1)  year(-1) , 95% Bayesian confidence interval (CI), 1.22-1.68) and early-successional coniferous forests (ESC) (1.42, CI, 1.30-1.56) than mixed forests (MIX) (0.80, CI, 0.50-1.11) and late-successional coniferous (LSC) forests (0.62, CI, 0.39-0.88). ΔAGB declined with forest age as well as calendar year. After accounting for the effects of forest age, ΔAGB declined by 0.035, 0.021, 0.032 and 0.069 Mg ha(-1)  year(-1) per calendar year in DEC, ESC, MIX and LSC forests, respectively. The ΔAGB declines resulted from increased tree mortality and reduced growth in all forest types except DEC, in which a large biomass loss from mortality was accompanied with a small increase in growth. With every degree of annual temperature increase, ΔAGB decreased by 1.00, 0.20, 0.55 and 1.07 Mg ha(-1)  year(-1) in DEC, ESC, MIX and LSC forests, respectively. With every cm decrease of annual climatic moisture availability, ΔAGB decreased 0.030, 0.045 and 0.17 Mg ha(-1)  year(-1) in ESC, MIX and LSC forests, but changed little in DEC forests. Our results suggest that persistent warming and decreasing water availability have profound negative effects on forest biomass in the boreal forests of western Canada. Furthermore, our results indicate that forest responses to climate change are strongly dependent on forest composition with late-successional coniferous forests being most vulnerable to climate changes in terms of aboveground biomass.

  2. 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.

  3. 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.

  4. Tree Circumference Dynamics in Four Forests Characterized Using Automated Dendrometer Bands.

    PubMed

    Herrmann, Valentine; McMahon, Sean M; Detto, Matteo; Lutz, James A; Davies, Stuart J; Chang-Yang, Chia-Hao; Anderson-Teixeira, Kristina J

    2016-01-01

    Stem diameter is one of the most commonly measured attributes of trees, forming the foundation of forest censuses and monitoring. Changes in tree stem circumference include both irreversible woody stem growth and reversible circumference changes related to water status, yet these fine-scale dynamics are rarely leveraged to understand forest ecophysiology and typically ignored in plot- or stand-scale estimates of tree growth and forest productivity. Here, we deployed automated dendrometer bands on 12-40 trees at four different forested sites-two temperate broadleaf deciduous, one temperate conifer, and one tropical broadleaf semi-deciduous-to understand how tree circumference varies on time scales of hours to months, how these dynamics relate to environmental conditions, and whether the structure of these variations might introduce substantive error into estimates of woody growth. Diurnal stem circumference dynamics measured over the bark commonly-but not consistently-exhibited daytime shrinkage attributable to transpiration-driven changes in stem water storage. The amplitude of this shrinkage was significantly correlated with climatic variables (daily temperature range, vapor pressure deficit, and radiation), sap flow and evapotranspiration. Diurnal variations were typically <0.5 mm circumference in amplitude and unlikely to be of concern to most studies of tree growth. Over time scales of multiple days, the bands captured circumference increases in response to rain events, likely driven by combinations of increased stem water storage and bark hydration. Particularly at the tropical site, these rain responses could be quite substantial, ranging up to 1.5 mm circumference expansion within 48 hours following a rain event. We conclude that over-bark measurements of stem circumference change sometimes correlate with but have limited potential for directly estimating daily transpiration, but that they can be valuable on time scales of days to weeks for characterizing

  5. Anthropogenic-driven rapid shifts in tree distribution lead to increased dominance of broadleaf species.

    PubMed

    Vayreda, Jordi; Martinez-Vilalta, Jordi; Gracia, Marc; Canadell, Josep G; Retana, Javier

    2016-12-01

    Over the past century, major shifts in the geographic distribution of tree species have occurred in response to changes in land use and climate. We analyse species distribution and abundance from about 33 000 forest inventory plots in Spain sampled twice over a period of 10-12 years. We show a dominance of range contraction (extinction), and demographic decline over range expansion (colonization), with seven of 11 species exhibiting extinction downhill of their distribution. Contrary to expectations, these dynamics are not always consistent with climate warming over the study period, but result from legacies in forest structure due to past land use change and fire occurrence. We find that these changes have led to the expansion of broadleaf species (i.e. family Fagaceae) over areas formerly dominated by conifer species (i.e. family Pinaceae), due to the greater capacity of the former to respond to most disturbances and their higher competitive ability. This recent and rapid transition from conifers to broadleaves has important implications in forest dynamics and ecosystem services they provide. The finding raises the question as to whether the increasing dominance of relatively drought-sensitive broadleaf species will diminish resilience of Mediterranean forests to very likely drier conditions in the future.

  6. 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.

  7. Another definition of forest canopy height

    NASA Astrophysics Data System (ADS)

    Nakai, T.; Sumida, A.; Kodama, Y.; Hara, T.

    2008-12-01

    Forest canopy height, the height of the highest vegetation components above ground level, is essential in normalizing micrometeorological parameters and in estimating forest biomass and carbon pools, but previous definitions of forest canopy height from inventory data bear uncertainties owing to arbitrary criteria of tall trees accounting for top height (i.e. mean height of tall trees selected by a certain definition) or to the effect of many shorter understory trees on Lorey's mean height (i.e. mean height weighted by basal area). We proposed a new concept of forest canopy height: the representative height of taller trees composing the crown surface or the upper canopy layer estimated on the basis of cumulative basal area from the shortest tree plotted against corresponding individual tree height. Because tall trees have large basal area, the cumulative basal area showing a sigmoidal curve would have an inflection point at a height class where many tall trees occur. Hence the forest canopy height is defined as the inflection point of the sigmoid function fitted to the cumulative basal area curve. This new forest canopy height is independent of the presence or absence of many shorter understory trees unlike Lorey's mean height, and is free from the definition of selecting the trees composing the upper canopy to determine their mean height. Applying this concept to actual forests, we found the new canopy height was larger than the arithmetic mean height and Lorey's mean height, and it was close to the aerodynamic canopy height determined by micrometeorological method, not only in the birch forest (even-aged pure stand) but also in the complex mixed forest of evergreen conifer and deciduous broadleaf species. Therefore the new canopy height would be suitable for intersite comparison studies and ground truth for remote sensing such as airborne laser scanning (ALS).

  8. 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.

  9. 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.

  10. 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

  11. 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 known

  12. Drought-deciduous behavior reduces nutrient losses from temperate deciduous trees under severe drought.

    PubMed

    Marchin, Renée; Zeng, Hainian; Hoffmann, William

    2010-08-01

    Nutrient resorption from senescing leaves is an important mechanism of nutrient conservation in temperate deciduous forests. Resorption, however, may be curtailed by climatic events that cause rapid leaf death, such as severe drought, which has been projected to double by the year 2100 in the eastern United States. During a record drought in the southeastern US, we studied 18 common temperate winter-deciduous trees and shrubs to understand how extreme drought affects nutrient resorption of the macronutrients N, P, K, and Ca. Four species exhibited drought-induced leaf senescence and maintained higher leaf water potentials than the remaining 14 species (here called drought-evergreen species). This strategy prevented extensive leaf desiccation during the drought and successfully averted large nutrient losses caused by leaf desiccation. These four drought-deciduous species were also able to resorb N, P, and K from drought-senesced leaves, whereas drought-evergreen species did not resorb any nutrients from leaves lost to desiccation during the drought. For Oxydendrum arboreum, the species most severely affected by the drought, our results indicate that trees lost 50% more N and P due to desiccation than would have been lost from fall senescence alone. For all drought-deciduous species, resorption of N and P in fall-senesced leaves was highly proficient, whereas resorption was incomplete for drought-evergreen species. The lower seasonal nutrient losses of drought-deciduous species may give them a competitive advantage over drought-evergreen species in the years following the drought, thereby impacting species composition in temperate deciduous forests in the future.

  13. Taurodontism in deciduous molars

    PubMed Central

    Bafna, Yash; Kambalimath, H V; Khandelwal, Vishal; Nayak, Prathibha

    2013-01-01

    Taurodont teeth are characterised by large pulp chambers at the expense of roots. An enlarged pulp chamber, apical displacement of the pulpal floor and no constriction at the level of the cement-enamel junction are the characteristic features of taurodont tooth. It appears more frequently as an isolated anomaly but its association with syndromes and other abnormalities have also been reported. Permanent dentition is more commonly affected than deciduous dentition. This paper presents a case report of taurodontism in relation to mandibular deciduous second molars. PMID:23737594

  14. Relationships between net primary productivity and stand age for several forest types and their influence on China's carbon balance.

    PubMed

    Wang, Shaoqiang; Zhou, Lei; Chen, Jingming; Ju, Weimin; Feng, Xianfeng; Wu, Weixing

    2011-06-01

    Affected by natural and anthropogenic disturbances such as forest fires, insect-induced mortality and harvesting, forest stand age plays an important role in determining the distribution of carbon pools and fluxes in a variety of forest ecosystems. An improved understanding of the relationship between net primary productivity (NPP) and stand age (i.e., age-related increase and decline in forest productivity) is essential for the simulation and prediction of the global carbon cycle at annual, decadal, centurial, or even longer temporal scales. In this paper, we developed functions describing the relationship between national mean NPP and stand age using stand age information derived from forest inventory data and NPP simulated by the BEPS (Boreal Ecosystem Productivity Simulator) model in 2001. Due to differences in ecobiophysical characteristics of different forest types, NPP-age equations were developed for five typical forest ecosystems in China (deciduous needleleaf forest (DNF), evergreen needleleaf forest in tropic and subtropical zones (ENF-S), deciduous broadleaf forest (DBF), evergreen broadleaf forest (EBF), and mixed broadleaf forest (MBF)). For DNF, ENF-S, EBF, and MBF, changes in NPP with age were well fitted with a common non-linear function, with R(2) values equal to 0.90, 0.75, 0.66, and 0.67, respectively. In contrast, a second order polynomial was best suitable for simulating the change of NPP for DBF, with an R(2) value of 0.79. The timing and magnitude of the maximum NPP varied with forest types. DNF, EBF, and MBF reached the peak NPP at the age of 54, 40, and 32 years, respectively, while the NPP of ENF-S maximizes at the age of 13 years. The highest NPP of DBF appeared at 122 years. NPP was generally lower in older stands with the exception of DBF, and this particular finding runs counter to the paradigm of age-related decline in forest growth. Evaluation based on measurements of NPP and stand age at the plot-level demonstrates the reliability

  15. 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

  16. 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

  17. 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

  18. 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.

  19. 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.

  20. Tree Circumference Dynamics in Four Forests Characterized Using Automated Dendrometer Bands

    PubMed Central

    McMahon, Sean M.; Detto, Matteo; Lutz, James A.; Davies, Stuart J.; Chang-Yang, Chia-Hao; Anderson-Teixeira, Kristina J.

    2016-01-01

    Stem diameter is one of the most commonly measured attributes of trees, forming the foundation of forest censuses and monitoring. Changes in tree stem circumference include both irreversible woody stem growth and reversible circumference changes related to water status, yet these fine-scale dynamics are rarely leveraged to understand forest ecophysiology and typically ignored in plot- or stand-scale estimates of tree growth and forest productivity. Here, we deployed automated dendrometer bands on 12–40 trees at four different forested sites—two temperate broadleaf deciduous, one temperate conifer, and one tropical broadleaf semi-deciduous—to understand how tree circumference varies on time scales of hours to months, how these dynamics relate to environmental conditions, and whether the structure of these variations might introduce substantive error into estimates of woody growth. Diurnal stem circumference dynamics measured over the bark commonly—but not consistently—exhibited daytime shrinkage attributable to transpiration-driven changes in stem water storage. The amplitude of this shrinkage was significantly correlated with climatic variables (daily temperature range, vapor pressure deficit, and radiation), sap flow and evapotranspiration. Diurnal variations were typically <0.5 mm circumference in amplitude and unlikely to be of concern to most studies of tree growth. Over time scales of multiple days, the bands captured circumference increases in response to rain events, likely driven by combinations of increased stem water storage and bark hydration. Particularly at the tropical site, these rain responses could be quite substantial, ranging up to 1.5 mm circumference expansion within 48 hours following a rain event. We conclude that over-bark measurements of stem circumference change sometimes correlate with but have limited potential for directly estimating daily transpiration, but that they can be valuable on time scales of days to weeks for

  1. Atmospheric particulate deposition in temperate deciduous forest ecosystems: interactions with the canopy and nutrient inputs in two beech stands of Northeastern France.

    PubMed

    Lequy, Emeline; Calvaruso, Christophe; Conil, Sébastien; Turpault, Marie-Pierre

    2014-07-15

    As wood harvests are expected to increase to satisfy the need for bio-energy in Europe, quantifying atmospheric nutrient inputs in forest ecosystems is essential for forest management. Current atmospheric measurements only take into account the <0.45 μm fraction and dry deposition is generally modeled. The aims of this study were to quantify atmospheric particulate deposition (APD), the >0.45 μm fraction of atmospheric deposition, below the canopy, to study the influence of the canopy on APD, and to determine the influence of APD below canopy to nutrient input-output budgets with a focus on base cations calcium, magnesium and potassium, and phosphorus. APD was sampled every four weeks by passive collectors. We divided APD into an organic and a mineral fraction, respectively POM and MDD. MDD was divided into a soluble and a hardly soluble fraction in hydrogen peroxide, referred to as S-MDD and H-MDD, respectively. In order to better understand the influence of the canopy on APD, we studied APD in three pathways below the canopy (litterfall, stemflow and throughfall), and in open field. Our results indicated that APD in throughfall (123 ± 64 kg ha(-1)year(-1)) was significantly higher and synchronic with that in open field (33 ±9 kg ha(-1)year(-1)) in the two study sites. This concerned both POM and MDD, suggesting a large interception of APD by foliar surfaces, which is rapidly washed off by rain within four weeks. Throughfall H-MDD was the main pathway with an average of 16 ± 2 kg ha(-1)year(-1). Stemflow and litterfall were neglected. In one study site, canopy intercepted about 8 kg ha(-1)year(-1) of S-MDD. Although base cations and phosphorus inputs by APD are lower than those of <0.45 μm deposition, they contributed from 5 to 32% to atmospheric deposition and improved the nutrient budget in one of the study sites.

  2. Orthodontic movement in deciduous teeth

    PubMed Central

    Consolaro, Alberto

    2015-01-01

    Deciduous teeth exfoliate as a result of apoptosis induced by cementoblasts, a process that reveals the mineralized portion of the root while attracting clasts. Root resorption in deciduous teeth is slow due to lack of mediators necessary to speed it up; however, it accelerates and spreads in one single direction whenever a permanent tooth pericoronal follicle, rich in epithelial growth factor (EGF), or other bone resorption mediators come near. The latter are responsible for bone resorption during eruption, and deciduous teeth root resorption and exfoliation. Should deciduous teeth be subjected to orthodontic movement or anchorage, mediators local levels will increase. Thus, one should be fully aware that root resorption in deciduous teeth will speed up and exfoliation will early occur. Treatment planning involving deciduous teeth orthodontic movement and/or anchorage should consider: Are clinical benefits relevant enough as to be worth the risk of undergoing early inconvenient root resorption? PMID:25992982

  3. Orthodontic movement in deciduous teeth.

    PubMed

    Consolaro, Alberto

    2015-01-01

    Deciduous teeth exfoliate as a result of apoptosis induced by cementoblasts, a process that reveals the mineralized portion of the root while attracting clasts. Root resorption in deciduous teeth is slow due to lack of mediators necessary to speed it up; however, it accelerates and spreads in one single direction whenever a permanent tooth pericoronal follicle, rich in epithelial growth factor (EGF), or other bone resorption mediators come near. The latter are responsible for bone resorption during eruption, and deciduous teeth root resorption and exfoliation. Should deciduous teeth be subjected to orthodontic movement or anchorage, mediators local levels will increase. Thus, one should be fully aware that root resorption in deciduous teeth will speed up and exfoliation will early occur. Treatment planning involving deciduous teeth orthodontic movement and/or anchorage should consider: Are clinical benefits relevant enough as to be worth the risk of undergoing early inconvenient root resorption?

  4. 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.

  5. 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.

  6. 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

  7. Leaf phenology and seasonal variation of photosynthesis of invasive Berberis thunbergii (Japanese barberry) and two co-occurring native understory shrubs in a northeastern United States deciduous forest.

    PubMed

    Xu, Cheng-Yuan; Griffin, Kevin L; Schuster, W S F

    2007-11-01

    Early leafing and extended leaf longevity can be important mechanisms for the invasion of the forest understory. We compared the leaf phenology and photosynthetic characteristics of Berberis thunbergii, an early leafing invasive shrub, and two co-occurring native species, evergreen Kalmia latifolia and late leafing Vaccinium corymbosum, throughout the 2004 growing season. Berberis thunbergii leafed out 1 month earlier than V. corymbosum and approximately 2 weeks prior to the overstory trees. The photosynthetic capacity [characterized by the maximum carboxylation rate of Rubisco (V (cmax)) and the RuBP regeneration capacity mediated by the maximum electron transport rate (J (max))] of B. thunbergii was highest in the spring open canopy, and declined with canopy closure. The 2003 overwintering leaves of K. latifolia displayed high V (cmax) and J (max) in spring 2004. In new leaves of K. latifolia produced in 2004, the photosynthetic capacity gradually increased to a peak in mid-September, and reduced in late November. V. corymbosum, by contrast, maintained low V (cmax) and J (max) throughout the growing season. In B. thunbergii, light acclimation was mediated by adjustment in both leaf mass per unit area and leaf N on a mass basis, but this adjustment was weaker or absent in K. latifolia and V. corymbosum. These results indicated that B. thunbergii utilized high irradiance in the spring while K. latifolia took advantage of high irradiance in the fall and the following spring. By contrast, V. corymbosum generally did not experience a high irradiance environment and was adapted to the low irradiance understory. The apparent success of B. thunbergii therefore, appeared related to a high spring C subsidy and subsequent acclimation to varying irradiance through active N reallocation and leaf morphological modifications.

  8. 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.

  9. Forest fire in the central Himalaya: climate and recovery of trees

    NASA Astrophysics Data System (ADS)

    Sharma, Subrat; Rikhari, H. C.

    A forest fire event is influenced by climatic conditions and is supported by accumulation of fuel on forest floor. After forest fire, photosynthetically active solar radiation was reduced due to accumulation of ash and dust particles in atmosphere. Post-fire impacts on Quercus leucotrichophora, Rhododendron arboreum and Lyonia ovalifolia in a broadleaf forest were analysed after a wild fire. Bark depth damage was greatest for L. ovalifolia and least for Q. leucotrichophora. Regeneration of saplings was observed for all the tree species through sprouting. Epicormic recovery was observed for the trees of all the species. Young trees of Q. leucotrichophora (<40 cm circumference at breast height) were susceptible to fire as evident by the lack of sprouting. Under-canopy tree species have a high potential for recovery as evident by greater length and diameter of shoots and numbers of buds and leaves per shoot than canopy species. Leaf area, leaf moisture and specific leaf area were greater in the deciduous species, with few exceptions, than in evergreen species.

  10. 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.

  11. 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

  12. 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.)

  13. Ecohydrology of a seasonal cloud forest in Dhofar: 1. Field experiment

    NASA Astrophysics Data System (ADS)

    Hildebrandt, Anke; Al Aufi, Mohammed; Amerjeed, Mansoor; Shammas, Mahaad; Eltahir, Elfatih A. B.

    2007-10-01

    We describe the ecohydrology of a unique semiarid broadleaf deciduous forest in Dhofar (Oman). The forest is surrounded by desert and is confined to a coastal area, where the summer wet season is characterized by a persistent dense cloud immersion. Using field observations, we show how clouds render the ecosystem particularly water conserving and therefore create a niche for a moist forest biome in a semiarid area in three ways. First, horizontal precipitation (collection of cloud droplets on tree canopies) added valuable water, such that about two times as much water was received below the canopy (net precipitation) compared to above (rainfall). Second, high stemflow, of about 30% to net precipitation, led to concentrated water input around the stems. Third, transpiration was suppressed during the cloudy summer season, which allowed for storage of the received water. It was only used after the end of the wet season and lasted for the following 3 months, which roughly doubled the length of the growing season. Our results demonstrate that cloud immersion may shape ecosystem hydrology in significant ways, particularly in semiarid environments.

  14. Anaerobic activities of bacteria and fungi in moderately acidic conifer and deciduous leaf litter.

    PubMed

    Reith, Frank; Drake, Harold L; Küsel, Kirsten

    2002-07-01

    Abstract The litter layer of forest soils harbors high amounts of labile organic matter, and anaerobic decomposition processes can be initiated when oxygen is consumed more rapidly than it is supplied by diffusion. In this study, two adjacent moderately acidic forest sites, a spruce and a beech-oak forest, were selected to compare the anaerobic bacterial and fungal activities and populations of conifer and deciduous leaf litter. Most probable number (MPN) estimates of general heterotrophic aerobes and anaerobes from conifer litter equaled those from deciduous leaf litter. H(2), ethanol, formate, and lactate were initially produced with similar rates in both anoxic conifer and deciduous leaf litter microcosms. These products were rapidly consumed in deciduous leaf but not in conifer litter microcosms. Supplemental ethanol and H(2) were consumed only by deciduous leaf litter and yielded additional amounts of acetate in stoichiometries indicative of ethanol- or H(2)-dependent acetogenesis. The negligible turnover of primary fermentation products in conifer litter might be due to the low numbers of acetogens and secondary fermenters present in conifer litter compared to deciduous leaf litter. Fungi capable of anaerobic growth made up only 0.01-0.1% of the total anaerobic microorganisms cultured from conifer and deciduous leaf litter, respectively. Metabolic product profiles obtained from the highest anoxic, growth-positive MPN dilutions supplemented with antibacterial agents indicated that the dominant population of fungi, apparently mainly yeast-like cells, produced H(2), ethanol, acetate, and lactate both in conifer and deciduous leaf litter. Thus, despite acidic conditions, bacteria appear to dominate in the decomposition of carbon in anoxic microsites of both conifer and deciduous leaf litter.

  15. 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...

  16. 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.

  17. Dynamic patterns of nitrogen: Phosphorus ratios in forest soils of China under changing environment

    NASA Astrophysics Data System (ADS)

    Chen, Leiyi; Li, Pin; Yang, Yuanhe

    2016-09-01

    Knowledge of nitrogen (N) and phosphorus (P) stoichiometry is essential for understanding biogeochemical cycle and ecosystem functioning. However, large-scale patterns in soil stoichiometry are not yet fully understood along environmental gradients nor over the temporal scale. Using a comprehensive data set and artificial neural network approach, we evaluated spatial and temporal patterns in topsoil N and P concentrations and N:P ratio across China's forests. Our results revealed that soil weathering stage, climatic factors (i.e., temperature and precipitation), and forest types jointly explained approximately 34.1% and 30.4% of spatial variations in soil N and P, respectively. By contrast, only precipitation could explain the variation in N:P ratio, with soil N:P ratio exhibiting a trend of increase along the precipitation gradient. The observed spatial patterns in soil N:P ratio were consistent with previous findings derived from plants and microbes, suggesting that variation in precipitation may induce the imbalance of N:P stoichiometry in forest ecosystems. Our results also indicated that topsoil N:P ratios exhibited a significant increase from the 1980s to 2000s. However, the associations of N:P dynamics with a single element largely depended on forest type. In evergreen forests, soil N:P dynamics were caused by increasing N and decreasing P. Conversely, N:P changes in deciduous broadleaf forests were triggered only by soil N accumulation. Overall, these results demonstrated a stoichiometric shift in soil N:P both spatially and temporally, implying that nutrient imbalance between soil N and P may be accelerated under global change scenarios.

  18. 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.

  19. Nonlinear response of canopy developmental rate to temperature in temperate and boreal forest in the Northern Hemisphere

    NASA Astrophysics Data System (ADS)

    Park, H.; Ho, C. H.; Jeong, S. J.

    2015-12-01

    Understanding the changes in vegetation annual cycle is crucial for improving our knowledge about various interactions between the terrestrial ecosystem and climate. However, our understanding about the vegetation seasonality is mostly confined to some phenological timings such as spring emergence and fall senescence. This study assessed large-scale variations in the vegetation green-up rate (VGrate), which indicates the rate of canopy development from winter dormancy to summer maturity, and its relationship over Northern Hemisphere temperate and boreal forests for 1982-2011. VGrate and local temperature changes show a positive correlation over the region of interest, and it indicates that a temperature increase during green-up period leads to faster canopy development. The responses of VGrate tend to be more sensitive to positive temperature anomalies than negative anomalies despite same magnitude of the temperature changes. These nonlinear responsiveness of VGrate to local temperature change is clearly observed in deciduous broadleaf forests over Eurasia compared to woodlands over North America. These results suggest that anomalous warming in green-up period would make canopy developments faster over wide temperate and boreal forest areas.

  20. [Early responses of soil fauna in three typical forests of south subtropical China to simulated N deposition addition].

    PubMed

    Xu, Guolian; Mo, Jiangming; Zhou, Guoyi

    2005-07-01

    In this paper, simulated N deposition addition (0, 50, 100 and 150 kg x hm(-2) x yr(-1)) by spreading water or NH4NO3 was conducted to study the early responses of soil fauna in three typical native forests (monsoon evergreen broadleaf forest, pine forest, and broadleaf-pine mixed forest) of subtropical China. The results showed that in monsoon evergreen broadleaf forest, N deposition addition had an obviously negative effect on the three indexes for soil fauna, but in pine forest, the positive effect was significant (P < 0. 05), and the soil fauna community could reach the level in mixed forest, even that in monsoon evergreen broadleaf forest at sometime. The responses in mixed forest were not obvious. In monsoon evergreen broadleaf forest, the negative effects were significant (P < 0.05) under medium N deposition, but not under low N deposition. In pine forest, the positive effect was significant (P < 0.05) under high N deposition, especially for the number of soil fauna groups. The results obtained might imply the N saturation-response mechanisms of forest ecosystems in subtropical China, and the conclusions from this study were also consisted with some related researches.

  1. A broadleaf species enhances an autotoxic conifers growth through belowground chemical interactions.

    PubMed

    Xia, Zhi-Chao; Kong, Chui-Hua; Chen, Long-Chi; Wang, Peng; Wang, Si-Long

    2016-09-01

    Plants may affect the performance of neighboring plants either positively or negatively through interspecific and intraspecific interactions. Productivity of mixed-species systems is ultimately the net result of positive and negative interactions among the component species. Despite increasing knowledge of positive interactions occurring in mixed-species tree systems, relatively little is known about the mechanisms underlying such interactions. Based on data from 25-year-old experimental stands in situ and a series of controlled experiments, we test the hypothesis that a broadleaf, non-N fixing species, Michelia macclurei, facilitates the performance of an autotoxic conifer Chinese fir (Cunninghamia lanceolata) through belowground chemical interactions. Chinese fir roots released the allelochemical cyclic dipeptide (6-hydroxy-1,3-dimethyl-8-nonadecyl-[1,4]-diazocane- 2,5-diketone) into the soil environment, resulting in self-growth inhibition, and deterioration of soil microorganisms that improve P availability. However, when grown with M. macclurei the growth of Chinese fir was consistently enhanced. In particular, Chinese fir enhanced root growth and distribution in deep soil layers. When compared with monocultures of Chinese fir, the presence of M. macclurei reduced release and increased degradation of cyclic dipeptide in the soil, resulting in a shift from self-inhibition to chemical facilitation. This association also improved the soil microbial community by increasing arbuscular mycorrhizal fungi, and induced the production of Chinese fir roots. We conclude that interspecific interactions are less negative than intraspecific ones between non-N fixing broadleaf and autotoxic conifer species. The impacts are generated by reducing allelochemical levels, enhancing belowground mutualisms, improving soil properties, and changing root distributions as well as the net effects of all the processes within the soil. In particular, allelochemical context alters the

  2. 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