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Sample records for early secondary forest

  1. Carbon cycling and net ecosystem production at an early stage of secondary succession in an abandoned coppice forest.

    PubMed

    Ohtsuka, Toshiyuki; Shizu, Yoko; Nishiwaki, Ai; Yashiro, Yuichiro; Koizumi, Hiroshi

    2010-07-01

    Secondary mixed forests are one of the dominant forest cover types in human-dominated temperate regions. However, our understanding of how secondary succession affects carbon cycling and carbon sequestration in these ecosystems is limited. We studied carbon cycling and net ecosystem production (NEP) over 4 years (2004-2008) in a cool-temperate deciduous forest at an early stage of secondary succession (18 years after clear-cutting). Net primary production of the 18-year-old forest in this study was 5.2 tC ha(-1 )year(-1), including below-ground coarse roots; this was partitioned into 2.5 tC ha(-1 )year(-1) biomass increment, 1.6 tC ha(-1 )year(-1) foliage litter, and 1.0 tC ha(-1 )year(-1) other woody detritus. The total amount of annual soil surface CO(2) efflux was 6.8 tC ha(-1 )year(-1), which included root respiration (1.9 tC ha(-1 )year(-1)) and heterotrophic respiration (RH) from soils (4.9 tC ha(-1 )year(-1)). The 18-year forest at this study site exhibited a great increase in biomass pool as a result of considerable total tree growth and low mortality of tree stems. In contrast, the soil organic matter (SOM) pool decreased markedly (-1.6 tC ha(-1 )year(-1)), although further study of below-ground detritus production and RH of SOM decomposition is needed. This young 18-year forest was a weak carbon sink (0.9 tC ha(-1 )year(-1)) at this stage of secondary succession. The NEP of this 18-year forest is likely to increase gradually because biomass increases with tree growth and with the improvement of the SOM pool through increasing litter and dead wood production with stand development.

  2. Seed Regeneration Potential of Canopy Gaps at Early Formation Stage in Temperate Secondary Forests, Northeast China

    PubMed Central

    Yan, Qiao-Ling; Zhu, Jiao-Jun; Yu, Li-Zhong

    2012-01-01

    Promoting the seed regeneration potential of secondary forests undergoing gap disturbances is an important approach for achieving forest restoration and sustainable management. Seedling recruitment from seed banks strongly determines the seed regeneration potential, but the process is poorly understood in the gaps of secondary forests. The objectives of the present study were to evaluate the effects of gap size, seed availability, and environmental conditions on the seed regeneration potential in temperate secondary forests. It was found that gap formation could favor the invasion of more varieties of species in seed banks, but it also could speed up the turnover rate of seed banks leading to lower seed densities. Seeds of the dominant species, Fraxinus rhynchophylla, were transient in soil and there was a minor and discontinuous contribution of the seed bank to its seedling emergence. For Quercus mongolica, emerging seedling number was positively correlated with seed density in gaps (R = 0.32, P<0.01), especially in medium and small gaps (<500 m2). Furthermore, under canopies, there was a positive correlation between seedling number and seed density of Acer mono (R = 0.43, P<0.01). Gap formation could promote seedling emergence of two gap-dependent species (i.e., Q. mongolica and A. mono), but the contribution of seed banks to seedlings was below 10% after gap creation. Soil moisture and temperature were the restrictive factors controlling the seedling emergence from seeds in gaps and under canopies, respectively. Thus, the regeneration potential from seed banks is limited after gap formation. PMID:22745771

  3. Drought resistance in early and late secondary successional species from a tropical dry forest: the interplay between xylem resistance to embolism, sapwood water storage and leaf shedding

    Treesearch

    Fernando Pineda-Garcia; Horacio Paz; Frederick C. Meinzer

    2013-01-01

    The mechanisms of drought resistance that allow plants to successfully establish at different stages of secondary succession in tropical dry forests are not well understood. We characterized mechanisms of drought resistance in early and late-successional species and tested whether risk of drought differs across sites at different successional stages, and whether early...

  4. Stimulating seedling growth in early stages of secondary forest succession: a modeling approach to guide tree liberation

    PubMed Central

    van Kuijk, Marijke; Anten, Niels P. R.; Oomen, Roelof J.; Schieving, Feike

    2014-01-01

    Excessive growth of non-woody plants and shrubs on degraded lands can strongly hamper tree growth and thus secondary forest succession. A common method to accelerate succession, called liberation, involves opening up the vegetation canopy around young target trees. This can increase growth of target trees by reducing competition for light with neighboring plants. However, liberation has not always had the desired effect, likely due to differences in light requirement between tree species. Here we present a 3D-model, which calculates photosynthetic rate of individual trees in a vegetation stand. It enables us to examine how stature, crown structure, and physiological traits of target trees and characteristics of the surrounding vegetation together determine effects of light on tree growth. The model was applied to a liberation experiment conducted with three pioneer species in a young secondary forest in Vietnam. Species responded differently to the treatment depending on their height, crown structure and their shade-tolerance level. Model simulations revealed practical thresholds over which the tree growth response is heavily influenced by the height and density of surrounding vegetation and gap radius. There were strong correlations between calculated photosynthetic rates and observed growth: the model was well able to predict growth of trees in young forests and the effects of liberation there upon. Thus, our model serves as a useful tool to analyze light competition between young trees and surrounding vegetation and may help assess the potential effect of tree liberation. PMID:25101100

  5. Stimulating seedling growth in early stages of secondary forest succession: a modeling approach to guide tree liberation.

    PubMed

    van Kuijk, Marijke; Anten, Niels P R; Oomen, Roelof J; Schieving, Feike

    2014-01-01

    Excessive growth of non-woody plants and shrubs on degraded lands can strongly hamper tree growth and thus secondary forest succession. A common method to accelerate succession, called liberation, involves opening up the vegetation canopy around young target trees. This can increase growth of target trees by reducing competition for light with neighboring plants. However, liberation has not always had the desired effect, likely due to differences in light requirement between tree species. Here we present a 3D-model, which calculates photosynthetic rate of individual trees in a vegetation stand. It enables us to examine how stature, crown structure, and physiological traits of target trees and characteristics of the surrounding vegetation together determine effects of light on tree growth. The model was applied to a liberation experiment conducted with three pioneer species in a young secondary forest in Vietnam. Species responded differently to the treatment depending on their height, crown structure and their shade-tolerance level. Model simulations revealed practical thresholds over which the tree growth response is heavily influenced by the height and density of surrounding vegetation and gap radius. There were strong correlations between calculated photosynthetic rates and observed growth: the model was well able to predict growth of trees in young forests and the effects of liberation there upon. Thus, our model serves as a useful tool to analyze light competition between young trees and surrounding vegetation and may help assess the potential effect of tree liberation.

  6. Drought resistance in early and late secondary successional species from a tropical dry forest: the interplay between xylem resistance to embolism, sapwood water storage and leaf shedding.

    PubMed

    Pineda-García, Fernando; Paz, Horacio; Meinzer, Frederick C

    2013-02-01

    The mechanisms of drought resistance that allow plants to successfully establish at different stages of secondary succession in tropical dry forests are not well understood. We characterized mechanisms of drought resistance in early and late-successional species and tested whether risk of drought differs across sites at different successional stages, and whether early and late-successional species differ in resistance to experimentally imposed soil drought. The microenvironment in early successional sites was warmer and drier than in mature forest. Nevertheless, successional groups did not differ in resistance to soil drought. Late-successional species resisted drought through two independent mechanisms: high resistance of xylem to embolism, or reliance on high stem water storage capacity. High sapwood water reserves delayed the effects of soil drying by transiently decoupling plant and soil water status. Resistance to soil drought resulted from the interplay between variations in xylem vulnerability to embolism, reliance on sapwood water reserves and leaf area reduction, leading to a tradeoff of avoidance against tolerance of soil drought, along which successional groups were not differentiated. Overall, our data suggest that ranking species' performance under soil drought based solely on xylem resistance to embolism may be misleading, especially for species with high sapwood water storage capacity. © 2012 Blackwell Publishing Ltd.

  7. Secondary Forest Age and Tropical Forest Biomass Estimation Using TM

    NASA Technical Reports Server (NTRS)

    Nelson, R. F.; Kimes, D. S.; Salas, W. A.; Routhier, M.

    1999-01-01

    The age of secondary forests in the Amazon will become more critical with respect to the estimation of biomass and carbon budgets as tropical forest conversion continues. Multitemporal Thematic Mapper data were used to develop land cover histories for a 33,000 Square kM area near Ariquemes, Rondonia over a 7 year period from 1989-1995. The age of the secondary forest, a surrogate for the amount of biomass (or carbon) stored above-ground, was found to be unimportant in terms of biomass budget error rates in a forested TM scene which had undergone a 20% conversion to nonforest/agricultural cover types. In such a situation, the 80% of the scene still covered by primary forest accounted for over 98% of the scene biomass. The difference between secondary forest biomass estimates developed with and without age information were inconsequential relative to the estimate of biomass for the entire scene. However, in futuristic scenarios where all of the primary forest has been converted to agriculture and secondary forest (55% and 42% respectively), the ability to age secondary forest becomes critical. Depending on biomass accumulation rate assumptions, scene biomass budget errors on the order of -10% to +30% are likely if the age of the secondary forests are not taken into account. Single-date TM imagery cannot be used to accurately age secondary forests into single-year classes. A neural network utilizing TM band 2 and three TM spectral-texture measures (bands 3 and 5) predicted secondary forest age over a range of 0-7 years with an RMSE of 1.59 years and an R(Squared) (sub actual vs predicted) = 0.37. A proposal is made, based on a literature review, to use satellite imagery to identify general secondary forest age groups which, within group, exhibit relatively constant biomass accumulation rates.

  8. Tropical secondary forest management influences frugivorous bat composition, abundance and fruit consumption in Chiapas, Mexico.

    PubMed

    Vleut, Ivar; Levy-Tacher, Samuel Israel; de Boer, Willem Frederik; Galindo-González, Jorge; Vazquez, Luis-Bernardo

    2013-01-01

    Most studies on frugivorous bat assemblages in secondary forests have concentrated on differences among successional stages, and have disregarded the effect of forest management. Secondary forest management practices alter the vegetation structure and fruit availability, important factors associated with differences in frugivorous bat assemblage structure, and fruit consumption and can therefore modify forest succession. Our objective was to elucidate factors (forest structural variables and fruit availability) determining bat diversity, abundance, composition and species-specific abundance of bats in (i) secondary forests managed by Lacandon farmers dominated by Ochroma pyramidale, in (ii) secondary forests without management, and in (iii) mature rain forests in Chiapas, Southern Mexico. Frugivorous bat species diversity (Shannon H') was similar between forest types. However, bat abundance was highest in rain forest and O. pyramidale forests. Bat species composition was different among forest types with more Carollia sowelli and Sturnira lilium captures in O. pyramidale forests. Overall, bat fruit consumption was dominated by early-successional shrubs, highest late-successional fruit consumption was found in rain forests and more bats consumed early-successional shrub fruits in O. pyramidale forests. Ochroma pyramidale forests presented a higher canopy openness, tree height, lower tree density and diversity of fruit than secondary forests. Tree density and canopy openness were negatively correlated with bat species diversity and bat abundance, but bat abundance increased with fruit abundance and tree height. Hence, secondary forest management alters forests' structural characteristics and resource availability, and shapes the frugivorous bat community structure, and thereby the fruit consumption by bats.

  9. Tropical Secondary Forest Management Influences Frugivorous Bat Composition, Abundance and Fruit Consumption in Chiapas, Mexico

    PubMed Central

    Vleut, Ivar; Levy-Tacher, Samuel Israel; de Boer, Willem Frederik; Galindo-González, Jorge; Vazquez, Luis-Bernardo

    2013-01-01

    Most studies on frugivorous bat assemblages in secondary forests have concentrated on differences among successional stages, and have disregarded the effect of forest management. Secondary forest management practices alter the vegetation structure and fruit availability, important factors associated with differences in frugivorous bat assemblage structure, and fruit consumption and can therefore modify forest succession. Our objective was to elucidate factors (forest structural variables and fruit availability) determining bat diversity, abundance, composition and species-specific abundance of bats in (i) secondary forests managed by Lacandon farmers dominated by Ochroma pyramidale, in (ii) secondary forests without management, and in (iii) mature rain forests in Chiapas, Southern Mexico. Frugivorous bat species diversity (Shannon H’) was similar between forest types. However, bat abundance was highest in rain forest and O. pyramidale forests. Bat species composition was different among forest types with more Carollia sowelli and Sturnira lilium captures in O. pyramidale forests. Overall, bat fruit consumption was dominated by early-successional shrubs, highest late-successional fruit consumption was found in rain forests and more bats consumed early-successional shrub fruits in O. pyramidale forests. Ochroma pyramidale forests presented a higher canopy openness, tree height, lower tree density and diversity of fruit than secondary forests. Tree density and canopy openness were negatively correlated with bat species diversity and bat abundance, but bat abundance increased with fruit abundance and tree height. Hence, secondary forest management alters forests’ structural characteristics and resource availability, and shapes the frugivorous bat community structure, and thereby the fruit consumption by bats. PMID:24147029

  10. Biomass resilience of Neotropical secondary forests.

    PubMed

    Poorter, Lourens; Bongers, Frans; Aide, T Mitchell; Almeyda Zambrano, Angélica M; Balvanera, Patricia; Becknell, Justin M; Boukili, Vanessa; Brancalion, Pedro H S; Broadbent, Eben N; Chazdon, Robin L; Craven, Dylan; de Almeida-Cortez, Jarcilene S; Cabral, George A L; de Jong, Ben H J; Denslow, Julie S; Dent, Daisy H; DeWalt, Saara J; Dupuy, Juan M; Durán, Sandra M; Espírito-Santo, Mario M; Fandino, María C; César, Ricardo G; Hall, Jefferson S; Hernandez-Stefanoni, José Luis; Jakovac, Catarina C; Junqueira, André B; Kennard, Deborah; Letcher, Susan G; Licona, Juan-Carlos; Lohbeck, Madelon; Marín-Spiotta, Erika; Martínez-Ramos, Miguel; Massoca, Paulo; Meave, Jorge A; Mesquita, Rita; Mora, Francisco; Muñoz, Rodrigo; Muscarella, Robert; Nunes, Yule R F; Ochoa-Gaona, Susana; de Oliveira, Alexandre A; Orihuela-Belmonte, Edith; Peña-Claros, Marielos; Pérez-García, Eduardo A; Piotto, Daniel; Powers, Jennifer S; Rodríguez-Velázquez, Jorge; Romero-Pérez, I Eunice; Ruíz, Jorge; Saldarriaga, Juan G; Sanchez-Azofeifa, Arturo; Schwartz, Naomi B; Steininger, Marc K; Swenson, Nathan G; Toledo, Marisol; Uriarte, Maria; van Breugel, Michiel; van der Wal, Hans; Veloso, Maria D M; Vester, Hans F M; Vicentini, Alberto; Vieira, Ima C G; Bentos, Tony Vizcarra; Williamson, G Bruce; Rozendaal, Danaë M A

    2016-02-11

    Land-use change occurs nowhere more rapidly than in the tropics, where the imbalance between deforestation and forest regrowth has large consequences for the global carbon cycle. However, considerable uncertainty remains about the rate of biomass recovery in secondary forests, and how these rates are influenced by climate, landscape, and prior land use. Here we analyse aboveground biomass recovery during secondary succession in 45 forest sites and about 1,500 forest plots covering the major environmental gradients in the Neotropics. The studied secondary forests are highly productive and resilient. Aboveground biomass recovery after 20 years was on average 122 megagrams per hectare (Mg ha(-1)), corresponding to a net carbon uptake of 3.05 Mg C ha(-1) yr(-1), 11 times the uptake rate of old-growth forests. Aboveground biomass stocks took a median time of 66 years to recover to 90% of old-growth values. Aboveground biomass recovery after 20 years varied 11.3-fold (from 20 to 225 Mg ha(-1)) across sites, and this recovery increased with water availability (higher local rainfall and lower climatic water deficit). We present a biomass recovery map of Latin America, which illustrates geographical and climatic variation in carbon sequestration potential during forest regrowth. The map will support policies to minimize forest loss in areas where biomass resilience is naturally low (such as seasonally dry forest regions) and promote forest regeneration and restoration in humid tropical lowland areas with high biomass resilience.

  11. Biomass resilience of Neotropical secondary forests

    NASA Astrophysics Data System (ADS)

    Poorter, Lourens; Bongers, Frans; Aide, T. Mitchell; Almeyda Zambrano, Angélica M.; Balvanera, Patricia; Becknell, Justin M.; Boukili, Vanessa; Brancalion, Pedro H. S.; Broadbent, Eben N.; Chazdon, Robin L.; Craven, Dylan; de Almeida-Cortez, Jarcilene S.; Cabral, George A. L.; de Jong, Ben H. J.; Denslow, Julie S.; Dent, Daisy H.; Dewalt, Saara J.; Dupuy, Juan M.; Durán, Sandra M.; Espírito-Santo, Mario M.; Fandino, María C.; César, Ricardo G.; Hall, Jefferson S.; Hernandez-Stefanoni, José Luis; Jakovac, Catarina C.; Junqueira, André B.; Kennard, Deborah; Letcher, Susan G.; Licona, Juan-Carlos; Lohbeck, Madelon; Marín-Spiotta, Erika; Martínez-Ramos, Miguel; Massoca, Paulo; Meave, Jorge A.; Mesquita, Rita; Mora, Francisco; Muñoz, Rodrigo; Muscarella, Robert; Nunes, Yule R. F.; Ochoa-Gaona, Susana; de Oliveira, Alexandre A.; Orihuela-Belmonte, Edith; Peña-Claros, Marielos; Pérez-García, Eduardo A.; Piotto, Daniel; Powers, Jennifer S.; Rodríguez-Velázquez, Jorge; Romero-Pérez, I. Eunice; Ruíz, Jorge; Saldarriaga, Juan G.; Sanchez-Azofeifa, Arturo; Schwartz, Naomi B.; Steininger, Marc K.; Swenson, Nathan G.; Toledo, Marisol; Uriarte, Maria; van Breugel, Michiel; van der Wal, Hans; Veloso, Maria D. M.; Vester, Hans F. M.; Vicentini, Alberto; Vieira, Ima C. G.; Bentos, Tony Vizcarra; Williamson, G. Bruce; Rozendaal, Danaë M. A.

    2016-02-01

    Land-use change occurs nowhere more rapidly than in the tropics, where the imbalance between deforestation and forest regrowth has large consequences for the global carbon cycle. However, considerable uncertainty remains about the rate of biomass recovery in secondary forests, and how these rates are influenced by climate, landscape, and prior land use. Here we analyse aboveground biomass recovery during secondary succession in 45 forest sites and about 1,500 forest plots covering the major environmental gradients in the Neotropics. The studied secondary forests are highly productive and resilient. Aboveground biomass recovery after 20 years was on average 122 megagrams per hectare (Mg ha-1), corresponding to a net carbon uptake of 3.05 Mg C ha-1 yr-1, 11 times the uptake rate of old-growth forests. Aboveground biomass stocks took a median time of 66 years to recover to 90% of old-growth values. Aboveground biomass recovery after 20 years varied 11.3-fold (from 20 to 225 Mg ha-1) across sites, and this recovery increased with water availability (higher local rainfall and lower climatic water deficit). We present a biomass recovery map of Latin America, which illustrates geographical and climatic variation in carbon sequestration potential during forest regrowth. The map will support policies to minimize forest loss in areas where biomass resilience is naturally low (such as seasonally dry forest regions) and promote forest regeneration and restoration in humid tropical lowland areas with high biomass resilience.

  12. The limited importance of size-asymmetric light competition and growth of pioneer species in early secondary forest succession in Vietnam.

    PubMed

    van Kuijk, Marijke; Anten, N P R; Oomen, R J; van Bentum, D W; Werger, M J A

    2008-08-01

    It is generally believed that asymmetric competition for light plays a predominant role in determining the course of succession by increasing size inequalities between plants. Size-related growth is the product of size-related light capture and light-use efficiency (LUE). We have used a canopy model to calculate light capture and photosynthetic rates of pioneer species in sequential vegetation stages of a young secondary forest stand. Growth of the same saplings was followed in time as succession proceeded. Photosynthetic rate per unit plant mass (P(mass): mol C g(-1) day(-1)), a proxy for plant growth, was calculated as the product of light capture efficiency [Phi(mass): mol photosynthetic photon flux density (PPFD) g(-1) day(-1)] and LUE (mol C mol PPFD(-1)). Species showed different morphologies and photosynthetic characteristics, but their light-capturing and light-use efficiencies, and thus P (mass), did not differ much. This was also observed in the field: plant growth was not size-asymmetric. The size hierarchy that was present from the very early beginning of succession remained for at least the first 5 years. We conclude, therefore, that in slow-growing regenerating vegetation stands, the importance of asymmetric competition for light and growth can be much less than is often assumed.

  13. The potential for species conservation in tropical secondary forests

    Treesearch

    Robin L. Chazdon; Carlos A. Peres; Daisy Dent; Douglas Sheil; Ariel E. Lugo; David Lamb; Nigel E. Stork; Scott E. Miller

    2009-01-01

    In the wake of widespread loss of old-growth forests throughout the tropics, secondary forests will likely play a growing role in the conservation of forest biodiversity. We considered a complex hierarchy of factors that interact in space and time to determine the conservation potential of tropical secondary forests. Beyond the characteristics of local forest patches,...

  14. The potential for species conservation in tropical secondary forests.

    PubMed

    Chazdon, Robin L; Peres, Carlos A; Dent, Daisy; Sheil, Douglas; Lugo, Ariel E; Lamb, David; Stork, Nigel E; Miller, Scott E

    2009-12-01

    In the wake of widespread loss of old-growth forests throughout the tropics, secondary forests will likely play a growing role in the conservation of forest biodiversity. We considered a complex hierarchy of factors that interact in space and time to determine the conservation potential of tropical secondary forests. Beyond the characteristics of local forest patches, spatial and temporal landscape dynamics influence the establishment, species composition, and persistence of secondary forests. Prospects for conservation of old-growth species in secondary forests are maximized in regions where the ratio of secondary to old-growth forest area is relatively low, older secondary forests have persisted, anthropogenic disturbance after abandonment is relatively low, seed-dispersing fauna are present, and old-growth forests are close to abandoned sites. The conservation value of a secondary forest is expected to increase over time, as species arriving from remaining old-growth forest patches accumulate. Many studies are poorly replicated, which limits robust assessments of the number and abundance of old-growth species present in secondary forests. Older secondary forests are not often studied and few long-term studies are conducted in secondary forests. Available data indicate that both old-growth and second-growth forests are important to the persistence of forest species in tropical, human-modified landscapes.

  15. Secondary Forests from Agricultural Abandonment in Amazonia 2000-2009

    NASA Technical Reports Server (NTRS)

    Morton, Douglas

    2010-01-01

    Ongoing negotiations to include reducing emissions from tropical deforestation and forest degradation (REDD+) in a post-Kyoto climate agreement highlight the critical role of satellite data for accurate and transparent accounting of forest cover changes. In addition to deforestation and degradation, knowledge of secondary forest dynamics is essential for full carbon accounting under REDD+. Land abandonment to secondary forests also frames one of the key tradeoffs for agricultural production in tropical forest countries-whether to incentivize secondary forest growth (for carbon sequestration and biodiversity conservation) or low-carbon expansion of agriculture or biofuels production in areas of secondary forests. We examined patterns of land abandonment to secondary forest across the arc of deforestation in Brazil and Bolivia using time series of annual Landsat and MODIS data from 2000-2009. Rates of land abandonment to secondary forest during 2002-2006 were less than 5% of deforestation rates in these years. Small areas of new secondary forest were scattered across the entire arc of deforestation, rather than concentrated in any specific region of the basin. Taken together, our analysis of the satellite data record emphasizes the difficulties of addressing the pool of new secondary forests in the context of REDD+ in Amazonia. Due to the small total area of secondary forests, land sparing through agricultural intensification will be an important element of efforts to reduce deforestation rates under REDD+ while improving agricultural productivity in Amazonia.

  16. Modeling forest disturbance and recovery in secondary subtropical dry forests of Puerto Rico

    NASA Astrophysics Data System (ADS)

    Holm, J. A.; Shugart, H. H., Jr.; Van Bloem, S. J.

    2015-12-01

    Because of human pressures, the need to understand and predict the long-term dynamics of subtropical dry forests is urgent. Through modifications to the ZELIG vegetation demographic model, including the development of species- and site-specific parameters and internal modifications, the capability to predict forest change within the Guanica State Forest in Puerto Rico can now be accomplished. One objective was to test the capability of this new model (i.e. ZELIG-TROP) to predict successional patterns of secondary forests across a gradient of abandoned fields currently being reclaimed as forests. Model simulations found that abandoned fields that are on degraded lands have a delayed response to fully recover and reach a mature forest status during the simulated time period; 200 years. The forest recovery trends matched predictions published in other studies, such that attributes involving early resource acquisition (i.e. canopy height, canopy coverage, density) were the fastest to recover, but attributes used for structural development (i.e. biomass, basal area) were relatively slow in recovery. Biomass and basal area, two attributes that tend to increase during later successional stages, are significantly lower during the first 80-100 years of recovery compared to a mature forest, suggesting that the time scale of resilience in subtropical dry forests needs to be partially redefined. A second objective was to investigate the long and short-term effects of increasing hurricane disturbances on vegetation structure and dynamics, due to hurricanes playing an important role in maintaining dry forest structure in Puerto Rico. Hurricane disturbance simulations within ZELIG-TROP predicted that increasing hurricane intensity (i.e. up to 100% increase) did not lead to a large shift in long-term AGB or NPP. However, increased hurricane frequency did lead to a 5-40% decrease in AGB, and 32-50% increase in NPP, depending on the treatment. In addition, the modeling approach used

  17. Resilience of tropical rain forests: tree community reassembly in secondary forests.

    PubMed

    Norden, Natalia; Chazdon, Robin L; Chao, Anne; Jiang, Yi-Huei; Vílchez-Alvarado, Braulio

    2009-05-01

    Understanding the recovery dynamics of ecosystems presents a major challenge in the human-impacted tropics. We tested whether secondary forests follow equilibrium or non-equilibrium dynamics by evaluating community reassembly over time, across different successional stages, and among multiple life stages. Based on long-term and static data from six 1-ha plots in NE Costa Rica, we show that secondary forests are undergoing reassembly of canopy tree and palm species composition through the successful recruitment of seedlings, saplings, and young trees of mature forest species. Such patterns were observed over time within sites and across successional stages. Floristic reassembly in secondary forests showed a clear convergence with mature forest community composition, supporting an equilibrium model. This resilience stems from three key factors co-occurring locally: high abundance of generalist species in the regional flora, high levels of seed dispersal, and local presence of old-growth forest remnants.

  18. Nutrient limitation in tropical secondary forests following different management practices.

    PubMed

    Nagy, R Chelsea; Rastetter, Edward B; Neill, Christopher; Porder, Stephen

    2017-04-01

    Secondary forests now make up more than one-half of all tropical forests, and constraints on their biomass accumulation will influence the strength of the terrestrial carbon (C) sink in the coming decades. However the variance in secondary tropical forest biomass for a given stand age and climate is high and our understanding of why is limited. We constructed a model of terrestrial C, nitrogen (N), and phosphorus (P) cycling to examine the influence of disturbance and management practices on nutrient limitation and biomass recovery in secondary tropical forests. The model predicted that N limited the rate of forest recovery in the first few decades following harvest, but that this limitation switched to P approximately 30-40 yr after abandonment, consistent with field data on N and P cycling from secondary tropical forest chronosequences. Simulated biomass recovery agreed well with field data of biomass accumulation following harvest (R(2)  = 0.80). Model results showed that if all biomass remained on site following a severe disturbance such as blowdown, regrowth approached pre-disturbance biomass in 80-90 yr, and recovery was faster following smaller disturbances such as selective logging. Field data from regrowth on abandoned pastures were consistent with simulated losses of nutrients in soil organic matter, particularly P. Following any forest disturbance that involved the removal of nutrients (i.e., except blowdown), forest regrowth produced reduced biomass relative to the initial state as a result of nutrient loss through harvest, leaching and/or sequestration by secondary minerals. Differences in nutrient availability accounted for 49-94% of the variance in secondary forest biomass C at a given stand age. Management lessons from this study are the importance of strategies that help retain nutrients on site, recognizing the role of coarse woody debris in immobilization and subsequent release of nutrients, and the potential for nutrient additions to enhance

  19. Early successional forest habitats and water resources

    Treesearch

    James Vose; Chelcy Ford

    2011-01-01

    Tree harvests that create early successional habitats have direct and indirect impacts on water resources in forests of the Central Hardwood Region. Streamflow increases substantially immediately after timber harvest, but increases decline as leaf area recovers and biomass aggrades. Post-harvest increases in stormflow of 10–20%, generally do not contribute to...

  20. Perspectives on secondary forest management in tropical humid lowland America.

    PubMed

    Kammesheidt, Ludwig

    2002-05-01

    Secondary forests regrowing on abandoned agricultural land constitute an important, albeit widely overlooked, component in the landscape matrix of tropical lowland America. These 'new' forest resources on private land-holdings derive either from unsustainable cattle-ranching practices of better-off farmers or are part of the crop/fallow system of resource-poor farmers. If previous land use was light, secondary forest management may offer an interesting use option to better-off farmers, providing that subsidies for stand improvement are given. Improved fallow systems using partly the successional vegetation may be a way to establish sustainable small-scale agriculture for resource-poor farmers. Given some technical and financial input, land-use systems based on secondary vegetation could play a vital role both in sustainable landscape management and biodiversity conservation.

  1. Modeling seasonal surface temperature variations in secondary tropical dry forests

    NASA Astrophysics Data System (ADS)

    Cao, Sen; Sanchez-Azofeifa, Arturo

    2017-10-01

    Secondary tropical dry forests (TDFs) provide important ecosystem services such as carbon sequestration, biodiversity conservation, and nutrient cycle regulation. However, their biogeophysical processes at the canopy-atmosphere interface remain unknown, limiting our understanding of how this endangered ecosystem influences, and responds to the ongoing global warming. To facilitate future development of conservation policies, this study characterized the seasonal land surface temperature (LST) behavior of three successional stages (early, intermediate, and late) of a TDF, at the Santa Rosa National Park (SRNP), Costa Rica. A total of 38 Landsat-8 Thermal Infrared Sensor (TIRS) data and the Surface Reflectance (SR) product were utilized to model LST time series from July 2013 to July 2016 using a radiative transfer equation (RTE) algorithm. We further related the LST time series to seven vegetation indices which reflect different properties of TDFs, and soil moisture data obtained from a Wireless Sensor Network (WSN). Results showed that the LST in the dry season was 15-20 K higher than in the wet season at SRNP. We found that the early successional stages were about 6-8 K warmer than the intermediate successional stages and were 9-10 K warmer than the late successional stages in the middle of the dry season; meanwhile, a minimum LST difference (0-1 K) was observed at the end of the wet season. Leaf phenology and canopy architecture explained most LST variations in both dry and wet seasons. However, our analysis revealed that it is precipitation that ultimately determines the LST variations through both biogeochemical (leaf phenology) and biogeophysical processes (evapotranspiration) of the plants. Results of this study could help physiological modeling studies in secondary TDFs.

  2. Early forest soils and their role in Devonian global change

    SciTech Connect

    Retallack, G.J.

    1997-04-25

    A paleosol in the Middle Devonian Aztec Siltstone of Victoria Land, Antarctica, is the most ancient known soil of well-drained forest ecosystems. Clay enrichment and chemical weathering of subsurface horizons in this and other Devonian forested paleosols culminate a long-term increase initiated during the Silurian. From Silurian into Devonian time, red clayey calcareous paleosols show a greater volume of roots and a concomitant decline in the density of animal burrows. These trends parallel the decline in atmospheric carbon dioxide determined from isotopic records of pedogenic carbonate in these same paleosols. The drawdown of carbon dioxide began well before the Devonian appearance of coals, large logs, and diverse terrestrial plants and animals, and it did not correlate with temporal variation in volcanic or metamorphic activity. The early Paleozoic greenhouse may have been curbed by the evolution of rhizospheres with an increased ratio of primary to secondary production and by more effective silicate weathering during Silurian time. 14 refs., 3 figs.

  3. Early Forest Soils and Their Role in Devonian Global Change

    PubMed

    Retallack

    1997-04-25

    A paleosol in the Middle Devonian Aztec Siltstone of Victoria Land, Antarctica, is the most ancient known soil of well-drained forest ecosystems. Clay enrichment and chemical weathering of subsurface horizons in this and other Devonian forested paleosols culminate a long-term increase initiated during the Silurian. From Silurian into Devonian time, red clayey calcareous paleosols show a greater volume of roots and a concomitant decline in the density of animal burrows. These trends parallel the decline in atmospheric carbon dioxide determined from isotopic records of pedogenic carbonate in these same paleosols. The drawdown of carbon dioxide began well before the Devonian appearance of coals, large logs, and diverse terrestrial plants and animals, and it did not correlate with temporal variation in volcanic or metamorphic activity. The early Paleozoic greenhouse may have been curbed by the evolution of rhizospheres with an increased ratio of primary to secondary production and by more effective silicate weathering during Silurian time.

  4. Early thinning experiments established by the Fort Valley Experimental Forest

    Treesearch

    Benjamin P. De Blois; Alex. J. Finkral; Andrew J. Sanchez Meador; Margaret M. Moore

    2008-01-01

    Between 1925 and 1936, the Fort Valley Experimental Forest (FVEF) scientists initiated a study to examine a series of forest thinning experiments in second growth ponderosa pine stands in Arizona and New Mexico. These early thinning plots furnished much of the early background for the development of methods used in forest management in the Southwest. The plots ranged...

  5. Liana effects on biomass dynamics strengthen during secondary forest succession.

    PubMed

    Lai, Hao Ran; Hall, Jefferson S; Turner, Benjamin L; van Breugel, Michiel

    2017-04-01

    Secondary forests are important carbon sinks, but their biomass dynamics vary markedly within and across landscapes. The biotic and abiotic drivers of this variation are still not well understood. We tested the effects of soil resource availability and competition by lianas on the biomass dynamics of young secondary tropical forests in Panama and assessed the extent to which liana effects were mediated by soil resource availability. Over a five-year period, growth, mortality, and recruitment of woody plants of ≥1 cm diameter were monitored in 84 plots in 3-30-year-old secondary forests across the Agua Salud site in central Panama. Biomass dynamics and the effects of lianas and soil resources were examined using (generalized) linear mixed-effect models and a model averaging approach. There was strong spatial and temporal variation in liana biomass within and across the plots. The relative biomass of lianas had a strong negative effect on overall tree growth, growth of understory trees decreased with soil fertility and dry season soil water content, and the effect of lianas on tree mortality varied with soil fertility. Tree recruitment was not associated with any of the predictor variables. Our model indicates that tree biomass growth across our landscape was reduced with 22% due to competition with lianas, and that the effect of lianas increased during succession, from 19% after five years to 32% after 30 years. The projected liana-induced growth reduction after 60 years was 47%, which was consistent with data from a nearby site. Our study shows that the observed liana proliferation across tropical forests may reduce the sequestration and storage of carbon in young secondary forests, with important implications for the carbon balance of tropical forest landscapes and consequently for global climate change. Our study highlights the need to incorporate lianas and soil variables in research on the biomass dynamics of secondary forest across tropical landscapes

  6. Rapid Shifts in Soil and Forest Floor Microbial Communities with Changes in Vegetation during Secondary Tropical Forest Succession

    NASA Astrophysics Data System (ADS)

    Smith, A.; Marin-Spiotta, E.; Balser, T. C.

    2012-12-01

    Soil microorganisms regulate fundamental biochemical processes in plant litter decomposition and soil organic matter (SOM) transformations. In order to predict how disturbance affects belowground carbon storage, it is important to understand how the forest floor and soil microbial community respond to changes in land cover, and the consequences on SOM formation and stabilization. We are measuring microbial functional diversity and activity across a long-term successional chronosequence of secondary forests regrowing on abandoned pastures in the wet subtropical forest life zone of Puerto Rico. Here we report intra- and interannual data on soil and litter microbial community composition (via phospholipid fatty acid analysis, PLFA) and microbial activity (via extracellular enzyme activity) from active pastures, secondary forests aged 20, 30, 40, 70, and 90-years, and primary forests. Microbial community composition and extracellular enzyme activity differed significantly by season in these wet subtropical ecosystems, even though differences in mean monthly precipitation between the middle of the dry season (January) and the wet season (July) is only 30mm. Despite seasonal differences, there was a persistent strong effect of land cover type and forest successional stage, or age, on overall microbial community PLFA structure. Using principal component analysis, we found differences in microbial community structure among active pastures, early, and late successional forests. The separation of soil microbes into early and late successional communities parallels the clustering of tree composition data. While the successional patterns held across seasons, the importance of different microbial groups driving these patterns differed seasonally. Biomarkers for gram-positive and actinobacteria (i15:0 and 16:0 10Me) were associated with early (20, 30 & 40 year old) secondary forests in the dry season. These younger forest communities were identified by the biomarker for

  7. Biodiversity and functional regeneration during secondary succession in a tropical dry forest: from microorganisms to mammals

    NASA Astrophysics Data System (ADS)

    do Espírito Santo, M. M.; Neves, F. S.; Valério, H. M.; Leite, L. O.; Falcão, L. A.; Borges, M.; Beirão, M.; Reis, R., Jr.; Berbara, R.; Nunes, Y. R.; Silva, A.; Silva, L. F.; Siqueira, P. R.

    2015-12-01

    In this study, we aimed to determine the changes on soil traits, forest structure and species richness and composition of multiple groups of organisms along secondary succession in a tropical dry forest (TDF) in southeastern Brazil. We defined three successional stages based in forest vertical and horizontal structure and age: early (18-25 years), intermediate (50-60 years) and late (no records of clearing). Five plots of 50 x 20 m were established per stage, and the following groups were sampled using specific techniques: rhizobacteria, mycorrhiza, trees and lianas, butterflies, ants, dung beetles, mosquitoes (Culicidae), birds and bats. We also determined soil chemical and physical characteristics and forest structure (tree height, density and basal area). Soil fertility increased along the successional gradient, and the same pattern was observed for all the forest structure variables. However, species richness and composition showed mixed results depending on the organism group. Three groups usually considered as good bioindicators of habitat quality did not differ in species richness and composition between stages: butterflies, ants and dung beetles. On the other hand, rizhobacteria and mycorrhiza differed both in species richness and composition between stages and may be more sensitive to changes in environmental conditions in TDFs. The other five groups differed either in species richness or composition between one or two pairs of successional stages. Although changes in abiotic conditions and forest structure match the predictions of classical successional models, the response of each group of organism is idiosyncratic in terms of diversity and ecological function, as a consequence of specific resource requirements and life-history traits. In general, diversity increased and functional groups changed mostly from early to intermediate-late stages, strengthening the importance of secondary forests to the maintenance of ecosystem integrity of TDFs.

  8. Gap model development, validation, and application to succession of secondary subtropical dry forests of Puerto Rico

    NASA Astrophysics Data System (ADS)

    Holm, J. A.; Shugart, H. H.; Van Bloem, S.; Larocque, G. R.

    2011-12-01

    Because of human pressures, the need to understand and predict the long-term dynamics and development of subtropical dry forests is urgent. Through modifications to the ZELIG simulation model, including the development of species- and site-specific parameters and internal modifications to the model, the capability to model and predict forest change within the 4500-ha Guanica State Forest in Puerto Rico can now be accomplished. Published datasets and additional data from the U.S. Forest Service Forest Inventory Analysis were used to parameterize the new gap model, ZELIG-TROP. We used data from a 1.44-ha permanent plot located inside the Guanica State Forest in Puerto Rico to test the model. Our first objective was to accurately re-create the observed forest succession for a Puerto Rican subtropical dry forest using ZELIG-TROP. For this objective, the model testing was successful. Simulated total basal area, species composition, total stem density, and biomass all closely resembled the observed Puerto Rican forest. Leaf area index was the variable predicted least accurately. Our second objective was to test the capability of ZELIG-TROP to predict successional patterns of secondary forests across a gradient of abandoned fields currently being reclaimed as forests. Abandoned fields that are on degraded lands do recover and have the potential to reach a mature forest status, but there is a delayed time period of lag time of 50-100 years. The forest recovery trends matched predictions published in other studies; attributes involving early resource acquisition (canopy height, canopy coverage, density) were the fastest to recover, but attributes used for structural development (biomass, basal area) were relatively slow in recovery. Recovery of abandoned fields, especially degraded systems, may take longer time periods, as simulated here. Biomass and basal area, two attributes that tend to increase during later successional stages in some studies, are significantly lower

  9. Conservation importance of early post-disturbance temperate forests

    Treesearch

    Charles Kwit; David I. King; Beverly Collins; Mark E. Swanson

    2014-01-01

    The early post-disturbance stage of temperate forest succession (also referred to as 'early-seral' or 'early-successional' forest) has been the subject of interest and debate. Often thought of as an ephemeral (and often disorganized) state of eventual closed-canopy systems, its direct and immediate role in conservation traditionally has been ignored...

  10. Early Forest Fire Detection Using Radio-Acoustic Sounding System

    PubMed Central

    Sahin, Yasar Guneri; Ince, Turker

    2009-01-01

    Automated early fire detection systems have recently received a significant amount of attention due to their importance in protecting the global environment. Some emergent technologies such as ground-based, satellite-based remote sensing and distributed sensor networks systems have been used to detect forest fires in the early stages. In this study, a radio-acoustic sounding system with fine space and time resolution capabilities for continuous monitoring and early detection of forest fires is proposed. Simulations show that remote thermal mapping of a particular forest region by the proposed system could be a potential solution to the problem of early detection of forest fires. PMID:22573967

  11. Growth of Secondary Forest in Puerto Rico Between 1980 and 1985.

    Treesearch

    P. L. Weaver; R. A. Birdsey

    1990-01-01

    Successive inventories in Puerto Rico provided the first estimates of secondary forest growth on a regional basis. The volume of growing stock trees increased by 32%, and timber volume by nearly 36%, on all classes of forest land between 1980 and 198.5. Timber volume growth rates (in m’ha-’ yr-’ ) varied by forest class and averaged 2.0 in young secondary forest, 6.9...

  12. Neotropical dry forests of the Caribbean: Secondary forest dynamics and restoration in St. Croix, US Virgin Islands

    NASA Astrophysics Data System (ADS)

    Daley, Brian F.

    Neotropical dry forests exist today mainly as secondary forests heavily influenced by exotic plants. This project analyzes land-cover change and secondary dry forest dynamics in three distinct phases (land cover change, secondary forest succession and forest rehabilitation), using St. Croix, US Virgin Islands as an example. Using Landsat satellite images and other data layers, I created classified land cover maps of St. Croix for 1992 and 2002. Forest was the dominant (56%) cover type on both dates, followed by development, grassland/pastures and water. A land cover change analysis comparing the two images revealed that 15% of the study area experienced a change either to (8%) or from (7%) forest. Grassland was the cover most likely to change and decreased from 16% to 11%, converted primarily to development. The overall result is a landscape trending toward younger forests, and increased forest fragmentation and development. In a second study, vegetation data from a chronosequence of secondary forests was analyzed for changes to forest structure, species composition and presence of exotic species. The leguminous exotic tree Leucaena leucocephala was by far the most frequently observed tree and dominated all stands, except those over 50 years old. Species diversity was significantly ( p<0.001) higher for forests in the two oldest age classes and there was a strong trend toward increasing canopy complexity with increased age. However, age class accounted for only a small portion of variability in species diversity, indicating other influencing factors. Slope, elevation, aspect and soil were not significant and sites with long histories of intensive agricultural land-use remained low in species diversity and dominated by exotics >50 years after abandonment. In a third experiment, a 'gap planting' method for establishing four rare native tree species was tested on a site experiencing arrested succession. All four species successfully established at >69% survival in 3m

  13. Assemblages of braconidae (Hymenoptera) at agricultural and secondary forest ecosystem

    NASA Astrophysics Data System (ADS)

    Razali, Rabibah; Din, Abdullah Muhaimin Mohammad; Yaakop, Salmah

    2016-11-01

    Braconids are parasitoid insects which parasitize other insects by injecting their eggs into the larvae and eventually killing the hosts. Due to this character, braconids play an important role in stabilizing the natural and human-made environment. The objective of this study was to evaluate the diversity and distribution of braconids in two ecosystems. Nine Malaise traps were installed in each ecosystem for 30 days at five sampling sites, namely Bukit Rupa (BR), Bukit Fraser (BF), Ladang Zamrud (LZ), Felda Lui Muda (FLM) and Cherating (Ch). Samples were collected and kept in 75% alcohol for identification process. Two types of ecosystem were selected namely forest (secondary forest) and agricultural (oil palm plantation, star fruit orchard) ecosystems. A total of 1201 individuals were collected in 18 subfamilies and 137 morphospecies. From the results, BR showed the highest H', as it was a natural habitat for the braconids. FLM and LZ also showed high H' values, while Ch was the lowest. Based on the cluster analysis, the clade was divided into two groups; the oil palm plantation (LZ, FLM) and forest ecosystem (BF, BR). Ch was considered an outgroup because the braconid spesies found there were specific to Bactocera spp. Based on the rarefaction curve, LZ had the most stable curve compared to the others due to high sample size.

  14. Secondary triage classification using an ensemble random forest technique.

    PubMed

    Azeez, Dhifaf; Gan, K B; Mohd Ali, M A; Ismail, M S

    2015-01-01

    Triage of patients in the emergency department is a complex task based on several uncertainties and ambiguous information. Triage must be implemented within two to five minutes to avoid potential fatality and increased waiting time. An intelligent triage system has been proposed for use in a triage environment to reduce human error. This system was developed based on the objective primary triage scale (OPTS) that is currently used in the Universiti Kebangsaan Malaysia Medical Center. Both primary and secondary triage models are required to develop this system. The primary triage model has been reported previously; this work focused on secondary triage modelling using an ensemble random forest technique. The randomized resampling method was proposed to balance the data unbalance prior to model development. The results showed that the 300% resampling gave a low out-of-bag error of 0.02 compared to 0.37 without pre-processing. This model has a sensitivity and specificity of 0.98 and 0.89, respectively, for the unseen data. With this combination, the random forest reduces the variance, and the randomized resembling reduces the bias, leading to the reduced out-of-bag error.

  15. Symbiotic N fixation is not down-regulated in mature versus secondary tropical forests in Bahia, Brazil.

    NASA Astrophysics Data System (ADS)

    Winbourne, J. B.; Daniel, P.; Porder, S.

    2016-12-01

    Carbon accumulation in secondary tropical forests is substantial, and thought to be limited at least in part by nitrogen (N) availability. Slash and burn agriculture and grazing remove N from the system, however, the abundance of symbiotic N fixing trees in young tropical forests suggests rapid N accumulation as forests regrow. Here we use statistically robust spatial sampling to quantify symbiotic (SNF) and asymbiotic N fixation across a chronosequence of re-growing tropical forests in the Mata Atlântica of Bahia, Brasil. The Mata Atlântica once stretched 1500 km along the east coast of Brasil, is currently 85% deforested, and is a target of national and international restoration efforts that rely heavily on the planting of legume species to facilitate forest regrowth. As expected, we found the highest rates of SNF early in forest succession, but these rates were low compared with prior estimates (16-year-old forests fixed 5.75 ± 2.2 kg N ha-1 yr-1), and did not significantly decline in older stands. Mature forests (>100 years old) fixed 4.3 kg N ha-1 yr-1. This rate is similar to measurements using the same method in intact forests in Costa Rica, and both estimates are 5 times lower than previous estimates of SNF inputs into mature tropical forests. In our study, SNF accounted for > 99% of the total N inputs via biological N fixation. Several intriguing possibilities emerge from these data: 1) contrary to expectations, abundant legumes early in succession do not dramatically increase N inputs in these regrowing tropical forests and 2) the hypothesis that N fixation is down regulated by facultative fixers once forests reach maturity is not consistent with our observations.

  16. Nitrogen alters carbon dynamics during early succession in boreal forest

    Treesearch

    Steven D. Allison; Tracy B. Gartner; Michelle C. Mack; Krista McGuire; Kathleen. Treseder

    2010-01-01

    Boreal forests are an important source of wood products, and fertilizers could be used to improve forest yields, especially in nutrient poor regions of the boreal zone. With climate change, fire frequencies may increase, resulting in a larger fraction of the boreal landscape present in early successional stages. Since most fertilization studies have focused on mature...

  17. Modeling carbon stocks in a secondary tropical dry forest in the Yucatan Peninsula, Mexico

    Treesearch

    Zhaohua Dai; Richard A. Birdsey; Kristofer D. Johnson; Juan Manuel Dupuy; Jose Luis Hernandez-Stefanoni; Karen. Richardson

    2014-01-01

    The carbon balance of secondary dry tropical forests of Mexico’s Yucatan Peninsula is sensitive to human and natural disturbances and climate change. The spatially explicit process model Forest-DeNitrification-DeComposition (DNDC) was used to estimate forest carbon dynamics in this region, including the effects of disturbance on carbon stocks. Model evaluation using...

  18. Earthworm abundance and species composition in abandoned tropical croplands: comparisons of tree plantations and secondary forests.

    Treesearch

    G. Gonzalez; X. Zou; S. Borges

    1996-01-01

    We compared patterns of earthworms abundance and species composition in tree plantation and secondary forest of Puerto Rico. Tree plantations included pine (Pinus caribea Morelet) and mahogany (Swietenia macrophylla King) established in the 1930's; 1960's; and 1970's; secondary forests were naturally regenerated in areas adjacent to these plantations. We...

  19. Comparing soil organic carbon dynamics in plantation and secondary forest in wet tropics in Puerto Rico

    Treesearch

    LI YIQING; MING XU; ZOU XIAOMING; PEIJUN SHI§; YAOQI ZHANG

    2005-01-01

    We compared the soil carbon dynamics between a pine plantation and a secondary forest, both of which originated from the same farmland abandoned in 1976 with the same cropping history and soil conditions, in the wet tropics in Puerto Rico from July 1996 to June 1997. We found that the secondary forest accumulated the heavy-fraction organic carbon (HF-OC) measured by...

  20. An Evaluation of "Forests of the World," a Project Learning Tree Secondary Module

    ERIC Educational Resources Information Center

    Ghent, Cynthia; Parmer, Giavanna; Haines, Sarah

    2013-01-01

    This study sought to determine whether a secondary level curricular model based on enhancing knowledge and awareness of global forest issues would have an effect on students' self-perceived knowledge of forest issues, actual content knowledge of these issues, and pro-environmental attitudes. The study instrument is the secondary module…

  1. Ant-diaspore interactions during secondary succession in the Atlantic forest of Brazil.

    PubMed

    Zwiener, Victor P; Bihn, Jochen H; Marques, Márcia C M

    2012-06-01

    Animal-plant interactions are important for the recovery of diversity and processes in secondary forests, which increasingly dominate the tropical landscape. We used a combination of observational and experimental approaches to study the interactions of ants with diaspores across a successional gradient of forests in Southern Brazil, from August 2007 to April 2008. In addition to diaspore removal rates, we assessed the species richness, diversity and behaviour of ants interacting with diaspores, in three replicated sites of four successional stages of forests. We recorded 22 ant species interacting with diaspores (an estimated 15% of the total species pool in the region). Species richness and diversity did not differ among successional stages but the behaviour of ants towards diaspores changed with the age of secondary forests. In old successional stages the removal of entire diaspores was more common than in young successional stages of forests. Concordantly, diaspore removal rates were lowest in the youngest successional stage of secondary forests and increased with the age of forests. These results indicate that ant-diaspore interactions in secondary forests are disturbed and lower removal rates in secondary forests are likely to constrain the recruitment of plant populations during secondary succession.

  2. The value of primary, secondary, and plantation forests for a neotropical herpetofauna.

    PubMed

    Gardner, Toby A; Ribeiro-Júnior, Marco Antônio; Barlow, Jos; Avila-Pires, Teresa Cristina Sauer; Hoogmoed, Marinus S; Peres, Carlos A

    2007-06-01

    Plantation forests and second-growth forests are becoming dominant components of many tropical forest landscapes. Yet there is little information available concerning the consequences of different forestry options for biodiversity conservation in the tropics. We sampled the leaf-litter herpetofauna of primary, secondary, and Eucalyptus plantation forests in the Jari River area of northeastern Brazilian Amazonia. We used four complementary sampling techniques, combined samples from 2 consecutive years, and collected 1739 leaf-litter amphibians (23 species) and 1937 lizards (30 species). We analyzed the data for differences among forest types regarding patterns of alpha and beta diversity, species-abundance distributions, and community structure. Primary rainforest harbored significantly more species, but supported a similar abundance of amphibians and lizards compared with adjacent areas of second-growth forest or plantations. Plantation forests were dominated by wide-ranging habitat generalists. Secondary forest faunas contained a number of species characteristic of primary forest habitat. Amphibian communities in secondary forests and Eucalyptus plantations formed a nested subset of primary forest species, whereas the species composition of the lizard community in plantations was distinct, and was dominated by open-area species. Although plantation forests are relatively impoverished, naturally regenerating forests can help mitigate some negative effects of deforestation for herpetofauna. Nevertheless, secondary forest does not provide a substitute for primary forest, and in the absence of further evidence from older successional stands, we caution against the optimistic claim that natural forest regeneration in abandoned lands will provide refuge for the many species that are currently threatened by deforestation.

  3. Succession of Ephemeral Secondary Forests and Their Limited Role for the Conservation of Floristic Diversity in a Human-Modified Tropical Landscape

    PubMed Central

    van Breugel, Michiel; Hall, Jefferson S.; Craven, Dylan; Bailon, Mario; Hernandez, Andres; Abbene, Michele; van Breugel, Paulo

    2013-01-01

    Both local- and landscape-scale processes drive succession of secondary forests in human-modified tropical landscapes. Nonetheless, until recently successional changes in composition and diversity have been predominantly studied at the patch level. Here, we used a unique dataset with 45 randomly selected sites across a mixed-use tropical landscape in central Panama to study forest succession simultaneously on local and landscape scales and across both life stages (seedling, sapling, juvenile and adult trees) and life forms (shrubs, trees, lianas, and palms). To understand the potential of these secondary forests to conserve tree species diversity, we also evaluated the diversity of species that can persist as viable metapopulations in a dynamic patchwork of short-lived successional forests, using different assumptions about the average relative size at reproductive maturity. We found a deterministic shift in the diversity and composition of the local plant communities as well as the metacommunity, driven by variation in the rate at which species recruited into and disappeared from the secondary forests across the landscape. Our results indicate that dispersal limitation and the successional niche operate simultaneously and shape successional dynamics of the metacommunity of these early secondary forests. A high diversity of plant species across the metacommunity of early secondary forests shows a potential for restoration of diverse forests through natural succession, when trees and fragments of older forests are maintained in the agricultural matrix and land is abandoned or set aside for a long period of time. On the other hand, during the first 32 years the number of species with mature-sized individuals was a relatively small and strongly biased sub-sample of the total species pool. This implies that ephemeral secondary forests have a limited role in the long-term conservation of tree species diversity in human-modified tropical landscapes. PMID:24349283

  4. Succession of ephemeral secondary forests and their limited role for the conservation of floristic diversity in a human-modified tropical landscape.

    PubMed

    van Breugel, Michiel; Hall, Jefferson S; Craven, Dylan; Bailon, Mario; Hernandez, Andres; Abbene, Michele; van Breugel, Paulo

    2013-01-01

    Both local- and landscape-scale processes drive succession of secondary forests in human-modified tropical landscapes. Nonetheless, until recently successional changes in composition and diversity have been predominantly studied at the patch level. Here, we used a unique dataset with 45 randomly selected sites across a mixed-use tropical landscape in central Panama to study forest succession simultaneously on local and landscape scales and across both life stages (seedling, sapling, juvenile and adult trees) and life forms (shrubs, trees, lianas, and palms). To understand the potential of these secondary forests to conserve tree species diversity, we also evaluated the diversity of species that can persist as viable metapopulations in a dynamic patchwork of short-lived successional forests, using different assumptions about the average relative size at reproductive maturity. We found a deterministic shift in the diversity and composition of the local plant communities as well as the metacommunity, driven by variation in the rate at which species recruited into and disappeared from the secondary forests across the landscape. Our results indicate that dispersal limitation and the successional niche operate simultaneously and shape successional dynamics of the metacommunity of these early secondary forests. A high diversity of plant species across the metacommunity of early secondary forests shows a potential for restoration of diverse forests through natural succession, when trees and fragments of older forests are maintained in the agricultural matrix and land is abandoned or set aside for a long period of time. On the other hand, during the first 32 years the number of species with mature-sized individuals was a relatively small and strongly biased sub-sample of the total species pool. This implies that ephemeral secondary forests have a limited role in the long-term conservation of tree species diversity in human-modified tropical landscapes.

  5. Long-term monitoring reveals an avian species credit in secondary forest patches of Costa Rica.

    PubMed

    Latta, Steven C; Brouwer, Nathan L; Olivieri, Alison; Girard-Woolley, Julie; Richardson, Judy F

    2017-01-01

    Degraded and secondary forests comprise approximately 50% of remaining tropical forest. Bird community characteristics and population trends in secondary forests are infrequently studied, but secondary forest may serve as a "safety net" for tropical biodiversity. Less understood is the occurrence of time-delayed, community-level dynamics such as an extinction debt of specialist species or a species credit resulting from the recolonization of forest patches by extirpated species. We sought to elucidate patterns and magnitudes of temporal change in avian communities in secondary forest patches in Southern Costa Rica biannually over a 10 year period during the late breeding season and mid-winter. We classified birds caught in mist nets or recorded in point counts by residency status, and further grouped them based on preferred habitat, sensitivity to disturbance, conservation priority, foraging guild, and foraging strata. Using hierarchical, mixed-effects models we tested for trends among species that share traits. We found that permanent-resident species increased over time relative to migrants. In both seasons, primary forest species generally increased while species typical of secondary forest, scrub, or edge declined. Species relatively sensitive to habitat disturbance increased significantly over time, whereas birds less sensitive to disturbance decreased. Similarly, generalists with higher habitat breadth scores declined. Because, we found very few changes in vegetation characteristics in secondary forest patches, shifts in the avian community toward primary forest species represent a species credit and are likely related to vegetation changes in the broader landscape. We suggest that natural regeneration and maturation of secondary forests should be recognized as a positive conservation development of potential benefit even to species typical of primary forest.

  6. Long-term monitoring reveals an avian species credit in secondary forest patches of Costa Rica

    PubMed Central

    Brouwer, Nathan L.; Olivieri, Alison; Girard-Woolley, Julie; Richardson, Judy F.

    2017-01-01

    Degraded and secondary forests comprise approximately 50% of remaining tropical forest. Bird community characteristics and population trends in secondary forests are infrequently studied, but secondary forest may serve as a “safety net” for tropical biodiversity. Less understood is the occurrence of time-delayed, community-level dynamics such as an extinction debt of specialist species or a species credit resulting from the recolonization of forest patches by extirpated species. We sought to elucidate patterns and magnitudes of temporal change in avian communities in secondary forest patches in Southern Costa Rica biannually over a 10 year period during the late breeding season and mid-winter. We classified birds caught in mist nets or recorded in point counts by residency status, and further grouped them based on preferred habitat, sensitivity to disturbance, conservation priority, foraging guild, and foraging strata. Using hierarchical, mixed-effects models we tested for trends among species that share traits. We found that permanent-resident species increased over time relative to migrants. In both seasons, primary forest species generally increased while species typical of secondary forest, scrub, or edge declined. Species relatively sensitive to habitat disturbance increased significantly over time, whereas birds less sensitive to disturbance decreased. Similarly, generalists with higher habitat breadth scores declined. Because, we found very few changes in vegetation characteristics in secondary forest patches, shifts in the avian community toward primary forest species represent a species credit and are likely related to vegetation changes in the broader landscape. We suggest that natural regeneration and maturation of secondary forests should be recognized as a positive conservation development of potential benefit even to species typical of primary forest. PMID:28674671

  7. [Regeneration characteristics of woody plant seedlings in typical secondary forests in Qinling Mountains].

    PubMed

    Kang, Bing; Liu, Shi-Rong; Wang, De-Xiang; Zhang, Ying; Liu, Hong-Ru; Du, Yan-Ling

    2011-12-01

    By using sampling plot method, an investigation was conducted on the regeneration characteristics of woody plant seedlings in five kinds of typical secondary forests (Pinus tabulaeformis, Quercus valiena var. acuteserrata, Betula albo-sinensis, Picea asperata, and Pinus armandii) in Qinling Mountains. There was an obvious species differentiation of woody plant seedlings and saplings in the forests. Except for Q. valiena var. acuteserrata and P. armandii forests, the similarity coefficient of the seedlings and saplings species in the forests was lower. The seedlings and saplings quantity, species richness index, Simpson dominance index, and evenness index were higher in P. tabulaeformis and Q. valiena var. acuteserrata forests, the lowest in B. albo-sinensis forest, and basically the same in P. asperata and P. armandii forests. The percentages of the seedlings and saplings in the five forests had significant differences (P < 0.05). Except in B. albo-sinensis forest where the percentage of the saplings was higher, the percentage of the seedlings in the other stands was larger, and in the order of P. asperata forest > P. tabulaeformis forest > Q. valiena var. acuteserrata forest > P. armandii forest, respectively. The sprouting percentage of the seedlings in different forests had significant difference (P < 0.05), and was in the sequence of P. armandii forest > P. asperata forest > B. albo-sinensis forest > Q. valiena var. acuteserrata forest > P. tabulaeformis forest. In Q. valiena var. acuteserrata and P. tabulaeformis forests, the percentage of tree seedlings was the highest, occupying 68% and 51.4% of the total number of woody seedlings, respectively, and their communities were in the medium succession period, with a stronger persistent regeneration capability; in P. asperata and P. armandii forests, the percentage of tree seedlings was 40% and 15%, respectively, and their communities were in the late succession period, with a rather poor regeneration capability

  8. Why are there more arboreal ant species in primary than in secondary tropical forests?

    PubMed

    Klimes, Petr; Idigel, Cliffson; Rimandai, Maling; Fayle, Tom M; Janda, Milan; Weiblen, George D; Novotny, Vojtech

    2012-09-01

    1. Species diversity of arboreal arthropods tends to increase during rainforest succession so that primary forest communities comprise more species than those from secondary vegetation, but it is not well understood why. Primary forests differ from secondary forests in a wide array of factors whose relative impacts on arthropod diversity have not yet been quantified. 2. We assessed the effects of succession-related determinants on a keystone ecological group, arboreal ants, by conducting a complete census of 1332 ant nests from all trees with diameter at breast height ≥ 5 cm occurring within two (unreplicated) 0·32-ha plots, one in primary and one in secondary lowland forest in New Guinea. Specifically, we used a novel rarefaction-based approach to match number, size distribution and taxonomic structure of trees in primary forest communities to those in secondary forest and compared the resulting numbers of ant species. 3. In total, we recorded 80 nesting ant species from 389 trees in primary forest but only 42 species from 295 trees in secondary forest. The two habitats did not differ in the mean number of ant species per tree or in the relationship between ant diversity and tree size. However, the between-tree similarity of ant communities was higher in secondary forest than in primary forest, as was the between-tree nest site similarity, suggesting that secondary trees were more uniform in providing nesting microhabitats. 4. Using our rarefaction method, the difference in ant species richness between two forest types was partitioned according to the effects of higher tree density (22·6%), larger tree size (15·5%) and higher taxonomic diversity of trees (14·3%) in primary than in secondary forest. The remaining difference (47·6%) was because of higher beta diversity of ant communities between primary forest trees. In contrast, difference in nest density was explained solely by difference in tree density. 5. Our study shows that reduction in plant taxonomic

  9. Gender-related distributions of Fraxinus mandshurica in secondary and old-growth forests

    NASA Astrophysics Data System (ADS)

    Zhang, Chunyu; Zhao, Xiuhai; Gao, Lushuang; Gadow, Klaus von

    2010-01-01

    This study presents new findings about gender-related spatial distributions of the strictly dioecious tree species Fraxinus mandshurica. The observations were collected in three large field plots in secondary and old-growth forests in northeastern China, covering the 4-year period from 2005 to 2008. Tree diameters were not significantly different between genders in the young secondary forests. In the old-growth forest, however, the diameters of male trees were significantly greater than those of female trees. The sex ratio did not significantly deviate from 1:1 in the secondary forests, but was male-biased in the old-growth forest. Spatial segregation between genders was found in the secondary forests, but male and female trees were spatially independent in the old-growth forest. This research complements the current knowledge about sex ratios in secondary and old-growth forests, and about spatial patterns and intra- and intersexual interactions of the dioecious species, F. mandshurica. The available evidence suggests that male and female individuals show a different response to specific microenvironments in the three forest successional stages, which suggests that there are differences in resource requirements between genders.

  10. Multi-temporal lidar test of chronosequence assumptions in secondary tropical forest

    NASA Astrophysics Data System (ADS)

    Becknell, J.; Porder, S.; Kellner, J. R.; Chazdon, R.

    2016-12-01

    Secondary forests make up more than half of all tropical forests and are a globally significant carbon sink. However, nearly everything known about secondary forest regeneration comes from chronosequence studies that substitute space for time to approximate long-term secondary succession. Here we examine the efficacy of chronosequence predictions over 11 years of forest regrowth using two lidar datasets collected over the La Selva Biological Station in 1998 and 2009, each covering 381 ha of secondary forest and 803 ha of mature forest. We use these data to ask: 1) Do lidar waveforms from different age classes predict forest structure changes from repeated measurements at the same location? 2) Do simulated chronosequences predict the landscape mean biomass change? 3) How do differences in plot size and number affect the accuracy and precision of chronosequence based biomass recovery estimates? Lidar waveforms indicate that tree height and forest structure was similar between 1998 and 2009 for any given age class. For example, an 11-20 year old forest in 1998 had similar lidar returns to an 11-20 year old forest in 2009. Simulated chronosequences predict the landscape mean biomass change, but the accuracy of predictions depends on the size and number of plots used in the chronosequence. In forest with 0-10 years in 1998, 86 to 99% of 1000 simulated chronosequences predict the landscape mean biomass change within 20 Mg/ha depending on the plot size and number. However, predictions in forests with 11-20 years in 1998 are less accurate with 60-71% of predictions within 20 Mg/ha of the landscape mean. With area kept equal, chronosequences with many small plots, rather than fewer larger plots, have a higher probability of accurately predicting the landscape mean biomass change over the 11 year period. Overall, our results suggest both deterministic and stochastic controls on biomass accumulation in these secondary forests.

  11. Biomass Accumulation Rates of Amazonian Secondary Forest and Biomass of Old-Growth Forests from Landsat Time Series and GLAS

    NASA Astrophysics Data System (ADS)

    Helmer, E.; Lefsky, M. A.; Roberts, D.

    2009-12-01

    We estimate the age of humid lowland tropical forests in Rondônia, Brazil, from a somewhat densely spaced time series of Landsat images (1975-2003) with an automated procedure, the Threshold Age Mapping Algorithm (TAMA), first described here. We then estimate a landscape-level rate of aboveground woody biomass accumulation of secondary forest by combining forest age mapping with biomass estimates from the Geoscience Laser Altimeter System (GLAS). Though highly variable, the estimated average biomass accumulation rate of 8.4 Mg ha-1 yr-1 agrees well with ground-based studies for young secondary forests in the region. In isolating the lowland forests, we map land cover and general types of old-growth forests with decision tree classification of Landsat imagery and elevation data. We then estimate aboveground live biomass for seven classes of old-growth forest. TAMA is simple, fast, and self-calibrating. By not using between-date band or index differences or trends, it requires neither image normalization nor atmospheric correction. In addition, it uses an approach to map forest cover for the self-calibrations that is novel to forest mapping with satellite imagery; it maps humid secondary forest that is difficult to distinguish from old-growth forest in single-date imagery; it does not assume that forest age equals time since disturbance; and it incorporates Landsat Multispectral Scanner (MSS) imagery. Variations on the work that we present here can be applied to other forested landscapes. Applications that use image time series will be helped by the free distribution of coregistered Landsat imagery, which began in December 2008, and of the Ice Cloud and land Elevation Satellite (ICESat) Vegetation Product, which simplifies the use of GLAS data. Finally, we demonstrate here for the first time how the optical imagery of fine spatial resolution that is viewable on Google Earth provides a new source of reference data for remote sensing applications related to land cover

  12. 18 Years of Recovery: Spatial Variation and Structure of a Secondary Forest Analyzed with Airborne Lidar Data in the Brazilian Atlantic Forest

    NASA Astrophysics Data System (ADS)

    dos-Santos, M. N.; Keller, M. M.; Scaranello, M. A., Sr.; Longo, M.; Daniel, P.

    2016-12-01

    Ongoing forest fragmentation in the tropics severely reduces the ability of remaining forests to store carbon and provide ecosystem services, however, secondary regeneration could offset the impacts of forest degradation. Previous plot-based forest inventory studies have shown that secondary regeneration is promoted at remnant forest edges. However, this process has not been studied at landscape scale. We used over 450 ha of lidar data to study the forest structure and spatial variation of secondary growth forest 18 years after swidden cultivation abandonment in Serra do Conduro State Park. Lidar data was acquired in December 2015 with a density of 93 points per square meter using an airborne scanning laser system (Optech Orion M-300). Serra do Conduru, a 10 000 ha State Park in Bahia was created in 1997 as part of a network of forest reserves with both old-growth forest and secondary forest aiming at establishing a central corridor of the Atlantic forest. The Brazilian Atlantic forest is a highly human modified and fragmented forest landscape reduced to 12.5% of its original extent. Prior to the establishment of the State Park, the area was a mosaic of forest and agricultural area. We created 10m wide buffers from the edge of the remnant forest into the secondary forest and generated lidar metrics for each strip in order to ask: does the distance from the remnant forest create a gradient effect on the secondary forest structure? We cross-compared the lidar metrics of the samples. Results demonstrate that distance from old-growth forest promotes spatial variation in forest recovery and forest structure.

  13. Tropical secondary forests regenerating after shifting cultivation in the Philippines uplands are important carbon sinks.

    PubMed

    Mukul, Sharif A; Herbohn, John; Firn, Jennifer

    2016-03-08

    In the tropics, shifting cultivation has long been attributed to large scale forest degradation, and remains a major source of uncertainty in forest carbon accounting. In the Philippines, shifting cultivation, locally known as kaingin, is a major land-use in upland areas. We measured the distribution and recovery of aboveground biomass carbon along a fallow gradient in post-kaingin secondary forests in an upland area in the Philippines. We found significantly higher carbon in the aboveground total biomass and living woody biomass in old-growth forest, while coarse dead wood biomass carbon was higher in the new fallow sites. For young through to the oldest fallow secondary forests, there was a progressive recovery of biomass carbon evident. Multivariate analysis indicates patch size as an influential factor in explaining the variation in biomass carbon recovery in secondary forests after shifting cultivation. Our study indicates secondary forests after shifting cultivation are substantial carbon sinks and that this capacity to store carbon increases with abandonment age. Large trees contribute most to aboveground biomass. A better understanding of the relative contribution of different biomass sources in aboveground total forest biomass, however, is necessary to fully capture the value of such landscapes from forest management, restoration and conservation perspectives.

  14. Tropical secondary forests regenerating after shifting cultivation in the Philippines uplands are important carbon sinks

    PubMed Central

    Mukul, Sharif A.; Herbohn, John; Firn, Jennifer

    2016-01-01

    In the tropics, shifting cultivation has long been attributed to large scale forest degradation, and remains a major source of uncertainty in forest carbon accounting. In the Philippines, shifting cultivation, locally known as kaingin, is a major land-use in upland areas. We measured the distribution and recovery of aboveground biomass carbon along a fallow gradient in post-kaingin secondary forests in an upland area in the Philippines. We found significantly higher carbon in the aboveground total biomass and living woody biomass in old-growth forest, while coarse dead wood biomass carbon was higher in the new fallow sites. For young through to the oldest fallow secondary forests, there was a progressive recovery of biomass carbon evident. Multivariate analysis indicates patch size as an influential factor in explaining the variation in biomass carbon recovery in secondary forests after shifting cultivation. Our study indicates secondary forests after shifting cultivation are substantial carbon sinks and that this capacity to store carbon increases with abandonment age. Large trees contribute most to aboveground biomass. A better understanding of the relative contribution of different biomass sources in aboveground total forest biomass, however, is necessary to fully capture the value of such landscapes from forest management, restoration and conservation perspectives. PMID:26951761

  15. Tropical secondary forests regenerating after shifting cultivation in the Philippines uplands are important carbon sinks

    NASA Astrophysics Data System (ADS)

    Mukul, Sharif A.; Herbohn, John; Firn, Jennifer

    2016-03-01

    In the tropics, shifting cultivation has long been attributed to large scale forest degradation, and remains a major source of uncertainty in forest carbon accounting. In the Philippines, shifting cultivation, locally known as kaingin, is a major land-use in upland areas. We measured the distribution and recovery of aboveground biomass carbon along a fallow gradient in post-kaingin secondary forests in an upland area in the Philippines. We found significantly higher carbon in the aboveground total biomass and living woody biomass in old-growth forest, while coarse dead wood biomass carbon was higher in the new fallow sites. For young through to the oldest fallow secondary forests, there was a progressive recovery of biomass carbon evident. Multivariate analysis indicates patch size as an influential factor in explaining the variation in biomass carbon recovery in secondary forests after shifting cultivation. Our study indicates secondary forests after shifting cultivation are substantial carbon sinks and that this capacity to store carbon increases with abandonment age. Large trees contribute most to aboveground biomass. A better understanding of the relative contribution of different biomass sources in aboveground total forest biomass, however, is necessary to fully capture the value of such landscapes from forest management, restoration and conservation perspectives.

  16. Contributions of secondary forest and nitrogen dynamics to terrestrial carbon uptake

    NASA Astrophysics Data System (ADS)

    Yang, X.; Richardson, T. K.; Jain, A. K.

    2010-04-01

    We use a terrestrial carbon-nitrogen cycle component of the Integrated Science Assessment Model (ISAM) to investigate the impacts of nitrogen dynamics on regrowing secondary forests over the 20th century. We further examine what the impacts of nitrogen deposition and land use change history are on terrestrial carbon uptake since preindustrial time. Our results suggest that global total net land use emissions for the 1990s associated with changes in cropland, pastureland, and wood harvest are 1.22 GtC/yr. Without considering the secondary forest regrowth, the estimated net global total land use emissions are 1.58 GtC/yr or about 0.36 GtC/yr higher than if secondary forest regrowth is considered. Results also show that without considering the nitrogen dynamics and deposition, the estimated global total secondary forest sink for the 1990s is 0.90 GtC/yr or about 0.54 GtC/yr higher than estimates that include the impacts of nitrogen dynamics and deposition. Nitrogen deposition alone is responsible for about 0.13 GtC/yr of the total secondary forest sink. While nitrogen is not a limiting nutrient in the intact primary forests in tropical regions, our study suggests that nitrogen becomes a limiting nutrient for regrowing secondary forests of the tropical regions, in particular Latin America and Tropical Africa. This is because land use change activities, especially wood harvest, removes large amounts of nitrogen from the system when slash is burnt or wood is removed for harvest. However, our model results show that carbon uptake is enhanced in the tropical secondary forests of the Indian region. We argue that this may be due to enhanced nitrogen mineralization and increased nitrogen availability following land use change in the Indian tropical forest ecosystems. Results also demonstrate that there is a significant amount of carbon accumulating in the Northern Hemisphere where most land use changes and forest regrowth has occurred in recent decades. This study indicates

  17. Contributions of secondary forest and nitrogen dynamics to terrestrial carbon uptake

    NASA Astrophysics Data System (ADS)

    Yang, X.; Richardson, T. K.; Jain, A. K.

    2010-10-01

    We use a terrestrial carbon-nitrogen cycle component of the Integrated Science Assessment Model (ISAM) to investigate the impacts of nitrogen dynamics on regrowing secondary forests over the 20th century. We further examine what the impacts of nitrogen deposition and land use change history are on terrestrial carbon uptake since preindustrial time. Our results suggest that global total net land use emissions for the 1990s associated with changes in cropland, pastureland, and wood harvest are 1.22 GtC/yr. Without considering the secondary forest regrowth, the estimated net global total land use emissions are 1.58 GtC/yr or about 0.36 GtC/yr higher than if secondary forest regrowth is considered. Results also show that without considering the nitrogen dynamics and deposition, the estimated global total secondary forest sink for the 1990s is 0.90 GtC/yr or about 0.54 GtC/yr higher than estimates that include the impacts of nitrogen dynamics and deposition. Nitrogen deposition alone is responsible for about 0.13 GtC/yr of the total secondary forest sink. While nitrogen is not a limiting nutrient in the intact primary forests in tropical regions, our study suggests that nitrogen becomes a limiting nutrient for regrowing secondary forests of the tropical regions, in particular Latin America and Tropical Africa. This is because land use change activities, especially wood harvest, removes large amounts of nitrogen from the system when slash is burnt or wood is removed for harvest. However, our model results show that carbon uptake is enhanced in the tropical secondary forests of the Indian region. We argue that this may be due to enhanced nitrogen mineralization and increased nitrogen availability following land use change in the Indian tropical forest ecosystems. Results also demonstrate that there is a significant amount of carbon accumulating in the Northern Hemisphere where most land use changes and forest regrowth has occurred in recent decades. This study indicates

  18. Measurement and modeling of rainfall interception by two differently aged secondary forests in upland eastern Madagascar

    NASA Astrophysics Data System (ADS)

    Prasad Ghimire, Chandra; Adrian Bruijnzeel, L.; Lubczynski, Maciek W.; Ravelona, Maafaka; Zwartendijk, Bob W.; van Meerveld, H. J. (Ilja)

    2017-02-01

    Secondary forests occupy a larger area than old-growth rain forests in many tropical regions but their hydrological functioning is still poorly understood. In particular, little is known about the various components of evapotranspiration in these possibly vigorously regenerating forests. This paper reports on a comparison of measured and modeled canopy interception losses (I) from a semi-mature (ca. 20 years) and a young (5-7 years) secondary forest in the lower montane rain forest zone of eastern Madagascar. Measurements of gross rainfall (P), throughfall (Tf), and stemflow (Sf) were made in both forests for one year (October 2014-September 2015) and the revised analytical model of Gash et al. (1995) was tested for the first time in a tropical secondary forest setting. Overall measured Tf, Sf and derived I in the semi-mature forest were 71.0%, 1.7% and 27.3% of incident P, respectively. Corresponding values for the young forest were 75.8%, 6.2% and 18.0%. The high Sf for the young forest reflects the strongly upward thrusting habit of the branches of the dominant species (Psiadia altissima), which favours funneling of P. The value of I for the semi-mature forest is similar to values reported for old-growth tropical lower montane rain forests elsewhere but I for the younger forest is higher than reported for similarly aged tropical lowland forests. These findings can be explained largely by the prevailing low rainfall intensities and the frequent occurrence of small rainfall events. The revised analytical model was able to reproduce measured cumulative I at the two sites accurately and succeeded in capturing the variability in I associated with the seasonal variability in rainfall intensity, provided that Tf-based values for the average wet-canopy evaporation rates were used instead of values derived with the Penman-Monteith equation.

  19. Loss of functional diversity of ant assemblages in secondary tropical forests.

    PubMed

    Bihn, Jochen H; Gebauer, Gerhard; Brandl, Roland

    2010-03-01

    Secondary forests and plantations increasingly dominate the tropical wooded landscape in place of primary forests. The expected reduction of biodiversity and its impact on ecological functions provided by these secondary forests are of major concern to society and ecologists. The potential effect of biodiversity loss on ecosystem functioning depends largely on the associated loss in the functional diversity of animal and plant assemblages, i.e., the degree of functional redundancy among species. However, the relationship between species and functional diversity is still poorly documented for most ecosystems. Here, we analyze how changes in the species diversity of ground-foraging ant assemblages translate into changes of functional diversity along a successional gradient of secondary forests in the Atlantic Forest of Brazil. Our analysis uses continuous measures of functional diversity and is based on four functional traits related to resource use of ants: body size, relative eye size, relative leg length, and trophic position. We find a strong relationship between species and functional diversity, independent of the functional traits used, with no evidence for saturation in this relationship. Recovery of species richness and diversity of ant assemblages in tropical secondary forests was accompanied by a proportional increase of functional richness and diversity of assemblages. Moreover, our results indicate that the increase in functional diversity along the successional gradient of secondary forests is primarily driven by rare species, which are functionally unique. The observed loss of both species and functional diversity in secondary forests offers no reason to believe that the ecological functions provided by secondary forests are buffered against species loss through functional redundancy.

  20. Growth of Secondary Forest in Puerto Rico Between 1980 and 1985

    Treesearch

    P.L. Weaver; R.A. Birdsey

    1990-01-01

    Successive inventories in Puerto Rico provided the first estimates of secondary forest growth on a regional basis. The volume of growing stock trees increased by 32%, and timber volume by nearly 36%, on all classes of forest land between 1980 and 198.5. Timber volume growth rates (in m3ha-1yr-1 )...

  1. Secondary forest regeneration on degraded tropical lands: the role of plantations as ‘foster ecosystems’

    Treesearch

    John A. Parrotta

    1993-01-01

    Forest plantations established on degraded sites can accelerate natural succession through their effects on vegetation structure, microclimate, and soils. Spatial and temporal patterns of secondary forest species regeneration were studied in permanent quadrats in Albizia lebbek planta1ion plots and control areas at a degraded coastal pasture in...

  2. Secondary forest succession following reproduction cutting on the Upper Coastal Plain of southeastern Arkansas, USA

    Treesearch

    Michael D. Cain; Michael G. Shelton

    2001-01-01

    To contribute to an understanding of forest management on secondary forest succession, we conducted vegetation surveys in a chronosequence of pine stands ranging in age from 1 to 59 years. Adjacent areas were compared at 1, 7, 12, and 17 years following two reproduction cutting methods (clearcuts or pine seed-tree cuts); a 59-year-old pine stand that...

  3. Carbon pools recover more quickly than plant biodiversity in tropical secondary forests

    PubMed Central

    Martin, Philip A.; Newton, Adrian C.; Bullock, James M.

    2013-01-01

    Although increasing efforts are being made to restore tropical forests, little information is available regarding the time scales required for carbon and plant biodiversity to recover to the values associated with undisturbed forests. To address this knowledge gap, we carried out a meta-analysis comparing data from more than 600 secondary tropical forest sites with nearby undisturbed reference forests. Above-ground biomass approached equivalence to reference values within 80 years since last disturbance, whereas below-ground biomass took longer to recover. Soil carbon content showed little relationship with time since disturbance. Tree species richness recovered after about 50 years. By contrast, epiphyte richness did not reach equivalence to undisturbed forests. The proportion of undisturbed forest trees and epiphyte species found in secondary forests was low and changed little over time. Our results indicate that carbon pools and biodiversity show different recovery rates under passive, secondary succession and that colonization by undisturbed forest plant species is slow. Initiatives such as the Convention on Biological Diversity and REDD+ should therefore encourage active management to help to achieve their aims of restoring both carbon and biodiversity in tropical forests. PMID:24197410

  4. Measurement and modelling of rainfall interception by tropical secondary forests in upland Eastern Madagascar

    NASA Astrophysics Data System (ADS)

    Prasad Ghimire, Chandra; van Meerveld, Ilja H. J.; Zwartendijk, Bob W.; Ravelona, Maafaka; Lahitiana, Jaona; Lubczynski, Maciek W.; Bruijnzeel, L. Adrian

    2016-04-01

    Secondary forests occupy a larger area than old-growth forest in many tropical regions but their hydrological functioning is still poorly understood. As part of a larger venture investigating the "trade-off" between the possibly strongly enhanced water use of vigorously regenerating secondary forest versus likely improved infiltration compared to degraded grassland (baseline situation) in Eastern Madagascar, this presentation reports on a comparison of measured and modelled canopy interception losses for a mature (ca. 20 years; basal area BA 35.5 m2 ha-1, LAI 3.39) and a young (5-7 years; BA 6.3 m2 ha-1, LAI 1.83) secondary forest. Measurements of gross rainfall (P), throughfall (TF) and stemflow (SF) were made in both forests over a one-year period (October 2014-September 2015). Interception losses (I) from the two forests were also simulated using the revised analytical model of Gash et al. (1995), representing a first for tropical secondary forest. Overall measured TF, SF and derived I in the mature secondary forest were 71.0%, 1.7% and 27.3% of incident P, respectively. Corresponding values for the young secondary forest were 75.8%, 6.2% and 18.0%. The high SF found for the latter forest reflects the strongly upward thrusting habit of the branches of the dominant species (Psiadia altissima) which favours funneling of incident P. The presently found I for the mature forest is similar to that reported for other tropical montane rainforests not affected by fog but that for the younger forest is higher than reported for similarly aged lowland forests. These findings can be explained by the prevailing low rainfall intensities and frequent occurrence of small rainfall events (~70% < 5 mm). The Gash model was able to reproduce measured cumulative I at both sites accurately and succeeded in capturing the variability in I associated with seasonal variability in rainfall characteristics, provided the TF-based value for wet-canopy evaporation rate was used instead of that

  5. Emissions of biogenic volatile organic compounds and subsequent formation of secondary organic aerosols in a Larix kaempferi forest

    NASA Astrophysics Data System (ADS)

    Mochizuki, T.; Miyazaki, Y.; Ono, K.; Wada, R.; Takahashi, Y.; Saigusa, N.; Kawamura, K.; Tani, A.

    2015-04-01

    We conducted simultaneous measurements of concentrations and above-canopy fluxes of isoprene and α-pinene, along with their oxidation products in aerosols in a Larix kaempferi (Japanese larch) forest in summer 2012. Vertical profiles of isoprene showed the maximum concentration near the forest floor with a peak around noon, whereas oxidation products of isoprene, i.e., methacrolein (MACR) and methyl vinyl ketone (MVK), showed higher concentrations near the canopy level of the forest. The vertical profile suggests large emissions of isoprene near the forest floor, likely due to Dryopteris crassirhizoma (a fern species), and the subsequent reaction within the canopy. The concentrations of α-pinene also showed highest values near the forest floor with maximums in the early morning and late afternoon. The vertical profiles of α-pinene suggest its large emissions from soil and litter in addition to emissions from L. kaempferi leaves at the forest site. Isoprene and its oxidation products in aerosols exhibited similar diurnal variations within the forest canopy, providing evidence for secondary organic aerosol (SOA) formation via oxidation of isoprene most likely emitted from the forest floor. Although high abundance of α-pinene was observed in the morning, its oxidation products in aerosols showed peaks in daytime, due to a time lag between the emission and atmospheric reactions of α-pinene to form SOA. Positive matrix factorization (PMF) analysis indicated that anthropogenic influence is the most important factor contributing to the elevated concentrations of molecular oxidation products of isoprene- (> 64%) and α-pinene-derived SOA (> 57%). The combination of the measured fluxes and vertical profiles of biogenic volatile organic compounds (BVOCs) suggests that the inflow of anthropogenic precursors/aerosols likely enhanced the formation of both isoprene- and α-pinene-SOA within the forest canopy even when the BVOC flux was relatively low. This study highlights

  6. Seasonal Variation in Seed Dispersal by Tamarins Alters Seed Rain in a Secondary Rain Forest

    PubMed Central

    Muñoz Lazo, Fernando Julio João; Huynen, Marie-Claude; Poncin, Pascal; Heymann, Eckhard W.

    2010-01-01

    Reduced dispersal of large seeds into degraded areas is one of the major factors limiting rain forest regeneration, as many seed dispersers capable of transporting large seeds avoid these sites with a limited forest cover. However, the small size of tamarins allows them to use small trees, and hence to disperse seeds into young secondary forests. Seasonal variations in diet and home range use might modify their contribution to forest regeneration through an impact on the seed rain. For a 2-yr period, we followed a mixed-species group of tamarins in Peru to determine how their role as seed dispersers in a 9-yr-old secondary-growth forest varied across seasons. These tamarins dispersed small to large seeds of 166 tree species, 63 of which were into a degraded area. Tamarins’ efficiency in dispersing seeds from primary to secondary forest varied across seasons. During the late wet season, high dietary diversity and long forays in secondary forest allowed them to disperse large seeds involved in later stages of regeneration. This occurred precisely when tamarins spent a more equal amount of time eating a high diversity of fruit species in primary forest and pioneer species in secondary forest. We hypothesized that well-balanced fruit availability induced the movement of seed dispersers between these 2 habitats. The noteworthy number of large-seeded plant species dispersed by such small primates suggests that tamarins play an important, but previously neglected, role in the regeneration and maintenance of forest structure. Electronic supplementary material The online version of this article (doi:10.1007/s10764-010-9413-7) contains supplementary material, which is available to authorized users. PMID:20651905

  7. Forests and Phenology: Designing the Early Warning System to Understand Forest Change

    NASA Astrophysics Data System (ADS)

    Pierce, T.; Phillips, M. B.; Hargrove, W. W.; Dobson, G.; Hicks, J.; Hutchins, M.; Lichtenstein, K.

    2010-12-01

    Vegetative phenology is the study of plant development and changes with the seasons, such as the greening-up and browning-down of forests, and how these events are influenced by variations in climate. A National Phenology Data Set, based on Moderate Resolution Imaging Spectroradiometer satellite images covering 2002 through 2009, is now available from work by NASA, the US Forest Service, and Oak Ridge National Laboratory. This new data set provides an easily interpretable product useful for detecting changes to the landscape due to long-term factors such as climate change, as well as finding areas affected by short-term forest threats such as insects or disease. The Early Warning System (EWS) is a toolset being developed by the US Forest Service and the University of North Carolina-Asheville to support distribution and use of the National Phenology Data Set. The Early Warning System will help research scientists, US Forest Service personnel, forest and natural resources managers, decision makers, and the public in the use of phenology data to better understand unexpected change within our nation’s forests. These changes could have multiple natural sources such as insects, disease, or storm damage, or may be due to human-induced events, like thinning, harvest, forest conversion to agriculture, or residential and commercial use. The primary goal of the Early Warning System is to provide a seamless integration between monitoring, detection, early warning and prediction of these forest disturbances as observed through phenological data. The system consists of PC and web-based components that are structured to support four user stages of increasing knowledge and data sophistication. Building Literacy: This stage of the Early Warning System educates potential users about the system, why the system should be used, and the fundamentals about the data the system uses. The channels for this education include a website, interactive tutorials, pamphlets, and other technology

  8. SECONDARY WASTE MANAGEMENT STRATEGY FOR EARLY LOW ACTIVITY WASTE TREATMENT

    SciTech Connect

    TW, CRAWFORD

    2008-07-17

    This study evaluates parameters relevant to River Protection Project secondary waste streams generated during Early Low Activity Waste operations and recommends a strategy for secondary waste management that considers groundwater impact, cost, and programmatic risk. The recommended strategy for managing River Protection Project secondary waste is focused on improvements in the Effiuent Treatment Facility. Baseline plans to build a Solidification Treatment Unit adjacent to Effluent Treatment Facility should be enhanced to improve solid waste performance and mitigate corrosion of tanks and piping supporting the Effiuent Treatment Facility evaporator. This approach provides a life-cycle benefit to solid waste performance and reduction of groundwater contaminants.

  9. Litterfall and decomposition in relation to soil carbon pools along a secondary forest chronosequence in Puerto Rico

    Treesearch

    R. Ostertag; E. Marín-Spiotta; W.L. Silver; J. Schulten

    2008-01-01

    Secondary forests are becoming increasingly widespread in the tropics, but our understanding of how secondary succession affects carbon (C) cycling and C sequestration in these ecosystems is limited. We used a well-replicated 80-year pasture to forest successional chronosequence and primary forest in Puerto Rico to explore the relationships among litterfall, litter...

  10. Quantifying early-seral forest composition with remote sensing

    Treesearch

    Rayma A. Cooley; Peter T. Wolter; Brian R. Sturtevant

    2016-01-01

    Spatially explicit modeling of recovering forest structure within two years following wildfire disturbance has not been attempted, yet such knowledge is critical for determining successional pathways. We used remote sensing and field data, along with digital climate and terrain data, to model and map early-seral aspen structure and vegetation species richness following...

  11. FIB Secondary Etching Method for Fabrication of Fine CNT Forest Metamaterials

    NASA Astrophysics Data System (ADS)

    Pander, Adam; Hatta, Akimitsu; Furuta, Hiroshi

    2017-10-01

    Anisotropic materials, like carbon nanotubes (CNTs), are the perfect substitutes to overcome the limitations of conventional metamaterials; however, the successful fabrication of CNT forest metamaterial structures is still very challenging. In this study, a new method utilizing a focused ion beam (FIB) with additional secondary etching is presented, which can obtain uniform and fine patterning of CNT forest nanostructures for metamaterials and ranging in sizes from hundreds of nanometers to several micrometers. The influence of the FIB processing parameters on the morphology of the catalyst surface and the growth of the CNT forest was investigated, including the removal of redeposited material, decreasing the average surface roughness (from 0.45 to 0.15 nm), and a decrease in the thickness of the Fe catalyst. The results showed that the combination of FIB patterning and secondary etching enabled the growth of highly aligned, high-density CNT forest metamaterials. The improvement in the quality of single-walled CNTs (SWNTs), defined by the very high G/D peak ratio intensity of 10.47, demonstrated successful fine patterning of CNT forest for the first time. With a FIB patterning depth of 10 nm and a secondary etching of 0.5 nm, a minimum size of 150 nm of CNT forest metamaterials was achieved. The development of the FIB secondary etching method enabled for the first time, the fabrication of SWNT forest metamaterials for the optical and infrared regime, for future applications, e.g., in superlenses, antennas, or thermal metamaterials.

  12. Early recovery of subtropical dry forest in southwestern Puerto Rico

    Treesearch

    Peter L. Weaver

    2011-01-01

    Tree cover and species composition were surveyed in 1998, 2003, and 2010 after the elimination of grazing and fire on the lower 32 hectares of the Tinaja tract at Laguna Cartagena National Wildlife Refuge in south-western Puerto Rico. Surveys of the secondary subtropical dry forest showed that stems increased 3.9 times, trees 6.7 times, basal area 3.3 times, and...

  13. Management of early-successional communities in central hardwood forests: with special emphasis on the ecology and management of oaks, ruffed grouse, and forest songbirds.

    Treesearch

    Frank R. III Thompson; Daniel R. Dessecker

    1997-01-01

    Describes the history, ecology, and silviculture of central hardwood forests and the status and ecology of early-successional forest songbirds and ruffed grouse. Concludes with management guidelines for early-successional communities in central hardwood forests.

  14. Community assembly of ectomycorrhizal fungi along a subtropical secondary forest succession.

    PubMed

    Gao, Cheng; Zhang, Yu; Shi, Nan-Nan; Zheng, Yong; Chen, Liang; Wubet, Tesfaye; Bruelheide, Helge; Both, Sabine; Buscot, François; Ding, Qiong; Erfmeier, Alexandra; Kühn, Peter; Nadrowski, Karin; Scholten, Thomas; Guo, Liang-Dong

    2015-01-01

    Environmental selection and dispersal limitation are two of the primary processes structuring biotic communities in ecosystems, but little is known about these processes in shaping soil microbial communities during secondary forest succession. We examined the communities of ectomycorrhizal (EM) fungi in young, intermediate and old forests in a Chinese subtropical ecosystem, using 454 pyrosequencing. The EM fungal community consisted of 393 operational taxonomic units (OTUs), belonging to 21 EM fungal lineages, in which three EM fungal lineages and 11 EM fungal OTUs showed significantly biased occurrence among the young, intermediate and old forests. The EM fungal community was structured by environmental selection and dispersal limitation in old forest, but only by environmental selection in young, intermediate, and whole forests. Furthermore, the EM fungal community was affected by different factors in the different forest successional stages, and the importance of these factors in structuring EM fungal community dramatically decreased along the secondary forest succession series. This study suggests that different assembly mechanisms operate on the EM fungal community at different stages in secondary subtropical forest succession. © 2014 The Authors New Phytologist © 2014 New Phytologist Trust.

  15. Early detection and secondary prevention of psychosis: facts and visions.

    PubMed

    Häfner, Heinz; Maurer, Kurt; Ruhrmann, Stephan; Bechdolf, Andreas; Klosterkötter, Joachim; Wagner, Michael; Maier, Wolfgang; Bottlender, Ronald; Möller, Hans-Jürgen; Gaebel, Wolfgang; Wölwer, Wolfgang

    2004-04-01

    As effective and practical approaches to primary and universal prevention of psychosis are lacking, intervention efforts are targeted at the early stages of schizophrenia to prevent (by way of secondary prevention) or postpone psychosis onset, reduce severity of illness or at least ameliorate the social consequences involved. Early intervention requires early detection and early recognition (diagnosis) of persons at risk and early prediction of psychosis. Within the German Research Network on Schizophrenia (GRNS) awareness programmes are being carried out in several German cities, and these efforts are already improving utilisation of early-recognition and early-prediction services by at risk persons. The empirical basis of developing a two-step early-recognition inventory and strategies of application will be discussed. This instrument is supplemented by a set of cognitive tests, prospectively validated in the GRNS. Results from preliminary analysis of data covering a two-year period demonstrate that the inventory and the cognitive tests are readily accepted. When used for screening in non-specialist settings and at the next level, i. e. at early-recognition centres, they seem to permit identification of at-risk persons. Early intervention is being tested 1) in a randomised controlled multi-centre trial consisting of a specially developed cognitive-behavioural therapy in the early (prepsychotic) prodromal state and 2) on additional treatment with appropriate doses of amisulpride in the late prodromal (early psychotic) state. Preliminary data from Study 1 covering 16.3 months show significantly fewer transitions to psychosis and from Study 2 reduced positive and negative symptoms and improved global functioning compared with controls who had received normal clinical treatment. As a result, both the early-recognition inventory plus cognitive tests and the two therapy strategies are feasible. We hope that the favourable trend indicated by the preliminary data will be

  16. The canopy interception-landslide initiation conundrum: insight from a tropical secondary forest in northern Thailand

    NASA Astrophysics Data System (ADS)

    Sidle, Roy C.; Ziegler, Alan D.

    2017-01-01

    The interception and smoothing effect of forest canopies on pulses of incident rainfall and its delivery to the soil has been suggested as a factor in moderating peak pore water pressure in soil mantles, thus reducing the risk of shallow landslides. Here we provide 3 years of rainfall and throughfall data in a tropical secondary dipterocarp forest characterized by few large trees in northern Thailand, along with selected soil moisture dynamics, to address this issue. Throughfall was an estimated 88 % of rainfall, varying from 86 to 90 % in individual years. Data from 167 events demonstrate that canopy interception was only weakly associated (via a nonlinear relationship) with total event rainfall, but not significantly correlated with duration, mean intensity, or antecedent 2-day precipitation (API2). Mean interception during small events (≤ 35 mm) was 17 % (n = 135 events) compared with only 7 % for large events (> 35 mm; n = 32). Examining small temporal intervals within the largest and highest intensity events that would potentially trigger landslides revealed complex patterns of interception. The tropical forest canopy had little smoothing effect on incident rainfall during the largest events. During events with high peak intensities, high wind speeds, and/or moderate-to-high pre-event wetting, measured throughfall was occasionally higher than rainfall during large event peaks, demonstrating limited buffering. However, in events with little wetting and low-to-moderate wind speed, early event rainfall peaks were buffered by the canopy. As rainfall continued during most large events, there was little difference between rainfall and throughfall depths. A comparison of both rainfall and throughfall depths to conservative mean intensity-duration thresholds for landslide initiation revealed that throughfall exceeded the threshold in 75 % of the events in which rainfall exceeded the threshold for both wet and dry conditions. Throughfall intensity for the 11 largest

  17. Secondary circulations above a solitary forest surrounded by semi-arid shrubland

    NASA Astrophysics Data System (ADS)

    Eder, Fabian; De Roo, Frederik; Rotenberg, Eyal; Yakir, Dan; Schmid, Hans Peter; Mauder, Matthias

    2015-04-01

    The dynamics of the heterogeneous atmospheric boundary layer are complex and still not fully understood. In particular, it is not known to what extent surface heterogeneities can induce secondary circulations. For this purpose, Doppler lidar and eddy-covariance measurements and large-eddy simulations were conducted at the Yatir forest in Israel, a pine forest that is surrounded by semi arid shrubland, in August and September 2013. Due to the low albedo of the forest and the increased turbulence intensity, the surface buoyancy flux was 220-290 W m-2 higher at the forest site than in the surrounding desert during the measurement campaign. Moreover, the forest is about 6 x 10 km large which should be sufficient for affecting the whole atmospheric boundary layer. However, the large-eddy simulation suggested that under ambient background wind (≈ 6 m s-1), the forest induces only a weak secondary circulation which should appear downwind of the forest. Nevertheless, persistent updrafts above the forest were detected with the Doppler lidar on 5 of the 16 measurement days. Such a circulation might have an impact on the validity of eddy-covariance fluxes, because its flux contribution cannot be reliably captured with a point measurement. We found that the energy balance closure was 80% at the desert site, but it was closed at the forest site, because the large eddies were broken up into smaller eddies there and those are captured by the eddy-covariance system.

  18. [Characteristics of soil macrofaunal community structure in secondary forest and forest plantations in western Qinling Mountains of Northwest China].

    PubMed

    Liu, Ji-Liang; Cao, Jing; Li, Shi-Jie; Pan, Chun-Lin; Pan, Cheng-Chen

    2012-09-01

    Long-term disturbance of human beings on secondary forest ecosystem would have profound impacts on belowground ecological processes, whereas the community structure and functional diversity of soil fauna would be sensitive to the changes of belowground ecological processes, with significance as an indicator of the changes. In this study, the method of hand-sorting was adopted to investigate the density of soil macrofaunal community in a secondary forest and the Pinus tabulaeformis, Larix kaempferi, Picea abie, and Picea asperata plantations of nearly 30 years old in Xiaolongshan forest area of western Qinling Mountains, and the PCA ordination and one-way ANOVA analysis were applied to analyze the community structure and trophic group composition of soil macrofauna in the five forest types. In the P. tabulaeformis and L. kaempferi plantations, the density of soil macrofaunal community was 3.0 and 2.1 times of that in the secondary forest, respectively, and the consumers/decomposers ratio of the community was obviously higher than that in the secondary forest. Among the plantations, P. tabulaeformis and L. kaempferi plantations had a significantly higher consumers/decomposers ratio of soil macrofaunal community than P. abies and P. asperata plantations. There was an obvious difference in community structure of soil macrofauna among the four plantations. The density of soil macrofaunal community in P. tabulaeformis and L. kaempferi plantations was 3.5 and 2.1 times higher than that in P. asperata plantation, respectively, whereas the group richness of soil macrofaunal community in P. tabulaeformis plantation was 1.5 times of that in P. abies and P. asperata plantations.

  19. Early secondary alveoloplasty in cleft lip and palate.

    PubMed

    Arangio, Paolo; Marianetti, Tito M; Tedaldi, Massimiliano; Ramieri, Valerio; Cascone, Piero

    2008-09-01

    The aims of this study were to present a personal surgical technique throughout the review of international literature concerning surgical techniques, objectives, and outcomes in early secondary alveoloplasty and to describe our personal surgical techniques in alveolar bone defect repair in cleft lip and palate.Throughout a literature analysis, it is now settled that early secondary alveoloplasty could reestablish the continuity of alveolar bone and prevent upper dental arch collapse after presurgical orthopedic upper maxilla expansion; it also might give a good bone support for teeth facing the cleft and allow the eruption of permanent elements with the bone graft and rebalance the symmetry of dental arch, improve facial aesthetic, guarantee an adequate amount of bone tissue for a further prosthetic reconstruction with implant, and finally close the eventual oronasal fistula.The surgical technique we are presenting permitted a total number of 35 early secondary alveoloplasty on which a long-term follow-up is still taking place.We can assess that early secondary alveoloplasty must be performed before permanent canine eruption. Iliac crest is the suggested donor site for bone grafting; orthopedic and orthodontic treatments must be performed in association with surgery, and if there is the dental element agenesia, an implantation treatment must be considered.

  20. Early Career Challenges in Secondary School Music Teaching

    ERIC Educational Resources Information Center

    Welch, G.; Purves, R.; Hargreaves, D.; Marshall, N.

    2011-01-01

    The article reports an Economic and Social Research Council-funded study of the early career experiences of secondary school music teachers in England, set within a wider national picture of decreasing age-related pupil engagement with school music, career perceptions of music teaching, variable patterns of teacher recruitment and possible…

  1. [Dynamics of soil fauna communities during succession process of secondary forests in Changbai Mountain].

    PubMed

    Tong, Fuchun; Wang, Qingli; Liu, Xingshuang; Xiao, Yihua

    2004-09-01

    The secondary succession of forest communities in Changbai Mountain might be divided into three stages, i.e., aggradation, transition, and steady states. The last stage will be arrived after about 100 years. At same time, the succession dynamics of various soil fauna groups were shown as: Saprophagous group was more abundant than other fauna groups, and its change trend was similar to the development of forest vegetation after disturbing; Phytophagous group had a higher amount during the prophase of forest succession, which was decreased with forest succession; the quantity of Carnivorous increased obviously after about 100-years-succession; and the composition of insect groups was that the unstable groups was more abundant when the forest was younger, but less abundant when the forest was older.

  2. The forgotten stage of forest succession: early-successional ecosystems on forest sites

    Treesearch

    Mark E. Swanson; Jerry F. Franklin; Robert L. Beschta; Charles M. Crisafulli; Dominick A. DellaSala; Richard L. Hutto; David B. Lindenmayer; Frederick J. Swanson

    2010-01-01

    Early-successional forest ecosystems that develop after stand-replacing or partial disturbances are diverse in species, processes, and structure. Post-disturbance ecosystems are also often rich in biological legacies, including surviving organisms and organically derived structures, such as woody debris. These legacies and postdisturbance plant communities provide...

  3. [Interspecies covariation analysis of dominant tree species in secondary succession of forest communities in Heishiding Natural Reserve, Guangdong Province].

    PubMed

    Zhou, Xianye; Wang, Bosun; Li, Mingguang; Chen, Zhanghe

    2004-03-01

    Based on a 2 x 2 contingency table, the Pearson product-moment correlation coefficient and Spearman rank correlation coefficient were used to analyses the interspecies covariation of dominant tree species in different communities of secondary succession series in Heishiding Natural Reserve, Guangdong Province. In early succession stage, 14 pairs of tree species showed a significant interspecies covariation, and 9 pairs of species showed a negative coraviation, indicating that the species pairs needed the same habitats, while five pairs of species showed a positive covariation, which indicated that the species pairs needed different habitats. In the stage of needle broad-leaved mixed forest, only 5 pairs of species showed a significant interspecies covariation, and they were all positive covariation, which indicated the main species needed the same habitats and the interspecies competition were going. In the stage of evergreen broadleaved forest dominated by heliophytes, 4 pairs of species showed a significant interspecies covariation, which was the least one in secondary succession series. Three pairs of them showed a positive covariation. It was the result of interspecies competition that the species pairs needed the same habitats. In the stage of evergreen broadleaved forest dominated by mesophytes, 20 pairs of species showed a significant interspecies covariation, which was the most one in secondary succession series. Nineteen pairs of them showed a positive covariation. It showed positive covariation between species in upper tree layer and in middle or lower tree layer, but dominant species in upper tree layer had no significant interspecies covariation.

  4. Belongingness in Early Secondary School: Key Factors that Primary and Secondary Schools Need to Consider.

    PubMed

    Vaz, Sharmila; Falkmer, Marita; Ciccarelli, Marina; Passmore, Anne; Parsons, Richard; Black, Melissa; Cuomo, Belinda; Tan, Tele; Falkmer, Torbjörn

    2015-01-01

    It is unknown if, and how, students redefine their sense of school belongingness after negotiating the transition to secondary school. The current study used longitudinal data from 266 students with, and without, disabilities who negotiated the transition from 52 primary schools to 152 secondary schools. The study presents the 13 most significant personal student and contextual factors associated with belongingness in the first year of secondary school. Student perception of school belongingness was found to be stable across the transition. No variability in school belongingness due to gender, disability or household-socio-economic status (SES) was noted. Primary school belongingness accounted for 22% of the variability in secondary school belongingness. Several personal student factors (competence, coping skills) and school factors (low-level classroom task-goal orientation), which influenced belongingness in primary school, continued to influence belongingness in secondary school. In secondary school, effort-goal orientation of the student and perception of their school's tolerance to disability were each associated with perception of school belongingness. Family factors did not influence belongingness in secondary school. Findings of the current study highlight the need for primary schools to foster belongingness among their students at an early age, and transfer students' belongingness profiles as part of the hand-over documentation. Most of the factors that influenced school belongingness before and after the transition to secondary are amenable to change.

  5. Belongingness in Early Secondary School: Key Factors that Primary and Secondary Schools Need to Consider

    PubMed Central

    Vaz, Sharmila; Falkmer, Marita; Ciccarelli, Marina; Passmore, Anne; Parsons, Richard; Black, Melissa; Cuomo, Belinda; Tan, Tele; Falkmer, Torbjörn

    2015-01-01

    It is unknown if, and how, students redefine their sense of school belongingness after negotiating the transition to secondary school. The current study used longitudinal data from 266 students with, and without, disabilities who negotiated the transition from 52 primary schools to 152 secondary schools. The study presents the 13 most significant personal student and contextual factors associated with belongingness in the first year of secondary school. Student perception of school belongingness was found to be stable across the transition. No variability in school belongingness due to gender, disability or household-socio-economic status (SES) was noted. Primary school belongingness accounted for 22% of the variability in secondary school belongingness. Several personal student factors (competence, coping skills) and school factors (low-level classroom task-goal orientation), which influenced belongingness in primary school, continued to influence belongingness in secondary school. In secondary school, effort-goal orientation of the student and perception of their school’s tolerance to disability were each associated with perception of school belongingness. Family factors did not influence belongingness in secondary school. Findings of the current study highlight the need for primary schools to foster belongingness among their students at an early age, and transfer students’ belongingness profiles as part of the hand-over documentation. Most of the factors that influenced school belongingness before and after the transition to secondary are amenable to change. PMID:26372554

  6. Soil carbon stocks decrease following conversion of secondary forests to rubber (Hevea brasiliensis) plantations.

    PubMed

    de Blécourt, Marleen; Brumme, Rainer; Xu, Jianchu; Corre, Marife D; Veldkamp, Edzo

    2013-01-01

    Forest-to-rubber plantation conversion is an important land-use change in the tropical region, for which the impacts on soil carbon stocks have hardly been studied. In montane mainland southeast Asia, monoculture rubber plantations cover 1.5 million ha and the conversion from secondary forests to rubber plantations is predicted to cause a fourfold expansion by 2050. Our study, conducted in southern Yunnan province, China, aimed to quantify the changes in soil carbon stocks following the conversion from secondary forests to rubber plantations. We sampled 11 rubber plantations ranging in age from 5 to 46 years and seven secondary forest plots using a space-for-time substitution approach. We found that forest-to-rubber plantation conversion resulted in losses of soil carbon stocks by an average of 37.4±4.7 (SE) Mg C ha(-1) in the entire 1.2-m depth over a time period of 46 years, which was equal to 19.3±2.7% of the initial soil carbon stocks in the secondary forests. This decline in soil carbon stocks was much larger than differences between published aboveground carbon stocks of rubber plantations and secondary forests, which range from a loss of 18 Mg C ha(-1) to an increase of 8 Mg C ha(-1). In the topsoil, carbon stocks declined exponentially with years since deforestation and reached a steady state at around 20 years. Although the IPCC tier 1 method assumes that soil carbon changes from forest-to-rubber plantation conversions are zero, our findings show that they need to be included to avoid errors in estimating overall ecosystem carbon fluxes.

  7. Soil Carbon Stocks Decrease following Conversion of Secondary Forests to Rubber (Hevea brasiliensis) Plantations

    PubMed Central

    de Blécourt, Marleen; Brumme, Rainer; Xu, Jianchu; Corre, Marife D.; Veldkamp, Edzo

    2013-01-01

    Forest-to-rubber plantation conversion is an important land-use change in the tropical region, for which the impacts on soil carbon stocks have hardly been studied. In montane mainland southeast Asia, monoculture rubber plantations cover 1.5 million ha and the conversion from secondary forests to rubber plantations is predicted to cause a fourfold expansion by 2050. Our study, conducted in southern Yunnan province, China, aimed to quantify the changes in soil carbon stocks following the conversion from secondary forests to rubber plantations. We sampled 11 rubber plantations ranging in age from 5 to 46 years and seven secondary forest plots using a space-for-time substitution approach. We found that forest-to-rubber plantation conversion resulted in losses of soil carbon stocks by an average of 37.4±4.7 (SE) Mg C ha−1 in the entire 1.2-m depth over a time period of 46 years, which was equal to 19.3±2.7% of the initial soil carbon stocks in the secondary forests. This decline in soil carbon stocks was much larger than differences between published aboveground carbon stocks of rubber plantations and secondary forests, which range from a loss of 18 Mg C ha−1 to an increase of 8 Mg C ha−1. In the topsoil, carbon stocks declined exponentially with years since deforestation and reached a steady state at around 20 years. Although the IPCC tier 1 method assumes that soil carbon changes from forest-to-rubber plantation conversions are zero, our findings show that they need to be included to avoid errors in estimating overall ecosystem carbon fluxes. PMID:23894456

  8. Patterns of plant functional variation and specialization along secondary succession and topography in a tropical dry forest

    NASA Astrophysics Data System (ADS)

    Sanaphre-Villanueva, Lucía; Dupuy, Juan Manuel; Andrade, José Luis; Reyes-García, Casandra; Jackson, Paula C.; Paz, Horacio

    2017-05-01

    Long-term human disturbance of tropical forests may favor generalist plant species leading to biotic homogenization. We aimed to a) assess if generalist species dominate across different successional ages and topographical positions in a tropical dry forest with a long history of human disturbance, b) to characterize functional traits associated with generalist and specialist species, and c) to assess if a predominance of generalists leads to a homogeneous functional structure across the landscape. We used a multinomial model of relative abundances to classify 118 woody species according to their successional/topographic habitat. Three species were classified as secondary-forest specialists, five as mature-forest specialists, 35 as generalists, and 75 as too rare to classify. According to topography, six species were hill specialists, eight flat-site specialists, 35 generalists, and 70 too rare. Generalists dominated across the landscape. Analysis of 14 functional traits from 65 dominant species indicated that generalists varied from acquisitive strategies of light and water early in succession to conservative strategies in older forests and on hills. Long-term human disturbance may have favored generalist species, but this did not result in functional homogenization. Further analyses considering other functional traits, and temporal and fine-scale microenvironmental variation are needed to better understand community assembly.

  9. Rapid Shifts in Soil Nutrients and Decomposition Enzyme Activity in Early Succession Following Forest Fire

    DOE PAGES

    Knelman, Joseph; Graham, Emily B.; Ferrenberg, Scott; ...

    2017-09-15

    In post-disturbance landscapes nutrient availability has proven a major control on ecological succession. In this study, we examined variation in connections between soil nutrient availability and decomposition extracellular enzyme activity (EEA) across post fire secondary succession in forest soils as well as after a secondary flood disturbance. We also examined possible linkages between edaphic properties and bacterial communities based on 16S rRNA gene analysis. We found that with advancing succession in a post-fire landscape, the relationship between soil nutrients and EEA became stronger over time. In general, late successional soils showed stronger connections between EEA and soil nutrient status, whilemore » early successional soils were marked by a complete decoupling of nutrients and EEA. We also found that soil moisture and bacterial communities of post-fire disturbance soils were susceptible to change following the secondary flood disturbance, while undisturbed, reference forest soils were not. Our results demonstrate that nutrient pools correlating with EEA change over time. While past work has largely focused on ecosystem succession on decadal timescales, our work suggests that nutrients shift in their relative importance as a control of decomposition EEA in the earliest stages of secondary succession. Thus, this work emphasizes the relevance of successional stage, even on short timescales, in predicting rates of carbon and nitrogen cycling, especially as disturbances become more frequent in a rapidly changing world.« less

  10. Contribution of Near Real Time MODIS-Based Forest Disturbance Detection Products to a National Forest Threat Early Warning System

    NASA Technical Reports Server (NTRS)

    Spruce, Joseph; Hargrove, William; Gasser, Gerald; Smoot, James; Kuper, Philip

    2011-01-01

    U.S. forests occupy approx. 751 million acres (approx. 1/3 of total land). These forests are exposed to multiple biotic and abiotic threats that collectively damage extensive acreages each year. Hazardous forest disturbances can threaten human life and property, bio-diversity and water supplies. Timely regional forest monitoring products are needed to aid forest management and decision making by the US Forest Service and its state and private partners. Daily MODIS data products provide a means to monitor regional forest disturbances on a weekly basis. In response, we began work in 2006 to develop a Near Real Time (NRT) forest monitoring capability, based on MODIS NDVI data, as part of a national forest threat early warning system (EWS)

  11. Simulating Secondary Succession of Elk Forage Values in a Managed Forest Landscape, Western Washington

    PubMed

    Jenkins; Starkey

    1996-09-01

    Modern timber management practices often influence forage production for elk (Cervus elaphus) on broad temporal and spatial scales in forested landscapes. We incorporated site-specific information on postharvesting forest succession and forage characteristics in a simulation model to evaluate past and future influences of forest management practices on forage values for elk in a commercially managed Douglas fir (Pseudotsuga menziesii, PSME)-western hemlock (Tsuga heterophylla, TSHE) forest in western Washington. We evaluated future effects of: (1) clear-cut logging 0, 20, and 40% of harvestable stands every five years; (2) thinning 20-year-old Douglas fir forests; and (3) reducing the harvesting cycle from 60 to 45 years. Reconstruction of historical patterns of vegetation succession indicated that forage values peaked in the 1960s and declined from the 1970s to the present, but recent values still were higher than may have existed in the unmanaged landscape in 1945. Increased forest harvesting rates had little short-term influence on forage trends because harvestable stands were scarce. Simulations of forest thinning also produced negligible benefits because thinning did not improve forage productivity appreciably at the stand level. Simulations of reduced harvesting cycles shortened the duration of declining forage values from approximately 30 to 15 years. We concluded that simulation models are useful tools for examining landscape responses of forage production to forest management strategies, but the options examined provided little potential for improving elk forages in the immediate future.KEY WORDS:Cervus elaphus; Elk; Forage; Forest management; Modeling; Secondary succession

  12. Mapping Secondary Forest Succession on Abandoned Agricultural Land in the Polish Carpathians

    NASA Astrophysics Data System (ADS)

    Kolecka, N.; Kozak, J.; Kaim, D.; Dobosz, M.; Ginzler, Ch.; Psomas, A.

    2016-06-01

    Land abandonment and secondary forest succession have played a significant role in land cover changes and forest cover increase in mountain areas in Europe over the past several decades. Land abandonment can be easily observed in the field over small areas, but it is difficult to map over the large areas, e.g., with remote sensing, due to its subtle and spatially dispersed character. Our previous paper presented how the LiDAR (Light Detection and Ranging) and topographic data were used to detect secondary forest succession on abandoned land in one commune located in the Polish Carpathians by means of object-based image analysis (OBIA) and GIS (Kolecka et al., 2015). This paper proposes how the method can be applied to efficiently map secondary forest succession over the entire Polish Carpathians, incorporating spatial sampling strategy supported by various ancillary data. Here we discuss the methods of spatial sampling, its limitations and results in the context of future secondary forest succession modelling.

  13. Spatial analysis of early successional, temperate forest community structure

    NASA Astrophysics Data System (ADS)

    Walker, R. H.; Williams, C. A.; MacLean, R. G.; Epstein, H. E.; Vanderhoof, M. K.

    2013-12-01

    The global importance of sequestration of carbon by temperate forests makes characterizing the regrowth of these forests post-disturbance both ecologically and economically important. High intensity disturbances, such as logging, result in substantial alteration of community composition post-disturbance, creating the potential for alterations to the cycling of carbon, water, and nutrients in the ecosystem. Because logging pressure in New England continues to increase, understanding how forest ecosystems in this region respond to disturbance is crucial. This study aims to characterize interspecies interactions within New England forests by identifying synchronous and asynchronous colocation of species following a disturbance. To accomplish this, line-intercept surveys of vegetation were conducted in a clearcut forest stand located within the Harvard Forest LTER site. Survey data collected two (2010) and five (2013) years post-clearcut were analyzed using a one-dimensional Ripley's K. From 2010 to 2013, an increase in the number of interspecies relationships was observed, indicating the development of community structure. Additionally, the analysis found an increase in total vegetative cover from 2010 to 2013, and also found the majority of observed interspecies relationships to be asynchronous relationships. Together, these results imply an increase in resource competition that had the potential to drive the increase in community structure. Specifically, an increase in community structure led to the development of three distinct sub-communities: homogenous fern, tree seedling canopy over ground cover, and shrub dominated. This creates a patchy landscape in the early successional forest that allows for high species diversity (Shannon's H = 2.455). Based on the results of the Ripley's K analyses, species demonstrated definite patterns of synchronicity and asynchronicity based on both specific species interactions as well as functional group interactions. These

  14. Heterogeneous movement of insectivorous Amazonian birds through primary and secondary forest: A case study using multistate models with radiotelemetry data

    USGS Publications Warehouse

    Hines, James; Powell, Luke L.; Wolfe, Jared D.; Johnson, Erik l.; Nichols, James D.; Stouffer, Phillip C.

    2015-01-01

    Given rates of deforestation, disturbance, and secondary forest accumulation in tropical rainforests, there is a great need to quantify habitat use and movement among different habitats. This need is particularly pronounced for animals most sensitive to disturbance, such as insectivorous understory birds. Here we use multistate capture–recapture models with radiotelemetry data to determine the successional stage at which within-day movement probabilities of Amazonian birds in secondary forest are similar to those in primary forest. We radio-tracked three common understory insectivore species in primary and secondary forest at the Biological Dynamics of Forest Fragments project near Manaus, Brazil: two woodcreepers, Glyphorynchus spirurus (n = 19) andXiphorhynchus pardalotus (n = 18), and the terrestrial antthrush Formicarius colma(n = 19). Forest age was a strong predictor of fidelity to a given habitat. All three species showed greater fidelity to primary forest than to 8–14-year-old secondary forest, indicating the latter’s relatively poor quality. The two woodcreeper species used 12–18-year-old secondary forest in a manner comparable to continuous forest, but F. colmaavoided moving even to 27–31-year-old secondary forest—the oldest at our site. Our results suggest that managers concerned with less sensitive species can assume that forest reserves connected by 12–18-year-old secondary forest corridors are effectively connected. On the other hand, >30 years are required after land abandonment before secondary forest serves as a primary forest-like conduit for movement by F. colma; more sensitive terrestrial insectivores may take longer still.

  15. Early thinning experiments established by the Fort Valley Experimental Forest (P-53)

    Treesearch

    Benjamin P. De Blois; Alex. J. Finkral; Andrew J. Sánchez Meador; Margaret M. Moore

    2008-01-01

    Between 1925 and 1936, the Fort Valley Experimental Forest (FVEF) scientists initiated a study to examine a series of forest thinning experiments in second growth ponderosa pine stands in Arizona and New Mexico. These early thinning plots furnished much of the early background for the development of methods used in forest management in the Southwest. The plots ranged...

  16. Patterns and trends of early successional forests in the Eastern United States

    Treesearch

    Margaret K. Trani; Robert T. Brooks; Thomas L. Schmidt; Victor A. Rudis; Christine M. Gabbard

    2001-01-01

    We assessed the status of early successional forest conditions for 33 Eastern States within the New England, Middle Atlantic, Great Lakes, Central Plains, Coastal South, and Interior South subregions. We used Forest Inventory and Analysis surveys to analyze trends from 1946 to 1998. Dramatic regional differences occurred in distribution of early successional forests....

  17. Rodent seed predation promotes differential recruitment among bird-dispersed trees in temperate secondary forests.

    PubMed

    García, Daniel; Obeso, José Ramón; Martínez, Isabel

    2005-07-01

    We investigated the role of seed predation by rodents in the recruitment of the fleshy-fruited trees Taxus baccata, Ilex aquifolium and Crataegus monogyna in temperate secondary forests in NW Spain. We measured the densities of dispersed seeds, early emerged seedlings, established recruits and adults, at four sites over a period of 2 years. Seed predation among species was compared by seed removal experiments and analysis of rodent larder-hoards. The three species differed markedly in local regeneration patterns. The rank order in the seed rain following decreasing seed density was Ilex, Taxus and Crataegus. However, Crataegus established 3.3 times more seedlings than Taxus. For all species, there was a positive linear relationship between the density of emerged seedlings and seed density, suggesting that recruitment was seed- rather than microsite-limited. A consistent pattern of seed selection among species was exerted by rodents, which preferred Taxus and, secondarily, Ilex seeds to Crataegus seeds. Predation ranking was the inverse of that of seed protection against predators, measured as the mass of woody coat per mass unit of the edible fraction. Recruitment potential, evaluated as the ratio of seedlings to seeds, was negatively related to seed predation, with the rank order Crataegus > Ilex > Taxus. The selective early recruitment limitation exerted by predation may have a demographic effect in the long term, as judged by the positive relationship between early seedling emergence and the density of established recruits. By modulating the pre-emptive competition for seed safe sites, rodents may preclude the progressive exclusion of species that produce low numbers of seeds (i.e. Crataegus) by those dominant in seed number (i.e. Ilex, Taxus), or at least foster the evenness for site occupation among seedlings of different species.

  18. How does vegetation structure influence woodpeckers and secondary cavity nesting birds in African cork oak forest?

    NASA Astrophysics Data System (ADS)

    Segura, Amalia

    2017-08-01

    The Great Spotted Woodpecker provides important information about the status of a forest in terms of structure and age. As a primary cavity creator, it provides small-medium size cavities for passerines. However, despite its interest as an ecosystem engineer, studies of this species in Africa are scarce. Here, spatially explicit predictive models were used to investigate how forest structural variables are related to both the Great Spotted Woodpecker and secondary cavity nesting birds in Maamora cork oak forest (northwest Morocco). A positive association between Great Spotted Woodpecker and both dead-tree density and large mature trees (>60 cm dbh) was found. This study area, Maamora, has an old-growth forest structure incorporating a broad range of size and condition of live and dead trees, favouring Great Spotted Woodpecker by providing high availability of foraging and excavating sites. Secondary cavity nesting birds, represented by Great Tit, African Blue Tit, and Hoopoe, were predicted by Great Spotted Woodpecker detections. The findings suggest that the conservation of the Maamora cork oak forest could be key to maintaining these hole-nesting birds. However, this forest is threatened by forestry practises and livestock overgrazing and the challenge is therefore to find sustainable management strategies that ensure conservation while allowing its exploitation.

  19. Diameter growth performance of tree functional groups in Puerto Rican secondary tropical forests.

    Treesearch

    Patricia Adame; Maria Uriarte; Thomas Brandeis

    2014-01-01

    Aim of study: Understanding the factors that control tree growth in successional stands is particularly important for quantifying the carbon sequestration potential and timber yield of secondary tropical forests. Understanding the factors that control tree growth in successional stands is particularly important for quantifying the carbon sequestration potential and...

  20. [Syagrus romanzoffiana (Arecaceae) seed utilization by ants in a secondary forest in South Brazil].

    PubMed

    Silva, Fernanda R; Begnini, Romualdo M; Klier, Vinícius A; Scherer, Karla Z; Lopes, Benedito C; Castellani, Tânia T

    2009-01-01

    Ants can nest in a wide variety of substracts. This paper shows Syagrus romanzoffiana seed utilization by ants in an Atlantic secondary forest. We report 29 seeds occupied by small-bodied ants, with 27 of them showing at least two ant development stages. Although a large number of seeds were sampled, a low level of ant occupation was observed.

  1. Diversity patterns of ground beetles and understory vegetation in mature, secondary, and plantation forest regions of temperate northern China

    PubMed Central

    Zou, Yi; Sang, Weiguo; Wang, Shunzhong; Warren-Thomas, Eleanor; Liu, Yunhui; Yu, Zhenrong; Wang, Changliu; Axmacher, Jan Christoph

    2015-01-01

    Plantation and secondary forests form increasingly important components of the global forest cover, but our current knowledge about their potential contribution to biodiversity conservation is limited. We surveyed understory plant and carabid species assemblages at three distinct regions in temperate northeastern China, dominated by mature forest (Changbaishan Nature Reserve, sampled in 2011 and 2012), secondary forest (Dongling Mountain, sampled in 2011 and 2012), and forest plantation habitats (Bashang Plateau, sampled in 2006 and 2007), respectively. The α-diversity of both taxonomic groups was highest in plantation forests of the Bashang Plateau. Beetle α-diversity was lowest, but plant and beetle species turnover peaked in the secondary forests of Dongling Mountain, while habitats in the Changbaishan Nature Reserve showed the lowest turnover rates for both taxa. Changbaishan Nature Reserve harbored the highest proportion of forest specialists. Our results suggest that in temperate regions of northern China, the protected larch plantation forest established over extensive areas might play a considerable role in maintaining a high biodiversity in relation to understory herbaceous plant species and carabid assemblages, which can be seen as indicators of forest disturbance. The high proportion of phytophagous carabids and the rarity of forest specialists reflect the relatively homogenous, immature status of the forest ecosystems on the Bashang Plateau. China's last remaining large old-growth forests like the ones on Changbaishan represent stable, mature ecosystems which require particular conservation attention. PMID:25691978

  2. Exploiting water versus tolerating drought: water-use strategies of trees in a secondary successional tropical dry forest.

    PubMed

    Pineda-García, Fernando; Paz, Horacio; Meinzer, Frederick C; Angeles, Guillermo

    2016-02-01

    In seasonal plant communities where water availability changes dramatically both between and within seasons, understanding the mechanisms that enable plants to exploit water pulses and to survive drought periods is crucial. By measuring rates of physiological processes, we examined the trade-off between water exploitation and drought tolerance among seedlings of trees of a tropical dry forest, and identified biophysical traits most closely associated with plant water-use strategies. We also explored whether early and late secondary successional species occupy different portions of trade-off axes. As predicted, species that maintained carbon capture, hydraulic function and leaf area at higher plant water deficits during drought had low photosynthetic rates, xylem hydraulic conductivity and growth rate under non-limiting water supply. Drought tolerance was associated with more dense leaf, stem and root tissues, whereas rapid resource acquisition was associated with greater stem water storage, larger vessel diameter and larger leaf area per mass invested. We offer evidence that the water exploitation versus drought tolerance trade-off drives species differentiation in the ability of tropical dry forest trees to deal with alternating water-drought pulses. However, we detected no evidence of strong functional differentiation between early and late successional species along the proposed trade-off axes, suggesting that the environmental gradient of water availability across secondary successional habitats in the dry tropics does not filter out physiological strategies of water use among species, at least at the seedling stage.

  3. Emissions of biogenic volatile organic compounds and subsequent formation of secondary organic aerosols in a Larix kaempferi forest

    NASA Astrophysics Data System (ADS)

    Mochizuki, T.; Miyazaki, Y.; Ono, K.; Wada, R.; Takahashi, Y.; Saigusa, N.; Kawamura, K.; Tani, A.

    2015-10-01

    We conducted simultaneous measurements of concentrations and above-canopy fluxes of isoprene and α-pinene, along with their oxidation products in aerosols in a Larix kaempferi (Japanese larch) forest in summer 2012. Vertical profiles of isoprene showed the maximum concentration near the forest floor with a peak around noon, whereas oxidation products of isoprene, i.e., methacrolein (MACR) and methyl vinyl ketone (MVK), showed higher concentrations near the canopy level of the forest. The vertical profile suggests large emissions of isoprene near the forest floor, likely due to Dryopteris crassirhizoma (a fern species), and the subsequent reaction within the canopy. The concentrations of α-pinene also showed highest values near the forest floor, with maximums in the early morning and late afternoon. The vertical profiles of α-pinene suggest its large emissions from soil and litter in addition to emissions from L. kaempferi leaves at the forest site. Isoprene and its oxidation products in aerosols exhibited similar diurnal variations within the forest canopy, providing evidence of secondary organic aerosol (SOA) formation via oxidation of isoprene most likely emitted from the forest floor. Although high abundance of α-pinene was observed in the morning, its oxidation products in aerosols showed peaks in daytime, due to a time lag between the emission and atmospheric reactions of α-pinene to form SOA. Positive matrix factorization (PMF) analysis indicated that anthropogenic influence is the most important factor contributing to the elevated concentrations of molecular oxidation products of isoprene- (> 64 %) and α-pinene-derived SOA (> 57 %). The combination of the measured fluxes and vertical profiles of biogenic volatile organic compounds (BVOCs) suggests that the inflow of anthropogenic precursors/aerosols likely enhanced the formation of both isoprene SOA and α-pinene SOA within the forest canopy even when the BVOC flux was relatively low. This study

  4. Quantifying the biodiversity value of tropical primary, secondary, and plantation forests

    PubMed Central

    Barlow, J.; Gardner, T. A.; Araujo, I. S.; Ávila-Pires, T. C.; Bonaldo, A. B.; Costa, J. E.; Esposito, M. C.; Ferreira, L. V.; Hawes, J.; Hernandez, M. I. M.; Hoogmoed, M. S.; Leite, R. N.; Lo-Man-Hung, N. F.; Malcolm, J. R.; Martins, M. B.; Mestre, L. A. M.; Miranda-Santos, R.; Nunes-Gutjahr, A. L.; Overal, W. L.; Parry, L.; Peters, S. L.; Ribeiro-Junior, M. A.; da Silva, M. N. F.; da Silva Motta, C.; Peres, C. A.

    2007-01-01

    Biodiversity loss from deforestation may be partly offset by the expansion of secondary forests and plantation forestry in the tropics. However, our current knowledge of the value of these habitats for biodiversity conservation is limited to very few taxa, and many studies are severely confounded by methodological shortcomings. We examined the conservation value of tropical primary, secondary, and plantation forests for 15 taxonomic groups using a robust and replicated sample design that minimized edge effects. Different taxa varied markedly in their response to patterns of land use in terms of species richness and the percentage of species restricted to primary forest (varying from 5% to 57%), yet almost all between-forest comparisons showed marked differences in community structure and composition. Cross-taxon congruence in response patterns was very weak when evaluated using abundance or species richness data, but much stronger when using metrics based upon community similarity. Our results show that, whereas the biodiversity indicator group concept may hold some validity for several taxa that are frequently sampled (such as birds and fruit-feeding butterflies), it fails for those exhibiting highly idiosyncratic responses to tropical land-use change (including highly vagile species groups such as bats and orchid bees), highlighting the problems associated with quantifying the biodiversity value of anthropogenic habitats. Finally, although we show that areas of native regeneration and exotic tree plantations can provide complementary conservation services, we also provide clear empirical evidence demonstrating the irreplaceable value of primary forests. PMID:18003934

  5. Quantifying the biodiversity value of tropical primary, secondary, and plantation forests.

    PubMed

    Barlow, J; Gardner, T A; Araujo, I S; Avila-Pires, T C; Bonaldo, A B; Costa, J E; Esposito, M C; Ferreira, L V; Hawes, J; Hernandez, M I M; Hoogmoed, M S; Leite, R N; Lo-Man-Hung, N F; Malcolm, J R; Martins, M B; Mestre, L A M; Miranda-Santos, R; Nunes-Gutjahr, A L; Overal, W L; Parry, L; Peters, S L; Ribeiro-Junior, M A; da Silva, M N F; da Silva Motta, C; Peres, C A

    2007-11-20

    Biodiversity loss from deforestation may be partly offset by the expansion of secondary forests and plantation forestry in the tropics. However, our current knowledge of the value of these habitats for biodiversity conservation is limited to very few taxa, and many studies are severely confounded by methodological shortcomings. We examined the conservation value of tropical primary, secondary, and plantation forests for 15 taxonomic groups using a robust and replicated sample design that minimized edge effects. Different taxa varied markedly in their response to patterns of land use in terms of species richness and the percentage of species restricted to primary forest (varying from 5% to 57%), yet almost all between-forest comparisons showed marked differences in community structure and composition. Cross-taxon congruence in response patterns was very weak when evaluated using abundance or species richness data, but much stronger when using metrics based upon community similarity. Our results show that, whereas the biodiversity indicator group concept may hold some validity for several taxa that are frequently sampled (such as birds and fruit-feeding butterflies), it fails for those exhibiting highly idiosyncratic responses to tropical land-use change (including highly vagile species groups such as bats and orchid bees), highlighting the problems associated with quantifying the biodiversity value of anthropogenic habitats. Finally, although we show that areas of native regeneration and exotic tree plantations can provide complementary conservation services, we also provide clear empirical evidence demonstrating the irreplaceable value of primary forests.

  6. Biomass accumulation rates of Amazonian secondary forest and biomass of old-growth forests from Landsat time series and the Geoscience Laser Altimeter System

    Treesearch

    E. H. Helmer; M. A. Lefsky; D. A. Roberts

    2009-01-01

    We estimate the age of humid lowland tropical forests in Rondônia, Brazil, from a somewhat densely spaced time series of Landsat images (1975–2003) with an automated procedure, the Threshold Age Mapping Algorithm (TAMA), first described here. We then estimate a landscape-level rate of aboveground woody biomass accumulation of secondary forest by combining forest age...

  7. Time series data of a broadleaved secondary forest in Japan as affected by deer and mass mortality of oak trees.

    PubMed

    Itô, Hiroki

    2017-01-01

    Abandonment of broadleaved secondary forests that have been used for various purposes may cause the loss of biodiversity. Some of these forests suffer from diseases such as Japanese oak wilt. An increasing number of deer also impact some of them. Monitoring and recording the status of such forests is important for their proper management. This data set provides a concrete example of temporal changes in a temperate broadleaved secondary forest. The forest has been damaged by mass mortality of oak trees caused by Japanese oak wilt disease. In addition, the forest has been under foraging pressure by sika deer (Cervus nippon Temminck). The data set can provide information on how such a forest has changed in species composition of the canopy and sub-canopy layers and in species occurrence in the understory layer.

  8. Time series data of a broadleaved secondary forest in Japan as affected by deer and mass mortality of oak trees

    PubMed Central

    2017-01-01

    Abstract Background Abandonment of broadleaved secondary forests that have been used for various purposes may cause the loss of biodiversity. Some of these forests suffer from diseases such as Japanese oak wilt. An increasing number of deer also impact some of them. Monitoring and recording the status of such forests is important for their proper management. New information This data set provides a concrete example of temporal changes in a temperate broadleaved secondary forest. The forest has been damaged by mass mortality of oak trees caused by Japanese oak wilt disease. In addition, the forest has been under foraging pressure by sika deer (Cervus nippon Temminck). The data set can provide information on how such a forest has changed in species composition of the canopy and sub-canopy layers and in species occurrence in the understory layer. PMID:28765719

  9. 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

  10. 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

  11. Monitoring Regional Forest Disturbances across the US with Near Real Time MODIS NDVI Products included in the ForWarn Forest Threat Early Warning System

    NASA Technical Reports Server (NTRS)

    Spruce, Joseph; Hargrove, William W.; Gasser, Gerald; Norman, Steve

    2013-01-01

    U.S. forests occupy approx.1/3 of total land area (approx. 304 million ha). Since 2000, a growing number of regionally evident forest disturbances have occurred due to abiotic and biotic agents. Regional forest disturbances can threaten human life and property, bio-diversity and water supplies. Timely regional forest disturbance monitoring products are needed to aid forest health management work. Near Real Time (NRT) twice daily MODIS NDVI data provide a means to monitor U.S. regional forest disturbances every 8 days. Since 2010, these NRT forest change products have been produced and posted on the US Forest Service ForWarn Early Warning System for Forest Threats.

  12. [Dynamics of forest community structure and complexity in the process of secondary succession in bedrock area of west Shanxi Province].

    PubMed

    Dong, Lin-Shui; Zhang, Xu-Dong; Zhou, Jin-Xing; Song, Ai-Yun

    2007-03-01

    In this paper, four plots representing the typical secondary succession stages of forest community were selected at the shady slope of bedrock area in Zhongyang County of West Shanxi, aimed to study the variation patterns of the structure and complexity of forest community in the process of secondary succession. The results showed that in the succession process of the community, there was an evident regularity in the variation of height and diameter class structure. The proportion of high and big individuals in the community increased gradually, while that of low and small ones increased first but decreased then. From the viewpoint of height class structure, the compositional complexity of tree species H (X), structural complexity of tree species H (Y/X), and complexity of whole community H (X,Y) all increased first, but decreased then with the succession. At the early, middle and arbor stages of succession, the H(X) value was 2.96, 3.85 and 3.75, while H (Y/X) value was 1.27, 1.66 and 1.37, respectively.

  13. Interannual Variations in Ecosystem Oxidative Ratio in Croplands, Deciduous Forest, Coniferous Forest, and Early Successional Forest Ecosystems

    NASA Astrophysics Data System (ADS)

    Masiello, C. A.; Hockaday, W. C.; Gallagher, M. E.; Calligan, L.

    2009-12-01

    Ecosystem net primary productivity (NPP) can vary significantly with annual variations in precipitation and temperature. These climate variations can also drive changes in plant carbon allocation patterns. Shifting allocation patterns can lead to variation in net ecosystem biochemical stocks (e.g. kg cellulose, lignin, protein, and lipid/ha), which can in turn lead to shifts in ecosystem oxidative ratio (OR). OR is the molar ratio of O2 released : CO2 fixed during biosynthesis. Major plant biochemicals vary substantially in oxidative ratio, ranging from average organic acid OR values of 0.75 to average lipid OR values of 1.37 (Masiello et al., 2008). OR is a basic property of ecosystem biochemistry, and is also an essential variable needed to constrain the size of the terrestrial biospheric carbon sink (Keeling et al., 1996). OR is commonly assumed to be 1.10 (e.g. Prentice et al., 2001), but small variations in net ecosystem OR can drive large errors in estimates of the size of the terrestrial carbon sink (Randerson et al., 2006). We hypothesized that interannual changes in climate may drive interannual variation in ecosystem OR values. Working at Kellogg Biological Station NSF LTER, we measured the annual average OR of coniferous and deciduous forests, an early successional forest, and croplands under both corn and soy. There are clear distinctions between individual ecosystems (e.g., the soy crops have a higher OR than the corn crops, and the coniferous forests have a higher OR than the deciduous forests), but the ecosystems themselves retained remarkably constant annual OR values between 1998 and 2008.

  14. [Composition and carbon storage of woody debris in moist evergreen broad-leaved forest and its secondary forests in Ailao Mountains of Yunnan Provinve].

    PubMed

    Yang, Li-Pan; Liu, Wen-Yao; Yang, Guo-Ping; Ma, Wen-Zhang; Li, Da-Wen

    2007-10-01

    This paper studied the composition and carbon storage of woody debris in the primary moist evergreen broad-leaved forest and its main secondary forests (regenerated Lithocarpus forest, Populus bonatii forest, and Alnus nepalensis forest) in Ailao Moutains of Yunnan Province. The results showed that in the primary forest, the carbon storage of woody debris amounted to 36.56 t x hm(-2). Castanopsis wattii, Lithocarpus xylocarpus and L. chintungensis were the main contributors, and most of them were the logs with larger diameter and at intermediate stage of decay. The unique environment of richer precipitation, higher humidity and lower temperature in the study area, and the decay-resistance of hardwood were favorable to the accumulation of woody debris. The three secondary forests had a carbon storage of 1.2-5.0 t x hm(-2), which decreased in the order of regenerated Lithocaropus forest > P. bonatii forest > A. nepalensis forest, showing a tendency of increasing carbon storage with succession course.

  15. Comparison of breeding bird and vegetation communities in primary and secondary forests of Great Smoky Mountains National Park

    USGS Publications Warehouse

    Simons, Theodore R.; Shriner, Susan A.; Farnsworth, George L.

    2006-01-01

    We compared breeding bird communities and vegetation characteristics at paired point locations in primary (undisturbed) and mature secondary forest (70-100 years old) sites in Great Smoky Mountains National Park, USA to understand how sites logged prior to creation of the park compare to undisturbed sites following 70 years of protection from human disturbance. We found that bird and vegetation communities are currently similar, but retain some differences in species composition. Rank abundance curves for primary and secondary forest bird communities showed very similar patterns of species dominance. Species composition was also similar on the two sites which shared 24 of the 25 most frequently recorded species. Nonetheless, comparisons of density estimates derived from distance sampling showed three bird species were more abundant on primary forest sites and that one bird species was significantly more abundant on secondary forest sites. Notably, comparisons based on raw counts (unadjusted for potential differences in detectability) produced somewhat different results. Analyses of vegetation samples for the paired sites also showed relative similarity, but with some differences between primary and secondary forests. Primary forest sites had more large trees (trees greater than 50 cm diameter at breast height) and late successional species. Primary forest sites had a denser tall shrub layer while secondary forest sites had a denser canopy layer. Nonetheless, tree species richness, basal area of live trees and number of standing snags did not differ between primary and secondary forest sites. Results indicate that breeding bird communities on sites within the park that were logged commercially 70 years ago are currently quite similar to bird communities on sites with no history of human disturbance. Similarities between the bird communities on previously disturbed and undisturbed sites in Great Smoky Mountains National Park may exceed those on more fragmented

  16. Changing gears during succession: shifting functional strategies in young tropical secondary forests.

    PubMed

    Craven, Dylan; Hall, Jefferson S; Berlyn, Graeme P; Ashton, Mark S; van Breugel, Michiel

    2015-09-01

    Adaptations to resource availability strongly shape patterns of community composition along successional gradients in environmental conditions. In the present study, we examined the extent to which variation in functional composition explains shifts in trait-based functional strategies in young tropical secondary forests during the most dynamic stage of succession (0-20 years). Functional composition of two size classes in 51 secondary forest plots was determined using community-weighted means of seven functional traits, which were intensively measured on 55 woody plant species (n = 875-1,761 individuals). Along the successional gradient in forest structure, there was a significant and consistent shift in functional strategies from resource acquisition to resource conservation. Leaf toughness and adult plant size increased significantly, while net photosynthetic capacity (A(mass)) decreased significantly during succession. Shifts in functional strategies within size classes for A(mass) and wood density also support the hypothesis that changes in functional composition are shaped by environmental conditions along successional gradients. In general, 'hard' functional traits, e.g., A(mass) and leaf toughness, linked to different facets of plant performance exhibited greater sensitivity to successional changes in forest structure than 'soft' traits, such as leaf mass area and leaf dry matter content. Our results also suggested that stochastic processes related to previous land-use history, dispersal limitation, and abiotic factors explained variation in functional composition beyond that attributed to deterministic shifts in functional strategies. Further data on seed dispersal vectors and distance and landscape configuration are needed to improve current mechanistic models of succession in tropical secondary forests.

  17. Wildlife of southern forests habitat & management (Chapter 2): Early History

    Treesearch

    James G. Dickson

    2003-01-01

    According to fossil records from coal beds, primeval forests of the South eons ago were complex forests of club moss trees and ferns (Burdette 1995). Since that time forest composition and distribution have changed in response to natural phenomena and later, to the influences of man. Over a long period of time primeval forests evolved from club mosses and ferns...

  18. Ecological and evolutionary variation in community nitrogen use traits during tropical dry forest secondary succession.

    PubMed

    Bhaskar, Radika; Porder, Stephen; Balvanera, Patricia; Edwards, Erika J

    2016-05-01

    We assessed the role of ecological and evolutionary processes in driving variation in leaf and litter traits related to nitrogen (N) use among tropical dry forest trees in old-growth and secondary stands in western Mexico. Our expectation was that legumes (Fabaceae), a dominant component of the regional flora, would have consistently high leaf N and therefore structure phylogenetic variation in N-related traits. We also expected ecological selection during succession for differences in nitrogen use strategies, and corresponding shifts in legume abundance. We used phylogenetic analyses to test for trait conservatism in foliar and litter N, C:N, and N resorption. We also evaluated differences in N-related traits between old-growth and secondary forests. We found a weak phylogenetic signal for all traits, partly explained by wide variation within legumes. Across taxa we observed a positive relationship between leaf and litter N, but no shift in resorption strategies along the successional gradient. Despite species turnover, N-resorption, and N-related traits showed little change across succession, suggesting that, at least for these traits, secondary forests rapidly recover ecosystem function. Collectively, our results also suggest that legumes should not be considered a single functional group from a biogeochemical perspective.

  19. Estimation of aboveground net primary productivity in secondary tropical dry forests using the Carnegie-Ames-Stanford approach (CASA) model

    NASA Astrophysics Data System (ADS)

    Cao, S.; Sanchez-Azofeifa, GA; Duran, SM; Calvo-Rodriguez, S.

    2016-07-01

    Although tropical dry forests (TDFs) cover roughly 42% of all tropical ecosystems, extensive deforestation and habitat fragmentation pose important limitations for their conservation and restoration worldwide. In order to develop conservation policies for this endangered ecosystem, it is necessary to quantify their provision of ecosystems services such as carbon sequestration and primary production. In this paper we explore the potential of the Carnegie-Ames-Stanford approach (CASA) for estimating aboveground net primary productivity (ANPP) in a secondary TDF located at the Santa Rosa National Park (SRNP), Costa Rica. We calculated ANPP using the CASA model (ANPPCASA) in three successional stages (early, intermediate, and late). Each stage has a stand age of 21 years, 32 years, and 50+ years, respectively, estimated as the age since land abandonment. Our results showed that the ANPPCASA for early, intermediate, and late successional stages were 3.22 Mg C ha-1 yr-1, 8.90 Mg C ha-1 yr-1, and 7.59 Mg C ha-1 yr-1, respectively, which are comparable with rates of carbon uptake in other TDFs. Our results indicate that key variables that influence ANPP in our dry forest site were stand age and precipitation seasonality. Incident photosynthetically active radiation and temperature were not dominant in the ANPPCASA. The results of this study highlight the potential of the use of remote sensing techniques and the importance of incorporating successional stage in accurate regional TDF ANPP estimation.

  20. Changes in early-successional hardwood forest area in four bird conservation regions across four decades

    Treesearch

    Sonja N. Oswalt; Kathleen E. Franzreb; David A. Buehler

    2012-01-01

    Early successional hardwood forests constitute important breeding habitat for many migratory songbirds. Declines in populations of these species suggest changes in habitat availability either on the species’ wintering grounds or on their early successional breeding grounds. We used Forest Inventory and Analysis data from 11 states across four decades to examine changes...

  1. Secondary Forest as a counterbalance on the deforestation effects: its role on evapotranspiration and water use efficiency

    NASA Astrophysics Data System (ADS)

    Von Randow, Rita C. S.; Tomasella, Javier; Von Randow, Celso; Araujo, Alessandro C.; Manzi, Antonio O.

    2017-04-01

    Since the 70's, the Amazon basin is under constant pressure first because of agricultural expansion, and recently also because of resources extraction. The conversion of pristine forest to other types of land cover as pasture and agriculture, affects the local water balance diminishing the evapotranspiration and increasing the discharge. Those changes can buffer the climate change effects and vice-versa. On the other hand, secondary forest growth resulting from abandoned deforested areas presents higher evaporative fraction (Giambelluca, 2002), leading to higher evapotranspiration rates than pristine forests, what can compensate the effects of deforestation on energy and water balances. In this work we will show four years of eddy flux measurements of a pristine forest and of a secondary growth about 20 years old, located in Central Amazonia, comparing the evapotranspiration and water use efficiency of both sites. The innovative aspect of the present work is the measurement of fluxes above a secondary growth forest in a relatively advanced stage. The measurements of eddy covariance are in accordance with the increase of evaporative fraction with the age of secondary forest presented by Giambelluca (2002). The yearly evaporative fraction (ratio of energy used for evapotranspiration to net radiation) on the primary forest was 0.74-0.81, while in the secondary forest it was 0.85-0.87. On the other hand, secondary forest shows a water use efficiency of 1.9 g C kg-1 H2O, while the pristine forest gives 2.9 g C kg-1 H2O.

  2. Local and Landscape Factors Determining Occurrence of Phyllostomid Bats in Tropical Secondary Forests

    PubMed Central

    Avila-Cabadilla, Luis Daniel; Sanchez-Azofeifa, Gerardo Arturo; Stoner, Kathryn Elizabeth; Alvarez-Añorve, Mariana Yolotl; Quesada, Mauricio; Portillo-Quintero, Carlos Alonso

    2012-01-01

    Neotropical forests are being increasingly replaced by a mosaic of patches of different successional stages, agricultural fields and pasture lands. Consequently, the identification of factors shaping the performance of taxa in anthropogenic landscapes is gaining importance, especially for taxa playing critical roles in ecosystem functioning. As phyllostomid bats provide important ecological services through seed dispersal, pollination and control of animal populations, in this study we assessed the relationships between phyllostomid occurrence and the variation in local and landscape level habitat attributes caused by disturbance. We mist-netted phyllostomids in 12 sites representing 4 successional stages of a tropical dry forest (initial, early, intermediate and late). We also quantitatively characterized the habitat attributes at the local (vegetation structure complexity) and the landscape level (forest cover, area and diversity of patches). Two focal scales were considered for landscape characterization: 500 and 1000 m. During 142 sampling nights, we captured 606 individuals representing 15 species and 4 broad guilds. Variation in phyllostomid assemblages, ensembles and populations was associated with variation in local and landscape habitat attributes, and this association was scale-dependent. Specifically, we found a marked guild-specific response, where the abundance of nectarivores tended to be negatively associated with the mean area of dry forest patches, while the abundance of frugivores was positively associated with the percentage of riparian forest. These results are explained by the prevalence of chiropterophilic species in the dry forest and of chiropterochorous species in the riparian forest. Our results indicate that different vegetation classes, as well as a multi-spatial scale approach must be considered for evaluating bat response to variation in landscape attributes. Moreover, for the long-term conservation of phyllostomids in anthropogenic

  3. Early school leaving among immigrants in Toronto secondary schools.

    PubMed

    Anisef, Paul; Brown, Robert S; Phythian, Kelli; Sweet, Robert; Walters, David

    2010-05-01

    While education statistics confirm that there is little difference in the dropout rates of native-born and immigrant youth, analyses of Toronto District School Board (TDSB) data have revealed significant variation in school persistence within immigrant groups. Among newcomer youth, the decision to leave school early has been reported to be strongly influenced by socioeconomic status as well as such factors as country of origin, age at arrival, generational status, family structure, and academic performance. While living in low-income conditions is thought to place both foreign- and Canadian-born youth at risk of poor school performance and early school withdrawal, their substantially higher incidence of poverty suggests that today's immigrant youth are likely to face greater obstacles to academic success that may in turn have detrimental, long-term consequences. This paper uses TDSB data to investigate the extent to which living below the low-income cutoff affects the likelihood of dropping out of secondary school, while taking into account generational status as well as a variety risk factors, noted above. Policy implications are discussed.

  4. Data base for early postfire succession in Northern Rocky Mountain forests

    Treesearch

    Peter F. Stickney; Robert B. Campbell

    2000-01-01

    Web site and CD-ROM include 21 pages of text plus electronic data for 55 succession sites including color plates, tables, and figures. Provides data on quantitative postfire changes of plant species and forest vegetation components for up to the first 25 years of secondary plant succession for 55 forest sites in northern Idaho and northwestern Montana. Cover (aerial...

  5. Effects of Interannual Climate Variability in Secondary Forests and Crops Under Traditional and Alternative Shifting Cultivation

    NASA Astrophysics Data System (ADS)

    Sa, T. D.; Guild, L. S.; Carvalho, C. J.; Potter, C. S.; Wickel, A. J.; Brienza, S.; Kato, M. A.; Kato, O.

    2002-12-01

    Regenerating forests play an important role in long-term carbon sequestration and sustainable landuse as they act as potentially important carbon and nutrient sinks during the shifting agriculture fallow period. The long-term functioning of secondary forests (capoeira) is increasingly threatened by a shortening fallow period during shifting cultivation due to demographic pressures and associated increased vulnerability to severe climatic events. Declining productivity and functioning of fallow forests of shifting cultivation combined with progressive loss of nutrients by successive burning and cropping activities has resulted in declining agricultural productivity. In addition to the effects of intense land use practices, droughts associated with El Ni¤o events are becoming more frequent and severe in moist tropical forests and negative effects on capoeira productivity could be considerable. In Igarape-Acu (near Belem, Para), we hypothesize that experimental alternative landuse/clearing practices (mulching and fallow vegetation improvement by planting with fast-growing leguminous tree species) may make capoeira and crops more resilient to the effects of agricultural pressures and drought through 1) increased biomass, soil organic matter and associated increase in soil water storage, and nutrient retention and 2) greater rooting depth of trees planted for fallow improvement. This experimental practice (mechanized chop-and-mulch with fallow improvement) has resulted in increased soil moisture during the cropping phase, reduced loss of nutrients and organic matter, and higher rates of secondary-forest biomass accumulation. We present preliminary data on water relations during the dry season of 2001 in capoeira and crops for both traditional slash-and-burn and alternative chop-and-mulch practices. These data will be used to test IKONOS data for the detection of moisture status differences. The principal goal of the research is to determine the extent to which capoeira

  6. Quantitative classification and environmental interpretation of secondary forests 18 years after the invasion of pine forests by Bursaphelenchus xylophilus (Nematoda: Aphelenchoididae) in China.

    PubMed

    Wang, Zhuang; Luo, You-Qing; Shi, Juan; Gao, Ruihe; Wang, Guoming

    2014-01-01

    With growing concerns over the serious ecological problems in pine forests (Pinus massoniana, P. thunbergii) caused by the invasion of Bursaphelenchus xylophilus (the pine wood nematode), a particular challenge is to determine the succession and restoration of damaged pine forests in Asia. We used two-way indicator species analysis and canonical correlation analysis for the hierarchical classification of existing secondary forests that have been restored since the invasion of B. xylophilus 18 years ago. Biserial correlation analysis was used to relate the spatial distribution of species to environmental factors. After 18 years of natural recovery, the original pine forest had evolved into seven types of secondary forest. Seven environmental factors, namely soil depth, humus depth, soil pH, aspect, slope position, bare rock ratio, and distance to the sea, were significantly correlated with species distribution. Furthermore, we proposed specific reform measures and suggestions for the different types of secondary forest formed after the damage and identified the factors driving the various forms of restoration. These results suggest that it is possible to predict the restoration paths of damaged pine forests, which would reduce the negative impact of B. xylophilus invasions.

  7. Root depth and morphology in response to soil drought: comparing ecological groups along the secondary succession in a tropical dry forest.

    PubMed

    Paz, Horacio; Pineda-García, Fernando; Pinzón-Pérez, Luisa F

    2015-10-01

    Root growth and morphology may play a core role in species-niche partitioning in highly diverse communities, especially along gradients of drought risk, such as that created along the secondary succession of tropical dry forests. We experimentally tested whether root foraging capacity, especially at depth, decreases from early successional species to old-growth forest species. We also tested for a trade-off between two mechanisms for delaying desiccation, the capacity to forage deeper in the soil and the capacity to store water in tissues, and explored whether successional groups separate along such a trade-off. We examined the growth and morphology of roots in response to a controlled-vertical gradient of soil water, among seedlings of 23 woody species dominant along the secondary succession in a tropical dry forest of Mexico. As predicted, successional species developed deeper and longer root systems than old-growth forest species in response to soil drought. In addition, shallow root systems were associated with high plant water storage and high water content per unit of tissue in stems and roots, while deep roots exhibited the opposite traits, suggesting a trade-off between the capacities for vertical foraging and water storage. Our results suggest that an increased capacity of roots to forage deeper for water is a trait that enables successional species to establish under the warm-dry conditions of the secondary succession, while shallow roots, associated with a higher water storage capacity, are restricted to the old-growth forest. Overall, we found evidence that the root depth-water storage trade-off may constrain tree species distribution along secondary succession.

  8. Modeling transcriptional networks regulating secondary growth and wood formation in forest trees.

    PubMed

    Liu, Lijun; Filkov, Vladimir; Groover, Andrew

    2014-06-01

    The complex interactions among the genes that underlie a biological process can be modeled and presented as a transcriptional network, in which genes (nodes) and their interactions (edges) are shown in a graphical form similar to a wiring diagram. A large number of genes have been identified that are expressed during the radial woody growth of tree stems (secondary growth), but a comprehensive understanding of how these genes interact to influence woody growth is currently lacking. Modeling transcriptional networks has recently been made tractable by next-generation sequencing-based technologies that can comprehensively catalog gene expression and transcription factor-binding genome-wide, but has not yet been extensively applied to undomesticated tree species or woody growth. Here we discuss basic features of transcriptional networks, approaches for modeling biological networks, and examples of biological network models developed for forest trees to date. We discuss how transcriptional network research is being developed in the model forest tree genus, Populus, and how this research area can be further developed and applied. Transcriptional network models for forest tree secondary growth and wood formation could ultimately provide new predictive models to accelerate hypothesis-driven research and develop new breeding applications. © 2013 Scandinavian Plant Physiology Society.

  9. Mapping Historic Gypsy Moth Defoliation with MODIS Satellite Data: Implications for Forest Threat Early Warning System

    NASA Technical Reports Server (NTRS)

    Spurce, Joseph P.; Hargrove, William; Ryan, Robert E.; Smooth, James C.; Prados, Don; McKellip, Rodney; Sader, Steven A.; Gasser, Jerry; May, George

    2008-01-01

    This viewgraph presentation reviews a project, the goal of which is to study the potential of MODIS data for monitoring historic gypsy moth defoliation. A NASA/USDA Forest Service (USFS) partnership was formed to perform the study. NASA is helping USFS to implement satellite data products into its emerging Forest Threat Early Warning System. The latter system is being developed by the USFS Eastern and Western Forest Threat Assessment Centers. The USFS Forest Threat Centers want to use MODIS time series data for regional monitoring of forest damage (e.g., defoliation) preferably in near real time. The study's methodology is described, and the results of the study are shown.

  10. Typhoon Haiyan's Effects on Interception Loss from a Secondary Tropical Forest near Tacloban, Leyte, the Philippines

    NASA Astrophysics Data System (ADS)

    Zhang, J.; van Meerveld, I. H. J.; Waterloo, M. J.; Bruijnzeel, L. A., Sr.

    2015-12-01

    Typhoon Haiyan made landfall in the central Philippines on November 8, 2013 as one of the strongest tropical cyclones ever recorded with maximum wind speed of 314 km h-1. It affected humans, infrastructure and forests, including the 22-year-old community-managed secondary forest at Manobo near Tacloban on Leyte island. As part of a larger investigation of the impacts of secondary forests on streamflow, gross rainfall (P), throughfall (TF) and stemflow (SF) were monitored between June 2013 and June 2014 using 2 tipping bucket rainfall gauges, 2 large (200 cm by 30 cm) throughfall gutters connected to tipping buckets, 24 roving throughfall gauges (491 cm2 each) and 12 stemflow collectors. Leaf Area Index (LAI) above each of the throughfall collectors was measured regularly using a Canopy Analyzer. Average throughfall, stemflow, and interception losses (I) were determined for three different periods:(i) pre-Haiyan (reference), (ii) damaged canopy post Haiyan, and (iii) recovered canopy. Before the forest was disturbed, cumulate TF/P, SF/P and I/P ratios and their standard error were 80.79 , 1.00 and 18.21 , respectively. During the period with the damaged canopy, the respective ratios were 90.89, 0.82 and 0.75, while 3 months after the passage of Haiyan the forest canopy had recovered more or less in terms of leaf surface area with cumulate TF/P, SF/P and I/P ratios of 87.86, 0.75,and 11.39, respectively. The respective trends reflected the changes in LAI, which dropped from 5.24 ± 0.79 to 3.80 ± 0.80 right after Haiyan, recuperating to 4.69 ± 0.62 after recovery. These changes in rainfall partitioning after typhoon Haiyan are less pronounced than those reported previously for hurricane-affected forests in the Caribbean and the Pacific, possibly because the Manobo forest was relatively sheltered topographically.

  11. Diversity and composition of tropical secondary forests recovering from large-scale clearing : results from the 1990 inventory in Puerto Rico

    Treesearch

    J. Danilo Chinea; Eileen H. Helmer

    2003-01-01

    The extensive recovery from agricultural clearing of Puerto Rican forests over the past half-century provides a good opportunity to study tropical forest recovery on a landscape scale. Using ordination and regression techniques, we analyzed forest inventory data from across Puerto Rico’s moist and wet secondary forests to evaluate their species composition and whether...

  12. Diversity and composition of tropical secondary forests recovering from large-scale clearing: results from the 1990 inventory in Puerto Rico.

    Treesearch

    J. Danilo Chinea; Eileen H. Helmer

    2003-01-01

    The extensive recovery from agricultural clearing of Puerto Rican forests over the past half-century provides a good opportunity to study tropical forest recovery on a landscape scale. Using ordination and regression techniques, we analyzed forest inventory data from across Puerto Rico’s moist and wet secondary forests to evaluate their species composition and whether...

  13. Surficial gains and subsoil losses of soil carbon and nitrogen during secondary forest development.

    PubMed

    Mobley, Megan L; Lajtha, Kate; Kramer, Marc G; Bacon, Allan R; Heine, Paul R; Richter, Daniel Deb

    2015-02-01

    Reforestation of formerly cultivated land is widely understood to accumulate above- and belowground detrital organic matter pools, including soil organic matter. However, during 40 years of study of reforestation in the subtropical southeastern USA, repeated observations of above- and belowground carbon documented that significant gains in soil organic matter (SOM) in surface soils (0-7.5 cm) were offset by significant SOM losses in subsoils (35-60 cm). Here, we extended the observation period in this long-term experiment by an additional decade, and used soil fractionation and stable isotopes and radioisotopes to explore changes in soil organic carbon and soil nitrogen that accompanied nearly 50 years of loblolly pine secondary forest development. We observed that accumulations of mineral soil C and N from 0 to 7.5 cm were almost entirely due to accumulations of light-fraction SOM. Meanwhile, losses of soil C and N from mineral soils at 35 to 60 cm were from SOM associated with silt and clay-sized particles. Isotopic signatures showed relatively large accumulations of forest-derived carbon in surface soils, and little to no accumulation of forest-derived carbon in subsoils. We argue that the land use change from old field to secondary forest drove biogeochemical and hydrological changes throughout the soil profile that enhanced microbial activity and SOM decomposition in subsoils. However, when the pine stands aged and began to transition to mixed pines and hardwoods, demands on soil organic matter for nutrients to support aboveground growth eased due to pine mortality, and subsoil organic matter levels stabilized. This study emphasizes the importance of long-term experiments and deep measurements when characterizing soil C and N responses to land use change and the remarkable paucity of such long-term soil data deeper than 30 cm. © 2014 John Wiley & Sons Ltd.

  14. Encouraging family forest owners to create early successional wildlife habitat in Southern New England.

    PubMed

    Buffum, Bill; Modisette, Christopher; McWilliams, Scott R

    2014-01-01

    Encouraging family forest owners to create early successional habitat is a high priority for wildlife conservation agencies in the northeastern USA, where most forest land is privately owned. Many studies have linked regional declines in wildlife populations to the loss of early successional habitat. The government provides financial incentives to create early successional habitat, but the number of family forest owners who actively manage their forests remains low. Several studies have analyzed participation of family forest owners in federal forestry programs, but no study to date has focused specifically on creation of wildlife habitat. The objective of our study was to analyze the experience of a group of wildlife-oriented family forest owners who were trained to create early successional habitat. This type of family forest owners represents a small portion of the total population of family forest owners, but we believe they can play an important role in creating wildlife habitat, so it is important to understand how outreach programs can best reach them. The respondents shared some characteristics but differed in terms of forest holdings, forestry experience and interest in earning forestry income. Despite their strong interest in wildlife, awareness about the importance of early successional habitat was low. Financial support from the federal government appeared to be important in motivating respondents to follow up after the training with activities on their own properties: 84% of respondents who had implemented activities received federal financial support and 47% would not have implemented the activities without financial assistance. In order to mobilize greater numbers of wildlife-oriented family forest owners to create early successional habitat we recommend focusing outreach efforts on increasing awareness about the importance of early successional habitat and the availability of technical and financial assistance.

  15. Encouraging Family Forest Owners to Create Early Successional Wildlife Habitat in Southern New England

    PubMed Central

    Buffum, Bill; Modisette, Christopher; McWilliams, Scott R.

    2014-01-01

    Encouraging family forest owners to create early successional habitat is a high priority for wildlife conservation agencies in the northeastern USA, where most forest land is privately owned. Many studies have linked regional declines in wildlife populations to the loss of early successional habitat. The government provides financial incentives to create early successional habitat, but the number of family forest owners who actively manage their forests remains low. Several studies have analyzed participation of family forest owners in federal forestry programs, but no study to date has focused specifically on creation of wildlife habitat. The objective of our study was to analyze the experience of a group of wildlife-oriented family forest owners who were trained to create early successional habitat. This type of family forest owners represents a small portion of the total population of family forest owners, but we believe they can play an important role in creating wildlife habitat, so it is important to understand how outreach programs can best reach them. The respondents shared some characteristics but differed in terms of forest holdings, forestry experience and interest in earning forestry income. Despite their strong interest in wildlife, awareness about the importance of early successional habitat was low. Financial support from the federal government appeared to be important in motivating respondents to follow up after the training with activities on their own properties: 84% of respondents who had implemented activities received federal financial support and 47% would not have implemented the activities without financial assistance. In order to mobilize greater numbers of wildlife-oriented family forest owners to create early successional habitat we recommend focusing outreach efforts on increasing awareness about the importance of early successional habitat and the availability of technical and financial assistance. PMID:24587160

  16. Tennessee's forest land area was stable 1999-2005 but early successional forest area declined

    Treesearch

    Christopher M. Oswalt

    2008-01-01

    A new analysis of the most recent (2005) annualized moving average data for Tennessee indicates that the area of forest land in the State remained stable between 1999 and 2005. Although trends in forest land area vary from region to region within the State, Tennessee neither lost nor gained forest land between 1999 and 2005. However, Tennessee had more than 2.5 times...

  17. Assessing Potential of VIIRS Data for Contribution to a Forest Threat Early Warning System

    NASA Technical Reports Server (NTRS)

    Spruce, Joseph P.

    2007-01-01

    This viewgraph presentation reviews the contributions by the Rapid Prototyping Capability (RPC) towards using Visible Infrared Imager / Radiometer Suite (VIIRS) data in assessing the damage to forests. The Healthy Forest Restoration Act of 2003 mandates development of national Early Warning System (EWS) for forest threat monitoring and mitigation. NASA Stennis is working with the US Forest Service to develop needed components of this EWS. The use of MODIS data for monitoring forest disturbance at broad regional scales is a componet of this program. This RPC experiment was initiated to assess potential of the MODIS follow-on, VIIRS, for monitoring forest disturbance at broad scales and thereby contributing to the EWS. This presentation reviews the potential use of the VIIRS to examine the damage to forests caused by gyspy moths in the West Virginia and Virginia area.

  18. Early positive effects of tree species richness on herbivory in a large-scale forest biodiversity experiment influence tree growth.

    PubMed

    Schuldt, Andreas; Bruelheide, Helge; Härdtle, Werner; Assmann, Thorsten; Li, Ying; Ma, Keping; von Oheimb, Goddert; Zhang, Jiayong

    2015-05-01

    Despite the importance of herbivory for the structure and functioning of species-rich forests, little is known about how herbivory is affected by tree species richness, and more specifically by random vs. non-random species loss. We assessed herbivore damage and its effects on tree growth in the early stage of a large-scale forest biodiversity experiment in subtropical China that features random and non-random extinction scenarios of tree mixtures numbering between one and 24 species. In contrast to random species loss, the non-random extinction scenarios were based on the tree species' local rarity and specific leaf area - traits that may strongly influence the way herbivory is affected by plant species richness. Herbivory increased with tree species richness across all scenarios and was unaffected by the different species compositions in the random and non-random extinction scenarios. Whereas tree growth rates were positively related to herbivory on plots with smaller trees, growth rates significantly declined with increasing herbivory on plots with larger trees. Our results suggest that the effects of herbivory on growth rates increase from monocultures to the most species-rich plant communities and that negative effects with increasing tree species richness become more pronounced with time as trees grow larger. Synthesis. Our results indicate that key trophic interactions can be quick to become established in forest plantations (i.e. already 2.5 years after tree planting). Stronger herbivory effects on tree growth with increasing tree species richness suggest a potentially important role of herbivory in regulating ecosystem functions and the structural development of species-rich forests from the very start of secondary forest succession. The lack of significant differences between the extinction scenarios, however, contrasts with findings from natural forests of higher successional age, where rarity had negative effects on herbivory. This indicates that the

  19. Early positive effects of tree species richness on herbivory in a large-scale forest biodiversity experiment influence tree growth

    PubMed Central

    Schuldt, Andreas; Bruelheide, Helge; Härdtle, Werner; Assmann, Thorsten; Li, Ying; Ma, Keping; von Oheimb, Goddert; Zhang, Jiayong

    2015-01-01

    Despite the importance of herbivory for the structure and functioning of species-rich forests, little is known about how herbivory is affected by tree species richness, and more specifically by random vs. non-random species loss. We assessed herbivore damage and its effects on tree growth in the early stage of a large-scale forest biodiversity experiment in subtropical China that features random and non-random extinction scenarios of tree mixtures numbering between one and 24 species. In contrast to random species loss, the non-random extinction scenarios were based on the tree species’ local rarity and specific leaf area – traits that may strongly influence the way herbivory is affected by plant species richness. Herbivory increased with tree species richness across all scenarios and was unaffected by the different species compositions in the random and non-random extinction scenarios. Whereas tree growth rates were positively related to herbivory on plots with smaller trees, growth rates significantly declined with increasing herbivory on plots with larger trees. Our results suggest that the effects of herbivory on growth rates increase from monocultures to the most species-rich plant communities and that negative effects with increasing tree species richness become more pronounced with time as trees grow larger. Synthesis. Our results indicate that key trophic interactions can be quick to become established in forest plantations (i.e. already 2.5 years after tree planting). Stronger herbivory effects on tree growth with increasing tree species richness suggest a potentially important role of herbivory in regulating ecosystem functions and the structural development of species-rich forests from the very start of secondary forest succession. The lack of significant differences between the extinction scenarios, however, contrasts with findings from natural forests of higher successional age, where rarity had negative effects on herbivory. This indicates that

  20. Do mature forest birds prefer early-successional habitat during the post-fledging period?

    Treesearch

    Carlin C. Chandler; David I. King; Richard B. Chandler

    2012-01-01

    Recent studies have highlighted the importance of the post-fledging period to bird populations, suggesting that the importance of this portion of the life cycle is equal to or greater than the nesting period. Nevertheless, few studies have compared abundance of forest nesting species between mature forest and early-successional habitats while controlling for...

  1. Do natural disturbances or the forestry practices that follow them convert forests to early successional communities?

    Treesearch

    J. Stephen Brewer; Christine Bertz; Jeffery B. Cannon; Jason D. Chesser; Erynn E. Maynard

    2012-01-01

    Stand-replacing natural disturbances in mature forests are traditionally seen as events that cause forests to revert to early stages of succession and maintain species diversity. In some cases, however, such transitions could be an artifact of salvage logging and may increase biotic homogenization. We present initial (two-year) results of a study of the effects of...

  2. Productivity of early successional shrubland birds in clearcuts and groupcuts in an eastern deciduous forest

    Treesearch

    David I. King; Richard M. DeGraaf; Curtice R. Griffin

    2001-01-01

    Uneven-aged forest management has been advocated as a silvicultural practice because of concerns about the negative effects of even-aged management on birds that dwell in mature forests. Recent evidence, however, indicates that in the northeastern United States, bird species that inhabit early successional habitats may be experiencing more widespread declines than...

  3. Functional groups show distinct differences in nitrogen cycling during early stand development: implications for forest management

    Treesearch

    Doug P. Aubrey; David R. Coyle; Mark D. Coleman

    2012-01-01

    Background and aims Nutrient acquisition of forest stands is controlled by soil resource availability and belowground production, but tree species are rarely compared in this regard. Here, we examine ecological and management implications of nitrogen (N) dynamics during early forest stand development in productive commercial tree species with narrow (Populus...

  4. Variation In Early-Successional Habitat Use Among Independent Juvenile Forest Breeding Birds

    Treesearch

    Alicia D. Burke; Frank R. Thompson; John Faaborg

    2017-01-01

    Adults and juveniles of some forest breeding birds shift habitat use during the post breeding season from late to early successional forest. Juveniles of smaller passerine species are difficult to radio-track, and there is limited information on their habitat preferences, especially once they become older and independent. We determined if independent hatch-year birds...

  5. Early northern hardwood silvicultural research at the Dukes Experimental Forest, Michigan

    Treesearch

    Laura S. Kenefic; Christel C. Kern

    2015-01-01

    Commercial lumber production in the Lake States, which began in the early 1800s with eastern white pine (Pinus strobus L.), shifted to hardwoods in the late 1800s (Whitney 1994). Much of the hardwood forest was rapidly cut over; as a consequence, mill capacity exceeded available stumpage by the 1920s (Eyre and Zillgitt 1953). The forest industry...

  6. Substantial secondary organic aerosol formation in a coniferous forest: observations of both day- and nighttime chemistry

    NASA Astrophysics Data System (ADS)

    Lee, Alex K. Y.; Abbatt, Jonathan P. D.; Leaitch, W. Richard; Li, Shao-Meng; Sjostedt, Steve J.; Wentzell, Jeremy J. B.; Liggio, John; Macdonald, Anne Marie

    2016-06-01

    Substantial biogenic secondary organic aerosol (BSOA) formation was investigated in a coniferous forest mountain region in Whistler, British Columbia. A largely biogenic aerosol growth episode was observed, providing a unique opportunity to investigate BSOA formation chemistry in a forested environment with limited influence from anthropogenic emissions. Positive matrix factorization of aerosol mass spectrometry (AMS) measurement identified two types of BSOA (BSOA-1 and BSOA-2), which were primarily generated by gas-phase oxidation of monoterpenes and perhaps sesquiterpenes. The temporal variations of BSOA-1 and BSOA-2 can be explained by gas-particle partitioning in response to ambient temperature and the relative importance of different oxidation mechanisms between day and night. While BSOA-1 arises from gas-phase ozonolysis and nitrate radical chemistry at night, BSOA-2 is likely less volatile than BSOA-1 and consists of products formed via gas-phase oxidation by OH radical and ozone during the day. Organic nitrates produced through nitrate radical chemistry can account for 22-33 % of BSOA-1 mass at night. The mass spectra of BSOA-1 and BSOA-2 have higher values of the mass fraction of m/z 91 (f91) compared to the background organic aerosol. Using f91 to evaluate BSOA formation pathways in this unpolluted, forested region, heterogeneous oxidation of BSOA-1 is a minor production pathway of BSOA-2.

  7. The long-term effects of planting and harvesting on secondary forest dynamics under climate change in northeastern China

    PubMed Central

    Yao, Jing; He, Xingyuan; He, Hongshi; Chen, Wei; Dai, Limin; Lewis, Bernard J.; Yu, Lizhong

    2016-01-01

    Unlike the virgin forest in the Changbaishan Nature Reserve in northeastern China, little research on a landscape scale has been conducted on secondary forests in the region under conditions of a warming climate. This research was undertaken in the upper Hun River region where the vegetation is representative of the typical secondary forest of northeastern China. The spatially explicit forest landscape model LANDIS was utilized to simulate the responses of forest restoration dynamics to anthropogenic disturbance (planting and harvesting) and evaluate the difference of the restoration process under continuation of current climatic conditions and climate warming. The results showed that: (1) The interaction of planting and harvesting has organizational scale effects on the forest. The combination of planting and harvesting policies has significant effects on the overall forest but not on individual species. (2) The area expansion of the historically dominant species Pinus koraiensis is less under climate warming than under continuation of current climatic conditions. These suggests that we should carefully take historically dominant species as the main focus for forest restoration, especially when they are near their natural distribution boundary, because they are probably less capable of successfully adapting to climate change. PMID:26725308

  8. The long-term effects of planting and harvesting on secondary forest dynamics under climate change in northeastern China.

    PubMed

    Yao, Jing; He, Xingyuan; He, Hongshi; Chen, Wei; Dai, Limin; Lewis, Bernard J; Yu, Lizhong

    2016-01-04

    Unlike the virgin forest in the Changbaishan Nature Reserve in northeastern China, little research on a landscape scale has been conducted on secondary forests in the region under conditions of a warming climate. This research was undertaken in the upper Hun River region where the vegetation is representative of the typical secondary forest of northeastern China. The spatially explicit forest landscape model LANDIS was utilized to simulate the responses of forest restoration dynamics to anthropogenic disturbance (planting and harvesting) and evaluate the difference of the restoration process under continuation of current climatic conditions and climate warming. The results showed that: (1) The interaction of planting and harvesting has organizational scale effects on the forest. The combination of planting and harvesting policies has significant effects on the overall forest but not on individual species. (2) The area expansion of the historically dominant species Pinus koraiensis is less under climate warming than under continuation of current climatic conditions. These suggests that we should carefully take historically dominant species as the main focus for forest restoration, especially when they are near their natural distribution boundary, because they are probably less capable of successfully adapting to climate change.

  9. The long-term effects of planting and harvesting on secondary forest dynamics under climate change in northeastern China

    NASA Astrophysics Data System (ADS)

    Yao, Jing; He, Xingyuan; He, Hongshi; Chen, Wei; Dai, Limin; Lewis, Bernard J.; Yu, Lizhong

    2016-01-01

    Unlike the virgin forest in the Changbaishan Nature Reserve in northeastern China, little research on a landscape scale has been conducted on secondary forests in the region under conditions of a warming climate. This research was undertaken in the upper Hun River region where the vegetation is representative of the typical secondary forest of northeastern China. The spatially explicit forest landscape model LANDIS was utilized to simulate the responses of forest restoration dynamics to anthropogenic disturbance (planting and harvesting) and evaluate the difference of the restoration process under continuation of current climatic conditions and climate warming. The results showed that: (1) The interaction of planting and harvesting has organizational scale effects on the forest. The combination of planting and harvesting policies has significant effects on the overall forest but not on individual species. (2) The area expansion of the historically dominant species Pinus koraiensis is less under climate warming than under continuation of current climatic conditions. These suggests that we should carefully take historically dominant species as the main focus for forest restoration, especially when they are near their natural distribution boundary, because they are probably less capable of successfully adapting to climate change.

  10. Sources of variation in foliar secondary chemistry in a tropical forest tree community.

    PubMed

    Sedio, Brian E; Rojas Echeverri, Juan C; Boya P, Cristopher A; Wright, S Joseph

    2017-03-01

    Specialist herbivores and pathogens could induce negative conspecific density dependence among their hosts and thereby contribute to the diversity of plant communities. A small number of hyperdiverse genera comprise a large portion of tree diversity in tropical forests. These closely related congeners are likely to share natural enemies. Diverse defenses could still allow congeners to partition niche space defined by natural enemies, but interspecific differences in defenses would have to exceed intraspecific variation in defenses. We ask whether interspecific variation in secondary chemistry exceeds intraspecific variation for species from four hyperdiverse tropical tree genera. We used novel methods to quantify chemical structural similarity for all compounds present in methanol extracts of leaf tissue. We sought to maximize intraspecific variation by selecting conspecific leaves from different ontogenetic stages (expanding immature vs. fully hardened mature), different light environments (deep understory shade vs. large forest gaps), and different seasons (dry vs. wet). Chemical structural similarity differed with ontogeny, light environment, and season, but interspecific differences including those among congeneric species were much larger. Our results suggest that species differences in secondary chemistry are large relative to within-species variation, perhaps sufficiently large to permit niche segregation among congeneric tree species based on chemical defenses.

  11. Distribution of bioluminescent fungi across old-growth and secondary tropical rain forest in Costa Rica.

    PubMed

    Seas-Carvajal, Carolina; Avalos, Gerardo

    2013-06-01

    Most research on bioluminescent fungi is concentrated on their taxonomic relationships, while the basics of their natural history and ecological relationships are poorly understood. In this study, we compared the distribution of bioluminescent fungi between old-growth and secondary forest as related to four different soil types at the tropical rainforest of La Selva Biological Station in Costa Rica. The study was conducted during the wet season of 2009. Bioluminescent fungi were sought following eight different transects distributed evenly in old-growth and secondary forests across four different soil types, covering an area of 9 420m2. We found fungi in four different substrates: litter, fallen branches, dead trunks, and roots, for a total of 61 samples. Correspondence analysis showed that the occurrence of fungi and soil types were related (inertia = 0.21, p = 0.071). We found a significant relationship between the presence of fungi and the distribution of soil types (X2 = 18.89, df = 9, p = 0.026). We found only three samples with fruiting bodies, two of which had Mycena and the other had one fungus of the order Xylariales (possibly Hypoxylon sp., Kretzschmariella sp., Xylaria sp.). Future work will concentrate on exploring other aspects of their ecology, such as their dispersal and substrate preference. This information will facilitate field identification and will foster more research on the distribution, seasonality, reproductive phenology and ecological requirements of this group of Fungi.

  12. [Dynamics of soil properties under secondary succession forest communities in Mt. Jinyun].

    PubMed

    Liu, Hongyan; Huang, Jianguo

    2005-11-01

    Mt. Jinyun is located in the north suburb of Chongqing, 30 km away from the city center. It is rich in forest plants, an epitome of forests in north tropical areas of China. Under anthropocentric disturbance, there still exist large numbers of succession communities, and the process of successive development follows the way of shrub-grassland (X1)-->coniferous forest (X2)-->coniferous-broad leaved mixed forest (X3)-->evergreen broad-leaved forest (X4). By now, soil and water conservation is very important in the Three Gorges area of Yangtze River, and the investigation on the secondary succession of the forests could help to realize the changes of the forests and soils under anthropocentric disturbance, and supply information on the protection of natural forests and the artificial reforestation of this area. In this paper, some typical and representative plant communities in different succession stages were selected to study the plant composition and type and the soil properties, with species diversity indices and canopy density investigated in many standard squares and soil physical and chemical characteristics analyzed. The results showed that there were obvious variations of soil properties with time. As the plant community developed from primary stage to climax, the contents of soil organic matter, total N, and available N and K increased in order of X1 < X2 < X3 < X4, soil pH changed from 5.23 (X1) to 4.06 (X4), soil base saturation varied from 58.3% (X1) to 37.7% (X4), and soil CEC increased with the succession. It was suggested that an intense soil acid leaching was occurred in Mt. Jinyun. The contents of soil organic matter and total N in different layers showed a trend of A>B>C, e. g., soil total nitrogen in evergreen broad leaved forest was 2.31(A), 0.66(B) and 0.12(C)g x kg(-1). Gray analysis was used to study the relationships of soil properties between the climax community and other three succession communities. The relation coefficient was 0.461 0 (X3

  13. [Regeneration characteristics and related affecting factors of Pinus tabulaeformis secondary forests in Qinling Mountains].

    PubMed

    Kang, Bing; Wang, De-xiang; Cui, Hong-an; Di, Wei-zhi; Du, Yan-ling

    2011-07-01

    The study with sampling plot method showed that in Pinus tabulaeformis secondary forests in Qinling Mountains, there were 36 tree species in regeneration layer, occupying 51.4% of the total. The dominant species were Quercus glandulifera, Quercus aliena var. acuteserrata, and Corylus heterophylla. The seedling bank was abundant, and with lower height class and age class. The main regeneration type was seedling, showing the forest being at its middle succession period. Stand density had significant effects on sapling and seedling densities (P<0.01). The sapling and seedling densities increased when the stand density increased from 580 trees x hm(-2) up to 1500 trees x hm(-2), but decreased with the further increase of stand density. Slope aspect also had significant effects on the seedling and sapling densities (P<0.05). The sapling density decreased gradually when the slope aspect changed from SW10 degrees to SW40 degrees, but increased with the slope aspect changed to shady slope (NE10 degrees). The forest regeneration characteristics differed at different slope positions, with the sapling and seedling densities being relatively higher in flat stand. From foot to top, the seedling density decreased, while the sapling density increased. The sapling density increased from the altitude 1159 m up to 1449 m but decreased from 1449 m up to 1658 m, while the seedling density all along had an increasing trend from lower altitude to higher altitude. It was suggested that the medium stand density on shady slope had the best natural regeneration. To rationally regulate stand density could be an effective way to accelerate the regeneration process of P. tabulaeformis forest.

  14. Spatial pattern of atmospherically deposited radiocesium on the forest floor in the early phase of the Fukushima Daiichi Nuclear Power Plant accident.

    PubMed

    Kato, Hiroaki; Onda, Yuichi; Wakahara, Taeko; Kawamori, Ayumi

    2017-09-29

    Spatial patterns of atmospherically deposited radiocesium on the forest floor and the temporal evolution were measured in two Japanese cedar stands and a secondary mixed broad-leaved forest in the early phase of the Fukushima Daiichi Nuclear Power Plant accident. In situ measurements of the (137)Cs gamma count were made using a portable germanium gamma ray detector. These measurements revealed that the forest floors were contaminated with radionuclides derived from the accident. In the cedar stands, the inter-canopy area had higher (137)Cs count rate relative to the under-canopy area, whereas no clear relationship was found between the radiocesium pattern and canopy cover in the mixed broad-leaved forest. Repeated radiocesium measurements revealed that the spatial pattern of radiocesium activity on the forest floor did not substantially change following additional deposition inputs. Furthermore, the magnitude of canopy cover partially explained spatial variability of the (137)Cs on the forest floor in cedar stands. These results suggest that canopy structure affected the genesis of the horizontal variability of atmospherically deposited radiocesium on the forest floor during the early phase of the Fukushima accident. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Impact of a drier Early-Mid-Holocene climate upon Amazonian forests.

    PubMed

    Mayle, Francis E; Power, Mitchell J

    2008-05-27

    This paper uses a palaeoecological approach to examine the impact of drier climatic conditions of the Early-Mid-Holocene (ca 8000-4000 years ago) upon Amazonia's forests and their fire regimes. Palaeovegetation (pollen data) and palaeofire (charcoal) records are synthesized from 20 sites within the present tropical forest biome, and the underlying causes of any emergent patterns or changes are explored by reference to independent palaeoclimate data and present-day patterns of precipitation, forest cover and fire activity across Amazonia. During the Early-Mid-Holocene, Andean cloud forest taxa were replaced by lowland tree taxa as the cloud base rose while lowland ecotonal areas, which are presently covered by evergreen rainforest, were instead dominated by savannahs and/or semi-deciduous dry forests. Elsewhere in the Amazon Basin there is considerable spatial and temporal variation in patterns of vegetation disturbance and fire, which probably reflects the complex heterogeneous patterns in precipitation and seasonality across the basin, and the interactions between climate change, drought- and fire susceptibility of the forests, and Palaeo-Indian land use. Our analysis shows that the forest biome in most parts of Amazonia appears to have been remarkably resilient to climatic conditions significantly drier than those of today, despite widespread evidence of forest burning. Only in ecotonal areas is there evidence of biome replacement in the Holocene. From this palaeoecological perspective, we argue against the Amazon forest 'dieback' scenario simulated for the future.

  16. Propagules of arbuscular mycorrhizal fungi in a secondary dry forest of Oaxaca, Mexico.

    PubMed

    Guadarrama, Patricia; Castillo-Argüero, Silvia; Ramos-Zapata, José A; Camargo-Ricalde, Sara L; Alvarez-Sánchez, Javier

    2008-03-01

    Plant cover loss due to changes in land use promotes a decrease in spore diversity of arbuscular mycorrhizal fungi (AMF), viable mycelium and, therefore, in AMF colonization, this has an influence in community diversity and, as a consequence, in its recovery. To evaluate different AMF propagules, nine plots in a tropical dry forest with secondary vegetation were selected: 0, 1, 7, 10, 14, 18, 22, 25, and 27 years after abandonment in Nizanda, Oaxaca, Mexico. The secondary vegetation with different stages of development is a consequence of slash and burn agriculture, and posterior abandonment. Soil samples (six per plot) were collected and percentage of AMF field colonization, extrarradical mycelium, viable spore density, infectivity and most probable number (MPN) ofAMF propagules were quantified through a bioassay. Means for field colonization ranged between 40% and 70%, mean of total mycelium length was 15.7 +/- 1.88 mg(-1) dry soil, with significant differences between plots; however, more than 40% of extracted mycelium was not viable, between 60 and 456 spores in 100 g of dry soil were recorded, but more than 64% showed some kind of damage. Infectivity values fluctuated between 20% and 50%, while MPN showed a mean value of 85.42 +/- 44.17 propagules (100 g dry soil). We conclude that secondary communities generated by elimination of vegetation with agricultural purposes in a dry forest in Nizanda do not show elimination of propagules, probably as a consequence of the low input agriculture practices in this area, which may encourage natural regeneration.

  17. Aboveground-belowground biodiversity linkages differ in early and late successional temperate forests

    PubMed Central

    Li, Hui; Wang, Xugao; Liang, Chao; Hao, Zhanqing; Zhou, Lisha; Ma, Sam; Li, Xiaobin; Yang, Shan; Yao, Fei; Jiang, Yong

    2015-01-01

    Understanding ecological linkages between above- and below-ground biota is critical for deepening our knowledge on the maintenance and stability of ecosystem processes. Nevertheless, direct comparisons of plant-microbe diversity at the community level remain scarce due to the knowledge gap between microbial ecology and plant ecology. We compared the α- and β- diversities of plant and soil bacterial communities in two temperate forests that represented early and late successional stages. We documented different patterns of aboveground-belowground diversity relationships in these forests. We observed no linkage between plant and bacterial α-diversity in the early successional forest, and even a negative correlation in the late successional forest, indicating that high bacterial α-diversity is not always linked to high plant α-diversity. Beta-diversity coupling was only found at the late successional stage, while in the early successional forest, the bacterial β-diversity was closely correlated with soil property distances. Additionally, we showed that the dominant competitive tree species in the late successional forest may play key roles in driving forest succession by shaping the soil bacterial community in the early successional stage. This study sheds new light on the potential aboveground-belowground linkage in natural ecosystems, which may help us understand the mechanisms that drive ecosystem succession. PMID:26184121

  18. Aboveground-belowground biodiversity linkages differ in early and late successional temperate forests.

    PubMed

    Li, Hui; Wang, Xugao; Liang, Chao; Hao, Zhanqing; Zhou, Lisha; Ma, Sam; Li, Xiaobin; Yang, Shan; Yao, Fei; Jiang, Yong

    2015-07-17

    Understanding ecological linkages between above- and below-ground biota is critical for deepening our knowledge on the maintenance and stability of ecosystem processes. Nevertheless, direct comparisons of plant-microbe diversity at the community level remain scarce due to the knowledge gap between microbial ecology and plant ecology. We compared the α- and β- diversities of plant and soil bacterial communities in two temperate forests that represented early and late successional stages. We documented different patterns of aboveground-belowground diversity relationships in these forests. We observed no linkage between plant and bacterial α-diversity in the early successional forest, and even a negative correlation in the late successional forest, indicating that high bacterial α-diversity is not always linked to high plant α-diversity. Beta-diversity coupling was only found at the late successional stage, while in the early successional forest, the bacterial β-diversity was closely correlated with soil property distances. Additionally, we showed that the dominant competitive tree species in the late successional forest may play key roles in driving forest succession by shaping the soil bacterial community in the early successional stage. This study sheds new light on the potential aboveground-belowground linkage in natural ecosystems, which may help us understand the mechanisms that drive ecosystem succession.

  19. Contribution of Near Real Time MODIS-Based Forest Disturbance Detection Products to a National Forest Threat Early Warning System

    NASA Astrophysics Data System (ADS)

    Spruce, J.; Hargrove, W. W.; Gasser, J.; Smoot, J.; Kuper, P.

    2011-12-01

    This presentation discusses an effort to compute and post weekly MODIS forest change products for the conterminous US (CONUS), as part of a web-based national forest threat early warning system (EWS) known as the U.S. Forest Change Assessment Viewer (FCAV). The US Forest Service, NASA, USGS, and ORNL are working collaboratively to contribute weekly change products to this EWS. Large acreages of the nation's forests are being disturbed by a growing multitude of biotic and abiotic threats that can act either singularly or in combination. When common at regional scales, such disturbances can pose hazards and threats to floral and faunal bio-diversity, ecosystem sustainability, ecosystem services, and human settlements across the conterminous US. Regionally evident forest disturbances range from ephemeral periodic canopy defoliation to stand replacement mortality events due to insects, disease, fire, hurricanes, tornadoes, ice, hail, and drought. Mandated by the Healthy Forest Restoration Act of 2003, this forest threat EWS has been actively developed since 2006 and on-line since 2010. The FCAV system employs 250-meter MODIS NDVI-based forest change products as a key element of the system, providing regional and CONUS scale products in near real time every 8 days. Each of our forest change products in FCAV is based on current versus historical 24 day composites of NDVI data gridded at 231.66 meter resolution. Current NDVI is derived from USGS eMODIS expedited products. MOD13 NDVI is used for constructing historical baselines. CONUS change products are computed for all forests as % change in the current versus historical NDVI for a given 24 day period. Change products are computed according to previous year, previous 3 year and previous 8 year historical baselines. The use of multiple baselines enables apparent forest disturbance anomalies to be more fully assessed. CONUS forest change products are posted each week on the FCAV, a web mapping service constructed and

  20. Secondary production in a Laminaria hyperborea kelp forest and variation according to wave exposure

    NASA Astrophysics Data System (ADS)

    Norderhaug, Kjell M.; Christie, Hartvig

    2011-11-01

    The secondary production of mobile invertebrate fauna in the Laminaria hyperborea (Gunn.) Foslie kelp forest increases with wave exposure level. This faunal group has a key function in transferring kelp carbon to higher levels in the food web. By using a size-frequency method the calculated production was 68 (±18) g D.W. m -2 yr -1 (±S.E.) at low, 250 (±57) at medium and 308 (±64) at high exposure levels. The calculations included 30 macrofauna species, which accounted for 96% of the specimens registered, with Gastropods, amphipods and bivalves being the most abundant taxa. The calculated secondary production is high, but comparable to that previously reported from other macrophyte systems and was 3%, 8% and 8% of the total primary production at low, medium and high exposure levels, respectively. Our results indicate that large quantities of Laminaria kelp are exported from the system, although the production of sessile animals was not taken into account. The most important factor in determining faunal densities and secondary production was probably habitat size but at low exposure levels the percentage of egg-carrying crustacean females and juveniles were lower than at medium and high exposure levels, thereby indicating lower fitness for animals at low exposure stations.

  1. Contribution of Near Real Time MODIS-Based Forest Disturbance Detection Products to a National Forest Threat Early Warning System

    NASA Technical Reports Server (NTRS)

    Spruce, Joseph P.; Hargrove, William; Glasser, Jerry; Kuper, Philip D.

    2011-01-01

    This presentation discusses an effort to compute and post weekly MODIS forest change products for the conterminous US (CONUS), as part of national forest threat early warning system (EWS) known as the U.S. Forest Change Assessment Viewer (FCAV). The US Forest Service, NASA, USGS, and ORNL are working collaboratively to contribute weekly change products to this EWS. Large acreages of the nation's forests are being disturbed by a growing multitude of biotic and abiotic threats that can act either singularly or in combination. When common at regional scales, such disturbances can pose hazards and threats to floral and faunal bio-diversity, ecosystem sustainability, ecosystem services, and human settlements across the conterminous US. Regionally evident forest disturbances range from ephemeral periodic canopy defoliation to stand replacement mortality events due to insects, disease, fire, hurricanes, tornadoes, ice, hail, and drought. Mandated by the Healthy Forest Restoration Act of 2003, this forest threat EWS has been actively developed since 2006 and on-line since 2010. This FCAV system employs 250-meter MODIS NDVI-based forest change products as a key element of the system, providing regional and CONUS scale products in near real time every 8 days. Each forest change product in FCAV is based on current versus historical 24 day composite NDVI data gridded at 231.66 meter resolution. Current NDVI is derived from USGS eMODIS expedited products. MOD13 NDVI is used for constructing historical baselines. CONUS change products are computed for all forests as % change in the current versus historical NDVI. Change products are computed according to previous year, previous 3 years and previous 8 year historical baselines. The use of multiple baselines enables disturbance anomaly phenology to be more fully assessed. CONUS forest change products are posted each week on the FCAV, a web mapping service maintained by the National Environmental Modeling and Analysis Center. The

  2. Humus layer is the main locus of secondary SO4 production in boreal forests

    NASA Astrophysics Data System (ADS)

    Houle, Daniel; Marty, Charles; Duchesne, Louis; Gagnon, Christian

    2014-02-01

    Identifying the sources of S exported from catchments and the reactivity of the large soil organic S pool is crucial to understand the mid- or long-term response of forested catchments to decreasing atmospheric S deposition and global warming. Sulfur fluxes as well as S and O isotopes of SO4 were measured in precipitation, throughfall, soil solutions and streams at two boreal forest catchments respectively dominated by black spruce (BS) and balsam fir (BF) in Quebec, Canada. Overall, δ34S-SO4 signature showed relatively small variations among various solution types. However, at both sites, δ18O-SO4 in precipitation (averages of 10.5-11.1‰) was decreased by 3.5-3.6‰ in throughfall because of the production of secondary SO4 through oxidation of SO2 deposited on the canopy. Throughfall δ18O-SO4 was decreased by a further 5.4-6.6‰ in the solution leaving the humus layer which was attributed to the production of secondary SO4 under the action of soil microorganisms through the oxidation of organic S during which the S atom acquired O from water and gaseous O2 present in the soil. A mixing equation based on known isotopic signature of each source suggested that ˜67-81% of the S-SO4 leaving the catchments had interacted with the canopy and the humus layer. The stability of δ18O-SO4 in the mineral soil solution and in the stream of both sites, suggests that SO4 does not undergo reduction-oxidation cycles after its passage through the humus layer. Despite its huge size, the organic S reservoir within the mineral soil would be largely inert. Given the chemical nature of SO4 transformation in the canopy, the humus layer would be responsible for nearly 100% of the biological production of secondary SO4 in the whole watershed at both sites. Taking into account the substantial production of dissolved organic S in the humus layer further emphasizes the crucial importance of the latter in the S cycling of boreal forests.

  3. Spatial and Temporal Relationships of Old-Growth and Secondary Forests in Indiana, USA

    Treesearch

    Martin A. Spetich; George R. Parker; Eric J. Gustafson

    1997-01-01

    We examined the spatial pattern of forests in Indiana to: (1) determine the extent, connectivity and percent edge of all forests, (2) examine the change in connectivity among these forests if all riparian zones were replanted to forest or other native vegetation, (3) determine the location, spatial dispersion and percent edge of current old-growth forest remnants, (4)...

  4. Forests

    Treesearch

    Louis R. Iverson; Mark W. Schwartz

    1994-01-01

    Originally diminished by development, forests are coming back: forest biomass is accumulating. Forests are repositories for many threatened species. Even with increased standing timber, however, biodiversity is threatened by increased forest fragmentation and by exotic species.

  5. Radiative forcing by forest and subsequent feedbacks in the early Eocene climate

    NASA Astrophysics Data System (ADS)

    Port, U.; Claussen, M.; Brovkin, V.

    2015-03-01

    Using the Max Planck Institute for Meteorology Earth System Model, we investigate the forcing of forests and the feedback triggered by forests in the pre-industrial climate and in the early Eocene climate (about 54 to 52 million years ago). Other than the interglacial, pre-industrial climate, the early Eocene climate was characterised by high temperatures which led to almost ice-free poles. We compare simulations in which all continents are covered either by dense forest or by bare soil. To isolate the effect of soil albedo, we choose either bright soils or dark soils, respectively. Considering bright soil, forests warm in both, the early Eocene climate and the current climate, but the warming differs due to differences in climate feedbacks. The lapse-rate and water-vapour feedback is stronger in early Eocene climate than in current climate, but strong and negative cloud feedbacks and cloud masking in the early Eocene climate outweigh the stronger positive lapse-rate and water-vapour feedback. In the sum, global mean warming is weaker in the early Eocene climate. Sea-ice related feedbacks are weak in the almost ice-free climate of the early Eocene leading to a weak polar amplification. Considering dark soil, our results change. Forests cools stronger in the early Eocene climate than in the current climate because the lapse-rate and water-vapour feedback is stronger in the early Eocene climate while cloud feedbacks and cloud masking are equally strong in both climates. The different temperature change by forest in both climates highlights the state-dependency of vegetation's impact on climate.

  6. Intra- and interspecific interactions of Scots pine and European beech in mixed secondary forests

    NASA Astrophysics Data System (ADS)

    Erfanifard, Yousef; Stereńczak, Krzysztof

    2017-01-01

    By the mid successional stages, secondary forests of Scots pine in Europe are dominated by mixed stands of pioneer Scots pine and late-successional European beech. The objective of this study was to explore the interactions of pine and beech with their conspecific and heterospecific neighbours in these forests. To accomplish the objective, pine and beech trees were stem-mapped in forty 500 m2 plots randomly located within 18 mixed stands in Milomlyn Forest District, northern Poland. The interactions within and between the species were analysed through two structurally different univariate and bivariate second-order summary statistics, i.e. pair correlation function g(r) and mark correlation function kmm(r). Field measurements showed that the overstorey was dominated by even-aged pine, whereas uneven-aged beech was the only species in the understorey. Pine trees presented an aggregation, while beech trees exhibited a dispersed structure in all stands. In addition, pine trees showed strong attraction to beech trees at small spatial scales (0-2 m). Negative correlation was found between tree height and diameter at breast height of beech, while there was no correlation between height and diameter of pine trees. We conclude that pine trees exhibit negative intraspecific interactions at small spatial scales that are mostly driven by their competitive interactions. Beech trees show strong positive intraspecific interactions and form clumps within pine canopy cover. The strong positive interspecific interactions of pine and beech are the outcome of their different shade tolerance. Our results help to explain successful coexistence of pine and beech in the study site and highlight detailed tree-tree interactions of the species in mixed stands.

  7. Early detection monitoring of Phytophthora ramorum in high-risk forests of California

    Treesearch

    Ross Meentemeyer; Elizabeth Lotz; David M. Rizzo; Kelly Buja; Walter Mark

    2006-01-01

    Early detection monitoring is essential for successful control of invasive organisms. Detection of invasions at an early stage of establishment when a population is small and isolated makes eradication more feasible and less costly. Sudden oak death, caused by the recently described pathogen Phytophthora ramorum, is an emerging forest disease that...

  8. Spider (Arachnida, Araneae) diversity in secondary and old-growth southern Atlantic forests of Paraná state, Brazil.

    PubMed

    Raub, Florian; Höfer, Hubert; Scheuermann, Ludger

    2017-07-01

    The data presented here have been collected in the southern part of the Atlantic Forest (Mata Atlântica) in the state of Paraná, Brazil within a bilateral scientific project (SOLOBIOMA). The project aimed to assess the quality of secondary forests of different regeneration stages in comparison with old-growth forests with regard to diversity of soil animals and related functions. The Atlantic Forest is a hotspot of biological diversity with an exceptionally high degree of endemic species, extending over a range of 3,500 km along the coast of Brazil. The anthropogenic pressure in the region is very high with three of the biggest cities of Brazil (São Paulo, Rio de Janeiro, and Curitiba) lying in its extension. An evaluation of the value of secondary forests for biodiversity conservation is becoming more and more important due to the complete disappearance of primary forests. In 2005, we sampled spiders in 12 sites of three successional stages (5-8, 10-15, 35-50 yr old, three replicates of each forest stage) and old-growth forests (> 100 yr untouched, also three replicates). All sites were inside a private nature reserve (Rio Cachoeira Nature Reserve). We repeated the sampling design and procedure in 2007 in a second private reserve (Itaqui Nature Reserve). The two nature reserves are within about 25 km of each other within a well preserved region of the Mata Atlântica, where the matrix of the landscape mosaic is still forest. A widely accepted standard protocol was used in a replicated sampling design to apply statistical analyses to the resulting data set and allow for comparison with other studies in Brazil. Spiders were sorted to family level and counted; the adult spiders further identified to species if possible or classified as morphospecies with the help of several spider specialists. © 2017 by the Ecological Society of America.

  9. Early College High Schools: A Proposed Solution to Secondary Transition Services

    ERIC Educational Resources Information Center

    Bridges, Jeanne M.; Maxwell, Gerri M.

    2015-01-01

    This qualitative case study examines the challenges facing rural secondary schools in transitioning youth from high school to post-secondary education and careers, and whether the interventions, strategies and support built into the Early College High School could offer a solution to this long-standing challenge to better meet the needs of special…

  10. Collaborative Leadership Practices among Ohio's Early College High School Principals and Their Post-Secondary Partners

    ERIC Educational Resources Information Center

    Carter, Allia L.

    2012-01-01

    This constructivist multiple-case study examined the collaborative leadership practices of seven secondary and seven post-secondary leaders who participate in Ohio's Early College High School Initiative (ECHSI). The 14 educational leaders in this study partnered in an effort to respond to the access and success of traditionally underrepresented…

  11. Resistance to wildfire and early regeneration in natural broadleaved forest and pine plantation

    NASA Astrophysics Data System (ADS)

    Proença, Vânia; Pereira, Henrique M.; Vicente, Luís

    2010-11-01

    The response of an ecosystem to disturbance reflects its stability, which is determined by two components: resistance and resilience. We addressed both components in a study of early post-fire response of natural broadleaved forest ( Quercus robur, Ilex aquifolium) and pine plantation ( Pinus pinaster, Pinus sylvestris) to a wildfire that burned over 6000 ha in NW Portugal. Fire resistance was assessed from fire severity, tree mortality and sapling persistence. Understory fire resistance was similar between forests: fire severity at the surface level was moderate to low, and sapling persistence was low. At the canopy level, fire severity was generally low in broadleaved forest but heterogeneous in pine forest, and mean tree mortality was significantly higher in pine forest. Forest resilience was assessed by the comparison of the understory composition, species diversity and seedling abundance in unburned and burned plots in each forest type. Unburned broadleaved communities were dominated by perennial herbs (e.g., Arrhenatherum elatius) and woody species (e.g., Hedera hibernica, Erica arborea), all able to regenerate vegetatively. Unburned pine communities presented a higher abundance of shrubs, and most dominant species relied on post-fire seeding, with some species also being able to regenerate vegetatively (e.g., Ulex minor, Daboecia cantabrica). There were no differences in diversity measures in broadleaved forest, but burned communities in pine forest shared less species and were less rich and diverse than unburned communities. Seedling abundance was similar in burned and unburned plots in both forests. The slower reestablishment of understory pine communities is probably explained by the slower recovery rate of dominant species. These findings are ecologically relevant: the higher resistance and resilience of native broadleaved forest implies a higher stability in the maintenance of forest processes and the delivery of ecosystem services.

  12. Cladophialophora inabaensis sp. nov., a New Species among the Dark Septate Endophytes from a Secondary Forest in Tottori, Japan

    PubMed Central

    Usui, Erika; Takashima, Yusuke; Narisawa, Kazuhiko

    2016-01-01

    A novel species of Cladophialophora is herein described from the natural environment of secondary forest soil in Japan, which was able to be colonized by the host plant root. Morphological observations indicated that the isolate is distinct from previously identified species, and, thus, is described as the new species, C. inabaensis sp. nov. PMID:27265343

  13. Heterogeneous movement of insectivorous Amazonian birds through primary and secondary forest: A case study using multistate models with radiotelemetry data

    Treesearch

    Luke L. Powell; Jared D. Wolfe; Erik I. Johnson; James E. Hines; James D. Nichols; Philip C Stouffer

    2015-01-01

    Given rates of deforestation, disturbance, and secondary forest accumulation in tropical rainforests, there is a great need to quantify habitat use and movement among different habitats. This need is particularly pronounced for animals most sensitive to disturbance, such as insectivorous understory birds. Here we use multistate capture–recapture models with...

  14. Secondary forest succession and tree planting at the Laguna Cartagena and Cabo Rojo wildlife refuges in southwestern Puerto Rico

    Treesearch

    P.L. Weaver; J.J. Schwagerl

    2008-01-01

    Secondary forest succession and tree planting are contributing to the recovery of the Cabo Rojo refuge (Headquarters and Salinas tracts) and Laguna Cartagena refuge (Lagoon and Tinaja tracts) of the Fish and Wildlife Service in southwestern Puerto Rico. About 80 species, mainly natives, have been planted on 44 ha during the past 25 y in an effort to reduce the threat...

  15. A comparative analysis of the diversity of woody vegetation in old-growth and secondary southern Appalachian cove forests

    Treesearch

    Lyle J. Guyon; Gary L. Rolfe; John M. Edgington; Guillermo A. Mendoza

    2003-01-01

    Characteristics of woody vegetation were compared across six different southern Appalachian cove forests. Trees greater than 6.35 cm dbh were point sampled and regeneration was tallied on 25 m² subplots at all study sites. Overstory composition and structure differed between secondary and old-growth sites, which were dominated by yellow-poplar and eastern...

  16. Cladophialophora inabaensis sp. nov., a New Species among the Dark Septate Endophytes from a Secondary Forest in Tottori, Japan.

    PubMed

    Usui, Erika; Takashima, Yusuke; Narisawa, Kazuhiko

    2016-09-29

    A novel species of Cladophialophora is herein described from the natural environment of secondary forest soil in Japan, which was able to be colonized by the host plant root. Morphological observations indicated that the isolate is distinct from previously identified species, and, thus, is described as the new species, C. inabaensis sp. nov.

  17. Early effects of forest fire on streamflow characteristics.

    Treesearch

    H.W. Berndt

    1971-01-01

    A comparison of streamflow records from three small mountain streams in north-central Washington before, during, and after a severe forest fire showed three immediate effects of destructive burning. These were: 1. Flow rate was greatly reduced while the fire was actively burning. 2. Destruction of vegetation in the riparian zone reduced...

  18. Potential of VIIRS Time Series Data for Aiding the USDA Forest Service Early Warning System for Forest Health Threats: A Gypsy Moth Defoliation Case Study

    NASA Technical Reports Server (NTRS)

    Spruce, Joseph P.; Ryan, Robert E.; McKellip, Rodney

    2008-01-01

    The Healthy Forest Restoration Act of 2003 mandated that a national forest threat Early Warning System (EWS) be developed. The USFS (USDA Forest Service) is currently building this EWS. NASA is helping the USFS to integrate remotely sensed data into the EWS, including MODIS data for monitoring forest disturbance at broad regional scales. This RPC experiment assesses the potential of VIIRS (Visible/Infrared Imager/Radiometer Suite) and MODIS (Moderate Resolution Imaging Spectroradiometer) data for contribution to the EWS. In doing so, the RPC project employed multitemporal simulated VIIRS and MODIS data for detecting and monitoring forest defoliation from the non-native Eurasian gypsy moth (Lymantria despar). Gypsy moth is an invasive species threatening eastern U.S. hardwood forests. It is one of eight major forest insect threats listed in the Healthy Forest Restoration Act of 2003. This RPC experiment is relevant to several nationally important mapping applications, including carbon management, ecological forecasting, coastal management, and disaster management

  19. Effects of the 2015/16 ENSO event on tropical trees in regrowing secondary forests in Central Panama

    NASA Astrophysics Data System (ADS)

    Bretfeld, M.; Ewers, B. E.; Hall, J. S.; Ogden, F. L.

    2016-12-01

    The 2015/16 El Niño-Southern Oscillation (ENSO) event ranks amongst the driest and hottest periods on record in Panama, with severe drought conditions reported for over 90% of the country. A predicted long-term transition into a drier climatic period makes this event an ideal opportunity to study the effects of drought on tropical tree species in secondary forests of central Panama. These forests are associated with desirable hydrological ecosystem services, characterized by reduced peak runoff during high precipitation events in the rainy season and increased base flow during the dry season ("sponge-effect"), making these forest invaluable for water provisioning for the Panama Canal's $2 billion business and Panama's thriving capital city. Starting in February 2015, we installed heat-ratio sap flow sensors in 76 trees (representing 42 different species) in secondary forests of three different ages (8, 25, and 80+ years) in the 15 km2 Agua Salud study area, located in the Panama Canal Watershed. Within each site, trees were selected to represent local tree size distribution. Additional sensors were installed on the roots of a subset of trees. Sap flow data were logged every 30 minutes and soil moisture was measured every 3 minutes at 10, 30, 50, and 100 cm depth. Pre-dawn, mid-day, and pre-dusk leaf water potentials were measured during the dry season (March 2016) and rainy season (July 2016). Meteorological data were taken from a nearby met-station ("Celestino"). Primary drivers of transpiration were vapor pressure deficit and solar radiation. Trees of the 25 and 80+ year old forests appear not water limited during the dry season following ENSO while reduced sap flow rates of trees in the 8 year old forest are indicative of a regulatory response to the drought. Younger understory trees in the 80+ year old forest showed no signs of a drought response. Throughout most of the dry season, volumetric water content at 30 and 50 cm depths was 8% lower in the 8 year old

  20. Secondary forest succession in a tropical dry forest: patterns of development across a 50-year chronosequence in lowland Bolivia

    Treesearch

    Deborah K. Kennard

    2002-01-01

    Stand structure, species richness and population structures of tree species were characterized in 12 stands representing 50 y of succession following slash-and-burn agriculture in a tropical dry forest in lowland Bolivia. Estimates of tree species richness, canopy cover and basal area reached or surpassed 75% of mature forest levels in the 5-, 8-, and 23-y-old stands...

  1. Early-seral stand age and forest structural changes in public and private forestlands in Western Oregon and Washington

    Treesearch

    Robert L Deal; Sharon Stanton; Matthew Betts; Zhiqiang. Yang

    2015-01-01

    Federal forests in the Pacific Northwest region have undergone exceptional changes in management over the past 20 years, and these changes have led to a reduction in regional timber production and significant changes in the management and current age structure of forests. Public lands include large areas of older forests with relatively little younger early-seral...

  2. Remnants of an ancient forest provide ecological context for Early Miocene fossil apes.

    PubMed

    Michel, Lauren A; Peppe, Daniel J; Lutz, James A; Driese, Steven G; Dunsworth, Holly M; Harcourt-Smith, William E H; Horner, William H; Lehmann, Thomas; Nightingale, Sheila; McNulty, Kieran P

    2014-01-01

    The lineage of apes and humans (Hominoidea) evolved and radiated across Afro-Arabia in the early Neogene during a time of global climatic changes and ongoing tectonic processes that formed the East African Rift. These changes probably created highly variable environments and introduced selective pressures influencing the diversification of early apes. However, interpreting the connection between environmental dynamics and adaptive evolution is hampered by difficulties in locating taxa within specific ecological contexts: time-averaged or reworked deposits may not faithfully represent individual palaeohabitats. Here we present multiproxy evidence from Early Miocene deposits on Rusinga Island, Kenya, which directly ties the early ape Proconsul to a widespread, dense, multistoried, closed-canopy tropical seasonal forest set in a warm and relatively wet, local climate. These results underscore the importance of forested environments in the evolution of early apes.

  3. Using Land Surface Phenology as the Basis for a National Early Warning System for Forest Disturbances

    NASA Astrophysics Data System (ADS)

    Hargrove, W. W.; Spruce, J.; Norman, S. P.; Hoffman, F. M.

    2011-12-01

    The National Early Warning System (EWS) provides an 8-day coast-to-coast snapshot of potentially disturbed forests across the U.S.. A prototype system has produced national maps of potential forest disturbances every eight days since January 2010, identifying locations that may require further investigation. Through phenology, the system shows both early and delayed vegetation development and detects all types of unexpected forest disturbances, including insects, disease, wildfires, frost and ice damage, tornadoes, hurricanes, blowdowns, harvest, urbanization, landslides, drought, flood, and climate change. The USDA Forest Service Eastern Forest Environmental Threat Assessment Center is collaborating with NASA Stennis Space Center and the Western Wildland Environmental Threat Assessment Center to develop the tool. The EWS uses differences in phenological responses between an expectation based on historical data and a current view to strategically identify potential forest disturbances and direct attention to locations where forest behavior seems unusual. Disturbance maps are available via the Forest Change Assessment Viewer (FCAV) (http://ews.forestthreats.org/gis), which allows resource managers and other users to see the most current national disturbance maps as soon as they are available. Phenology-based detections show not only vegetation disturbances in the classical sense, but all departures from normal seasonal vegetation behavior. In 2010, the EWS detected a repeated late-frost event at high elevations in North Carolina, USA, that resulted in delayed seasonal development, contrasting with an early spring development at lower elevations, all within close geographic proximity. Throughout 2011, there was a high degree of correspondence between the National Climatic Data Center's North American Drought Monitor maps and EWS maps of phenological drought disturbance in forests. Urban forests showed earlier and more severe phenological drought disturbance than

  4. Habitat differences in dung beetle assemblages in an African savanna-forest ecotone: implications for secondary seed dispersal.

    PubMed

    Kunz, Britta K; Krell, Frank-Thorsten

    2011-06-01

    The probability and pattern of secondary seed dispersal by dung beetles (Scarabaeinae) depend on their community structure and composition at the site of primary deposition, which, in turn, seem to be strongly determined by vegetation. Consequently, we expected pronounced differences in secondary seed dispersal between forest and savanna in the northern Ivory Coast, West Africa. We found 99 dung beetle species at experimentally exposed dung piles of the olive baboon (Papio anubis (Lesson, 1827)), an important primary seed disperser in West Africa. Seventy-six species belonged to the roller and tunneler guilds, which are relevant for secondary seed dispersal. Most species showed a clear habitat preference. Contrary to the Neotropics, species number and abundance were much higher in the savanna than in the forest. Rollers and tunnelers each accounted for approximately 50% of the individuals in the savanna, but in the forest rollers made up only 4%. Seeds deposited into the savanna by an omnivorous primary disperser generally have a higher overall probability of being more rapidly dispersed secondarily by dung beetles than seeds in the forest. Also, rollers disperse seeds over larger distances. In contrast to other studies, small rollers were active in dispersal of large seeds, which were seemingly mistaken for dung balls. Our results suggest that rollers can remove seeds from any plant dispersed in primate dung in this ecosystem.

  5. Population structure and spatial pattern of main tree species in secondary Betula platyphylla forest in Ziwuling Mountains, China.

    PubMed

    Kang, Di; Guo, Yaoxin; Ren, Chengjie; Zhao, Fazhu; Feng, Yongzhong; Han, Xinhui; Yang, Gaihe

    2014-11-03

    This study investigated a typical secondary Betula platyphylla forest in the Ziwuling Mountains, Loess Plateau, China. In the sample plot, the DBH (diameter at breast height) class structure of B. platyphylla was bimodal. Individuals with small and large DBH values were abundant. The DBH structures of Quercus wutaishanica and Pinus tabulaeformis were close to that of the logistic model, thus suggesting the increasing population of these species. B. platyphylla and Populus davidiana showed random spatial distributions at almost all scales. However, Q. wutaishanica and P. tabulaeformis were significantly clumped at small scales. B. platyphylla had a negative spatial relation with Q. wutaishanica at small spatial scales. P. tabulaeformis and Q. wutaishanica showed negative spatial correlations at small scales, but they had positive correlations at large scales. These results suggest that P. tabulaeformis and Q. wutaishanica shared habitat preferences at these scales. In the future, the secondary B. platyphylla forest in the Ziwuling Mountains in the Loess Plateau will probably change into a multi-species mixed forest (Quercus-Pinus mixed forest). Assisted restoration strategies must be employed to improve the regeneration dynamics of the forest in the long term.

  6. In situ secondary organic aerosol formation from ambient pine forest air using an oxidation flow reactor

    NASA Astrophysics Data System (ADS)

    Palm, B. B.; Campuzano-Jost, P.; Ortega, A. M.; Day, D. A.; Kaser, L.; Jud, W.; Karl, T.; Hansel, A.; Hunter, J. F.; Cross, E. S.; Kroll, J. H.; Peng, Z.; Brune, W. H.; Jimenez, J. L.

    2015-11-01

    Ambient air was oxidized by OH radicals in an oxidation flow reactor (OFR) located in a montane pine forest during the BEACHON-RoMBAS campaign to study biogenic secondary organic aerosol (SOA) formation and aging. High OH concentrations and short residence times allowed for semi-continuous cycling through a large range of OH exposures ranging from hours to weeks of equivalent (eq.) atmospheric aging. A simple model is derived and used to account for the relative time scales of condensation of low volatility organic compounds (LVOCs) onto particles, condensational loss to the walls, and further reaction to produce volatile, non-condensing fragmentation products. More SOA production was observed in the OFR at nighttime (average 4 μg m-3 when LVOC fate corrected) compared to daytime (average 1 μg m-3 when LVOC fate corrected), with maximum formation observed at 0.4-1.5 eq. days of photochemical aging. SOA formation followed a similar diurnal pattern to monoterpenes, sesquiterpenes, and toluene + p-cymene concentrations, including a substantial increase just after sunrise at 07:00 LT. Higher photochemical aging (> 10 eq. days) led to a decrease in new SOA formation and a loss of preexisting OA due to heterogeneous oxidation followed by fragmentation and volatilization. When comparing two different commonly used methods of OH production in OFRs (OFR185 and OFR254), similar amounts of SOA formation were observed. We recommend the OFR185 mode for future forest studies. Concurrent gas-phase measurements of air after OH oxidation illustrate the decay of primary VOCs, production of small oxidized organic compounds, and net production at lower ages followed by net consumption of terpenoid oxidation products as photochemical age increased. New particle formation was observed in the reactor after oxidation, especially during times when precursor gas concentrations and SOA formation were largest. Approximately 6 times more SOA was formed in the reactor from OH oxidation than

  7. Succession influences wild bees in a temperate forest landscape: the value of early successional stages in naturally regenerated and planted forests.

    PubMed

    Taki, Hisatomo; Okochi, Isamu; Okabe, Kimiko; Inoue, Takenari; Goto, Hideaki; Matsumura, Takeshi; Makino, Shun'ichi

    2013-01-01

    In many temperate terrestrial forest ecosystems, both natural human disturbances drive the reestablishment of forests. Succession in plant communities, in addition to reforestation following the creation of open sites through harvesting or natural disturbances, can affect forest faunal assemblages. Wild bees perform an important ecosystem function in human-altered and natural or seminatural ecosystems, as they are essential pollinators for both crops and wild flowering plants. To maintain high abundance and species richness for pollination services, it is important to conserve and create seminatural and natural land cover with optimal successional stages for wild bees. We examined the effects of forest succession on wild bees. In particular, we evaluated the importance of early successional stages for bees, which has been suspected but not previously demonstrated. A range of successional stages, between 1 and 178 years old, were examined in naturally regenerated and planted forests. In total 4465 wild bee individuals, representing 113 species, were captured. Results for total bees, solitary bees, and cleptoparasitic bees in both naturally regenerated and planted conifer forests indicated a higher abundance and species richness in the early successional stages. However, higher abundance and species richness of social bees in naturally regenerated forest were observed as the successional stages progressed, whereas the abundance of social bees in conifer planted forest showed a concave-shaped relationship when plotted. The results suggest that early successional stages of both naturally regenerated and conifer planted forest maintain a high abundance and species richness of solitary bees and their cleptoparasitic bees, although social bees respond differently in the early successional stages. This may imply that, in some cases, active forest stand management policies, such as the clear-cutting of planted forests for timber production, would create early successional

  8. Mechanism Underlying the Spatial Pattern Formation of Dominant Tree Species in a Natural Secondary Forest

    PubMed Central

    Jia, Guodong; Yu, Xinxiao; Fan, Dengxing; Jia, Jianbo

    2016-01-01

    Studying the spatial pattern of plant species may provide significant insights into processes and mechanisms that maintain stand stability. To better understand the dynamics of naturally regenerated secondary forests, univariate and bivariate Ripley’s L(r) functions were employed to evaluate intra-/interspecific relationships of four dominant tree species (Populus davidiana, Betula platyphylla, Larix gmelinii and Acer mono) and to distinguish the underlying mechanism of spatial distribution. The results showed that the distribution of soil, water and nutrients was not fragmented but presented clear gradients. An overall aggregated distribution existed at most distances. No correlation was found between the spatial pattern of soil conditions and that of trees. Both positive and negative intra- and interspecific relationships were found between different DBH classes at various distances. Large trees did not show systematic inhibition of the saplings. By contrast, the inhibition intensified as the height differences increased between the compared pairs. Except for Larix, universal inhibition of saplings by upper layer trees occurred among other species, and this reflected the vertical competition for light. Therefore, we believe that competition for light rather than soil nutrients underlies the mechanism driving the formation of stand spatial pattern in the rocky mountainous areas examined. PMID:27028757

  9. Mechanism Underlying the Spatial Pattern Formation of Dominant Tree Species in a Natural Secondary Forest.

    PubMed

    Jia, Guodong; Yu, Xinxiao; Fan, Dengxing; Jia, Jianbo

    2016-01-01

    Studying the spatial pattern of plant species may provide significant insights into processes and mechanisms that maintain stand stability. To better understand the dynamics of naturally regenerated secondary forests, univariate and bivariate Ripley's L(r) functions were employed to evaluate intra-/interspecific relationships of four dominant tree species (Populus davidiana, Betula platyphylla, Larix gmelinii and Acer mono) and to distinguish the underlying mechanism of spatial distribution. The results showed that the distribution of soil, water and nutrients was not fragmented but presented clear gradients. An overall aggregated distribution existed at most distances. No correlation was found between the spatial pattern of soil conditions and that of trees. Both positive and negative intra- and interspecific relationships were found between different DBH classes at various distances. Large trees did not show systematic inhibition of the saplings. By contrast, the inhibition intensified as the height differences increased between the compared pairs. Except for Larix, universal inhibition of saplings by upper layer trees occurred among other species, and this reflected the vertical competition for light. Therefore, we believe that competition for light rather than soil nutrients underlies the mechanism driving the formation of stand spatial pattern in the rocky mountainous areas examined.

  10. Control of Boreal Forest Soil Microbial Communities and Processes by Plant Secondary Compounds

    NASA Astrophysics Data System (ADS)

    Leewis, M. C.; Leigh, M. B.

    2016-12-01

    Plants release an array of secondary plant metabolites (SPMEs), which vary widely between plant species/progenies and may drive shifts in soil microbial community structure and function. We hypothesize that SPMEs released through litterfall and root turnover in the boreal forest control ecosystem carbon cycling by inhibiting microbial decomposition processes, which are overcome partially by increased aromatic biodegradation of microbial communities that also fortuitously prime soils for accelerated biodegradation of contaminants. Soils and litter (stems, roots, senescing leaves) were collected from 3 different birch progenies from Iceland, Finland, and Siberia that have been reported to contain different SPME content (low, medium, high, respectively) due to differences in herbivory pressure over their natural history, as well as black spruce, all growing in a long-term common tree garden at the Kevo Subarctic Field Research Institute, Finland. We characterized the SPME content of these plant progenies and used a variety of traditional microbiological techniques (e.g., enzyme assays, litter decomposition and contaminant biodegradation rates) and molecular techniques (e.g., high-throughput amplicon sequencing for bacteria and fungi) to assess how different levels of SPMEs may correlate to shifts in microbial community structure and function. Microbial communities (bacterial and fungal) significantly varied in composition as well as leaf litter and diesel biodegradation rates, in accordance with the phytochemistry of the trees present. This study offers novel, fundamental information about phytochemical controls on ecosystem processes, resilience to contaminants, and microbial decomposition processes.

  11. Toward a national early warning system for forest disturbances using remotely sensed canopy phenology

    Treesearch

    William W. Hargrove; Joseph P. Spruce; Gerald E. Gasser; Forrest M. Hoffman

    2009-01-01

    Imagine a national system with the ability to quickly identify forested areas under attack from insects or disease. Such an early warning system might minimize surprises such as the explosion of caterpillars referred to in the quotation above. Moderate resolution (ca. 500m) remote sensing repeated at frequent (ca. weekly) intervals could power such a monitoring system...

  12. California forests show early indications of both range shifts and local persistence under climate change

    Treesearch

    Josep M. Serra-Diaz; Janet Franklin; Whalen W. Dillon; Alexandra D. Syphard; Frank W. Davis; Ross K. Meentemeyer

    2015-01-01

    Aim Forest regeneration data provide an early signal of the persistence and migration of tree species, so we investigated whether species shifts due to climate change exhibit a common signal of response or whether changes vary by species. Location California Floristic Province, United...

  13. Geospatiotemporal data mining in an early warning system for forest threats in the United States

    Treesearch

    F.M. Hoffman; R.T. Mills; J. Kumar; S.S. Vulli; W.W. Hargrove

    2010-01-01

    We investigate the potential of geospatiotemporal data mining of multi-year land surface phenology data (250 m Normalized Difference Vegetation Index (NDVI) values derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) in this study) for the conterminous United States as part of an early warning system to identify threats to forest ecosystems. Cluster...

  14. Phytophthora ramorum early detection surveys for forests in the United States, 2003-2006

    Treesearch

    S.W. Oak; A.H. Elledge; E.K. Yockey; W.D. Smith; B.M. Tkacz

    2008-01-01

    Risk-based early detection surveys in U.S. forests were conducted between 2003 and 2006 using 100 m vegetation transects. Thirty-nine states surveyed 3,570 locations in states with endemic Phytophthora ramorum; states where the pathogen had been confirmed only in woody ornamental nurseries; and states that had received potentially infected stock but...

  15. The vertical development of early successional forests in northern Michigan, USA

    Treesearch

    Kurt S. Pregitzer; Brain J. Palik

    1993-01-01

    1. Studies have shown that differences in height growth rates are characteristic of tree species that differ in understory tolerance and relative successional status. Less-tolerant species have greater juvenile height growth rates than more-tolerant species and thus, in a mixed-species forest, the former gain an early competitive advantage after a stand-initiating...

  16. Secondary forest succession and tree planting at the Laguna Cartagena and Cabo Rojo wildlife refuges in southwestern Puerto Rico.

    PubMed

    Weaver, Peter L; Schwagerl, Joseph J

    2008-12-01

    Secondary forest succession and tree planting are contributing to the recovery of the Cabo Rojo refuge (Headquarters and Salinas tracts) and Laguna Cartagena refuge (Lagoon and Tinaja tracts) of the Fish and Wildlife Service in southwestern Puerto Rico. About 80 species, mainly natives, have been planted on 44 ha during the past 25 y in an effort to reduce the threat of grass fires and to restore wildlife habitat. A 2007 survey of 9-y-old tree plantings on the Lagoon tract showed satisfactory growth rates for 16 native species. Multiple stems from individual trees at ground level were common. A sampling of secondary forest on the entire 109 ha Tinaja tract disclosed 141 native tree species, or 25% of Puerto Rico's native tree flora, along with 20 exotics. Five tree species made up about 58% of the total basal area, and seven species were island endemics. Between 1998 and 2003, tree numbers and basal area, as well as tree heights and diameter at breast height values (diameter at 1.4 m above the ground), increased on the lower 30 ha of the Tinaja tract. In this area, much of it subject to fires and grazing through 1996, exotic trees made up 25% of the species. Dry forest throughout the tropics is an endangered habitat, and its recovery (i.e., in biomass, structure, and species composition) at Tinaja may exceed 500 y. Future forests, however, will likely contain some exotics.

  17. Establishment of the evergreen broad-leaved tree species Castanopsis cuspidata in an abandoned secondary forest in western Japan.

    PubMed

    Hirayama, Kimiko; Kawamura, Shota; Nishimura, Tatsuya; Takahara, Hikaru

    2010-09-01

    Recently, populations of Castanopsis cuspidata have often expanded into secondary forests in western Japan. To determine the establishment processes of this species, we analyzed its spatial distribution in a secondary forest dominated by Quercus variabilis and Quercus serrata that is located adjacent to a stand dominated by C. cuspidata. Saplings, defined as >or=30 cm stem length (SL) and <5 cm diameter at breast height (DBH), were abundant and their size distribution was inversely J-shaped, indicating continuous recruitment. Although seedlings (SL < 30 cm) and small saplings (30 or=40 m from the nearest adults, suggesting that there is animal-aided dispersal of acorns. The distribution of larger-sized individuals (>or=100 cm SL) of C. cuspidata was unrelated to distance from the nearest flowering C. cuspidata or dominant Quercus species (>or=5 cm DBH), but was associated with dead Pinus densiflora trees, which were abundant at the site. Thus, the establishment of C. cuspidata in this forest is controlled mainly by two factors, viz. patterns of acorn dispersal by animals, and forest disturbance regime (i.e., deaths of pine trees).

  18. [Physical and chemical properties of throughfall in main forest types of secondary forest ecosystem in montane regions of eastern Liaoning Province, China].

    PubMed

    Xi, Xing-jun; Yan, Qiao-ling; Yu, Li-zhong; Zhu, Jiao-jun; Zhang, Cai-hong; Zhang, Jin-xin; Liu, Chang-xia

    2009-09-01

    From July to September 2008, a measurement was made on the physical and chemical properties of bulk precipitation and throughfall in five main forest types, i.e., larch plantation (LP), Fraxinus rhynchophylla stand (FR), mixed forest stand (MF), Korean pine plantation (KP), and Mongolian oak stand (MO), of secondary forest ecosystem in montane regions of eastern Liaoning Province, China. Comparing with bulk precipitation, the throughfall in the five forest types was significantly acidified (P < 0.05), and the acidification degree was in the order of KP > LP > MF > MO > FR. The conductivity and total dissolved solids of the throughfall increased significantly (P < 0.05), and were in the sequence of MO > FR > LP > MF > KP. The dissolved oxygen concentration of the throughfall lowered significantly (P < 0.05), with the rank of KP > MF > FR > MO > LP, while the Cl- concentration increased significantly, ranked as LP > MO > MF > FR > KP. The NO3-concentrations of the throughfall in FR, MO and MF were higher, while those in LP and KP were lower than that of the bulk precipitation.

  19. Secondary seed dispersal by dung beetles in an Amazonian forest fragment of Colombia: influence of dung type and edge effect.

    PubMed

    Santos-Heredia, Carolina; Andresen, Ellen; Stevenson, Pablo

    2011-12-01

    Seeds of many plant species are secondarily dispersed by dung beetles, but the outcome of this interaction is highly context-specific. Little is known about how certain anthropogenic disturbances affect this plant-animal interaction. The aims of this study were to assess the effect of dung type on secondary dispersal by dung beetles in a forest fragment, and to determine whether this interaction is affected by edge effects. Using pitfall traps, we captured dung beetles attracted to dung of 2 frugivorous mammals: woolly monkeys and howler monkeys. We found differences between both dung beetle assemblages, but these differences were not consistent in time. Using seeds surrounded by both dung types, we carried out a field experiment using seeds of 2 plant species. We found that the probability of secondary dispersal by dung beetles was higher for seeds placed in woolly monkey dung. Finally, we carried out a field experiment using plastic beads as seed mimics to assess edge effects. We found that secondary seed dispersal by dung beetles was negatively affected by edges. The disruption of plant-animal interactions along anthropogenic forest edges could have long-term negative effects on forest dynamics by affecting processes of regeneration.

  20. [Gap features and renewal dynamics in secondary natural Pinus tabulaeformis forest in hilly loess region].

    PubMed

    Zhang, Xi-Biao; Wang, Rui-Juan; Zhou, Tian-Lin; Sgangguan, Zhou-Ping

    2008-10-01

    Taking the secondary natural Pinus tabulaeformis forest in hilly loess region as research object, the shape, size structure, distribution, gap-maker features, and renewal dynamics of gaps were investigated. The results showed that the areas of canopy gap (CG) and extended gap (EG) appeared to have a skewed and small gap- dominated distribution. The CGs had an average area of 31.15 m2, and those with an area of 20-40 m2 made up the highest proportions in number and area, accounting for 38.24% and 30.50%, respectively; while the EGs had an average area of 58.04 m2, and those with an area of 30-60 m2 made up the highest proportions in number and area, accounting for 36.77% and 27.79%, respectively. The average CG area accounted for 53.67% of the average EG area. The gaps were mainly elliptical, and their ages were mainly within 10-20 years, which occupied 33.82% of the total. The gaps were mainly with a height of 14-16 m, and those with a height of 18-22 m made up 36.8% of the total. The gaps were mainly formed by the trees being broken at their bases and the standing dead trees, which made up 47. 66% and 23.44% of all gap-makers, respectively, and thinning and unlawful felling were the major factors in gap formation. The tree deaths from lowered resistance due to tree- ageing, drought, and pest and diseases were one of the reasons for gap formation. The gap-makers per gap numbered 1.89 on average, and most of the gaps were formed by two gap-makers. The gap-makers were mainly Pinus tabulaeformis, followed by Populus davidiana, Betula platyphylla, and Quercus liaotungensis. The diameters of the gap-makers appeared to have a remarkably skewed normal distribution, and the diameters commonly ranged in 10-20 cm and 21-30 cm, taking up 25.0% and 45.31%, respectively. This skewed normal distribution agreed with the skewed area distribution of the gaps. In forest gap, trees had a better regeneration condition, and Chinese pine seedings had no age-discontinuity; while in the

  1. Determination of the biogenic secondary organic aerosol fraction in the boreal forest by NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Finessi, E.; Decesari, S.; Paglione, M.; Giulianelli, L.; Carbone, C.; Gilardoni, S.; Fuzzi, S.; Saarikoski, S.; Raatikainen, T.; Hillamo, R.; Allan, J.; Mentel, Th. F.; Tiitta, P.; Laaksonen, A.; Petäjä, T.; Kulmala, M.; Worsnop, D. R.; Facchini, M. C.

    2012-01-01

    The study investigates the sources of fine organic aerosol (OA) in the boreal forest, based on measurements including both filter sampling (PM1) and online methods and carried out during a one-month campaign held in Hyytiälä, Finland, in spring 2007. Two aerosol mass spectrometers (Q-AMS, ToF-AMS) were employed to measure on-line concentrations of major non-refractory aerosol species, while the water extracts of the filter samples were analyzed by nuclear magnetic resonance (NMR) spectroscopy for organic functional group characterization of the polar organic fraction of the aerosol. AMS and NMR spectra were processed separately by non-negative factorization algorithms, in order to apportion the main components underlying the submicrometer organic aerosol composition and depict them in terms of both mass fragmentation patterns and functional group compositions. The NMR results supported the AMS speciation of oxidized organic aerosol (OOA) into two main fractions, which could be generally labelled as more and less oxidized organics. The more oxidized component was characterized by a mass spectrum dominated by the m/z 44 peak, and in parallel by a NMR spectrum showing aromatic and aliphatic backbones highly substituted with oxygenated functional groups (carbonyls/carboxyls and hydroxyls). Such component, contributing on average 50% of the OA mass throughout the observing period, was associated with pollution outbreaks from the Central Europe. The less oxidized component was enhanced in concomitance with air masses originating from the North-to-West sector, in agreement with previous investigations conducted at this site. NMR factor analysis was able to separate two distinct components under the less oxidized fraction of OA. One of these NMR-factors was associated with the formation of terrestrial biogenic secondary organic aerosol (BSOA), based on the comparison with spectral profiles obtained from laboratory experiments of terpenes photo-oxidation. The second NMR

  2. An Early Warning System for Identification and Monitoring of Disturbances to Forest Ecosystems

    NASA Astrophysics Data System (ADS)

    Marshall, A. A.; Hoffman, F. M.; Kumar, J.; Hargrove, W. W.; Spruce, J.; Mills, R. T.

    2011-12-01

    Forest ecosystems are susceptible to damage due to threat events like wildfires, insect and disease attacks, extreme weather events, land use change, and long-term climate change. Early identification of such events is desired to devise and implement a protective response. The mission of the USDA Forest Service is to sustain the health, diversity, and productivity of the nation's forests. However, limited resources for aerial surveys and ground-based inspections are insufficient for monitoring the large areas covered by the U.S. forests. The USDA Forest Service, Oak Ridge National Laboratory, and NASA Stennis Space Center are developing an early warning system for the continuous tracking and long-term monitoring of disturbances and responses in forest ecosystems using high resolution satellite remote sensing data. Geospatiotemporal data mining techniques were developed and applied to normalized difference vegetation index (NDVI) products derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) MOD 13 data at 250 m resolution on eight day intervals. Representative phenologically similar regions, or phenoregions, were developed for the conterminous United States (CONUS) by applying a k-means clustering algorithm to the NDVI data spanning the full eight years of the MODIS record. Annual changes in the phenoregions were quantitatively analyzed to identify the significant changes in phenological behavior. This methodology was successfully applied for identification of various forest disturbance events, including wildfire, tree mortality due to Mountain Pine Beetle, and other insect infestation and diseases, as well as extreme events like storms and hurricanes in the United States. Where possible, the results were validated and quantitatively compared with aerial and ground-based survey data available from different agencies. This system was able to identify most of the disturbances reported by aerial and ground-based surveys, and it also identified

  3. Role of MODIS Vegetation Phenology Products in the U.S. for Warn Early Warning System for Forest Threats

    NASA Technical Reports Server (NTRS)

    Spruce, Joseph; Hargrove, William; Norman, Steve; Gasser, Gerald; Smoot, James; Kuper, Philip

    2012-01-01

    U.S. forests occupy approx 751 million acres (approx 1/3 of total land). Several abiotic and biotic damage agents disturb, damage, kill, and/or threaten these forests. Regionally extensive forest disturbances can also threaten human life and property, bio-diversity and water supplies. timely regional forest disturbance monitoring products are needed to aid forest health management work at finer scales. daily MODIS data provide a means to monitor regional forest disturbances on a weekly basis, leveraging vegetation phenology. In response, the USFS and NASA began collaborating in 2006 to develop a Near Real Time (NRT) forest monitoring capability, based on MODIS NDVI data, as part of a national forest threat Early Warning System (EWS).

  4. Toward a National Early Warning System for Forest Disturbances Using Remotely Sensed Land-Surface Phenology

    NASA Astrophysics Data System (ADS)

    Hargrove, W. W.; Spruce, J.

    2010-12-01

    A prototype National Early Warning System (EWS) for Forest Disturbances was established in 2010 by producing national maps showing potential forest disturbance across the conterminous United States at 231m resolution every 8 days. Each map is based on Land-Surface Phenology (LSP), calculated using temporally smoothed MODIS MOD13 imagery obtained over the preceding 24-day analysis window. Potential disturbance maps are generated by comparing a spatially and temporally specific historical expectation of normal NDVI "greenness" with NDVI "greenness" from a series of current satellite views. Three different disturbance products are produced using differing lengths of historical baseline periods to calculate the expected normal greenness. The short-term baseline products show only disturbances newer than one year ago, while the intermediate baseline products show disturbances since the prior three years, and the long-term baseline products show all disturbances over the MODIS historical period. A Forest Change Assessment Viewer website, http://ews.forestthreats.org/NPDE/NPDE.html, showcases the three most recent national disturbance maps in full spatial context. Although 2010 was a wet el Nino year without major forest problems, disturbances in 2010 in MI, NY, CO and LA will be highlighted. Forest disturbances caused by wildfire, hurricanes, tornadoes, hail, ice storms, and defoliating insects, including fall cankerworms, forest tent caterpillars, gypsy moths, baldcypress leafrollers and winter moths were successfully detected during the 2009 and 2010 field seasons. The EWS was used in 2010 to detect and alert Forest Health Monitoring (FHM) Aerial Disturbance Survey personnel to an otherwise-unknown outbreak of forest tent caterpillar and baldcypress leafroller in the Atchafalaya and Pearl River regions of southern Louisiana. A local FHM Program Coordinator verified these EWS-detected outbreaks. Many defoliator-induced disturbances were ephemeral, and were followed by

  5. No signs of soil organic matter accumulation and of changes in nutrient (N-P) limitation during tropical secondary forest succession in the wet tropics of Southwest Costa Rica

    NASA Astrophysics Data System (ADS)

    Wanek, Wolfgang; Oberdorfer, Sarah; Oberleitner, Florian; Hietz, Peter; Dullinger, Stefan; Zehetner, Franz

    2017-04-01

    N and P availability, but high microbial N:P ratios and very low Olsen P, indicating P limitation across the whole chronosequence due to strong chemical soil weathering and P fixation to Fe and Al oxides. In contrast we found an intermittent decrease in soil pH and in base saturation from pastures to young secondary forests and later increases towards old-growth forests. This dip in base saturation is most likely related to the high demand for base cations during rapid biomass build-up (particularly Ca-rich wood) during early secondary succession which is later counterbalanced by cation pumping by deep rooting trees from cation-rich deep soil layers and redistribution to the topsoils through litterfall and root turnover. The presented results on SOM and nutrient dynamics will be set in relation to aboveground biomass recovery at the same sites, and compared to other forest chronosequences in the tropics, to better understand climate and nutrient effects on the recovery of tropical forests after abandonment of agricultural land.

  6. Early vegetational changes on a forested wetland constructed for mitigation

    USGS Publications Warehouse

    Perry, M.C.; Osenton, P.C.; Sibrel, C.B.

    1997-01-01

    Changes in vegetation were studied on 15 acres of a 35 acre forested wetland created as a mitigation site in Anne Arundel County, Maryland during 1994-96. Meter-square sampling on four different hydrologic elevations determined that grasses initially dominated the area, but decreased from 59 percent in 1994 to 51 percent in 1995 and 30 percent in 1996. Herbaceous non-grass plants (forbs) increased from 19 percent to 56 percent in the three-year period. Area with no plant cover decreased from 21 percent in 1994 to 11 percent in 1995, and 10 percent in 1996. Woody plants comprised 2 percent of the cover in 1994, increased to 4 percent in 1995, and remained at 4 percent in 1996. The increase of woody plants was mainly from natural regeneration (pioneer) plants. Monitoring of the transplanted trees and shrubs indicated 35 percent mortality and little growth of surviving plants. The pioneer woody plant forming most of the cover was black willow (Salix nigra). Differences in the vegetation were observed among the four elevations, although no differences were observed for the major vegetation classes between plots that were planted and those that were not planted with woody plants. Dominant grass species was redtop (Agrostis stolonifera), which comprised 51 percent of the cover in 1994 and 42 percent cover in 1995 and 23 percent in 1996. Other species that were common were bush clover (Lespedeza cuneata), Japanese clover (Lespedeza striata) and flat pea (Lathyrus sylvestris). All four of these dominant species were part of the original seed mixtures that were seeded on the site. A total of 134 species of plants was recorded on the site indicating a fairly diverse community for a newly established habitat.

  7. Conservation thinning in secondary forest: negative but mild effect on land molluscs in closed-canopy mixed oak forest in Sweden.

    PubMed

    Rancka, Birte; von Proschwitz, Ted; Hylander, Kristoffer; Götmark, Frank

    2015-01-01

    Secondary succession is changing the character of many temperate forests and often leads to closed-canopy stands. In such forests set aside for conservation, habitat management alternatives need to be tested experimentally, but this is rarely done. The Swedish Oak Project compares two often debated alternatives: minimal intervention and non-traditional active management (conservation thinning) on plots of each type replicated at 25 sites. We study responses of several taxa, and here report results for land molluscs. They are considered to be sensitive to more open, drier forest and we predicted a negative effect of the thinning (26% reduction of the basal area; mean value for 25 experimental forests). We sampled molluscs in the litter in ten 20 x 25 cm subplots, and by standardised visual search, in each plot. In total, we recorded 53 species of snails and slugs (24 369 individuals) and the mean species richness in plots was 17. Two seasons after thinning, mean (± SE) species richness had decreased by 1.4 (± 0.9) species in thinning plots, but increased by 0.7 (± 1.0) species in minimal intervention plots, a significant but small change with considerable variation among sites. In matched comparisons with minimal intervention, thinning reduced the overall abundance of molluscs. Most species responded negatively to thinning - but only five of the 53 species were significantly affected, and reproduction seemed to be negatively affected in only one species. An ordination analysis did not reveal any particular change in the species community due to thinning. Thus, the negative effect of conservation thinning on land molluscs was apparently mild - one reason was that many trees, shrubs and other forest structures remained after the treatment. Conservation thinning may be recommended, since other taxa are favoured, but minimal intervention is also a useful form of management for molluscs and saproxylic taxa.

  8. Conservation Thinning in Secondary Forest: Negative but Mild Effect on Land Molluscs in Closed-Canopy Mixed Oak Forest in Sweden

    PubMed Central

    Rancka, Birte; von Proschwitz, Ted; Hylander, Kristoffer; Götmark, Frank

    2015-01-01

    Secondary succession is changing the character of many temperate forests and often leads to closed-canopy stands. In such forests set aside for conservation, habitat management alternatives need to be tested experimentally, but this is rarely done. The Swedish Oak Project compares two often debated alternatives: minimal intervention and non-traditional active management (conservation thinning) on plots of each type replicated at 25 sites. We study responses of several taxa, and here report results for land molluscs. They are considered to be sensitive to more open, drier forest and we predicted a negative effect of the thinning (26% reduction of the basal area; mean value for 25 experimental forests). We sampled molluscs in the litter in ten 20 x 25 cm subplots, and by standardised visual search, in each plot. In total, we recorded 53 species of snails and slugs (24 369 individuals) and the mean species richness in plots was 17. Two seasons after thinning, mean (± SE) species richness had decreased by 1.4 (± 0.9) species in thinning plots, but increased by 0.7 (± 1.0) species in minimal intervention plots, a significant but small change with considerable variation among sites. In matched comparisons with minimal intervention, thinning reduced the overall abundance of molluscs. Most species responded negatively to thinning – but only five of the 53 species were significantly affected, and reproduction seemed to be negatively affected in only one species. An ordination analysis did not reveal any particular change in the species community due to thinning. Thus, the negative effect of conservation thinning on land molluscs was apparently mild – one reason was that many trees, shrubs and other forest structures remained after the treatment. Conservation thinning may be recommended, since other taxa are favoured, but minimal intervention is also a useful form of management for molluscs and saproxylic taxa. PMID:25803452

  9. Key role of symbiotic dinitrogen fixation in tropical forest secondary succession

    NASA Astrophysics Data System (ADS)

    Batterman, Sarah A.; Hedin, Lars O.; van Breugel, Michiel; Ransijn, Johannes; Craven, Dylan J.; Hall, Jefferson S.

    2013-10-01

    Forests contribute a significant portion of the land carbon sink, but their ability to sequester CO2 may be constrained by nitrogen, a major plant-limiting nutrient. Many tropical forests possess tree species capable of fixing atmospheric dinitrogen (N2), but it is unclear whether this functional group can supply the nitrogen needed as forests recover from disturbance or previous land use, or expand in response to rising CO2 (refs 6, 8). Here we identify a powerful feedback mechanism in which N2 fixation can overcome ecosystem-scale deficiencies in nitrogen that emerge during periods of rapid biomass accumulation in tropical forests. Over a 300-year chronosequence in Panama, N2-fixing tree species accumulated carbon up to nine times faster per individual than their non-fixing neighbours (greatest difference in youngest forests), and showed species-specific differences in the amount and timing of fixation. As a result of fast growth and high fixation, fixers provided a large fraction of the nitrogen needed to support net forest growth (50,000kg carbon per hectare) in the first 12years. A key element of ecosystem functional diversity was ensured by the presence of different N2-fixing tree species across the entire forest age sequence. These findings show that symbiotic N2 fixation can have a central role in nitrogen cycling during tropical forest stand development, with potentially important implications for the ability of tropical forests to sequester CO2.

  10. Key role of symbiotic dinitrogen fixation in tropical forest secondary succession.

    PubMed

    Batterman, Sarah A; Hedin, Lars O; van Breugel, Michiel; Ransijn, Johannes; Craven, Dylan J; Hall, Jefferson S

    2013-10-10

    Forests contribute a significant portion of the land carbon sink, but their ability to sequester CO2 may be constrained by nitrogen, a major plant-limiting nutrient. Many tropical forests possess tree species capable of fixing atmospheric dinitrogen (N2), but it is unclear whether this functional group can supply the nitrogen needed as forests recover from disturbance or previous land use, or expand in response to rising CO2 (refs 6, 8). Here we identify a powerful feedback mechanism in which N2 fixation can overcome ecosystem-scale deficiencies in nitrogen that emerge during periods of rapid biomass accumulation in tropical forests. Over a 300-year chronosequence in Panama, N2-fixing tree species accumulated carbon up to nine times faster per individual than their non-fixing neighbours (greatest difference in youngest forests), and showed species-specific differences in the amount and timing of fixation. As a result of fast growth and high fixation, fixers provided a large fraction of the nitrogen needed to support net forest growth (50,000 kg carbon per hectare) in the first 12 years. A key element of ecosystem functional diversity was ensured by the presence of different N2-fixing tree species across the entire forest age sequence. These findings show that symbiotic N2 fixation can have a central role in nitrogen cycling during tropical forest stand development, with potentially important implications for the ability of tropical forests to sequester CO2.

  11. Development of Preservice Teachers' Value Orientations during a Secondary Methods Course and Early Field Experience

    ERIC Educational Resources Information Center

    Sofo, Seidu; Curtner-Smith, Matthew D.

    2010-01-01

    Few studies have examined the value orientations of physical education preservice teachers (PTs). The purposes of this study were to: (1) describe the extent to which one cohort of PTs' value orientations changed and developed during a secondary methods course and early field experience (EFE); and (2) determine why PTs' value orientations changed…

  12. Development of Preservice Teachers' Value Orientations during a Secondary Methods Course and Early Field Experience

    ERIC Educational Resources Information Center

    Sofo, Seidu; Curtner-Smith, Matthew D.

    2010-01-01

    Few studies have examined the value orientations of physical education preservice teachers (PTs). The purposes of this study were to: (1) describe the extent to which one cohort of PTs' value orientations changed and developed during a secondary methods course and early field experience (EFE); and (2) determine why PTs' value orientations changed…

  13. Simulating secondary succession of elk forage values in a managed forest landscape, western Washington

    NASA Astrophysics Data System (ADS)

    Jenkins, Kurt; Starkey, Edward

    1996-09-01

    Modern timber management practices often influence forage production for elk ( Cervus elaphus) on broad temporal and spatial scales in forested landscapes. We incorporated site-specific information on postharvesting forest succession and forage characteristics in a simulation model to evaluate past and future influences of forest management practices on forage values for elk in a commercially managed Douglas fir ( Pseudotsuga menziesii, PSME)-western hemlock ( Tsuga heterophylla, TSHE) forest in western Washington. We evaluated future effects of: (1) clear-cut logging 0, 20, and 40% of harvestable stands every five years; (2) thinning 20-year-old Douglas fir forests; and (3) reducing the harvesting cycle from 60 to 45 years. Reconstruction of historical patterns of vegetation succession indicated that forage values peaked in the 1960s and declined from the 1970s to the present, but recent values still were higher than may have existed in the unmanaged landscape in 1945. Increased forest harvesting rates had little short-term influence on forage trends because harvestable stands were scarce. Simulations of forest thinning also produced negligible benefits because thinning did not improve forage productivity appreciably at the stand level. Simulations of reduced harvesting cycles shortened the duration of declining forage values from approximately 30 to 15 years. We concluded that simulation models are useful tools for examining landscape responses of forage production to forest management strategies, but the options examined provided little potential for improving elk forages in the immediate future.

  14. Simulating secondary succession of elk forage values in a managed forest landscape, western Washington

    USGS Publications Warehouse

    Jenkins, Kurt J.; Starkey, Edward E.

    1996-01-01

    Modern timber management practices often influence forage production for elk (Cervus elaphus) on broad temporal and spatial scales in forested landscapes. We incorporated site-specific information on postharvesting forest succession and forage characteristics in a simulation model to evaluate past and future influences of forest management practices on forage values for elk in a commercially managed Douglas fir (Pseudotsuga menziesii, PSME)-western hemlock (Tsuga heterophylla, TSHE) forest in western Washington. We evaluated future effects of: (1) clear-cut logging 0, 20, and 40% of harvestable stands every five years; (2) thinning 20-year-old Douglas fir forests; and (3) reducing the harvesting cycle from 60 to 45 years. Reconstruction of historical patterns of vegetation succession indicated that forage values peaked in the 1960s and declined from the 1970s to the present, but recent values still were higher than may have existed in the unmanaged landscape in 1945. Increased forest harvesting rates had little short-term influence on forage trends because harvestable stands were scarce. Simulations of forest thinning also produced negligible benefits because thinning did not improve forage productivity appreciably at the stand level. Simulations of reduced harvesting cycles shortened the duration of declining forage values from approximately 30 to 15 years. We concluded that simulation models are useful tools for examining landscape responses of forage production to forest management strategies, but the options examined provided little potential for improving elk forages in the immediate future.

  15. Relative importance of different secondary successional pathways in an Alaskan boreal forest

    Treesearch

    Thomas A. Kurkowski; Daniel H. Mann; T. Scott Rupp; David L. Verbyla

    2008-01-01

    Postfire succession in the Alaskan boreal forest follows several different pathways, the most common being self-replacement and species-dominance relay. In self-replacement, canopy-dominant tree species replace themselves as the postfire dominants. It implies a relatively unchanging forest composition through time maintained by trees segregated within their respective...

  16. Management Effectiveness of a Secondary Coniferous Forest for Landscape Appreciation and Psychological Restoration

    PubMed Central

    Fujiwara, Akio; Saito, Haruo; Horiuchi, Masahiro

    2017-01-01

    We investigated the influence of forest management on landscape appreciation and psychological restoration in on-site settings by exposing respondents to an unmanaged, dense coniferous (crowding) forest and a managed (thinned) coniferous forest; we set the two experimental settings in the forests of the Fuji Iyashinomoroi Woodland Study Center. The respondents were individually exposed to both settings while sitting for 15 min and were required to answer three questionnaires to analyze the psychological restorative effects before and after the experiment (feeling (the Profile of Mood States), affect (the Positive and Negative Affect Schedule), and subjective restorativeness (the Restorative Outcome Scale). To compare landscape appreciation, they were required to answer another two questionnaires only after the experiment, for scene appreciation (the semantic differential scale) and for the restorative properties of each environment (the Perceived Restorativeness Scale). Finally, we obtained these findings: (1) the respondents evaluated each forest environment highly differently and evaluated the thinned forest setting more positively; (2) the respondents’ impressions of the two physical environments did not appear to be accurately reflected in their evaluations; (3) forest environments have potential restorative effects whether or not they are managed, but these effects can be partially enhanced by managing the forests. PMID:28718831

  17. Management Effectiveness of a Secondary Coniferous Forest for Landscape Appreciation and Psychological Restoration.

    PubMed

    Takayama, Norimasa; Fujiwara, Akio; Saito, Haruo; Horiuchi, Masahiro

    2017-07-18

    We investigated the influence of forest management on landscape appreciation and psychological restoration in on-site settings by exposing respondents to an unmanaged, dense coniferous (crowding) forest and a managed (thinned) coniferous forest; we set the two experimental settings in the forests of the Fuji Iyashinomoroi Woodland Study Center. The respondents were individually exposed to both settings while sitting for 15 min and were required to answer three questionnaires to analyze the psychological restorative effects before and after the experiment (feeling (the Profile of Mood States), affect (the Positive and Negative Affect Schedule), and subjective restorativeness (the Restorative Outcome Scale). To compare landscape appreciation, they were required to answer another two questionnaires only after the experiment, for scene appreciation (the semantic differential scale) and for the restorative properties of each environment (the Perceived Restorativeness Scale). Finally, we obtained these findings: (1) the respondents evaluated each forest environment highly differently and evaluated the thinned forest setting more positively; (2) the respondents' impressions of the two physical environments did not appear to be accurately reflected in their evaluations; (3) forest environments have potential restorative effects whether or not they are managed, but these effects can be partially enhanced by managing the forests.

  18. Gap model development, validation, and application to succession of secondary subtropical dry forests of Puerto Rico

    Treesearch

    Jennifer A. Holm; H.H. Shugart; Skip J. Van Bloem; G.R. Larocque

    2012-01-01

    Because of human pressures, the need to understand and predict the long-term dynamics and development of subtropical dry forests is urgent. Through modifications to the ZELIG simulation model, including the development of species- and site-specific parameters and internal modifications, the capability to model and predict forest change within the 4500-ha Guanica State...

  19. Detection of Interannual Climate Variability in Secondary Forests and Crops Under Traditional and Alternative Shifting Cultivation Using Ikonos Data

    NASA Astrophysics Data System (ADS)

    Sa, T.; Guild, L.; Carvalho, C.; Wickel, A.; Brienza, S.; Kato, M.; Kato, O.; Leibs, C.

    2004-12-01

    Regenerating forests play an important role in long-term carbon sequestration and sustainable landuse as they act as potentially important carbon and nutrient sinks during the shifting agriculture fallow period. The long-term functioning of secondary forests (capoeira) is increasingly threatened by a shortening fallow period during shifting cultivation due to demographic pressures and associated increased vulnerability to severe climatic events. Declining productivity and functioning of fallow forests of shifting cultivation combined with progressive loss of nutrients by successive burning and cropping activities has resulted in declining agricultural productivity. In addition to the effects of intense land use practices, droughts associated with El Nino events are becoming more frequent and severe in moist tropical forests and negative effects on capoeira productivity could be considerable. The principal goal of the research is to determine the extent to which capoeira and agricultural fields are susceptible to extreme climate events (drought) under contrasting landuse/clearing practices. In Igarape-Açu (near Belem, Para), we hypothesize that experimental alternative landuse/clearing practices (mulching) may make capoeira and crops more resilient to the effects of agricultural pressures and drought through increased biomass, soil organic matter and associated increase in soil water storage, and nutrient retention. This experimental practice (mechanized chop-and-mulch) has resulted in increased soil moisture during the cropping phase, reduced loss of nutrients and organic matter, and higher rates of secondary-forest biomass accumulation. This project aims to measure water availability and it's relation to secondary forest and crop productivity in the Brazilian Amazon. We have conducted field efforts during two dry seasons (August-December). Field data on water relations were collected during the dry season of 2001 and 2002 in capoeira and crops for both

  20. Radiocaesium partitioning in Japanese cedar forests following the "early" phase of Fukushima fallout redistribution.

    PubMed

    Coppin, Frederic; Hurtevent, Pierre; Loffredo, Nicolas; Simonucci, Caroline; Julien, Anthony; Gonze, Marc-Andre; Nanba, Kenji; Onda, Yuichi; Thiry, Yves

    2016-11-23

    Our study focused on radiocaesium ((137)Cs) partitioning in forests, three vegetation periods after the Fukushima Daiichi nuclear power plant accident. (137)Cs distribution in forest components (organic and mineral soil layers as well as tree compartments: stem, bark, needles, branches and roots) was measured for two Japanese cedar stand ages (17 and 33 years old). The results showed that around 85% of the initial deposit was found in the forest floor and topsoil. For the youngest stand almost 70% of the deposit is present in the forest floor, whereas for the oldest stand 50% is present in the 0-3 cm mineral soil layer. For trees, old and perennial organs (including dead and living needles and branches, litter fall and outer bark) directly exposed to the fallout remained the most contaminated. The crown concentrated 61-69% of the total tree contamination. Surprisingly the dead organs concentrated 25 ± 9% (young cedars) to 36 ± 20% (mature cedar) of the trees' residual activity, highlighting the importance of that specific compartment in the early post-accident phase for Japanese cedar forests. Although the stem (including bark) represents the highest biomass pool, it only concentrates 3.3% and 4.6% of the initial (137)Cs deposit for mature and young cedars, respectively.

  1. Primary and Secondary Controls on Measurements of Forest Height Using Large-Footprint Lidar at the Hubbard Brook LTER

    NASA Technical Reports Server (NTRS)

    Knox, Robert G.; Blair, J. Bryan; Schwarz, Paul A.; Hofton, Michelle A.; Dubayah, Ralph; Smith, David E. (Technical Monitor)

    2000-01-01

    On September 26, 1999, we mapped canopy structure over 90% of the Hubbard Brook Experimental Forest in White Mountain National Forest, New Hampshire, using the Laser Vegetation Imaging Sensor (LVIS). This airborne instrument was configured to emulate data expected from the Vegetation Canopy Lidar (VCL) space mission. We compared above ground heights of the tallest surfaces detected by lidar with average forest canopy heights estimated from tree-based measurements in or near 346 0.05 ha plots (made in autumn of 1997 and 1998). Vegetation heights had by far the predominant influence on lidar top heights, but with this large data set we were able to measure two significant secondary effects: those of steepness or slope of the underlying terrain and of tree crown form. The size of the slope effect was intermediate between that expected from models of homogeneous canopy layers and for solitary tree crowns. The first detected surfaces were also proportionately taller for plots with more basal area in broad leaved northern hardwoods than for mostly coniferous plots. We expected this because of the contrast between the shapes of cumulative distributions of surface area for elliptical or hemi-elliptical tree crowns and those for conical crowns. Correcting for these secondary effects, when appropriate data are available for calibration, may improve vegetation structure estimates in regional studies using VCL or similar lidar data sources.

  2. Primary and Secondary Controls on Measurements of Forest Height Using Large-Footprint Lidar at the Hubbard Brook LTER

    NASA Technical Reports Server (NTRS)

    Knox, Robert G.; Blair, J. Bryan; Schwarz, Paul A.; Hofton, Michelle A.; Dubayah, Ralph; Smith, David E. (Technical Monitor)

    2000-01-01

    On September 26, 1999, we mapped canopy structure over 90% of the Hubbard Brook Experimental Forest in White Mountain National Forest, New Hampshire, using the Laser Vegetation Imaging Sensor (LVIS). This airborne instrument was configured to emulate data expected from the Vegetation Canopy Lidar (VCL) space mission. We compared above ground heights of the tallest surfaces detected by lidar with average forest canopy heights estimated from tree-based measurements in or near 346 0.05 ha plots (made in autumn of 1997 and 1998). Vegetation heights had by far the predominant influence on lidar top heights, but with this large data set we were able to measure two significant secondary effects: those of steepness or slope of the underlying terrain and of tree crown form. The size of the slope effect was intermediate between that expected from models of homogeneous canopy layers and for solitary tree crowns. The first detected surfaces were also proportionately taller for plots with more basal area in broad leaved northern hardwoods than for mostly coniferous plots. We expected this because of the contrast between the shapes of cumulative distributions of surface area for elliptical or hemi-elliptical tree crowns and those for conical crowns. Correcting for these secondary effects, when appropriate data are available for calibration, may improve vegetation structure estimates in regional studies using VCL or similar lidar data sources.

  3. [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.

  4. Monitoring Regional Forest Disturbances across the US with near Real Time MODIS NDVI Products Resident to the ForWarn Forest Threat Early Warning System

    NASA Technical Reports Server (NTRS)

    Spruce, Joseph P.; Hargrove, William W.; Gasser, Gerald

    2013-01-01

    Forest threats across the US have become increasingly evident in recent years. Sometimes these have resulted in regionally evident disturbance progressions (e.g., from drought, bark beetle outbreaks, and wildfires) that can occur across multiyear durations and have resulted in extensive forest overstory mortality. In addition to stand replacement disturbances, other forests are subject to ephemeral, sometimes yearly defoliation from various insects and varying types and intensities of ephemeral damage from storms. Sometimes, after prolonged severe disturbance, signs of recovery in terms of Normalized Difference Vegetation Index (NDVI) can occur. The growing prominence and threat of forest disturbances in part have led to the formation and implementation of the 2003 Healthy Forest Restoration Act which mandated that national forest threat early warning system be developed and deployed. In response, the US Forest Service collaborated with NASA, DOE Oakridge National Laboratory, and the USGS Eros Data Center to build and roll-out the near real time ForWarn early warning system for monitoring regionally evident forest disturbances. Given the diversity of disturbance types, severities, and durations, ForWarn employs multiple historical baselines that are used with current NDVI to derive a suite of six forest change products that are refreshed every 8 days. ForWarn employs daily quarter kilometer MODIS NDVI data from the Aqua and Terra satellites, including MOD13 data for deriving historical baseline NDVIs and eMODIS 7 NDVI for compiling current NDVI. In doing so, the Time Series Product Tool and the Phenological Parameters Estimation Tool are used to temporally de-noise, fuse, and aggregate current and historical MODIS NDVIs into 24 day composites refreshed every 8 days with 46 dates of products per year. The 24 day compositing interval enables disturbances to be detected, while minimizing the frequency of residual atmospheric contamination. Forest change products are

  5. Comparison of Hensen's node and retinoic acid in secondary axis induction in the early chick embryo.

    PubMed

    Chen, Y; Solursh, M

    1992-10-01

    Retinoic acid (RA) and Hensen's node, the organizer center in the chick embryo, have been shown to have polarizing activity when applied or grafted into the chick limb bud. Here we investigate and compare the effects of RA and grafted Hensen's node on the early chick embryo. Anion exchange beads soaked with RA at concentrations ranging from 5 to 100 ng/ml and implanted on the anterior side or on the left side of the host anteroposterior axis of a stage 4 chick embryo in ovo have the ability to induce secondary axis formation, while beads soaked with RA of the same concentration and implanted on the right side or on the posterior side of the host axis are unable to induce the secondary axis. All of the induced axes contain trunk-tail structures. Hensen's node from quail embryos implanted into the early chick blastoderm could also cause the formation of secondary axes in addition to self-differentiation of the graft into a secondary axis. Both RA and grafted Hensen's node caused the inhibition of forebrain development with an increase in hindbrain development and the host heart to loop in an abnormal direction. The results support the hypothesis that Hensen's node is a source of RA which is involved in early embryogenesis. Alternatively, RA might stimulate the formation of Hensen's nodal properties in adjacent tissue.

  6. Soil-atmosphere N2O and CH4 exchanges was suppressed by litter layer in a subtropical secondary forest

    NASA Astrophysics Data System (ADS)

    Cui, J. J.; Lai, D. Y. F.

    2016-12-01

    Forest soil has a great potential in affecting future climate change through biogeochemical cycling and exchanging greenhouse gases (GHGs) with the atmosphere. As a proxy of changing atmospheric CO2 concentration, enhanced litter production arising from CO2 fertilization can affect soil GHG fluxes and induce feedbacks to the climate system. However, these litter-soil- atmosphere interactions remain unclear, especially in subtropical forests. In this study, we carried out static chamber measurements and field manipulations in a subtropical secondary forest in Hong Kong over one year to investigate the temporal variations and controls, as well as the effects of changing litter amounts on soil-atmosphere GHG fluxes. Our results show distinct seasonal pattern of GHG fluxes and soil parameters over the study period. While CO2 flux did not respond significantly to litter manipulation, regression analysis indicates that CO2 flux was regulated by soil temperature and soil moisture. Litter reduction stimulated mean N2O emissions by 105%, and the positive effect was most pronounced during the hot-humid season from May to October. On the other hand, litter addition was found to reduce CH4 uptake by 32%. Our findings suggest that the presence of litter might serve a physical barrier for gas diffusion. It is suggested that the biogeochemical feedback arising from litterfall should be taken into account in simulating the response of forest GHG fluxes to future global change.

  7. Supporting and Inhibiting the Well-Being of Early Career Secondary School Teachers: Extending Self-Determination Theory

    ERIC Educational Resources Information Center

    Hobson, Andrew J.; Maxwell, Bronwen

    2017-01-01

    This paper reports an original examination of the well-being of early career secondary school teachers in England, which extends the evidence bases relating to early career teachers' working lives, teacher well-being, self-determination theory and performativity, respectively. Drawing on a secondary analysis of qualitative data generated for four…

  8. Post-fire tree establishment and early cohort development in conifer forests of the western Cascades of Oregon, USA

    Treesearch

    Alan J. Tepley; Frederick J. Swanson; Thomas A. Spies

    2014-01-01

    Early-seral ecosystems make important contributions to regional biodiversity by supporting high abundance and diversity of many plant and animal species that are otherwise rare or absent from closed-canopy forests. Therefore, the period of post-fire tree establishment is a key stage in forest stand and ecosystem development that can be viewed in the context of...

  9. Soil nutrients and microbial activity after early and late season prescribed burns in a Sierra Nevada mixed conifer forest

    Treesearch

    Sarah T. Hamman; Ingrid C. Burke; Eric E. Knapp

    2008-01-01

    Restoring the natural fire regime to forested systems that have experienced fire exclusion throughout the past century can be a challenge due to the heavy fuel loading conditions. Fire is being re-introduced to mixed conifer forests in the Sierra Nevada through both early season and late season prescribed burns, even though most fires historically occurred in the late...

  10. Effects of the Forest Floor and Acorn Placement on Establishment and Early Development of Water Oak Seedlings

    Treesearch

    Yanfei Guo; Michael G. Shelton; B.R. Lockhart

    1999-01-01

    Effects of the forest floor (0, 10, 20, 30,40, and 50 Mg/ha) and acorn placement (buried 1.5 cm below the soil surface, pressed into the soil surface, and placed within the forest floor) on establishment and early development of water oak (Quercus nigra L.) seedlings were tested in a 6 x 3 factorial study in southeastern Arkansas. Increasing...

  11. Spatial Simulation of the Dynamics of Establishment of Secondary Forest in Abandoned Pasture in the Central Amazon

    NASA Astrophysics Data System (ADS)

    Rebel, K. T.; Riha, S. J.; Rondon, M. A.; Feldpausch, T. R.; Fernandes, E. C.

    2001-05-01

    In the Amazon, approximately 35 million hectares of primary forest that was converted to pasture is now being abandoned. This represents about 70% of all pastureland that was previously established. The dynamics of reconversion of this land to secondary forest is of interest because the length of time required for pasture to convert to secondary forest will impact net primary productivity and the amount of carbon being stored on abandoned pastures. In addition, the length of time required for pasture to convert to secondary forest may depend on the size of the pasture, whether it is surrounded by primary or secondary forest, and on pasture productivity at the time of abandonment. Pasture productivity at the time of abandonment will depend primarily on the age structure of the pasture grasses and on weediness, which are influenced by grazing and fire history. Also, an understanding of the dynamics of conversion of pastureland to forest can serve as the basis for management strategies to inhibit pasture conversion. A spatial, dynamic model of the conversion of pasture to secondary forest was developed using the PCRaster Dynamic Modeling Package. This software provides a computer language specially developed for modeling temporal and spatial processes in a GIS, and is well suited for the development of ecological, dynamic models. The model of pasture conversion is implemented for the central Amazon. We assume that succession involves only three plant types: pasture grass, weeds and woody plants. The pasture grass is parameterized for Brachiaria (brizantha, humidicola), the weeds for Borreria and Rolandra, and the woody plants for Vismia spp. The model uses a 1m x 1m grid and 2-month time step. Each initial plant and each surviving propagule is referred to as a plant and only occupies one grid cell. A number of values are calculated for each grid cell for each time-step. These include whether vegetation is present and, if so, which species, the age of the species, the

  12. Monitoring Regional Forest Disturbances across the US with Near Real Time MODIS NDVI Products included in the ForWarn Forest Threat Early Warning System

    NASA Astrophysics Data System (ADS)

    Spruce, J.; Hargrove, W. W.; Gasser, J.; Norman, S. P.

    2013-12-01

    Forest threats across the US have become increasingly evident in recent years. These include regionally extensive disturbances (e.g., from drought, bark beetle outbreaks, and wildfires) that can occur across multiyear durations and result in extensive forest mortality. In addition, forests can be subject to ephemeral, sometimes yearly defoliation from various insects and types of storm damage. After prolonged severe disturbance, signs of forest recovery can vary in terms of satellite-based Normalized Difference Vegetation Index (NDVI) values. The increased extent and threat of forest disturbances in part led to the enactment of the 2003 Healthy Forest Restoration Act, which mandated that a national forest threat Early Warning System (EWS) be deployed. In response, the US Forest Service collaborated with NASA, DOE Oak Ridge National Laboratory, and the USGS Eros Data Center to build the near real time ForWarn forest threat EWS for monitoring regionally evident forest disturbances, starting on-line operations in 2010. Given the diversity of disturbance types, severities, and durations, ForWarn employs multiple historical baselines used with current NDVI to derive a suite of six nationwide 'weekly' forest change products. ForWarn uses daily 232 meter MODIS Aqua and Terra satellite NDVI data, including MOD13 products for deriving historical baseline NDVIs and eMODIS products for compiling current NDVI. Separately pre-processing the current and historical NDVIs, the Time Series Product Tool and the Phenological Parameters Estimation Tool are used to temporally reduce noise, fuse, and aggregate MODIS NDVIs into 24 day composites refreshed every 8 days with 46 dates of forest change products per year. The 24 day compositing interval typically enables new disturbances to be detected, while minimizing the frequency of residual atmospheric contamination. ForWarn's three standard forest change products compare current NDVI to that from the previous year, previous 3 years, and

  13. Understanding landowner intentions to create early successional forest habitat in the northeastern United States

    USGS Publications Warehouse

    Dayer, Ashley A.; Stedman, Richard C.; Allred, Shorna B.; Rosenberg, Kenneth V.; Fuller, Angela K.

    2016-01-01

    Early successional forest habitat (ESH) and associated wildlife species in the northeastern United States are in decline. One way to help create early successional forest conditions is engaging private forest landowners in even-aged forest management because their limited participation may have contributed to declines in ESH for wildlife species of high conservation concern. We applied the reasoned action approach from social psychology to predict intentions of landowners in the 13-county Southern Tier of New York State, USA, to conduct patch-cuts, which is a type of even-aged forest management. We tested the predictive ability of the model using data from a mail survey of landowners conducted from November 2010 to January 2011. Landowner intention to conduct patch-cuts was high (55% of respondents), with attitude being the strongest direct predictor of behavioral intention. Our results suggest that patch-cutting intentions are most likely expressed by landowners who think the behavior is good for their land and wildlife, believe in positive outcomes of land and wildlife management, belong to a game wildlife organization, and have conducted patch-cuts in the past. Strategies to engage more landowners in ESH management will have the highest likelihood of success if outreach efforts focus on influencing behavioral beliefs and subsequently attitudes, possibly working with game wildlife organizations to communicate a unified message for habitat conservation, including the importance of maintaining and creating ESH. Our results demonstrate the importance of social science research to increase the likelihood that conservation targets for declining wildlife species are met. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

  14. Stand structural diversity rather than species diversity enhances aboveground carbon storage in secondary subtropical forests in Eastern China

    NASA Astrophysics Data System (ADS)

    Ali, Arshad; Yan, En-Rong; Chen, Han Y. H.; Chang, Scott X.; Zhao, Yan-Tao; Yang, Xiao-Dong; Xu, Ming-Shan

    2016-08-01

    Stand structural diversity, typically characterized by variances in tree diameter at breast height (DBH) and total height, plays a critical role in influencing aboveground carbon (C) storage. However, few studies have considered the multivariate relationships of aboveground C storage with stand age, stand structural diversity, and species diversity in natural forests. In this study, aboveground C storage, stand age, tree species, DBH and height diversity indices, were determined across 80 subtropical forest plots in Eastern China. We employed structural equation modelling (SEM) to test for the direct and indirect effects of stand structural diversity, species diversity, and stand age on aboveground C storage. The three final SEMs with different directions for the path between species diversity and stand structural diversity had a similar goodness of fit to the data. They accounted for 82 % of the variation in aboveground C storage, 55-59 % of the variation in stand structural diversity, and 0.1 to 9 % of the variation in species diversity. Stand age demonstrated strong positive total effects, including a positive direct effect (β = 0.41), and a positive indirect effect via stand structural diversity (β = 0.41) on aboveground C storage. Stand structural diversity had a positive direct effect on aboveground C storage (β = 0.56), whereas there was little total effect of species diversity as it had a negative direct association with, but had a positive indirect effect, via stand structural diversity, on aboveground C storage. The negligible total effect of species diversity on aboveground C storage in the forests under study may have been attributable to competitive exclusion with high aboveground biomass, or a historical logging preference for productive species. Our analyses suggested that stand structural diversity was a major determinant for variations in aboveground C storage in the secondary subtropical forests in Eastern China. Hence, maintaining tree DBH and

  15. Succession stage variation in population size in an early-successional herb in a peri-urban forest

    NASA Astrophysics Data System (ADS)

    Van Rossum, Fabienne

    2009-03-01

    Urban and peri-urban forests incur high anthropogenic pressures (e.g. recreational activities, artificialization, and eutrophication). Plant species from early-successional, transient, forest habitats, often characterized by a short life span and a persistent seed bank in the soil may differ from late-successional species in key-factors for population persistence. This study investigated variation in population size and seedling recruitment for different forest succession stages and three consecutive years in Centaurium erythraea, an early-successional biennial herb, occurring in a peri-urban forest of Brussels urban zone (Belgium). Forest succession stage had a significant impact on C. erythraea population size and on its temporal fluctuation. Populations in closing vegetation (evolving to late-succession stages) showed small population sizes and a low number of recruits compared to populations from stable early-succession vegetation and clearcuts. The number of recruits was the highest after clearcutting, which can be related to the expression of the soil seed bank. Populations showed year-to-year variation in size (flowering individuals and recruits), even in stable (over three years) early-succession forest vegetation. In the absence of disturbance changing succession stage, population size is expected to depend on seed set of the previous years and subsequent seedling recruitment, which can be affected by environmental stochasticity. Opening gaps in the herbaceous vegetation may stimulate seedling recruitment, also in unoccupied patches where "cryptic" seed populations are present in the soil. Forest path and road verges, despite their potential negative impact on forests, can constitute refuge habitats for early-successional forest plant species. Their management should involve the preservation of these species.

  16. Use of Current 2010 Forest Disturbance Monitoring Products for the Conterminous United States in Aiding a National Forest Threat Early Warning System

    NASA Technical Reports Server (NTRS)

    Spruce, Joseph P.; Hargrove, William; Gasser, J.; Smoot, J.; Kuper, P.

    2010-01-01

    This presentation discusses contributions of near real time (NRT) MODIS forest disturbance detection products for the conterminous United States to an emerging national forest threat early warning system (EWS). The latter is being developed by the USDA Forest Service s Eastern and Western Environmental Threat Centers with help from NASA Stennis Space Center and the Oak Ridge National Laboratory. Building off work done in 2009, this national and regional forest disturbance detection and viewing capability of the EWS employs NRT MODIS NDVI data from the USGS eMODIS group and historical NDVI data from standard MOD13 products. Disturbance detection products are being computed for 24 day composites that are refreshed every 8 days. Products for 2010 include 42 dates of the 24 day composites. For each compositing date, we computed % change in forest maximum NDVI products for 2010 with respect to each of three historical baselines of 2009, 2007-2009, and 2003-2009,. The three baselines enable one to view potential current, recent, and longer term forest disturbances. A rainbow color table was applied to each forest change product so that potential disturbances (NDVI drops) were identified in hot color tones and growth (NDVI gains) in cold color tones. Example products were provided to end-users responsible for forest health monitoring at the Federal and State levels. Large patches of potential forest disturbances were validated based on comparisons with available reference data, including Landsat and field survey data. Products were posted on two internet mapping systems for US Forest Service internal and collaborator use. MODIS forest disturbance detection products were computed and posted for use in as little as 1 day after the last input date of the compositing period. Such products were useful for aiding aerial disturbance detection surveys and for assessing disturbance persistence on both inter- and intra-annual scales. Multiple 2010 forest disturbance events were

  17. Use of Current 2010 Forest Disturbance Monitoring Products for the Conterminous United States in Aiding a National Forest Threat Early Warning System

    NASA Astrophysics Data System (ADS)

    Spruce, J.; Hargrove, W. W.; Gasser, J.; Smoot, J.; Kuper, P.

    2010-12-01

    This presentation discusses contributions of near real time (NRT) MODIS forest disturbance detection products for the conterminous United States to an emerging national forest threat early warning system (EWS). The latter is being developed by the USDA Forest Service’s Eastern and Western Environmental Threat Centers with help from NASA Stennis Space Center and the Oak Ridge National Laboratory. Building off work done in 2009, this national and regional forest disturbance detection and viewing capability of the EWS employs NRT MODIS NDVI data from the USGS eMODIS group and historical NDVI data from standard MOD13 products. Disturbance detection products are being computed for 24 day composites that are refreshed every 8 days. Products for 2010 include 42 dates of the 24 day composites. For each compositing date, we computed % change in forest maximum NDVI products for 2010 with respect to each of three historical baselines of 2009, 2007-2009, and 2003-2009. The three baselines enable one to view potential current, recent, and longer term forest disturbances. A rainbow color table was applied to each forest change product so that potential disturbances (NDVI drops) were identified in hot color tones and growth (NDVI gains) in cold color tones. Example products were provided to end-users responsible for forest health monitoring at the Federal and State levels. Large patches of potential forest disturbances were validated based on comparisons with available reference data, including Landsat and field survey data. Products were posted on two internet mapping systems for US Forest Service internal and collaborator use. MODIS forest disturbance detection products were computed and posted for use in as little as 1 day after the last input date of the compositing period. Such products were useful for aiding aerial disturbance detection surveys and for assessing disturbance persistence on both inter- and intra-annual scales. Multiple 2010 forest disturbance events were

  18. Dynamics of hardwood patches in a conifer matrix: 54 years of change in a forested landscape in Coastal Oregon, USA.

    Treesearch

    Rebecca S.H. Kennedy; Tomas A. Spies

    2005-01-01

    Changes to minor patch types in forested landscapes may have large consequences for forest biodiversity. The effects of forest management and environment on these secondary patch types are often poorly understood. For example, do early-to-mid successional minor patch types become more expansive as late successional forest types are fragmented or do they also become...

  19. Intraocular pressure elevation during early postoperative period after secondary intraocular lens implantation in children and adolescents.

    PubMed

    Trivedi, Rupal H; Boden, John H; Mickler, Casey; Wilson, M Edward

    2012-09-01

    To look at the intraocular pressure (IOP) spike in the early postoperative period after secondary intraocular lens (IOL) implantation in children. Miles Center for Pediatric Ophthalmology, Medical University of South Carolina, South Carolina, USA. Retrospective chart review. The postoperative day-1 examination of patients having secondary IOL implantation by the same surgeon was reviewed for an IOP greater than 26 mm Hg. In patients with an IOP spike, the medical history and examination findings that might be associated with the rise were evaluated. Review of 85 patient charts (133 eyes) identified 9 eyes that developed an IOP spike during the early postoperative period. Six eyes were symptomatic, with symptoms including pain, ocular discomfort, nausea, and emesis, and 6 eyes had preoperative aphakic glaucoma, which was controlled with medication. Six of 22 eyes (27%) with preoperative aphakic glaucoma and 3 of 111 eyes (3%) without glaucoma (P<.001) developed an acute IOP rise (relative risk, 10.1). The high incidence of a symptomatic early IOP spike in patients with aphakic glaucoma warrants meticulous ophthalmic viscosurgical device removal at the end of surgery, consideration of the routine use of prophylactic topical and/or systemic glaucoma medication, and monitoring during the early postoperative period. Copyright © 2012 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  20. Functional groups show distinct differences in nitrogen cycling during early stand development: implications for forest management.

    SciTech Connect

    Aubrey, Doug, P.; Coyle, David, R. Coleman, Mark, D.

    2011-08-26

    Nutrient acquisition of forest stands is controlled by soil resource availability and belowground production, but tree species are rarely compared in this regard. Here, we examine ecological and management implications of nitrogen (N) dynamics during early forest stand development in productive commercial tree species with narrow (Populus deltoides Bartr. and Platanus occidentalis L.) and broad (Liquidambar styraciflua L. and Pinus taeda L.) site requirements while grown with a range of nutrient and water resources. We constructed N budgets by measuring N concentration ([N]) and N content (N{sub C}) of above- and belowground perennial and ephemeral tissues, determined N uptake (N{sub UP}), and calculated N use efficiency (NUE). Forest stands regulated [N] within species-specific operating ranges without clear temporal or treatment patterns, thus demonstrating equilibrium between tissue [N] and biomass accumulation. Forest stand N{sub C} and N{sub UP} increased with stand development and paralleled treatment patterns of biomass accumulation, suggesting productivity is tightly linked to N{sub UP}. Inclusion of above- and belowground ephemeral tissue turnover in N{sub UP} calculations demonstrated that maximum N demand for narrow-sites adapted species exceeded 200 kg N ha{sup -1} year{sup -1} while demand for broad-site adapted species was below this level. NUE was species dependent but not consistently influenced by N availability, suggesting relationships between NUE and resource availability were species dependent. Based on early stand development, species with broad site adaptability are favored for woody cropping systems because they maintain high above- and belowground productivity with minimal fertilization requirements due to higher NUE than narrow site adapted species.

  1. Roles of birds and bats in early tropical-forest restoration.

    PubMed

    de la Peña-Domene, Marinés; Martínez-Garza, Cristina; Palmas-Pérez, Sebastián; Rivas-Alonso, Edith; Howe, Henry F

    2014-01-01

    Restoration of tropical forest depended in large part on seed dispersal by fruit-eating animals that transported seeds into planted forest patches. We tested effectiveness of dispersal agents as revealed by established recruits of tree and shrub species that bore seeds dispersed by birds, bats, or both. We documented restoration of dispersal processes over the first 76 months of experimental restoration in southern Mexico. Mixed-model repeated-measures randomized-block ANOVAs of seedlings recruited into experimental controls and mixed-species plantings from late-secondary and mature forest indicated that bats and birds played different roles in the first years of a restoration process. Bats dispersed pioneer tree and shrub species to slowly regenerating grassy areas, while birds mediated recruitment of later-successional species into planted stands of trees and to a lesser extent into controls. Of species of pioneer trees and shrubs established in plots, seven were primarily dispersed by birds, three by bats and four by both birds and bats. Of later-successional species recruited past the seedling stage, 13 were of species primarily dispersed by birds, and six were of species dispersed by both birds and bats. No later-successional species primarily dispersed by bats established in control or planted plots. Establishment of recruited seedlings was ten-fold higher under cover of planted trees than in grassy controls. Even pre-reproductive trees drew fruit-eating birds and the seeds that they carried from nearby forest, and provided conditions for establishment of shade-tolerant tree species. Overall, after 76 months of cattle exclusion, 94% of the recruited shrubs and trees in experimental plots were of species that we did not plant.

  2. Roles of Birds and Bats in Early Tropical-Forest Restoration

    PubMed Central

    de la Peña-Domene, Marinés; Martínez-Garza, Cristina; Palmas-Pérez, Sebastián; Rivas-Alonso, Edith; Howe, Henry F.

    2014-01-01

    Restoration of tropical forest depended in large part on seed dispersal by fruit-eating animals that transported seeds into planted forest patches. We tested effectiveness of dispersal agents as revealed by established recruits of tree and shrub species that bore seeds dispersed by birds, bats, or both. We documented restoration of dispersal processes over the first 76 months of experimental restoration in southern Mexico. Mixed-model repeated-measures randomized-block ANOVAs of seedlings recruited into experimental controls and mixed-species plantings from late-secondary and mature forest indicated that bats and birds played different roles in the first years of a restoration process. Bats dispersed pioneer tree and shrub species to slowly regenerating grassy areas, while birds mediated recruitment of later-successional species into planted stands of trees and to a lesser extent into controls. Of species of pioneer trees and shrubs established in plots, seven were primarily dispersed by birds, three by bats and four by both birds and bats. Of later-successional species recruited past the seedling stage, 13 were of species primarily dispersed by birds, and six were of species dispersed by both birds and bats. No later-successional species primarily dispersed by bats established in control or planted plots. Establishment of recruited seedlings was ten-fold higher under cover of planted trees than in grassy controls. Even pre-reproductive trees drew fruit-eating birds and the seeds that they carried from nearby forest, and provided conditions for establishment of shade-tolerant tree species. Overall, after 76 months of cattle exclusion, 94% of the recruited shrubs and trees in experimental plots were of species that we did not plant. PMID:25118608

  3. Changes in understory species occurrence of a secondary broadleaved forest after mass mortality of oak trees under deer foraging pressure.

    PubMed

    Itô, Hiroki

    2016-01-01

    The epidemic of mass mortality of oak trees by Japanese oak wilt has affected secondary deciduous broadleaved forests that have been used as coppices in Japan. The dieback of oak trees formed gaps in the crown that would be expected to enhance the regeneration of shade-intolerant pioneer species. However, foraging by sika deer Cervus nippon has also affected forest vegetation, and the compound effects of both on forest regeneration should be considered when they simultaneously occur. A field study was conducted in Kyôto City, Japan to investigate how these compound effects affected the vegetation of the understory layer of these forests. The presence/absence of seedlings and saplings was observed for 200 quadrats sized 5 m ×5 m for each species in 1992, before the mass mortality and deer encroachment, and in 2014 after these effects. A hierarchical Bayesian model was constructed to explain the occurrence, survival, and colonization of each species with their responses to the gaps that were created, expanded, or affected by the mass mortality of Quercus serrata trees. The species that occurred most frequently in 1992, Eurya japonica, Quercus glauca, and Cleyera japonica, also had the highest survival probabilities. Deer-unpalatable species such as Symplocos prunifolia and Triadica sebifera had higher colonization rates in the gaps, while the deer-palatable species Aucuba japonica had the smallest survival probability. The gaps thus promoted the colonization of deer-unpalatable plant species such as Symplocos prunifolia and Triadica sebifera. In the future, such deer-unpalatable species may dominate gaps that were created, expanded, or affected by the mass mortality of oak trees.

  4. Changes in understory species occurrence of a secondary broadleaved forest after mass mortality of oak trees under deer foraging pressure

    PubMed Central

    2016-01-01

    The epidemic of mass mortality of oak trees by Japanese oak wilt has affected secondary deciduous broadleaved forests that have been used as coppices in Japan. The dieback of oak trees formed gaps in the crown that would be expected to enhance the regeneration of shade-intolerant pioneer species. However, foraging by sika deer Cervus nippon has also affected forest vegetation, and the compound effects of both on forest regeneration should be considered when they simultaneously occur. A field study was conducted in Kyôto City, Japan to investigate how these compound effects affected the vegetation of the understory layer of these forests. The presence/absence of seedlings and saplings was observed for 200 quadrats sized 5 m ×5 m for each species in 1992, before the mass mortality and deer encroachment, and in 2014 after these effects. A hierarchical Bayesian model was constructed to explain the occurrence, survival, and colonization of each species with their responses to the gaps that were created, expanded, or affected by the mass mortality of Quercus serrata trees. The species that occurred most frequently in 1992, Eurya japonica, Quercus glauca, and Cleyera japonica, also had the highest survival probabilities. Deer-unpalatable species such as Symplocos prunifolia and Triadica sebifera had higher colonization rates in the gaps, while the deer-palatable species Aucuba japonica had the smallest survival probability. The gaps thus promoted the colonization of deer-unpalatable plant species such as Symplocos prunifolia and Triadica sebifera. In the future, such deer-unpalatable species may dominate gaps that were created, expanded, or affected by the mass mortality of oak trees. PMID:28028480

  5. Tree mortality from fire and bark beetles following early and late season prescribed fires in a Sierra Nevada mixed-conifer forest

    USGS Publications Warehouse

    Schwilk, Dylan W.; Knapp, Eric E.; Ferrenberg, Scott; Keeley, Jon E.; Caprio, Anthony C.

    2006-01-01

    Over the last century, fire exclusion in the forests of the Sierra Nevada has allowed surface fuels to accumulate and has led to increased tree density. Stand composition has also been altered as shade tolerant tree species crowd out shade intolerant species. To restore forest structure and reduce the risk of large, intense fires, managers have increasingly used prescription burning. Most fires prior to EuroAmerican settlement occurred during the late summer and early fall and most prescribed burning has taken place during the latter part of this period. Poor air quality and lack of suitable burn windows during the fall, however, have resulted in a need to conduct more prescription burning earlier in the season. Previous reports have suggested that burning during the time when trees are actively growing may increase mortality rates due to fine root damage and/or bark beetle activity. This study examines the effects of fire on tree mortality and bark beetle attacks under prescription burning during early and late season. Replicated early season burn, late season burn and unburned control plots were established in an old-growth mixed conifer forest in the Sierra Nevada that had not experienced a fire in over 120 years. Although prescribed burns resulted in significant mortality of particularly the smallest tree size classes, no difference between early and late season burns was detected. Direct mortality due to fire was associated with fire intensity. Secondary mortality due to bark beetles was not significantly correlated with fire intensity. The probability of bark beetle attack on pines did not differ between early and late season burns, while the probability of bark beetle attack on firs was greater following early season burns. Overall tree mortality appeared to be primarily the result of fire intensity rather than tree phenology at the time of the burns. Early season burns are generally conducted under higher fuel moisture conditions, leading to less fuel

  6. A comparison of the leaf-litter ant fauna in a secondary atlantic forest with an adjacent pine plantation in southeastern Brazil.

    PubMed

    Pacheco, Renata; Silva, Rogério R; Morini, Maria S de C; Brandão, Carlos R F

    2009-01-01

    We investigated the influence of Pinus afforestation on the structure of leaf-litter ant communities in the southeastern Brazilian Atlantic Forest, studying an old secondary forest and a nearly 30 year-old never managed Pinus elliottii reforested area. A total of 12,826 individual ants distributed among 95 species and 32 genera were obtained from 50 1 m(2) samples/ habitat. Of these, 60 species were recorded in the pine plantation and 82 in the area of Atlantic forest; almost 50% of the species found in the secondary forest area were also present in the pine plantation. The number of species per sample was significantly higher in the secondary forest than in the pine plantation. Forest-adapted taxa are the most responsible for ant species richness differences between areas, and the pine plantation is richer in species classified as soil or litter omnivorous-dominants. The specialized ant predators registered in the pine plantation, as seven Dacetini, two Basiceros, two Attini and two Discothyrea, belong to widely distributed species. The NMDS (non-metric multidimensional scaling) ordination also suggested strong differences in similarity among samples of the two areas. Furthermore, this analysis indicated higher sample heterogeneity in the secondary forest, with two clusters of species, while in the pine plantation the species belong to a single cluster. We applied the ant mosaic hypothesis to explain the distribution of the leaf-litter fauna and spatial autocorrelation tests among samples. We argue that the results are likely related to differences in quality and distribution of the leaf-litter between the pine plantation and the secondary area.

  7. The Tropical Ecology, Assessment and Monitoring (TEAM) Network: An early warning system for tropical rain forests.

    PubMed

    Rovero, Francesco; Ahumada, Jorge

    2017-01-01

    While there are well established early warning systems for a number of natural phenomena (e.g. earthquakes, catastrophic fires, tsunamis), we do not have an early warning system for biodiversity. Yet, we are losing species at an unprecedented rate, and this especially occurs in tropical rainforests, the biologically richest but most eroded biome on earth. Unfortunately, there is a chronic gap in standardized and pan-tropical data in tropical forests, affecting our capacity to monitor changes and anticipate future scenarios. The Tropical Ecology, Assessment and Monitoring (TEAM) Network was established to contribute addressing this issue, as it generates real time data to monitor long-term trends in tropical biodiversity and guide conservation practice. We present the Network and focus primarily on the Terrestrial Vertebrates protocol, that uses systematic camera trapping to detect forest mammals and birds, and secondarily on the Zone of Interaction protocol, that measures changes in the anthroposphere around the core monitoring area. With over 3 million images so far recorded, and managed using advanced information technology, TEAM has created the most important data set on tropical forest mammals globally. We provide examples of site-specific and global analyses that, combined with data on anthropogenic disturbance collected in the larger ecosystem where monitoring sites are, allowed us to understand the drivers of changes of target species and communities in space and time. We discuss the potential of this system as a candidate model towards setting up an early warning system that can effectively anticipate changes in coupled human-natural system, trigger management actions, and hence decrease the gap between research and management responses. In turn, TEAM produces robust biodiversity indicators that meet the requirements set by global policies such as the Aichi Biodiversity Targets. Standardization in data collection and public sharing of data in near real time

  8. Synthesis of the conservation value of the early-successional stage in forests of eastern North America

    Treesearch

    David I. King; Scott. Schlossberg

    2014-01-01

    As a result of changes in natural and anthropogenic disturbance regimes, the extent of early-successional forest across much of eastern North American is near historic lows, and continues to decline. This has caused many scientists to identify the conservation of early-successional species as a high priority. In this synthesis, we discuss the conservation implications...

  9. Early augmented language intervention for children with developmental delays: potential secondary motor outcomes.

    PubMed

    Whitmore, Ani S; Romski, Mary Ann; Sevcik, Rose A

    2014-09-01

    This exploratory study examined the potential secondary outcome of an early augmented language intervention that incorporates speech-generating devices (SGD) on motor skill use for children with developmental delays. The data presented are from a longitudinal study by Romski and colleagues. Toddlers in the augmented language interventions were either required (Augmented Communication-Output; AC-O) or not required (Augmented Communication-Input; AC-I) to use the SGD to produce an augmented word. Three standardized assessments and five event-based coding schemes measured the participants' language abilities and motor skills. Toddlers in the AC-O intervention used more developmentally appropriate motor movements and became more accurate when using the SGD to communicate than toddlers in the AC-I intervention. AAC strategies, interventionist/parent support, motor learning opportunities, and physical feedback may all contribute to this secondary benefit of AAC interventions that use devices.

  10. [Early corrective osteotomy after secondary displaced distal radius fractures in children].

    PubMed

    Boeckers, P; Gehrmann, S V; Wild, M; Schädel-Höpfner, M; Windolf, J

    2014-02-01

    Secondary fracture displacement before osseous consolidation of distal radius fractures in children occasionally leads to restricted forearm rotation. So far, there is no consistent treatment recommendation to correct this complication. We report on 5 children with an age of 8-13 years (mean age 12.3 years, 4 boys, 1 girl) with secondary displaced distal radius fractures and high functional deficits in forearm rotation (mean ROM for pro-/supination 70-0-30°) after osseous consolidation. We performed corrective osteotomies of the distal radius using a palmar approach after a mean of 38 days. Stabilisation was achieved with a fixed-angle plate system. At the final follow-up examination (mean 9 months) the forearm rotation was normal. No complications were observed. We consider corrective osteotomies of the distal radius in children with deficits of forearm rotation to be a possible strategy. Early corrective osteotomies can lead to a predictable increase of function through reestablishing normal articulation.

  11. Breeding, Early-Successional Bird Response to Forest Harvests for Bioenergy.

    PubMed

    Grodsky, Steven M; Moorman, Christopher E; Fritts, Sarah R; Castleberry, Steven B; Wigley, T Bently

    2016-01-01

    Forest regeneration following timber harvest is a principal source of habitat for early-successional birds and characterized by influxes of early-successional vegetation and residual downed woody material. Early-successional birds may use harvest residues for communication, cover, foraging, and nesting. Yet, increased market viability of woody biomass as bioenergy feedstock may intensify harvest residue removal. Our objectives were to: 1) evaluate effects of varying intensities of woody biomass harvest on the early-successional bird community; and (2) document early-successional bird use of harvest residues in regenerating stands. We spot-mapped birds from 15 April- 15 July, 2012-2014, in six woody biomass removal treatments within regenerating stands in North Carolina (n = 4) and Georgia (n = 4), USA. Treatments included clearcut harvest followed by: (1) traditional woody biomass harvest with no specific retention target; (2) 15% retention with harvest residues dispersed; (3) 15% retention with harvest residues clustered; (4) 30% retention with harvest residues dispersed; (5) 30% retention with harvest residues clustered; and (6) no woody biomass harvest (i.e., reference site). We tested for treatment-level effects on breeding bird species diversity and richness, early-successional focal species territory density (combined and individual species), counts of breeding birds detected near, in, or on branches of harvest piles/windrows, counts of breeding bird behaviors, and vegetation composition and structure. Pooled across three breeding seasons, we delineated 536 and 654 territories and detected 2,489 and 4,204 birds in the North Carolina and Georgia treatments, respectively. Woody biomass harvest had limited or short-lived effects on the early-successional, breeding bird community. The successional trajectory of vegetation structure, rather than availability of harvest residues, primarily drove avian use of regenerating stands. However, many breeding bird species

  12. Breeding, Early-Successional Bird Response to Forest Harvests for Bioenergy

    PubMed Central

    Grodsky, Steven M.; Moorman, Christopher E.; Fritts, Sarah R.; Castleberry, Steven B.; Wigley, T. Bently

    2016-01-01

    Forest regeneration following timber harvest is a principal source of habitat for early-successional birds and characterized by influxes of early-successional vegetation and residual downed woody material. Early-successional birds may use harvest residues for communication, cover, foraging, and nesting. Yet, increased market viability of woody biomass as bioenergy feedstock may intensify harvest residue removal. Our objectives were to: 1) evaluate effects of varying intensities of woody biomass harvest on the early-successional bird community; and (2) document early-successional bird use of harvest residues in regenerating stands. We spot-mapped birds from 15 April– 15 July, 2012–2014, in six woody biomass removal treatments within regenerating stands in North Carolina (n = 4) and Georgia (n = 4), USA. Treatments included clearcut harvest followed by: (1) traditional woody biomass harvest with no specific retention target; (2) 15% retention with harvest residues dispersed; (3) 15% retention with harvest residues clustered; (4) 30% retention with harvest residues dispersed; (5) 30% retention with harvest residues clustered; and (6) no woody biomass harvest (i.e., reference site). We tested for treatment-level effects on breeding bird species diversity and richness, early-successional focal species territory density (combined and individual species), counts of breeding birds detected near, in, or on branches of harvest piles/windrows, counts of breeding bird behaviors, and vegetation composition and structure. Pooled across three breeding seasons, we delineated 536 and 654 territories and detected 2,489 and 4,204 birds in the North Carolina and Georgia treatments, respectively. Woody biomass harvest had limited or short-lived effects on the early-successional, breeding bird community. The successional trajectory of vegetation structure, rather than availability of harvest residues, primarily drove avian use of regenerating stands. However, many breeding bird

  13. Seed rain dynamics following disturbance exclusion in a secondary tropical dry forest in Morelos, Mexico.

    PubMed

    Ceccon, Eliane; Hernández, Patricia

    2009-01-01

    In most of the legally protected areas in Mexico local inhabitants use natural resources, such as fire wood or cattle grazing. These frequent but low-intensity disturbances have consequences at various levels of the tropical ecosystems and strongly impact forest structure and its regeneration capacity. Despite their importance, the effects of these perturbations in many aspects of tropical forest ecology and in the forest's capacity to recover after disturbance exclusion remain poorly understood. Understanding the impact of these processes on tropical forests is necessary for rehabilitating these forests and enhancing their productivity. In this study, we evaluate the impact of twelve years of exclusion (E) of cattle grazing and fire wood extraction in the composition and dynamics of seed rain, and compare this assessment to a similar analysis in an area where these perturbations continued (without exclusion, WE). We found a strong seasonality in seed rain (96% of seeds fell in the dry season) in both areas. There were no significant differences between E and WE sites in relation to overall seed density, species richness and diversity. However, the distribution along the year of seed species density was significantly different among the E and WE sites. The Jaccard's similarity index between E and WE sites was relatively low (0.57). Barochory was the most common dispersal mode observed among the 23 species in terms of seed species density (48%), followed by anemochory (39%) and zoochory (13%). In relation to seed density, anemochory was the most frequent dispersal mode (88%). Most species in the zone were categorized as small seeds (92%), and there were no significant differences in the distribution of seed size between E and WE. The spatial pattern of dispersal of the four species with the highest relative importance value index, in both areas, was aggregated. Twelve years of disturbance exclusion were not enough to fully restore the seed rain of the area; some

  14. Early stent thrombosis secondary to food allergic reaction: Kounis syndrome following rice pudding ingestion

    PubMed Central

    Tzanis, Georgios; Bonou, Maria; Mikos, Nikolaos; Biliou, Smaragda; Koniari, Ioanna; Kounis, Nicholas G; Barbetseas, John

    2017-01-01

    Kounis syndrome is the concurrence of coronary spasm, acute myocardial infarction or stent thrombosis, with allergic reactions in the setting of mast-cell and platelet activation. In this report Kounis syndrome manifesting as stent thrombosis with left ventricular thrombus formation was triggered by a food-induced allergic reaction. The allergic reaction to food was confirmed by oral rice pudding ingredients challenge test while skin tests were inconclusive. To our knowledge, this is first report of early stent thrombosis secondary to food allergic reaction in a 70-year-old man patient who was found to have left ventricular thrombus and undiagnosed hypertrophic cardiomyopathy. PMID:28400926

  15. Influence of secondary structure on recovery from pauses during early stages of RNA transcription.

    PubMed

    Klopper, A V; Bois, J S; Grill, S W

    2010-03-01

    The initial stages of transcription by RNA polymerase are frequently marked by pausing and stalling events. These events have been linked to an inactive backtracked state in which the polymerase diffuses along the template DNA. We investigate theoretically the influence of RNA secondary structure in confining this diffusion. The effective confinement length peaks at transcript lengths commensurate with early stalling. This finite-size effect accounts for slow progress at the beginning of transcription, which we illustrate via stochastic hopping models for backtracking polymerases.

  16. Influence of secondary structure on recovery from pauses during early stages of RNA transcription

    NASA Astrophysics Data System (ADS)

    Klopper, A. V.; Bois, J. S.; Grill, S. W.

    2010-03-01

    The initial stages of transcription by RNA polymerase are frequently marked by pausing and stalling events. These events have been linked to an inactive backtracked state in which the polymerase diffuses along the template DNA. We investigate theoretically the influence of RNA secondary structure in confining this diffusion. The effective confinement length peaks at transcript lengths commensurate with early stalling. This finite-size effect accounts for slow progress at the beginning of transcription, which we illustrate via stochastic hopping models for backtracking polymerases.

  17. Iatrogenic Femoral Pseudoaneurysm and Secondary Ipsilateral Deep Vein Thrombosis: An Indication for Early Surgical Exploration.

    PubMed

    Papadakis, Marios; Zirngibl, Hubert; Floros, Nikolaos

    2016-07-01

    Pseudoaneurysm formation often complicates transfemoral interventional procedures. Nonsurgical treatment consists of femoral compression and thrombin injection under ultrasound guidance. We report a 74-year-old man who was diagnosed with a pseudoaneurysm, following coronary angiography. Duplex ultrasound revealed deep vein thrombosis of the ipsilateral common femoral vein. Ultrasound-guided thrombin injection was unsuccessfully performed, and the patient subsequently underwent surgical exploration for repair of the pseudoaneurysm and release of the venous compression. The increased local inflammation, because of the thrombosis, added in surgical difficulties. We conclude that early surgical intervention should be considered as a primary strategy in patients with femoral pseudoaneurysms and deep vein thrombosis secondary to femoral compression.

  18. Disturbance history and stand dynamics in secondary and old-growth forests of the Southern Appalachian Mountains, USA

    Treesearch

    Sarah M. Butler; Alan S. White; Katherine J. Elliott; Robert S Seymour

    2014-01-01

    BUTLER, S. M. (Family Forest Research Center, University of Massachusetts, Amherst, MA 01003), A. S. WHITE (School of Forest Resources, University of Maine, Orono, ME 04469-5755), K. J. ELLIOTT (Coweeta Hydrologic Laboratory, Center for Forest Watershed Science, Southern Research Station, USDA Forest Service, Otto, NC 28763) AND R. S. SEYMOUR (School of Forest...

  19. Overwinter survival of neotropical migratory birds in early successional and mature tropical forests

    USGS Publications Warehouse

    Conway, C.J.; Powell, G.V.N.; Nichols, J.D.

    1995-01-01

    Many Neotropical migratory species inhabit both mature and early successional forest on their wintering grounds, yet comparisons of survival rates between habitats are lacking. Consequently, the factors affecting habitat suitability for Neotropical migrants and the potential effects of tropical deforestation on migrants are not well understood. We estimated over-winter survival and capture probabilities of Wood Thrush (Hylocichla mustelina), Ovenbird (Seiurus aurocapillus), Hooded Warbler (Wilsonia citrina), and Kentucky Warbler (Oporomis formosus) inhabiting two common tropical habitat types, mature and early-successional forest. Our results suggest that large differences (for example, ratio of survival rates (gamma) < 0.85) in overwinter survival between these habitats do not exist for any of these species. Age ratios did not differ between habitats, but males were more common in forest habitats and females more common in successional habitats for Hooded Warblers and Kentucky Warblers. Future research on overwinter survival should address the need for age- and sex-specific survival estimates before we can draw strong conclusions regarding winter habitat suitability. Our estimates of over-winter survival extrapolated to annual survival rates that were generally lower than previous estimates of annual survival of migratory birds. Capture probability differed between habitats for Kentucky Warblers, but our results provide strong evidence against large differences in capture probability between habitats for Wood Thrush, Hooded Warblers, and Ovenbirds. We found no temporal or among site differences in survival or capture probability for any of the four species. Additional research is needed to examine the effects of winter habitat use on survival during migration and between-winter survival.

  20. Starch grains reveal early root crop horticulture in the Panamanian tropical forest.

    PubMed

    Piperno, D R; Ranere, A J; Holst, I; Hansell, P

    2000-10-19

    Native American populations are known to have cultivated a large number of plants and domesticated them for their starch-rich underground organs. Suggestions that the likely source of many of these crops, the tropical forest, was an early and influential centre of plant husbandry have long been controversial because the organic remains of roots and tubers are poorly preserved in archaeological sediments from the humid tropics. Here we report the occurrence of starch grains identifiable as manioc (Manihot esculenta Crantz), yams (Dioscorea sp.) and arrowroot (Maranta arundinacea L.) on assemblages of plant milling stones from preceramic horizons at the Aguadulce Shelter, Panama, dated between 7,000 and 5,000 years before present (BP). The artefacts also contain maize starch (Zea mays L.), indicating that early horticultural systems in this region were mixtures of root and seed crops. The data provide the earliest direct evidence for root crop cultivation in the Americas, and support an ancient and independent emergence of plant domestication in the lowland Neotropical forest.

  1. Detection of smoke plume for a land-based early forest fire detection system

    NASA Astrophysics Data System (ADS)

    Saghri, John; Jacobs, John; Davenport, Tim; Garges, David

    2015-09-01

    A promising daytime smoke plume detection for a land-based early forest fire detection system is proposed. The visible video imagery from a land-based monitoring camera is processed to detect the smoke which likely rises in an early stage of a forest fire. Unlike the fire core and its surrounding heat which are detected via day/night infrared imaging, the relatively cold smoke plume can only be captured in the visible spectrum of light. The smoke plume is detected via exploitation of its temporal signature. This is accomplished via Principal Component Transformation (PCT) operations on consecutive sequences of visible video frames followed by spatial filtering of one of the resulting low-order Principal Component (PC) images. It is shown that the blue channel of the Red, Green, Blue (RGB) color camera is most effective in detecting the smoke plume. Smoke plume is clearly detected and isolated via simple blurring, thresholding, and median filtering of one of the resulting low-order principle component (PC) images. The robustness of this PCA-based method relative to simple temporal frame differencing and use of color, i.e., visible spectral signature of smoke, are discussed. Various parameters of the system including the required observation time and number of frames to retain for PCT, selection of which low-order PC to use, and types and sizes of the filters applied to the selected PC image to detect and isolate the smoke plume, are discussed.

  2. Litter thickness, but not root biomass, explains the average and spatial structure of soil hydraulic conductivity in secondary forests and coffee agroecosystems in Veracruz, Mexico.

    PubMed

    Marín-Castro, B E; Negrete-Yankelevich, S; Geissert, D

    2017-12-31

    Secondary forests and coffee agroecosystems are considered good alternatives for conservation of a high capacity for water filtration in the soil where tropical montane cloud forests (TMCF) once grew; however, it is not clear which characteristics of the vegetation modulate the field saturated hydraulic conductivity of the soil (Kfs) and whether these characteristics persist in such derived systems. Here, we explore how changes in vegetation between secondary forests and coffee agroecosystems have consequences for the average value and spatial variation of litter thickness and root biomass, and whether these differences can explain the Kfs and its spatial distribution. We found that the thickest litter, greatest total biomass and thickest roots are in the secondary forest of the north of the study area. The litter is spatially structured in patches of ca. 12m at plot scale in the secondary forest and coffee agroecosystem of the southern area. Like the Kfs, the thickness of the litter and biomass of the thick (>2mm), medium (1-2mm) and fine (<1mm) roots are spatially distributed on a north to south gradient at landscape scale. Our linear model indicates that geographic area (north or south), land use and litter thickness explain the Kfs and its spatial distribution along this gradient. Even on inclusion of the antecedent soil moisture and percentage of clays (found to explain Kfs in a previous study), it was not possible to eliminate from the model geographic area and land use, due to their high explanatory power. However, antecedent soil moisture became redundant on inclusion of the litter layer, which had a greater explanatory power. Our modeling suggests that undiscovered differences prevail between the geographic areas and secondary forest and coffee agroecosystems (possibly related to the edaphogenesis and management practices) that determine the Kfs. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. [Species composition and point pattern analysis of standing trees in secondary Betula albosinensis forest in Xiaolongshan of west Qinling Mountains].

    PubMed

    Guo, Yao-xin; Kang, Bing; Li, Gang; Wang, De-xiang; Yang, Gai-he; Wang, Da-wei

    2011-10-01

    An investigation was conducted on the species composition and population diameter-class structure of a typical secondary Betula albo-sinensis forest in Xiaolongshan of west Qinling Mountains, and the spatial distribution pattern and interspecific correlations of the main populations were analyzed at multiple scales by the O-ring functions of single variable and double variables. In the test forest, B. albo-sinensis was obviously dominant, but from the analysis of DBH class distribution, the B. albo-sinensis seedlings were short of, and the natural regeneration was very poor. O the contrary, the regeneration of Abies fargesii and Populus davidianas was fine. B. albo-sinensis and Salix matsudana had a random distribution at almost all scales, while A. fargesii and P. davidianas were significantly clumped at small scale. B. albo-sinensis had positive correlations with A. fargesii and P. davidianas at medium scale, whereas S. matsudana had negative correlations with B. albo-sinensis, A. fargesii, and P. davidianas at small scale. No significant correlations were observed between other species. The findings suggested that the spatial distribution patterns of the tree species depended on their biological characteristics at small scale, but on the environmental heterogeneity at larger scales. In a period of future time, B. albo-sinensis would still be dominant, but from a long-term view, it was necessary to take some artificial measures to improve the regeneratio of B. albo-sinensis.

  4. Modeling transcriptional networks regulating secondary growth and wood formation in forest trees

    Treesearch

    Lijun Liu; Vladimir Filkov; Andrew Groover

    2013-01-01

    The complex interactions among the genes that underlie a biological process can be modeled and presented as a transcriptional network, in which genes (nodes) and their interactions (edges) are shown in a graphical form similar to a wiring diagram. A large number of genes have been identified that are expressed during the radial woody growth of tree stems (secondary...

  5. Deposition pattern and throughfall fluxes in secondary cool temperate forest, South Korea

    NASA Astrophysics Data System (ADS)

    Kumar Gautam, Mukesh; Lee, Kwang-Sik; Song, Byeong-Yeol

    2017-07-01

    Chemistry and deposition fluxes in the rainfall and throughfall of red pine (Pinus densiflora), black locust (Robinia pseudoacacia), and chestnut (Castanea crenata) monocultures, and mixed red pine-black locust-chestnut stands were examined in a nutrient-limited cool temperate forest of central South Korea. Throughfall was enriched in both basic and acidic constituents relative to rainfall, suggesting that both dry deposition and canopy leaching are important sources of throughfall constituents. Net throughfall fluxes (NTFs) of cations and anions significantly differed among four different stands as well as seasonally. Red pine exhibited highest fluxes (TF and NTF) for Ca2+, black locust for K+, mixed stands for Mg2+, and chestnut for Na+. In contrast, NTF of SO42-, NO3-, and NH4+was highest in the red pine, intermediate in the chestnut and mixed stands, and lowest in the black locust. In general, canopy uptake of H+ and NH4+ for all stands was higher in summer than in winter. Dry deposition appears to play a major role in atmospheric deposition to this cool temperate forest, especially in summer. Dry deposition for both cations and anions displayed high spatial variability, even though stands were adjacent to one another and experienced identical atmospheric deposition loads. Canopy leaching of K+ (95-78% of NTF), Mg2+ (92-23% of NTF), and Ca2+ (91-12% of NTF) was highest for the black locust, lowest for chestnut, and intermediate for the red pine and mixed stands. The present study documented significant changes in throughfall chemistry and NTF among different forest stands, which presumably be related with the differences in the canopy characteristics and differences in their scavenging capacity for dry deposition and canopy exchange. Difference in the canopy retention of H+ and base cation leaching suggests that canopy exchange was mainly driven by weak acid excretion and lesser by H+ exchange reaction. Our results indicate that despite a high base cation

  6. Toward a National Early Warning System for Forest Disturbances Using Remotely Sensed Canopy Phenology

    SciTech Connect

    HargroveJr., William Walter; Spruce, Joe; Gasser, Gerry; Hoffman, Forrest M

    2009-01-01

    Imagine a national system with the ability to quickly identify forested areas under attack from insects or disease. Such an early warning system might minimize surprises such as the explosion of caterpillars referred to in the quotation to the left. Moderate resolution (ca. 500m) remote sensing repeated at frequent (ca. weekly) intervals could power such a monitoring system that would respond in near real-time. An ideal warning system would be national in scope, automated, able to improve its prognostic ability with experience, and would provide regular map updates online in familiar and accessible formats. Such a goal is quite ambitious - analyzing vegetation change weekly at a national scale with moderate resolution is a daunting task. The foremost challenge is discerning unusual or unexpected disturbances from the normal backdrop of seasonal and annual changes in vegetation conditions. A historical perspective is needed to define a 'baseline' for expected, normal behavior against which detected changes can be correctly interpreted. It would be necessary to combine temperature, precipitation, soils, and topographic information with the remotely sensed data to discriminate and interpret the changing vegetation conditions on the ground. Conterminous national coverage implies huge data volumes, even at a moderate resolution (250-500m), and likely requires a supercomputing capability. Finally, such a national warning system must carefully balance the rate of successful threat detection with false positives. Since 2005, the USDA Forest Service has partnered with the NASA Stennis Space Center and Oak Ridge National Laboratory to develop methods for monitoring environmental threats, including native insects and diseases, wildfire, invasive pests and pathogens, tornados, hurricanes, and hail. These tools will be instrumental in helping the Forest Service's two Environmental Threat Assessment Centers better meet their Congressional mandate to help track the health of the

  7. Early Secondary Neurologic Deterioration After Blunt Spinal Trauma: A Review of the Literature.

    PubMed

    Oto, Brandon; Corey, Domenic John; Oswald, James; Sifford, Derek; Walsh, Brooks

    2015-10-01

    The objectives were to review published reports of secondary neurologic deterioration in the early stages of care after blunt spinal trauma and describe its nature, context, and associated risk factors. The authors searched the MEDLINE, EMBASE, and CINAHL databases for English-language studies. Cases were included meeting the criteria age 16 years or older, nonpenetrating trauma, and experiencing neurologic deterioration during prehospital or emergency department (ED) care prior to definitive management (e.g., discharge, spinal clearance by computed tomography, admission to an inpatient service, or surgical intervention). Results were qualitatively analyzed for characteristics and themes. Forty-one qualifying cases were identified from 12 papers. In 30 cases, the new deficits were apparently spontaneous and were not detected until routine reassessment. In 12 cases the authors did attribute deterioration to temporally associated precipitants, seven of which were possibly iatrogenic; these included removal of a cervical collar, placement of a halo device, patient agitation, performance of flexion/extension films, "unintentional manipulation," falling in or near the ED, and forced collar application in patients with ankylosing spondylitis. Thirteen cases occurred during prehospital care, none of them sudden and movement-provoked, and all reported by a single study. Published reports of early secondary neurologic deterioration after blunt spinal trauma are exceptionally rare and generally poorly documented. High-risk features may include altered mental status and ankylosing spondylitis. It is unclear how often events are linked with spontaneous patient movement and whether such events are preventable. © 2015 by the Society for Academic Emergency Medicine.

  8. Effects of local-scale decontamination in a secondary forest contaminated after the Fukushima nuclear power plant accident.

    PubMed

    Ayabe, Yoshiko; Hijii, Naoki; Takenaka, Chisato

    2017-09-01

    We investigated whether local-scale decontamination (removal of the litter layer, superficial soil layer, and understory) in a secondary forest contaminated by the Fukushima nuclear power plant accident reduced (137)Cs contamination of the soil and litter. We also measured (137)Cs concentrations in plants and in the web-building spider Nephila clavata (Nephilidae: Arachnida), as an indicator species, to examine (137)Cs contamination in arthropods. One month after decontamination, the total (137)Cs contamination (soil + litter) was reduced by 20% (100 kBq·m(-2)) relative to that in an adjacent untreated (i.e., contaminated) area, which was however not statistically significant. Four months after decontamination, (137)Cs in the decontaminated area had increased to a level similar to those in the untreated area, and the air radiation dose in the decontaminated area was about 2.1 μSv·h(-1), significantly higher than that in the untreated area (1.9 μSv·h(-1)). This may have been attributed to a torrential rain event. Although no statistically significant reduction was observed, most spiders had a lower (137)Cs contamination than that before the decontamination. This implied that the decontamination may have reduced (137)Cs transfer from soil via litter to N. clavata through the detrital food chains, but may not have reduced the amount of (137)Cs transfer through grazing food chains because the concentration of (137)Cs in living tree leaves was not reduced by the decontamination. In autumn, about 2 kBq·m(-2) of (137)Cs was supplied from foliage to the ground by litterfall. The results suggested that removal of the litter and superficial soil layers in a contaminated forest may be ineffective. The present study suggests that the local-scale decontamination in a secondary forest had no effect on the reduction of (137)Cs contamination in the treated area. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. WET AND DRY SEASON ECOSYSTEM LEVEL FLUXES OF ISOPRENE AND MONOTERPENES FROM A SOUTHEAST ASIAN SECONDARY FOREST AND RUBBER TREE PLANTATION

    EPA Science Inventory

    Canopy scale fluxes of isoprene and monoterpenes were investigated in both wet and dry seasons above a rubber tree (Hevea brasiliensis)/secondary tropical forest in the Yunnan province of southwestern China. Drought conditions were unusually high during the dry season experiment....

  10. WET AND DRY SEASON ECOSYSTEM LEVEL FLUXES OF ISOPRENE AND MONOTERPENES FROM A SOUTHEAST ASIAN SECONDARY FOREST AND RUBBER TREE PLANTATION

    EPA Science Inventory

    Canopy scale fluxes of isoprene and monoterpenes were investigated in both wet and dry seasons above a rubber tree (Hevea brasiliensis)/secondary tropical forest in the Yunnan province of southwestern China. Drought conditions were unusually high during the dry season experiment....

  11. Losing All Interest in School: Social Participation as a Predictor of the Intention to Leave Upper Secondary School Early

    ERIC Educational Resources Information Center

    Frostad, Per; Pijl, Sip Jan; Mjaavatn, Per Egil

    2015-01-01

    Early school leaving in upper secondary education is a serious problem for both students and society. Several reviews have shown that there is no simple cause of early school leaving, but it seems to relate to demographic variables, social factors, academic achievement, and school factors. In this study, data from 2,045 students aged 16 from upper…

  12. Losing All Interest in School: Social Participation as a Predictor of the Intention to Leave Upper Secondary School Early

    ERIC Educational Resources Information Center

    Frostad, Per; Pijl, Sip Jan; Mjaavatn, Per Egil

    2015-01-01

    Early school leaving in upper secondary education is a serious problem for both students and society. Several reviews have shown that there is no simple cause of early school leaving, but it seems to relate to demographic variables, social factors, academic achievement, and school factors. In this study, data from 2,045 students aged 16 from upper…

  13. Promoting Pedagogical Content Knowledge Development for Early Career Secondary Teachers in Science and Technology Using Content Representations

    ERIC Educational Resources Information Center

    Williams, John; Eames, Chris; Hume, Anne; Lockley, John

    2012-01-01

    Background: This research addressed the key area of early career teacher education and aimed to explore the use of a "content representation" (CoRe) as a mediational tool to develop early career secondary teacher pedagogical content knowledge (PCK). This study was situated in the subject areas of science and technology, where sound…

  14. Sap flow based transpiration estimates in species-rich secondary forests of different ages in central Panama during a wet-season drought

    NASA Astrophysics Data System (ADS)

    Bretfeld, M.; Ewers, B. E.; Hall, J. S.; Ogden, F. L.

    2015-12-01

    Many landscapes that were previously covered by mature tropical forests in central Panama today comprise of a mosaic of mature forest fragments, pastures and agricultural land, and regrowing secondary forests. An increasing demand for water due to urbanization and the expansion of the Panama Canal, along with a predicted transition into a dryer climatic period necessitate a better understanding regarding the effects of land use and land use history on hydrological processes. Such knowledge, including water storage, residence times, and fluxes is essential to develop effective land management strategies and propose incentives to alter land use practices to enhance hydrological services. To quantify transpiration rates at different stages of secondary forest succession, we measured sap flow in forests growing for 8, ~25, and 80+ years since last known land use in the 15 km2 "Agua Salud" study area, located in central Panama. In each forest, we selected a subset of at least 15 individuals, representing the local tree size distribution, and recorded data from heat-ratio sap flow sensors every 30 minutes starting in February 2015. All instrumented trees were identified to species and compared to local species distributions. Basal area in the three forest types was 9.1, 10.8, and 50.2 m2 ha-1 for 8, ~25, and 80+ year old forests, respectively. Average daily transpiration was highly correlated to forest age, with highest rates in the oldest forest (3.0 to 18.2 mm ha-1 day-1), followed by intermediate (1.2 to 6.7 mm ha-1 day-1) and youngest forests (0.2 to 2.7 mm ha-1 day-1), suggesting roughly a doubling in transpiration from 8 to ~25 year old forests, despite similar basal area, and again from ~25 to 80+ year old forests. Flow rates in individual trees generally reflected the dry-to-wet season transition but behaved differently in response to the unprecedentedly dry conditions during the first half of 2015 in central Panama.

  15. Modelling the climatic drivers determining secondary growth in Mediterranean forests using a process-based model and multiproxy data

    NASA Astrophysics Data System (ADS)

    Gea-Izquierdo, Guillermo; Guibal, Frederic; Joffre, Richard; Ourcival, Jean-Marc; Simioni, Guillaume; Guiot, Joel

    2015-04-01

    Different physiological processes determine gross primary productivity (GPP) and carbon allocation in relation to environmental forcing. Climatic variability limits these two processes differently and this needs to be properly addressed in process-based forest models. Generally, empirical models have been preferentially used in dendrochronological studies. However, it is necessary to better address the interaction between climate and other factors such as CO2 to properly assess the instability in the climate-growth response expressed by trees and increase the accuracy of the modelled relationships both in forward and inverse models. In this study we evolved an existing mechanistic model originally developed with dendrochronological data. The model was calibrated to fit a combination of eddy covariance CO2 flux data, dendrochronological time series of secondary growth and forest inventory data at two Mediterranean evergreen forests. Among other differences with the original formulation, the model was modified to be climate explicit in the key processes addressing acclimation of photosynthesis and allocation. It succeeded to fit both the high- and the low-frequency response of stand GPP and carbon allocation to the stem as calculated from tree-rings. Simulations suggest a decrease in mean stomatal conductance in response to environmental changes and an increase in mean annual intrinsic water use efficiency in both species during the last 50 years. However, this was not translated on a parallel simulated increase in ecosystem water use efficiency. A long-term decrease in annual GPP matched the local trend in precipitation since the 1970s observed in one site. In contrast, GPP did not show a negative trend and the trees buffered the climatic variability observed at the site where long-term precipitation remained stable. Long-term trends in GPP did not match those in growth, in agreement with the C-sink hypothesis. There is a great potential to use the model with

  16. [Trap-nests used by Centris (Heterocentris) terminata Smith (Hymenoptera: Apidae, Centridini) at secondary Atlantic Forest fragments, in Salvador, Bahia State].

    PubMed

    Drummont, Patrícia; Silva, Fabiana O da; Viana, Blandina F

    2008-01-01

    Ninety-five nests of Centris (Heterocentris) terminata Smith were collected in trap-nests, during November/2001 and January/2003, at two fragments (PZGV e CFO-UFBA) of secondary Atlantic Forest, in Salvador, Bahia State (13 degrees 01' W e 38 degrees 30' S). The highest nest frequencies occurred from December to February (summer), with no nests foundations from August to October (winter - early spring). Two-hundred eight adults emerged from 347 brood cells, being 164 males and 116 females (1: 0.42). During the study period sex ratio was male biased (chi2 = 9.342; gl = 10; P < 0.05). C. terminata nested in holes with diameters 6, 8, 10 mm, but 84,2% were constructed in 8 and 10 mm. nests had one to seven cells arranged in a linear series with the cells partitions built with a mixture of sand and resin or oil. Male is significantly smaller than female, which emerges from the first cells constructed. Immature mortality occurred in 14.1% of brood cells (n = 49), of which 13.0% were due fail in development and 1.2% due to parasitism of Coelioxys sp. (Hymenoptera: Megachilidae) e Tetraonyx sp. (Coleoptera: Meloidae). In the study site, weather, mainly pluviosity, rather than natural enemies influenced seasonal population abundance. The long period of nesting activity, local abundance and usage of trap nests, suggest the potential of C. terminata for management aiming at pollination of native and cultivated plants.

  17. Toward A National Early Warning System for Forest Disturbances Using Remotely Sensed Land Surface Phenology

    SciTech Connect

    HargroveJr., William Walter; Spruce, Joe; Gasser, Gerry; Hoffman, Forrest M

    2009-12-01

    We are using a statistical clustering method for delineating homogeneous ecoregions as a basis for identifying disturbances in forests through time over large areas, up to national and global extents. Such changes can be shown relative to past conditions, or can be predicted relative to present conditions, as with forecasts of future climatic change. This quantitative ecoregion approach can be used to predict destinations for populations whose local environments are forecast to become unsuitable and are forced to migrate as their habitat shifts, and is also useful for predicting the susceptibility of new locations to invasive species like Sudden Oak Death. EFETAC and our sister western center WWETAC, along with our NASA and ORNL collaborators, are designing a new national-scale early warning system for forest threats, called FIRST. Envisioned as a change-detection system, FIRST will identify all land surface cover changes at the MODIS observational scale, and then try to discriminate normal, expected seasonal changes from locations having unusual activity that may represent potential forest threats. As a start, we have developed new national data sets every 16 days from 2002 through 2008, based on land surface phenology, or timing of leaf-out in the spring and brown-down in the fall. Changes in such phenological maps will be shown to contain important information about vegetation health status across the United States. The standard deviation of the duration of fall can be mapped, showing places where length of fall is relatively constant or is variable in length from year to year.

  18. 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.

  19. 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

  20. 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.

  1. An early look at forest regeneration indicator results for the Midwest and Northeast United States

    Treesearch

    William H. McWilliams; James A. Westfall

    2015-01-01

    Interacting regeneration stressors create challenges for policy makers and managers who are tasked with making decisions for restoring forest following major disturbances, such as harvest or catastrophic mortality. Concern over an aging forest, dwindling young forest habitat, and restoration of native forests in the midwest and northeast United States has resulted in...

  2. Bryophyte species diversity in secondary forests dominated by the introduced species Spathodea campanulata Beauv. in Puerto Rico

    Treesearch

    M. E. Perez; I. Sastre de Jesús; A. E. Lugo; O. J. Abelleira Martínez

    2012-01-01

    The introduced tree species Spathodea campanulata (Bignoniaceae) forms novel forests in Puerto Rico, these having emerged after the abandonment of fields in the mid-20th century and resulting in forests with a new species composition. We assessed bryophyte species richness in these novel forests and sought correlations with geological substrate, past land use, forest...

  3. [Temporal variations of soil microbial biomass and enzyme activities during the secondary succession of primary broadleaved-Pinus koraiensis forests in Changbai Mountains of Northeast].

    PubMed

    Hu, Song; Zhang, Ying; Shi, Rong-Jiu; Han, Si-Qin; Li, Hui; Xu, Hui

    2013-02-01

    By the method of space-for-time Substitution, and taking the matured (>200 years old) and over-matured (>200 years old) primary broadleaved-Pinus koraiensis forests and, their secondary forests at different succession stages (20-, 30-, 50-, 80-, and 100 years old Betula platphylla forests) in Changbai Mountains of Northeast China as test objects, this paper studied the temporal variations of soil organic carbon, soil microbial biomass, and soil enzyme activities during the secondary succession of primary broadleaved-Pinus koraiensis forests in the Mountains. Under the 20- and 80 years old B. platphylla forests, the soil organic carbon content in humus layer was the highest (154.8 and 154.3 g.kg-1, respectively); while under the matured and over-matured primary broad-leaved-Pinus koraiensis forests, this organic carbon content was relatively low, being 141. 8 and 133. 4 g.kg , respectively. The soil microbial biomass carbon and microbial quotient and the activities of soil cellulase, peroxidase, acid phosphatase, and cellobiase under the 50- and 80 years old B. platphylla forests were the highest, but the activity of soil polyphenol oxidase was the lowest, which revealed that under middle-aged and matured B. platphylla forests, soil organic carbon had a faster turnover rate, and was probably in a stronger accumulation phase. Statistical analysis showed that the soil microbial biomass carbon had significant positive correlations with the soil organic carbon, total nitrogen, and available phosphorus (r = 0.943, 0. 963, and 0.953, respectively;

  4. Geospatiotemporal Data Mining in an Early Warning System for Forest Threats in the United States

    SciTech Connect

    Hoffman, Forrest M; Mills, Richard T; Kumar, Jitendra; Vulli, Srinivasa S; HargroveJr., William Walter

    2010-01-01

    We investigate the potential of geospatiotemporal data mining of multi-year land surface phenology data (250~m Normalized Difference Vegetation Index (NDVI) values derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) in this study) for the conterminous United States as part of an early warning system to identify threats to forest ecosystems. Cluster analysis of this massive data set, using high-performance computing, provides a basis for several possible approaches to defining the bounds of ``normal'' phenological patterns, indicating healthy vegetation in a given geographic location. We demonstrate the applicability of such an approach, using it to identify areas in Colorado, USA, where an ongoing mountain pine beetle outbreak has caused significant tree mortality.

  5. Archeological treasures protection based on early forest wildfire multi-band imaging detection system

    NASA Astrophysics Data System (ADS)

    Gouverneur, B.; Verstockt, S.; Pauwels, E.; Han, J.; de Zeeuw, P. M.; Vermeiren, J.

    2012-10-01

    Various visible and infrared cameras have been tested for the early detection of wildfires to protect archeological treasures. This analysis was possible thanks to the EU Firesense project (FP7-244088). Although visible cameras are low cost and give good results during daytime for smoke detection, they fall short under bad visibility conditions. In order to improve the fire detection probability and reduce the false alarms, several infrared bands are tested ranging from the NIR to the LWIR. The SWIR and the LWIR band are helpful to locate the fire through smoke if there is a direct Line Of Sight. The Emphasis is also put on the physical and the electro-optical system modeling for forest fire detection at short and longer ranges. The fusion in three bands (Visible, SWIR, LWIR) is discussed at the pixel level for image enhancement and for fire detection.

  6. In situ secondary organic aerosol formation from ambient pine forest air using an oxidation flow reactor

    NASA Astrophysics Data System (ADS)

    Palm, Brett B.; Campuzano-Jost, Pedro; Ortega, Amber M.; Day, Douglas A.; Kaser, Lisa; Jud, Werner; Karl, Thomas; Hansel, Armin; Hunter, James F.; Cross, Eben S.; Kroll, Jesse H.; Peng, Zhe; Brune, William H.; Jimenez, Jose L.

    2016-03-01

    An oxidation flow reactor (OFR) is a vessel inside which the concentration of a chosen oxidant can be increased for the purpose of studying SOA formation and aging by that oxidant. During the BEACHON-RoMBAS (Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics & Nitrogen-Rocky Mountain Biogenic Aerosol Study) field campaign, ambient pine forest air was oxidized by OH radicals in an OFR to measure the amount of SOA that could be formed from the real mix of ambient SOA precursor gases, and how that amount changed with time as precursors changed. High OH concentrations and short residence times allowed for semicontinuous cycling through a large range of OH exposures ranging from hours to weeks of equivalent (eq.) atmospheric aging. A simple model is derived and used to account for the relative timescales of condensation of low-volatility organic compounds (LVOCs) onto particles; condensational loss to the walls; and further reaction to produce volatile, non-condensing fragmentation products. More SOA production was observed in the OFR at nighttime (average 3 µg m-3 when LVOC fate corrected) compared to daytime (average 0.9 µg m-3 when LVOC fate corrected), with maximum formation observed at 0.4-1.5 eq. days of photochemical aging. SOA formation followed a similar diurnal pattern to monoterpenes, sesquiterpenes, and toluene+p-cymene concentrations, including a substantial increase just after sunrise at 07:00 local time. Higher photochemical aging (> 10 eq. days) led to a decrease in new SOA formation and a loss of preexisting OA due to heterogeneous oxidation followed by fragmentation and volatilization. When comparing two different commonly used methods of OH production in OFRs (OFR185 and OFR254-70), similar amounts of SOA formation were observed. We recommend the OFR185 mode for future forest studies. Concurrent gas-phase measurements of air after OH oxidation illustrate the decay of primary VOCs, production of small oxidized organic

  7. In situ secondary organic aerosol formation from ambient pine forest air using an oxidation flow reactor

    DOE PAGES

    Palm, Brett B.; Campuzano-Jost, Pedro; Ortega, Amber M.; ...

    2016-03-08

    An oxidation flow reactor (OFR) is a vessel inside which the concentration of a chosen oxidant can be increased for the purpose of studying SOA formation and aging by that oxidant. During the BEACHON-RoMBAS (Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics & Nitrogen–Rocky Mountain Biogenic Aerosol Study) field campaign, ambient pine forest air was oxidized by OH radicals in an OFR to measure the amount of SOA that could be formed from the real mix of ambient SOA precursor gases, and how that amount changed with time as precursors changed. High OH concentrations and short residence times allowed formore » semicontinuous cycling through a large range of OH exposures ranging from hours to weeks of equivalent (eq.) atmospheric aging. A simple model is derived and used to account for the relative timescales of condensation of low-volatility organic compounds (LVOCs) onto particles; condensational loss to the walls; and further reaction to produce volatile, non-condensing fragmentation products. More SOA production was observed in the OFR at nighttime (average 3 µg m–3 when LVOC fate corrected) compared to daytime (average 0.9 µg m–3 when LVOC fate corrected), with maximum formation observed at 0.4–1.5 eq. days of photochemical aging. SOA formation followed a similar diurnal pattern to monoterpenes, sesquiterpenes, and toluene+p-cymene concentrations, including a substantial increase just after sunrise at 07:00 local time. Higher photochemical aging (>10 eq. days) led to a decrease in new SOA formation and a loss of preexisting OA due to heterogeneous oxidation followed by fragmentation and volatilization. When comparing two different commonly used methods of OH production in OFRs (OFR185 and OFR254-70), similar amounts of SOA formation were observed. We recommend the OFR185 mode for future forest studies. Concurrent gas-phase measurements of air after OH oxidation illustrate the decay of primary VOCs, production of small

  8. The RAISE Connection Program for Early Psychosis: Secondary Outcomes and Mediators and Moderators of Improvement

    PubMed Central

    Marino, Leslie; Nossel, Ilana; Choi, Jean C.; Nuechterlein, Keith; Wang, Yuanjia; Essock, Susan; Bennett, Melanie; McNamara, Karen; Mendon, Sapna; Dixon, Lisa

    2015-01-01

    The aims of this study were to explore secondary outcomes of a coordinated specialty care program for persons with early psychosis, including quality of life and recovery, as well as to explore mediators and moderators of improvement in occupational and social functioning and symptoms. Sixty-five individuals across two sites were enrolled and received services for up to two years. Trajectories for individuals’ outcomes, over time were examined using linear and quadratic mixed-effects models with repeated measures. In addition, baseline prognostic factors of participant improvement in social and occupational functioning were explored based on previous literature and expert opinion of the analytic team. Results demonstrate that the program was effective in improving quality of life and recovery, over time. Furthermore, processing speed was identified as a significant moderator of improvement in occupational GAF, and treatment fidelity, engagement, and family involvement were identified as mediators of improvement in social and occupational functioning. PMID:25900546

  9. Principled Improvement in Science: Forces and proportional relations in early secondary-school teaching

    NASA Astrophysics Data System (ADS)

    Howe, Christine; Ilie, Sonia; Guardia, Paula; Hofmann, Riikka; Mercer, Neil; Riga, Fran

    2015-01-01

    In response to continuing concerns about student attainment and participation in science and mathematics, the epiSTEMe project took a novel approach to pedagogy in these two disciplines. Using principles identified as effective in the research literature (and combining these in a fashion not previously attempted), the project developed topic modules for early secondary-school teaching in the UK, arranged for their implementation in classrooms, and evaluated the results. This paper reports the development, implementation, and evaluation of one of the epiSTEMe science modules. Entitled Forces and Proportional Relations, the module covers standard curricular material in the domain of forces, while paying particular attention to the proportional nature of many key constructs. It was developed in collaboration with a small group of teachers; implemented subsequently in 16 classrooms, in all cases involving students from the first year of secondary school; and evaluated through comparison with first-year students in 13 control classrooms who were studying the topic using established methods. Evaluation addressed topic mastery and opinions about the topic and the manner in which it was taught. While further research is required before definite conclusions are warranted, results relating to topic mastery provide grounds for optimism about the epiSTEMe approach. Furthermore, student opinions about the module were positive.

  10. [Effects of light quality on the seed germination of main tree species in a secondary forest ecosystem of Northeast China].

    PubMed

    Zhang, Min; Zhu, Jiao-Jun; Yan, Qiao-Ling

    2012-10-01

    This paper explored the effects of light quality on the seed germination of five dominant tree species (Larix kaempferi, Phellodendron amurense, Acer mono, Fraxinus mandshurica, and Pinus koraiensis) in a secondary forest ecosystem of Northeast China, based on the experiments with the seeds of the five tree species in laboratory and those of the P. koraiensis and L. kaempferi in the field. Four treatments of different light quality were designed in laboratory (taking dark as the control), and three treatments of R/FR (the ratio of red light and far red light intensity) were installed in the field. The laboratory experiment showed that light quality had less effect on the seed germination of L. kaempferi, but the seed germination rates of the other four tree species were significantly different under the treatments of different light quality. P. amurense had the highest seed germination rate under white light, whereas A. mono, F. mandshurica, and P. koraiensis had the highest one under the alternative irradiation with red light and far red light (R-FR-R). In consistence with the results in laboratory, the seed germination rate of P. koraiensis in the field decreased with decreasing R/FR ratio, while that of L. kaempferi was less affected. Under natural condition, the R-FR-R fluctuated with the activity of sun-fleck, and the seed germination patterns of A. mono, F. mandshurica, and P. koraiensis could be the adaptation to the sun-fleck environment in forest stand. The germination of large seeds was significantly affected by light quality.

  11. [Effects of harvest disturbance on soil CH4 flux in a secondary hardwood forest in Northeast china].

    PubMed

    Hai-Long, Sun

    2013-10-01

    From June, 2007 to October, 2009, a measurement with static chamber/gas chromatograph techniques was conducted on the soil CH4 flux in a typical secondary hardwood forest in Northeast China under the effects of different harvest disturbances, i.e., uncut (control), clear cutting (including both farming and reforestation after clear cutting), 50% stand volume removed, and 25% stand volume removed. In all of the four treatments, the soil was the sink of atmospheric CH4, but cutting decreased the soil CH4 uptake flux, with the order of uncut (-85.03 microg CH4 x m;(-2) x h(-1)) > 50% stand volume removed (-80.31 microg CH4 x m(-2) x h(-1)) > 25% stand volume removed (-70.97 microg CH4 x m(-2)h(-1)) > farming after clear cutting (-65.57 microg CH4 x m(-2) x h(-1)) > reforestation after clear cutting (-62.02 miocrog CH4 x m(-2) x h(-1)). During the study period, the seasonal patterns of the soil CH4 uptake flux in all treatments were similar, with a higher value in growth season and a lower one in winter. After the harvest disturbance, the soil temperature, humidity, and NO(3-)-N, and NH(4+)-N contents were all increased, and the soil CH4 flux had a significant quadratic correlation with soil temperature, and a negative linear correlation with soil moisture content. It was suggested that the increase of the soil moisture, NO(3-)-N, and NHa(4+)-N contents after the forest harvest was the main cause of the decrease of the soil CH4 uptake flux.

  12. Substantial secondary organic aerosol formation in a coniferous forest: observations of both day and night time chemistry

    NASA Astrophysics Data System (ADS)

    Lee, A. K. Y.; Abbatt, J. P. D.; Leaitch, W. R.; Li, S.-M.; Sjostedt, S. J.; Wentzell, J. J. B.; Liggio, J.; Macdonald, A. M.

    2015-10-01

    Substantial biogenic secondary organic aerosol (BSOA) formation was investigated in a coniferous forest mountain region at Whistler, British Columbia. A largely biogenic aerosol growth episode was observed, providing a unique opportunity to investigate BSOA formation chemistry in a forested environment with limited influence from anthropogenic emissions. Positive matrix factorization of aerosol mass spectrometry (AMS) measurement identified two types of BSOA (BSOA-1 and BSOA-2), which were primarily generated by gas-phase oxidation of monoterpenes and perhaps sesquiterpenes. The temporal variations of BSOA-1 and BSOA-2 can be explained by gas-particle partitioning in response to ambient temperature and the relative importance of different oxidation mechanisms between day and night. While BSOA-1 will arise from gas-phase ozonolysis and nitrate radical chemistry at night, BSOA-2 is less volatile than BSOA-1 and consists of products formed via gas-phase oxidation by the OH radical and ozone during the day. Organic nitrates produced through nitrate radical chemistry can account for 22-33 % of BSOA-1 mass at night. The mass spectra of BSOA-1 and BSOA-2 have higher values of the mass fraction of m/z 91 (f91) compared to the background organic aerosol, and so f91 is used as an indicator of BSOA formation pathways. A comparison between laboratory studies in the literature and our field observations highlights the potential importance of gas-phase formation chemistry of BSOA-2 type materials that may not be captured in smog chamber experiments, perhaps due to the wall loss of gas-phase intermediate products.

  13. Assessment on ground-level nitrogen dioxide (NO2) and ammonia (NH3) at secondary forest of Mata Ayer and Kangar, Perlis

    NASA Astrophysics Data System (ADS)

    Abdullah, Nadiah Syafiqah; Kamarudin, Latifah Munirah; Hamidin, Nasrul; Zakaria, Ammar; Gunasagaran, Rajeshkumar; Shakaff, Ali Yeon Md.

    2017-03-01

    The current ground-level concentrations of nitrogen dioxide (NO2) and ammonia (NH3) within forests in Perlis are unknown and hardly investigated. The continual infrastructure development of Perlis and human activities may have played a major role in contributing to the decline of air quality in Perlis. Nitrogen-based trace gases may cause environmental effects while they are airborne or deposited on the ground. Due to the uncertainty of nitrogen trace gases level, this study was conducted to investigate the NO2 and NH3 concentrations within Mata Ayer secondary forest and Kangar. A portable gas monitor-sensor (Aeroqual Series 500) was used to assess the ground-level NO2 and NH3 concentrations, ambient air temperature, and relative humidity. The measurements were conducted in June 2015 between 9:30 am to 4:30 pm. The average NO2 and NH3 concentrations were 0.062 ppm and 0.040 ppm at the secondary forest of Mata Ayer and were found lower than Kangar (0.069 ppm and 0.125 ppm). The ambient air temperature and relative humidity in Kangar were found associated with NO2 (r = -0.420 and r = 0.315) and NH3 (r = -0.423 and r = 0.496). However, this was not the case at Mata Ayer secondary forest. The results indicated that human activities may have influenced the quality of ambient air in Perlis.

  14. Early-successional ectomycorrhizal fungi effectively support extracellular enzyme activities and seedling nitrogen accumulation in mature forests.

    PubMed

    Nicholson, Bailey A; Jones, Melanie D

    2017-04-01

    After stand-replacing disturbance, regenerating conifer seedlings become colonized by different ectomycorrhizal fungi (EMF) than the locally adapted EMF communities present on seedlings in mature forests. We studied whether EMF species that colonized subalpine fir (Abies lasiocarpa) seedlings in clearcuts differed from those that colonized seedlings in adjacent mature forests with respect to mycorrhizoplane extracellular enzyme activities (EEAs) and N status of the seedlings. We tested two alternate hypotheses: (1) that EEAs would differ between the two EMF communities, with higher activities associated with forest-origin communities, and (2) that acclimation to soil environment was considerable enough that EEAs would be determined primarily by the soil type in which the ectomycorrhizas were growing. Naturally colonized fir seedlings were reciprocally transplanted between clearcuts and forests, carrying different EMF communities with them. EEAs were influenced more by destination environment than by EMF community. EEAs were as high in early-successional as in late-successional communities in both destination environments. Buds of clearcut-origin seedlings had the same or higher N contents as forest seedlings after a growing season in either environment. These results indicate that (i) symbiotic EMF and/or their associated microbial communities demonstrate substantial ability to acclimate to new field environments; (ii) the ability to produce organic matter-degrading enzymes is not a trait that necessarily distinguishes early- and late-successional EMF communities in symbiosis; (iii) early-successional EMF are as capable of supporting seedling N accumulation in forest soils as late-successional EMF; and (iv) disturbed ecosystems where early-successional EMF are present should have high resilience for organic matter degradation.

  15. Radiometric correction of multi-temporal Landsat data for characterization of early successional forest patterns in western Oregon.

    Treesearch

    Todd A. Schroeder; Warren B. Cohen; Conghe Song; Morton J. Canty; Zhiqiang. Yang

    2006-01-01

    Detecting and characterizing continuous changes in early forest succession using multi-temporal satellite imagery requires atmospheric correction procedures that are both operationally reliable, and that result in comparable units (e-g., surface reflectance). This paper presents a comparison of five atmospheric correction methods (2 relative, 3 absolute) used to...

  16. 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.

  17. Late Mesolithic and early Neolithic forest disturbance: a high resolution palaeoecological test of human impact hypotheses

    NASA Astrophysics Data System (ADS)

    Innes, James B.; Blackford, Jeffrey J.; Rowley-Conwy, Peter A.

    2013-10-01

    The transition in north-west Europe from the hunter-gatherer societies of the Late Mesolithic to the pioneer farming societies of the early Neolithic is not well understood, either culturally or palaeoecologically. In Britain the final transition was rapid but it is unclear whether novel Neolithic attributes were introduced by immigrants who supplanted the native hunter-gatherers, or whether the latest Mesolithic foragers gradually adopted elements of the Neolithic economic package. In this study, relatively coarse- (10 mm interval) and fine-resolution (2 mm), multi-proxy palaeoecological data including pollen, charcoal and NPPs including fungi, have been used to investigate two phases of vegetation disturbance of (a) distinctly Late Mesolithic and (b) early Neolithic age, at an upland site in northern England in a region with both a Neolithic and a Late Mesolithic archaeological presence. We identify and define the palaeoecological characteristics of these two disturbance phases, about a millennium apart, in order to investigate whether differing land-use techniques can be identified and categorised as of either foraging or early farming cultures. The Late Mesolithic phase is defined by the repetitive application of fire to the woodland to encourage a mosaic of productive vegetation regeneration patches, consistent with the promotion of Corylus and to aid hunting. In this phase, weed species including Plantago lanceolata, Rumex and Chenopodiaceae are frequent, taxa which are normally associated with the first farmers. The early Neolithic phase, including an Ulmus decline, has characteristics consistent with 'forest farming', possibly mainly for domestic livestock, with an inferred succession of tree girdling, fire-prepared cultivation, and coppice-woodland management. Such fine-resolution, potentially diagnostic land-use signatures may in future be used to recognise the cultural complexion of otherwise enigmatic woodland disturbance phases during the centuries of

  18. Very early demonstration of secondary pyramidal tract degeneration by computed tomography.

    PubMed

    Kazui, S; Kuriyama, Y; Sawada, T; Imakita, S

    1994-11-01

    While magnetic resonance imaging has revealed progressive changes in the pyramidal tract in accordance with histopathologic stages of wallerian degeneration secondary to a supratentorial lesion, computed tomography (CT) has only demonstrated a shrinkage of the pyramidal tract in the midbrain or pons during the chronic stage. We present a patient with frontoparietal subcortical hemorrhage in whom serial CT scans clearly demonstrated wallerian degeneration along the axis of the pyramidal tract early in the acute stage. A 63-year-old man with a history of hypertension suddenly developed a deterioration of consciousness, transcortical mixed aphasia, and dense hemiplegia on the right side. CT scans revealed a massive intracerebral hematoma in the frontoparietal subcortices of the left hemisphere. Although initial CT did not detect any hypodense areas along the left pyramidal tract below the hematoma, ill-defined areas of decreased density appeared in the posterior limb of the internal capsule, cerebral peduncle of the midbrain, and pontine base of the left side on day 13 after the stroke. These areas became well demarcated on day 22 and persisted thereafter. An extensive hematoma can interrupt the pyramidal tract fibers that arise not only from the motor cortex and caudal premotor cortex but also from the somatosensory and parietal cortices, allowing very early CT demonstration of wallerian degeneration of the pyramidal tract.

  19. Evidence for a significant proportion of Secondary Organic Aerosol from isoprene above a maritime tropical forest

    NASA Astrophysics Data System (ADS)

    Robinson, N. H.; Hamilton, J. F.; Allan, J. D.; Langford, B.; Oram, D. E.; Chen, Q.; Docherty, K.; Farmer, D. K.; Jimenez, J. L.; Ward, M. W.; Hewitt, C. N.; Barley, M. H.; Jenkin, M. E.; Rickard, A. R.; Martin, S. T.; McFiggans, G.; Coe, H.

    2011-02-01

    Isoprene is the most abundant non-methane biogenic volatile organic compound (BVOC), but the processes governing secondary organic aerosol (SOA) formation from isoprene oxidation are only beginning to become understood and selective quantification of the atmospheric particulate burden remains difficult. Organic aerosol above a tropical rainforest located in Danum Valley, Borneo, Malaysia, a high isoprene emission region, was studied during Summer 2008 using Aerosol Mass Spectrometry and offline detailed characterisation using comprehensive two dimensional gas chromatography. Observations indicate that a substantial fraction (up to 15% by mass) of atmospheric sub-micron organic aerosol was observed as methylfuran (MF) after thermal desorption. This observation was associated with the simultaneous measurements of established gas-phase isoprene oxidation products methylvinylketone (MVK) and methacrolein (MACR). Observations of MF were also made during experimental chamber oxidation of isoprene. Positive matrix factorisation of the AMS organic mass spectral time series produced a robust factor which accounts for an average of 23% (0.18 μg m-3), reaching as much as 53% (0.50 μg m-3) of the total oraganic loading, identified by (and highly correlated with) a strong MF signal. Assuming that this factor is generally representative of isoprene SOA, isoprene derived aerosol plays a significant role in the region. Comparisons with measurements from other studies suggest this type of isoprene SOA plays a role in other isoprene dominated environments, albeit with varying significance.

  20. Early impacts of forest restoration treatments on the ectomycorrhizal fungal community and fine root biomass in a mixed conifer forest.

    Treesearch

    Jane E. Smith; Donaraye McKay; Greg Brenner; Jim McIver; Joseph W. Spatafora

    2005-01-01

    1. The obligate symbiosis formed between ectomycorrhizal fungi (EMF) and roots of tree species in the Pinaceae influences nutrient uptake and surrounding soil structure. Understanding how EMF respond to prescribed fire and thinning will assist forest managers in selecting fuel-reducing restoration treatments that maintain critical soil processes and site productivity....

  1. [Sandflies (Diptera, psychodidae) in a secondary forest area in the Paco do Lumiar city, Maranhao, Brazil: a leishmaniasis transmission area].

    PubMed

    Barros, V L; Rebêlo, J M; Silva, F S

    2000-01-01

    This paper analyzes the wealth of species, relative abundance, seasonal fluctuation, and nocturnal activity of sandflies. The field survey was conducted in a "capoeira" (secondary forest) area in the county of Paço do Lumiar, Maranhão, where cutaneous and transmission of visceral leishmaniasis frequently occurs. Sandflies were captured by CDC-type light traps from 6:00 PM to 6:00 AM, once a month, from March 1997 to February 1998. A total of 489 specimens were collected (251 males and 238 females), distributed among 10 species: Lutzomyia antunesi (45.19%), Lutzomyia whitmani (29.4%), Lutzomyia longipalpis (7.56%), Lutzomyia sordelli (6.34%), Lutzomyia flaviscutellata (4.5%), Brumptomyia avellari (4.09%), Lutzomyia evandroi (1.85%), Lutzomyia umbratilis (0.61%), Lutzomyia corossoniensis (0.41%), and Lutzomyia trispinosa (0.41%). The sandflies were present year round, with higher abundance during the rainy season. They were present in all intervals studied, with the highest frequency between 12:00 PM and 1:00 AM (31%).

  2. Browsing preference and ecological carrying capacity of sambar deer (Cervus unicolor brookei) on secondary vegetation in forest plantation.

    PubMed

    Ismail, Dahlan; Jiwan, Dawend

    2015-02-01

    The browsing preference and ecological carrying capacity (ECC) of sambar deer (Cervus unicolor brookei) in acacia plantations for management and conservation of the ecosystem were investigated at Sabal Forest Reserve in Sarawak, Malaysia. The identification of the species browsed by the sambar deer was based on an observation of the plant parts consumed. ECC estimation was based on body weight (BW) and the physiological stages of animals browsed in six fenced 4-ha paddocks. Sambar deer were found foraging on only 29 out of 42 species of secondary vegetation in the acacia plantation. The remaining species are too high for the deer to reach. Planted species, Shorea macrophylla are not palatable to the deer. This augurs well for the integration of sambar deer into shorea plantations. The most frequently exploited plants were Ficus spp. Sambar deer preferred woody species more than non-woody species and they are browser animals. By producing metabolizable energy of 19,000 to 27,000 MJ/ha, the ECC was five head/ha to 5.25 head/ha. Given its contribution to the conservation of wildlife and its capacity to sustain the ecosystem, the sambar deer integrated farming system offers a promising strategy for the future of tropical forestry management.

  3. [Plant biodiversity and community structure of semi-humid evergreen broadleaved forests at different secondary succession stages].

    PubMed

    Wang, Zhenhong; Duan, Changqun; Yang, Jiansong

    2006-09-01

    To analyze the relationships between plant diversity and community structure of semi-humid evergreen broadleaved forests at different secondary succession stage in the Samachang area of Yunnan Province, some numeral indices were tested, and the results showed that the plant diversity increased gradually with succession, and the species number reached 24 at the latest succession stage. There was a positive linear correlation between plant individual density and species diversity, which could be described by y = 506. 99x + 554.56. A negative correlation was observed between the average height of plant individuals and plant species diversity, and the equation y = -0. 3862x + 11.406 could describe it well. The crown density and basal area increased in logarithm with plant species diversity, and the two equations y = 21.756 1n x + 11.607 and y = 7.4028 ln x + 9.6198 could describe the relations. No regular patterns were observed for the changes of aboveground biomass and plant individual density with plant species diversity. The relations of plant species with plant individual number could also be described by negative power function. Plant competition was intensified with plant species diversity, and each plant species might take the strategy to conserve its greatest population, and to avoid decreasing to less than its critical population, which led to a high individual density, and might change the structural character of the community.

  4. 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.

  5. Litter manipulation and associated invertebrate fauna in secondary forest, central Amazonia, Brazil

    NASA Astrophysics Data System (ADS)

    Santos, Evanira M. R.; Franklin, Elizabeth; Luizão, Flávio J.

    2008-11-01

    Plant litter from selected tree species has been used for improving soil productivity in low-input systems of secondary vegetation in Central Amazon, leading to different conditions for invertebrates. Soil invertebrate assemblages were monitored to test the effects of adding litter types of contrasting nutritional quality and periods of exposure on the development of the community. We established four second growth plots with 80 subplots of 3 m 2 from which the original litter was removed and replaced in 60 subplots. Twenty subplots received Hevea brasiliensis leaves, 20 others Carapa guianensis leaves, and another 20 an equal mixture of H. brasiliensis, C. guianensis and Vismia guianensis. Twenty subplots were left with the original litter. Litter and mineral soil (5 cm deep) sub-horizons were collected after 45, 100, 160, 240 and 300 days of exposure. The invertebrates were extracted using Kempson apparatus. At the day 210, the litter was replenished to match the surrounding litter. Regression analyses showed no significant effect of litter type, but the period of exposure did affect the community in both sub-horizons. Only after the litter replenishment, the type of litter and periods of exposure affected the community in the litter sub-horizon. Because we tried to isolate the effects of litter composition from other large-scale phenomena, several factors interfered in the experiment and potential problems were identified to optimize the investigation. The sampling design must be improved by using a larger number of subsamples for each kind of litter within each plot. Coarse parameters of Order and Family were suited to detect major environmental patterns on soil invertebrates, but taxonomic resolution to species and/or morphospecies is required to detect more subtle effects. Future manipulations should also be done on a longer time scale, and the replicates need to be spread over larger areas to capture the natural variations within the ecosystems.

  6. History of early settlement and land use on the Bent Creek Experimental Forest Buncombe County, NC

    Treesearch

    William A. Nesbitt

    1941-01-01

    This report has been prepared for two reasons: first, it is believed that a description of past land use on the Bent Creek Experimental Forest may enable the research forester to better interpret the forest conditions as he finds them today; and second, a record of the rise and fall of a once prosperous rural community will be preserved for its future sociological...

  7. Early forest thinning changes aboveground carbon distribution among pools, but not total amount

    Treesearch

    Michael S. Schaedel; Andrew J. Larson; David L. R. Affleck; Travis Belote; John M. Goodburn; Deborah S. Page-Dumroese

    2017-01-01

    Mounting concerns about global climate change have increased interest in the potential to use common forest management practices, such as forest density management with thinning, in climate change mitigation and adaptation efforts. Long-term effects of forest density management on total aboveground C are not well understood, especially for precommercial thinning (PCT)...

  8. Early Impacts of Residential Development on Wood Thrushes in an Urbanizing Forest

    Treesearch

    L. E. Friesen; E. D. Cheskey; M. D. Cadman; V. E. Martin; R. J. MacKay

    2005-01-01

    Environmental protection policies sometimes protect forests along an advancing suburban front although many of the forests may be brought into close proximity to residential housing. Research suggests that even when forests are physically preserved, their bird communities are simplified as the surroundings become urbanized. However, little is known of the time required...

  9. Early development of mixed-species studs on the Wayne Nation Forest

    Treesearch

    Eric R. Norland; Dr. David M. Hix

    1993-01-01

    The species compositions of many upland hardwood forests in southeastern Ohio appear to be changing. Since the arrival of settlers, most of the mixed mesophytic forest has been cleared at least once as a result of timber cutting, burning, and agriculture. The compositions of the second- and third-growth forests are shifting toward a smaller component of oaks (...

  10. Projected Effects of CO2 Enrichment on Community Dynamics and Carbon Cycling in an Early-successional Forest

    NASA Astrophysics Data System (ADS)

    Miller, A. D.; Dietze, M.; DeLucia, E. H.; Anderson-Teixeira, K. J.

    2013-12-01

    Early-successional forests are strong carbon (C) sinks that play an important role in the global C cycle. Elevated CO2 may alter C cycling in regenerating forests both directly through ecophysiological mechanisms and indirectly through altered community dynamics, which may be particularly important in early successional forests with high community turnover. Thus, to discriminate impacts of CO2 enrichment on C cycles in regenerating forests it is necessary to characterize how the physiological and successional mechanisms that regulate the C cycle are altered by climate change. Because species are known to display differential growth stimulus under CO2 enrichment, and these species-specific effects are grouped by classic plant functional type, we hypothesize that successional trajectories will be altered in high CO2 forests, compared to forests regenerating under historic climatic conditions. To test this hypothesis, we use the Ecosystem Demography model (ED2), a height- and successional-structured terrestrial biosphere model to predict possible effects of elevated CO2 on forest succession. Using data from the Duke Free Air CO2 Enrichment (FACE) experiment and a nearby chronosequence of pine forests to parameterize and evaluate the model, we use ED2 to project how plant demography and competition will react to elevated CO2 over a 50-100 year time frame. We evaluate the sensitivity of model results to a variety of model configurations, and demonstrate that the outcomes are largely robust to structural uncertainty regarding assumptions about nitrogen limitation and water availability. The model predicts that elevated CO2 will alter C cycling directly through ecophysiological effect and indirectly through altered community dynamics, which in turn affect C cycling. For instance, late-successional hardwood species will receive more benefit on average from elevated CO2, than early-successional hardwoods. After 50 years of 550 ppm CO2, late-successional hardwoods experience

  11. The Hydrologic Response of Forestry Plantations and Secondary Succession in Comparison to Tropical Mature Forest and Pasture in the Panama Canal Watershed

    NASA Astrophysics Data System (ADS)

    Litt, G.; Briceno, J. C.; Crouch, T. D.; Ogden, F. L.

    2012-12-01

    Land use change in the Panama Canal Watershed may have far reaching effects on water quality and water quantity. Dry season water quantity is of particular interest for sustaining and expanding canal operations, therefore an increased understanding of tropical hydrological processes and their relationship to land use may improve management practices by the Panama Canal Authority. The long term Agua Salud Project in the Panama Canal Watershed monitors a number of hydrological factors across various tropical land use types. We hypothesize that the plantations and the secondary succession plot more closely resemble the mature forest's runoff characteristics. In this study we investigate the differences in runoff ratios between the following experimental plots: a teak (tectona grandis) plantation, a native-species plantation and a native secondary succession plot. Results are compared to past analyses on mature forest and pasture control plots while utilizing three years of continuously monitored hydrologic data.

  12. Photosynthesis of seedlings of Otoba novogranatensis (Myristicaceae) and Ruagea glabra (Meliaceae) in abandoned pasture, secondary forest and plantation habitats in Costa Rica.

    PubMed

    Loik, Michael E; Cole, Rebecca J; Holl, Karen D; Sady, Gabriel C

    2013-09-01

    Enrichment planting in naturally recovering secondary forests or in tree plantations is increasingly being used as strategy to restore later-successional, large-seeded tropical forest trees. We seeded two tree species (Otoba novogranatensis and Ruagea glabra) in three agricultural sites in Southern Costa Rica: abandoned pastures, eight to ten year old secondary forests and three year old tree plantations (containing two N-fixing of four total tree species). We measured micrometeorological conditions, soil water content, plant water potential, leaf area, foliar C and N, and photosynthesis to better understand mechanistic responses of seedlings to conditions in the different successional habitats. Micrometeorological conditions, soil water content, and plant water potential were generally similar across habitats. Certain aspects of leaves (such as Specific Leaf Area and foliar N content), and photosynthesis (e.g. quantum yield and electron transport rate) were highest in the plantations, intermediate in the secondary forests, and lowest in abandoned pastures. Enhanced rates of photosynthetic biochemistry (such as Vxmax and Jmax) and Photosystem II efficiency (e.g. thermal energy dissipation) occurred in leaves from the plantations compared to the abandoned pastures, which may be related to higher leaf %N content. Results suggest that foliar N may be of greater importance than soil water content and micrometeorological factors in driving differences in photosynthetic processes across planting habitats. Planting seeds of these two species in plantations containing three year old trees (including two N-fixing species) enhances certain aspects of their photosynthesis and growth, compared to seedlings in abandoned pastures with non-native grasses, and thus can help increase forest recovery on abandoned agricultural lands.

  13. Avian diversity and feeding guilds in a secondary forest, an oil palm plantation and a paddy field in riparian areas of the kerian river basin, perak, malaysia.

    PubMed

    Azman, Nur Munira; Latip, Nurul Salmi Abdul; Sah, Shahrul Anuar Mohd; Akil, Mohd Abdul Muin Md; Shafie, Nur Juliani; Khairuddin, Nurul Liyana

    2011-12-01

    The diversity and the feeding guilds of birds in three different habitats (secondary forest, oil palm plantation and paddy field) were investigated in riparian areas of the Kerian River Basin (KRB), Perak, Malaysia. Point-count observation and mist-netting methods were used to determine bird diversity and abundance. A total of 132 species of birds from 46 families were recorded in the 3 habitats. Species diversity, measured by Shannon's diversity index, was 3.561, 3.183 and 1.042 in the secondary forest, the paddy field and the oil palm plantation, respectively. The vegetation diversity and the habitat structure were important determinants of the number of bird species occurring in an area. The relative abundance of the insectivore, insectivore-frugivore and frugivore guilds was greater in the forest than in the monoculture plantation. In contrast, the relative abundance of the carnivore, granivore and omnivore guilds was higher in the plantation. The results of the study show that the conversion of forest to either oil palm plantation or paddy fields produced a decline in bird diversity and changes in the distribution of bird feeding guilds.

  14. Avian Diversity and Feeding Guilds in a Secondary Forest, an Oil Palm Plantation and a Paddy Field in Riparian Areas of the Kerian River Basin, Perak, Malaysia

    PubMed Central

    Azman, Nur Munira; Latip, Nurul Salmi Abdul; Sah, Shahrul Anuar Mohd; Akil, Mohd Abdul Muin Md; Shafie, Nur Juliani; Khairuddin, Nurul Liyana

    2011-01-01

    The diversity and the feeding guilds of birds in three different habitats (secondary forest, oil palm plantation and paddy field) were investigated in riparian areas of the Kerian River Basin (KRB), Perak, Malaysia. Point-count observation and mist-netting methods were used to determine bird diversity and abundance. A total of 132 species of birds from 46 families were recorded in the 3 habitats. Species diversity, measured by Shannon’s diversity index, was 3.561, 3.183 and 1.042 in the secondary forest, the paddy field and the oil palm plantation, respectively. The vegetation diversity and the habitat structure were important determinants of the number of bird species occurring in an area. The relative abundance of the insectivore, insectivore-frugivore and frugivore guilds was greater in the forest than in the monoculture plantation. In contrast, the relative abundance of the carnivore, granivore and omnivore guilds was higher in the plantation. The results of the study show that the conversion of forest to either oil palm plantation or paddy fields produced a decline in bird diversity and changes in the distribution of bird feeding guilds. PMID:24575217

  15. Stress in mangrove forests: early detection and preemptive rehabilitation are essential for future successful worldwide mangrove forest management

    USGS Publications Warehouse

    Lewis, Roy R; Milbrandt, Eric C; Brown, Benjamin; Krauss, Ken W.; Rovai, Andre S; Beever, James W.; Flynn, Laura L

    2016-01-01

    Mangrove forest rehabilitation should begin much sooner than at the point of catastrophic loss. We describe the need for “mangrove forest heart attack prevention”, and how that might be accomplished in a general sense by embedding plot and remote sensing monitoring within coastal management plans. The major cause of mangrove stress at many sites globally is often linked to reduced tidal flows and exchanges. Blocked water flows can reduce flushing not only from the seaward side, but also result in higher salinity and reduced sediments when flows are blocked landward. Long-term degradation of function leads to acute mortality prompted by acute events, but created by a systematic propensity for long-term neglect of mangroves. Often, mangroves are lost within a few years; however, vulnerability is re-set decades earlier when seemingly innocuous hydrological modifications are made (e.g., road construction, blocked tidal channels), but which remain undetected without reasonable large-scale monitoring.

  16. Truancy in Late Elementary and Early Secondary Education: The Influence of Social Bonds and Self-Control--The TRAILS Study

    ERIC Educational Resources Information Center

    Veenstra, Rene; Lindenberg, Siegwart; Tinga, Frank; Ormel, Johan

    2010-01-01

    Some pupils already show unexcused, illegal, surreptitious absences in elementary education or the first years of secondary education. Are weak social bonds (see also Hirschi, 1969) and a lack of self-control (Gottfredson & Hirschi, 1990) indicative of truancy at an early age? Of the children in our sample, 5% were persistent truants in late…

  17. Open Experimentation on Phenomena of Chemical Reactions via the Learning Company Approach in Early Secondary Chemistry Education

    ERIC Educational Resources Information Center

    Beck, Katharina; Witteck, Torsten; Eilks, Ingo

    2010-01-01

    Presented is a case study on the implementation of open and inquiry-type experimentation in early German secondary chemistry education. The teaching strategy discussed follows the learning company approach. Originally adopted from vocational education, the learning company method is used to redirect lab-oriented classroom practice towards a more…

  18. Investigating the Stress Levels of Early Childhood, Primary and Secondary Pre-Service Teachers during Teaching Practicum

    ERIC Educational Resources Information Center

    Geng, Gretchen; Midford, Richard; Buckworth, Jenny

    2015-01-01

    This study investigated stress levels of pre-service teachers (PSTs) across three categories of teaching context: early childhood, primary and secondary. This paper focused on exploring the stressors in the completion of tasks in teaching practicum in the three categories of teaching context and an awareness of and access to support systems. The…

  19. Open Experimentation on Phenomena of Chemical Reactions via the Learning Company Approach in Early Secondary Chemistry Education

    ERIC Educational Resources Information Center

    Beck, Katharina; Witteck, Torsten; Eilks, Ingo

    2010-01-01

    Presented is a case study on the implementation of open and inquiry-type experimentation in early German secondary chemistry education. The teaching strategy discussed follows the learning company approach. Originally adopted from vocational education, the learning company method is used to redirect lab-oriented classroom practice towards a more…

  20. Secondary Analysis of an Electronic Surveillance System Combined with Multi-focal Interventions for Early Detection of Sepsis.

    PubMed

    Westra, Bonnie L; Landman, Sean; Yadav, Pranjul; Steinbach, Michael

    2017-01-18

    To conduct an independent secondary analysis of a multi-focal intervention for early detection of sepsis that included implementation of change management strategies, electronic surveillance for sepsis, and evidence based point of care alerting using the POC AdvisorTM application.

  1. Truancy in Late Elementary and Early Secondary Education: The Influence of Social Bonds and Self-Control--The TRAILS Study

    ERIC Educational Resources Information Center

    Veenstra, Rene; Lindenberg, Siegwart; Tinga, Frank; Ormel, Johan

    2010-01-01

    Some pupils already show unexcused, illegal, surreptitious absences in elementary education or the first years of secondary education. Are weak social bonds (see also Hirschi, 1969) and a lack of self-control (Gottfredson & Hirschi, 1990) indicative of truancy at an early age? Of the children in our sample, 5% were persistent truants in late…

  2. Do natural disturbances or the forestry practices that follow them convert forests to early-successional communities?

    PubMed

    Brewer, J Stephen; Bertz, Christine A; Cannon, Jeffery B; Chesser, Jason D; Maynard, Erynn E

    2012-03-01

    Stand-replacing natural disturbances in mature forests are traditionally seen as events that cause forests to revert to early stages of succession and maintain species diversity. In some cases, however, such transitions could be an artifact of salvage logging and may increase biotic homogenization. We present initial (two-year) results of a study of the effects of tornado damage and the combined effects of tornado damage and salvage logging on environmental conditions and ground cover plant communities in mixed oak-pine forests in north central Mississippi. Plots were established in salvage-logged areas, adjacent to plots established before the storm in unlogged areas, spanning a gradient of storm damage intensity. Vegetation change directly attributable to tornado damage was driven primarily by a reduction in canopy cover but was not consistent with a transition to an early stage of succession. Although we observed post-storm increases of several disturbance indicators (ruderals), we also observed significant increases in the abundance of a few species indicative of upland forests. Increases in flowering were just as likely to occur in species indicative of forests as in species indicative of open woodlands. Few species declined as a result of the tornado, resulting in a net increase in species richness. Ruderals were very abundant in salvage-logged areas, which contained significantly higher amounts of bare ground and greater variance in soil penetrability than did damaged areas that were not logged. In contrast to unlogged areas severely damaged by the tornado, most upland forest indicators were not abundant in logged areas. Several of the forest and open-woodland indicators that showed increased flowering in damaged areas were absent or sparse in logged areas. Species richness was lower in salvage-logged areas than in adjacent damaged areas but similar to that in undamaged areas. These results suggest that salvage logging prevented positive responses of several

  3. Early forest fire detection using principal component analysis of infrared video

    NASA Astrophysics Data System (ADS)

    Saghri, John A.; Radjabi, Ryan; Jacobs, John T.

    2011-09-01

    A land-based early forest fire detection scheme which exploits the infrared (IR) temporal signature of fire plume is described. Unlike common land-based and/or satellite-based techniques which rely on measurement and discrimination of fire plume directly from its infrared and/or visible reflectance imagery, this scheme is based on exploitation of fire plume temporal signature, i.e., temperature fluctuations over the observation period. The method is simple and relatively inexpensive to implement. The false alarm rate is expected to be lower that of the existing methods. Land-based infrared (IR) cameras are installed in a step-stare-mode configuration in potential fire-prone areas. The sequence of IR video frames from each camera is digitally processed to determine if there is a fire within camera's field of view (FOV). The process involves applying a principal component transformation (PCT) to each nonoverlapping sequence of video frames from the camera to produce a corresponding sequence of temporally-uncorrelated principal component (PC) images. Since pixels that form a fire plume exhibit statistically similar temporal variation (i.e., have a unique temporal signature), PCT conveniently renders the footprint/trace of the fire plume in low-order PC images. The PC image which best reveals the trace of the fire plume is then selected and spatially filtered via simple threshold and median filter operations to remove the background clutter, such as traces of moving tree branches due to wind.

  4. [Effects of cutting intensity on spatial heterogeneity of topsoil temperature in secondary forest in Maoershan region of Heilongjian Province].

    PubMed

    Gu, Jiacun; Wang, Zhengquan; Han, Youzhi; Wang, Xiangrong; Mei, Li; Zhang, Xiujuan; Cheng, Yunhuan

    2006-12-01

    This paper studied the effects of different cutting intensity on the spatial heterogeneity of topsoil (3 - 5 cm) temperature in the secondary forest in Maoershan region of Heilongjiang Province. Three treatments were installed, i.e., no cutting (treatment A), 50% of randomly cutting (treatment B), and clear cutting (treatment C). Based on the requirements of geostatistic analysis, there were 160, 154 and 154 sampling points with a spatial distance of 0.5 - 56 m in the treatments A, B and C, respectively. Topsoil temperature was measured by thermometer in spring and summer during the two years after cutting, and the spatial heterogeneity of the temperature was analyzed by semivariogram and Kriging arithmetic. The results showed that after cutting, the mean value of topsoil temperature had an increase of 0.6 - 4.2 degrees C (P < 0.001), and correlated positively with cutting intensity. The spatial heterogeneity and variation degree of topsoil temperature also increased with the increasing intensity of cutting. As for the small scale spatial heterogeneity of topsoil temperature, it was also increased after cutting, but the scale was mainly within the range of < 20 m and the composition of spatial heterogeneity was slightly affected. The comparison of Kriging maps suggested that in treatments B and C, the spatial pattern strength of topsoil temperature was enhanced, and the difference between treatments B and C and treatment A was larger in spring than in summer. In treatments B and C, topsoil temperature fluctuated and had similar distribution patterns in the same seasons; while in treatment A, the temperature had a relatively even distribution within the year.

  5. Promoting pedagogical content knowledge development for early career secondary teachers in science and technology using content representations

    NASA Astrophysics Data System (ADS)

    Williams, John; Eames, Chris; Hume, Anne; Lockley, John

    2012-11-01

    Background: This research addressed the key area of early career teacher education and aimed to explore the use of a 'content representation' (CoRe) as a mediational tool to develop early career secondary teacher pedagogical content knowledge (PCK). This study was situated in the subject areas of science and technology, where sound teacher knowledge is particularly important to student engagement. Purpose: The study was designed to examine whether such a tool (a CoRe), co-designed by an early career secondary teacher with expert content and pedagogy specialists, can enhance the PCK of early career teachers. The research questions were: How can experts in content and pedagogy work together with early career teachers to develop one science topic CoRe and one technology topic CoRe to support the development of PCK for early career secondary teachers? How does the use of a collaboratively designed CoRe affect the planning of an early career secondary teacher in science or technology? How has engagement in the development and use of an expert-informed CoRe developed an early career teacher's PCK? Sample: The research design incorporated a unique partnership between two expert classroom teachers, two content experts, four early career teachers, and four researchers experienced in science and technology education. Design: This study employed an interpretivist-based methodology and an action research approach within a four-case study design. Data were gathered using qualitative research methods focused on semi-structured interviews, observations and document analysis. Results: The study indicated that CoRes, developed through this collaborative process, helped the early career teachers focus on the big picture of the topic, emphasize particularly relevant areas of content and consider alternative ways of planning for their teaching. Conclusions: This paper presents an analysis of the process of CoRe development by the teacher-expert partnerships and the effect that had on

  6. Relative importance of early-successional forests and shrubland habitats to mammals in the northeastern United States

    USGS Publications Warehouse

    Fuller, T.K.; DeStefano, S.

    2003-01-01

    The majority of the 60 native terrestrial mammal species that reside in the northeastern United States (US) utilize resources from several habitats on a seasonal basis. However, as many as 20 species demonstrate some preference for early-successional forests, shrublands, or old-field habitats. A few of these (e.g. lagomorphs) can be considered obligate users of these habitats, and the specialist carnivores (e.g. felids) that prey on them may consequently also prefer such habitats. Other mammal species that prefer these habitats certainly depend on them to lesser and varying degrees; thus, the consequences of reducing or eliminating early-successional forests, shrublands, or old-field habitats across the landscape will likely have varying demographic consequences, and thus importance, to those species. ?? 2003 Elsevier B.V. All rights reserved.

  7. Early indications of drought impacts on forests in the southeastern United States

    Treesearch

    Michael K. Crosby; Zhaofei Fan; Martin A. Spetich; Ted Leininger; Xingang Fan

    2015-01-01

    In the southeastern United States, drought can pose a significant threat to forests by reducing the  amount of available water, thereby stressing trees. Destructive changes in crown conditions provide the first visible  indication of a problem in a forested area, making it a useful indicator for problems within an  ecosystem. Forest Health and Monitoring (FHM) and...

  8. Spatial and seasonal variations of leaf area index (LAI) in subtropical secondary forests related to floristic composition and stand characters

    NASA Astrophysics Data System (ADS)

    Zhu, Wenjuan; Xiang, Wenhua; Pan, Qiong; Zeng, Yelin; Ouyang, Shuai; Lei, Pifeng; Deng, Xiangwen; Fang, Xi; Peng, Changhui

    2016-07-01

    Leaf area index (LAI) is an important parameter related to carbon, water, and energy exchange between canopy and atmosphere and is widely applied in process models that simulate production and hydrological cycles in forest ecosystems. However, fine-scale spatial heterogeneity of LAI and its controlling factors have yet to be fully understood in Chinese subtropical forests. We used hemispherical photography to measure LAI values in three subtropical forests (Pinus massoniana-Lithocarpus glaber coniferous and evergreen broadleaved mixed forests, Choerospondias axillaris deciduous broadleaved forests, and L. glaber-Cyclobalanopsis glauca evergreen broadleaved forests) from April 2014 to January 2015. Spatial heterogeneity of LAI and its controlling factors were analysed using geostatistical methods and the generalised additive models (GAMs) respectively. Our results showed that LAI values differed greatly in the three forests and their seasonal variations were consistent with plant phenology. LAI values exhibited strong spatial autocorrelation for the three forests measured in January and for the L. glaber-C. glauca forest in April, July, and October. Obvious patch distribution pattern of LAI values occurred in three forests during the non-growing period and this pattern gradually dwindled in the growing season. Stem number, crown coverage, proportion of evergreen conifer species on basal area basis, proportion of deciduous species on basal area basis, and forest types affected the spatial variations in LAI values in January, while stem number and proportion of deciduous species on basal area basis affected the spatial variations in LAI values in July. Floristic composition, spatial heterogeneity, and seasonal variations should be considered for sampling strategy in indirect LAI measurement and application of LAI to simulate functional processes in subtropical forests.

  9. Diversity of Mosquitoes (Diptera: Culicidae) Attracted to Human Subjects in Rubber Plantations, Secondary Forests, and Villages in Luang Prabang Province, Northern Lao PDR.

    PubMed

    Tangena, Julie-Anne A; Thammavong, Phoutmany; Malaithong, Naritsara; Inthavong, Thavone; Ouanesamon, Phuthasone; Brey, Paul T; Lindsay, Steve W

    2017-05-15

    The impact of the rapid expansion of rubber plantations in South-East Asia on mosquito populations is uncertain. We compared the abundance and diversity of adult mosquitoes using human-baited traps in four typical rural habitats in northern Lao PDR: secondary forests, immature rubber plantations, mature rubber plantations, and villages. Generalized estimating equations were used to explore differences in mosquito abundance between habitats, and Simpson's diversity index was used to measure species diversity. Over nine months, 24,927 female mosquitoes were collected, including 51 species newly recorded in Lao PDR. A list of the 114 mosquito species identified is included. More mosquitoes, including vector species, were collected in the secondary forest than immature rubber plantations (rainy season, odds ratio [OR] 0.33, 95% confidence interval [CI] 0.31-0.36; dry season, 0.46, 95% CI 0.41-0.51), mature rubber plantations (rainy season, OR 0.25, 95% CI 0.23-0.27; dry season, OR 0.25, 95% CI 0.22-0.28), and villages (rainy season, OR 0.13, 95% CI 0.12-0.14; dry season, 0.20, 95% CI 0.18-0.23). All habitats showed high species diversity (Simpson's indexes between 0.82-0.86) with vectors of dengue, Japanese encephalitis (JE), lymphatic filariasis, and malaria. In the secondary forests and rubber plantations, Aedes albopictus (Skuse), a dengue vector, was the dominant mosquito species, while in the villages, Culex vishnui (Theobald), a JE vector, was most common. This study has increased the overall knowledge of mosquito fauna in Lao PDR. The high abundance of Ae. albopictus in natural and man-made forests warrants concern, with vector control measures currently only implemented in cities and villages. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  10. Stress in mangrove forests: Early detection and preemptive rehabilitation are essential for future successful worldwide mangrove forest management.

    PubMed

    Lewis, Roy R; Milbrandt, Eric C; Brown, Benjamin; Krauss, Ken W; Rovai, André S; Beever, James W; Flynn, Laura L

    2016-08-30

    Mangrove forest rehabilitation should begin much sooner than at the point of catastrophic loss. We describe the need for "mangrove forest heart attack prevention", and how that might be accomplished in a general sense by embedding plot and remote sensing monitoring within coastal management plans. The major cause of mangrove stress at many sites globally is often linked to reduced tidal flows and exchanges. Blocked water flows can reduce flushing not only from the seaward side, but also result in higher salinity and reduced sediments when flows are blocked landward. Long-term degradation of function leads to acute mortality prompted by acute events, but created by a systematic propensity for long-term neglect of mangroves. Often, mangroves are lost within a few years; however, vulnerability is re-set decades earlier when seemingly innocuous hydrological modifications are made (e.g., road construction, blocked tidal channels), but which remain undetected without reasonable large-scale monitoring. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Options for managing early-successional forest and shrubland bird habitats in the northeastern United States

    Treesearch

    Richard M. DeGraaf; Mariko Yamasaki

    2003-01-01

    Historically, forests in the northeastern United States were disturbed by fire, wind, Native American agriculture, flooding, and beavers (Castor canadensis). Of these, wind and beavers are now the only sources of natural disturbance. Most disturbance-dependent species, especially birds, are declining throughout the region whereas species affiliated with mature forests...

  12. Understanding the Danish Forest School Approach: Early Years Education in Practice. Understanding the... Approach

    ERIC Educational Resources Information Center

    Williams-Siegfredsen, Jane

    2011-01-01

    "Understanding the Danish Forest School Approach" is a much needed source of information for those wishing to extend and consolidate their understanding of the Forest School Approach in Denmark and how it is used in the teaching and learning of young children. It will enable the reader to analyse the essential elements of this Approach…

  13. Effects of wildfire on densities of secondary cavity-nesting birds in ponderosa pine forests of northern Arizona

    Treesearch

    Jill K. Dwyer; William M. Block

    2000-01-01

    Many catastrophic wildfires burned throughout forests in Arizona during the spring and summer of 1996 owing to severely dry conditions. One result of these fires was a loss of preexisting tree cavities for reproduction. In ponderosa pine (Pinus ponderosa) forests most cavities are found in dead trees; therefore, snags are a very important habitat...

  14. Daily MODIS data trends of hurricane-induced forest impact and early recovery

    USGS Publications Warehouse

    Ramsey, Elijah W.; Spruce, Joseph; Rangoonwala, Amina; Suzuoki, Yukihiro; Smoot, James; Gasser, Jerry; Bannister, Terri

    2011-01-01

    We studied the use of daily satellite data from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensors to assess wetland forest damage and recovery from Hurricane Katrina (29 August 2005 landfall). Processed MODIS daily vegetation index (VI) trends were consistent with previously determined impact and recovery patterns provided by the "snapshot" 25 m Landsat Thematic Mapper optical and RADARSAT-1 synthetic aperture radar satellite data. Phenological trends showed high 2004 and 2005 pre-hurricane temporal correspondence within bottomland hardwood forest communities, except during spring green-up, and temporal dissimilarity between these hardwoods and nearby cypress-tupelo swamp forests (Taxodium distichum [baldcypress] and Nyssa aquatica [water tupelo]). MODIS VI trend analyses established that one year after impact, cypress-tupelo and lightly impacted hardwood forests had recovered to near pre-hurricane conditions. In contrast, canopy recovery lagged in the moderately and severely damaged hardwood forests, possibly reflecting regeneration of pre-hurricane species and stand-level replacement by invasive trees.

  15. Daily MODIS Data Trends of Hurricane-Induced Forest Impact and Early Recovery

    NASA Technical Reports Server (NTRS)

    Ramsey, Elijah, III; Spruce, Joseph; Rangoonwala, Amina; Suzuoki, Yukihiro; Smoot, James; Gasser, Jerry; Bannister, Terri

    2011-01-01

    We studied the use of daily satellite data from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensors to assess wetland forest damage and recovery from Hurricane Katrina (29 August 2005 landfall). Processed MODIS daily vegetation index (VI) trends were consistent with previously determined impact and recovery patterns provided by the "snapshot" 25 m Landsat Thematic Mapper optical and RADARSAT-1 synthetic aperture radar satellite data. Phenological trends showed high 2004 and 2005 pre-hurricane temporal correspondence within bottomland hardwood forest communities, except during spring green-up, and temporal dissimilarity between these hardwoods and nearby cypress-tupelo swamp forests (Taxodium distichum [baldcypress] and Nyssa aquatica [water tupelo]). MODIS VI trend analyses established that one year after impact, cypress-tupelo and lightly impacted hardwood forests had recovered to near prehurricane conditions. In contrast, canopy recovery lagged in the moderately and severely damaged hardwood forests, possibly reflecting regeneration of pre-hurricane species and stand-level replacement by invasive trees.

  16. Daily MODIS Data Trends of Hurricane-Induced Forest Impact and Early Recovery

    NASA Technical Reports Server (NTRS)

    Ramsey, Elijah, III; Spruce, Joseph; Rangoonwala, Amina; Suzuoki, Yukihiro; Smoot, James; Gasser, Jerry; Bannister, Terri

    2011-01-01

    We studied the use of daily satellite data from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensors to assess wetland forest damage and recovery from Hurricane Katrina (29 August 2005 landfall). Processed MODIS daily vegetation index (VI) trends were consistent with previously determined impact and recovery patterns provided by the "snapshot" 25 m Landsat Thematic Mapper optical and RADARSAT-1 synthetic aperture radar satellite data. Phenological trends showed high 2004 and 2005 pre-hurricane temporal correspondence within bottomland hardwood forest communities, except during spring green-up, and temporal dissimilarity between these hardwoods and nearby cypress-tupelo swamp forests (Taxodium distichum [baldcypress] and Nyssa aquatica [water tupelo]). MODIS VI trend analyses established that one year after impact, cypress-tupelo and lightly impacted hardwood forests had recovered to near prehurricane conditions. In contrast, canopy recovery lagged in the moderately and severely damaged hardwood forests, possibly reflecting regeneration of pre-hurricane species and stand-level replacement by invasive trees.

  17. Secondary formation of oxalic acid and related organic species from biogenic sources in a larch forest at the northern slope of Mt. Fuji

    NASA Astrophysics Data System (ADS)

    Mochizuki, Tomoki; Kawamura, Kimitaka; Miyazaki, Yuzo; Wada, Ryuichi; Takahashi, Yoshiyuki; Saigusa, Nobuko; Tani, Akira

    2017-10-01

    To better understand the formation of water-soluble organic aerosols in the forest atmosphere, we measured low molecular weight (LMW) dicarboxylic acids, oxocarboxylic acids, α-dicarbonyls, unsaturated fatty acids (UFAs), and water-soluble organic carbon (WSOC) in aerosols from a Larix kaempferi forest located at the northern slope of Mt. Fuji, Japan, in summer 2012. Concentrations of dicarboxylic acids, oxocarboxylic acids, α-dicarbonyls, and WSOC showed maxima in daytime. Relative abundance of oxalic acid in LMW dicarboxylic acids was on average 52% and its average concentration was 214 ng m-3. We found that diurnal and temporal variations of oxalic acid are different from those of isoprene and α-pinene, whereas biogenic secondary organic aerosols (BSOAs) derived from isoprene and α-pinene showed similar variations with oxalic acid. The mass concentration ratios of oxalic acid/BSOAs were relatively constant, although a large variation in the concentrations of toluene that is an anthropogenic volatile organic compound was observed. These results suggest that formation of oxalic acid is associated with the oxidation of isoprene and α-pinene with O3 and other oxidants in the forest atmosphere. In addition, concentrations of UFAs were observed, for the first time, to decrease dramatically during daytime in the forest. Mass concentration ratios of azelaic acid to UFAs showed a positive correlation with O3, suggesting that UFAs are oxidized to yield azelaic acid, which may be further decomposed to oxalic acid in the forest atmosphere. We found that contributions of oxalic acid to WSOC are significantly high ranging from 3.7 to 9.7% (average 6.0%). This study demonstrates that forest ecosystem is an important source of oxalic acid and other dicarboxylic acids in the atmosphere.

  18. Fungal and Bacterial Communities in the Rhizosphere of Pinus tabulaeformis Related to the Restoration of Plantations and Natural Secondary Forests in the Loess Plateau, Northwest China

    PubMed Central

    Yu, Hong-Xia; Wang, Chun-Yan; Tang, Ming

    2013-01-01

    Chinese pine (Pinus tabulaeformis Carr.) is widely planted for restoration in destroyed ecosystems of the Loess Plateau in China. Although soil microbial communities are important subsurface components of the terrestrial ecosystems, little is known about fungal and bacterial communities in the rhizosphere of planted and natural P. tabulaeformis forests in the region. In this study, fungal and bacterial communities in the rhizosphere of P. tabulaeformis were analyzed by nested PCR-DGGE (denaturing gradient gel electrophoresis). Diversity analysis revealed that the values of the Shannon-Wiener index (H) and the Simpson index (D) of fungal communities were higher in natural secondary forests than in plantations except for the 3-year-old site. Moreover, the values of species richness, H, and D of the bacterial communities were also higher in the former. Totally, 18 fungal and 19 bacterial DGGE band types were successfully retrieved and sequenced. The dominant fungi in the rhizosphere of P. tabulaeformis belonged to the phylum of Basidiomycota, while the dominant bacteria belonged to the phylum of Proteobacteria. Principal component analysis indicated that fungal and bacterial species were more unitary in plantations than in natural secondary forests, and the majority of them were more likely to appear in the latter. Correlation analysis showed no significant correlation between the fungal and bacterial community diversities. PMID:24459438

  19. Early Estimates of Public Elementary and Secondary Education Statistics: School Year 2001-02.

    ERIC Educational Resources Information Center

    McDowell, Lena M.; Johnson, Frank

    2002-01-01

    Provides current-year estimates of key statistics for public elementary and secondary schools during the 2001-2002 school year. Data, from the National Center for Education Statistics Common Core of Data, show that student membership in public elementary and secondary education has increased by 1.45 million students since fall 1997 to…

  20. Reduced deep soil water uptake through forest conversion to pasture in Amazonia

    SciTech Connect

    Jipp, P.H.; Nepstad, D.C. Woods Hole Research Center, MA )

    1993-06-01

    Forests of eastern Amazonia are being replaced by pastures and secondary forests. We measured soil water storage and flux in adjacent forest and pasture ecosystems using Time Domain Reflectometry sensors installed in the walls of deep (9-m) shafts. The forest withdrew 597+/-25 mm of soil water stored below 1 m depth during the 1991 dry season (Jun-Dec), 1.7 times more than the pasture. Uptake from the bottom of the forest soil profile continued even after rainfall resumed in early 1992. The hydrologic impacts of tropical deforestation may be most severe for evergreen forests with deep rooting zones in areas of seasonal drought.

  1. Secondary Organic Aerosol Formation and Aging in a Flow Reactor in the Forested Southeast US during SOAS

    NASA Astrophysics Data System (ADS)

    Hu, W.; Palm, B. B.; Hacker, L.; Campuzano Jost, P.; Day, D. A.; Simoes de Sa, S.; Fry, J.; Ayres, B. R.; Draper, D. C.; Ortega, A. M.; Kiendler-Scharr, A.; Panujoka, A.; Virtanen, A.; Miettinen, P.; Krechmer, J.; Canagaratna, M. R.; Thompson, S.; Yatavelli, L. R.; Stark, H.; Worsnop, D. R.; Lechner, M.; Martin, S. T.; Farmer, D.; Brown, S. S.; Jimenez, J. L.

    2013-12-01

    A major field campaign (Southern Oxidant and Aerosol Study, SOAS) was conducted in summer 2013 in a forested area (Centreville Supersite) in the southeast U.S. To investigate secondary organic aerosol (SOA) formation from biogenic volatile organic compounds (BVOCs), 3 flow reactors (potential aerosol mass, PAM) were used to expose ambient air to oxidants and their output was analyzed by state-of-art gas and aerosol instruments including a High-Resolution Aerosol Mass Spectrometer (HR-AMS), a High-Resolution Proton-Transfer Reaction Time-of-Flight Mass Spectrometer (PTR-TOFMS), and for the first time, two different High-Resolution Time-of-Flight Chemical Ionization Mass Spectrometers (HRToF-CIMS), and an SMPS. Ambient air was exposed 24/7 to variable concentrations of each of the 3 main atmospheric oxidants (OH, O3 and NO3) to investigate SOA formation and aging. The OH exposure was estimated by 3 different methods (empirical parameterization, carbon monoxide consumption, and chemical box model). Effective OH exposures up to 7e12 molec cm-3 s were achieved, which is equivalent to over a month of aging in the atmosphere. High SOA formation of up to 12 μg m-3 above ambient concentrations of 5 μg m-3 was observed under intermediate OH exposures, while very high OH exposures led to destruction of ambient OA by ≈ 30%, indicating shifting contributions of functionalization vs. fragmentation, which is similar to previous results from urban and terpene-dominated environments. The highest SOA enhancements were 3-4 times higher than the ambient OA. More SOA is typically formed during nighttime when terpenes are higher and lower during daytime when isoprene is higher. SOA formation is also observed after exposure of ambient air to O3 or NO3, although the amount and oxidation was lower than for OH exposure. Formation of organic nitrates in the NO3 reaction will be discussed. High SOA formation (above 40 μg m-3) and a large number of CIMS ions, indicating many different

  2. Potential of VIIRS Data for Regional Monitoring of Gypsy Moth Defoliation: Implications for Forest Threat Early Warning System

    NASA Astrophysics Data System (ADS)

    Spruce, J. P.; Ryan, R. E.; Smoot, J. C.; Prados, D. L.; McKellip, R. D.; Sader, S. A.; Gasser, G.; May, G.; Hargrove, W.

    2007-12-01

    A NASA RPC (Rapid Prototyping Capability) experiment was conducted to assess the potential of VIIRS (Visible/Infrared Imager/Radiometer Suite) data for monitoring non-native gypsy moth (Lymantria dispar) defoliation of forests. This experiment compares defoliation detection products computed from simulated VIIRS and from MODIS (Moderate Resolution Imaging Spectroradiometer) time series products as potential inputs to a forest threat EWS (Early Warning System) being developed for the USFS (USDA Forest Service). Gypsy moth causes extensive defoliation of broadleaved forests in the United States and is specifically identified in the Healthy Forest Restoration Act (HFRA) of 2003. The HFRA mandates development of a national forest threat EWS. This system is being built by the USFS, and NASA is aiding integration of needed satellite data products into this system, including MODIS products. This RPC experiment enabled the MODIS follow-on, VIIRS, to be evaluated as a data source for EWS forest monitoring products. The experiment included 1) assessment of MODIS-simulated VIIRS NDVI products, and 2) evaluation of gypsy moth defoliation mapping products from MODIS-simulated VIIRS and from MODIS NDVI time series data. This experiment employed MODIS data collected over the approx. 15 million acre mid-Appalachian Highlands during the annual peak defoliation time frame (June 10 through July 27) during 2000-2006. NASA Stennis Application Research Toolbox software was used to produce MODIS-simulated VIIRS data and NASA Stennis Time Series Product Tool software was employed to process MODIS and MODIS-simulated VIIRS time series data scaled to planetary reflectance. MODIS-simulated VIIRS data was assessed through comparison to Hyperion-simulated VIIRS data using data collected during gypsy moth defoliation. Hyperion- simulated MODIS data showed a high correlation with actual MODIS data. MODIS-simulated VIIRS data for the same date showed moderately high correlation with Hyperion

  3. Long-term results of bilateral congenital cataract treated with early cataract surgery, aphakic glasses and secondary IOL implantation.

    PubMed

    Kim, Dong-Hyun; Kim, Jeong Hun; Kim, Seong-Joon; Yu, Young Suk

    2012-05-01

    To evaluate the long-term visual outcome after early surgery of bilateral dense congenital cataracts, aphakic correction with glasses and secondary intraocular lens (IOL) implantation around 2 years of age. The medical records of paediatric patients who underwent cataract extraction, aphakic correction and secondary IOL implantation from 1993 to 2004 at Seoul National University Children's Hospital were reviewed retrospectively. Age at secondary IOL implantation, axial length (AL), best corrected visual acuity (BCVA), refractive error, ocular alignment, stereopsis, and postoperative ocular complications were recorded. Thirty-seven paediatric bilateral pseudophakic patients were identified with a mean follow-up period of 81.4 months. Best corrected visual acuity of 20/40 or better were attained in 44.0% of eyes, and the median BCVA was 20/50. Preoperative factors associated with poor visual prognosis included cataract surgery after 8 weeks of age, interocular AL difference of 0.5 mm or more, and glaucoma. Amblyopic eyes showed more myopic change compared to fellow eyes. Good or moderate binocular function was achieved in 18.9% of all patients. Incidences of strabismus, glaucoma, posterior capsular opacity formation were 46.0%, 32.4% and 4.0%, respectively. Good postoperative BCVA and binocular function were achieved in most healthy children with bilateral dense congenital cataract and no posterior segment pathology. Early cataract surgery, aphakic correction with glasses and secondary IOL implantation around 2 years of age appears to be appropriate methods. © 2010 The Authors. Journal compilation © 2010 Acta Ophthalmol.

  4. Vegetation in group-selection openings: Early trends. Forest Service research note

    SciTech Connect

    McDonald, P.M.; Anderson, P.J.; Fiddler, G.O.

    1997-12-01

    Nine openings that ranged from 0.2 to 1.6 acres and were grouped into small, medium, and large size classes comprised the initial group-selection cut on the Boggs Mountain State Forest in north central California. Five growing seasons after site preparation by pile and burn, 81 plant species in 35 families were present. Forbs, ferns, graminoids, manzanita, other shrubs, and ponderosa pine seedlings were sampled in a variety of environments that ranged from the surrounding forest to near plot centers. Few statistically significant differences were found among opening sizes, but developing trends suggest that significant differences will occur in the near future. Many statistical differences were present when the location of the vegetation in the forest and openings was tested. In general, the density of manzanita, other shrubs, and ferns in the openings was greater than that in the forest. Cover of pine seedlings, manzanita, ferns, and forbs showed similar trends.

  5. 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

  6. Secondary Organic Aerosol Formation and Aging in a Flow Reactor in the Forested Southeast US during SOAS

    NASA Astrophysics Data System (ADS)

    Hu, W.; Palm, B. B.; Hacker, L.; Campuzano Jost, P.; Day, D. A.; de Sá, S. S.; Ayres, B. R.; Draper, D.; Fry, J.; Ortega, A. M.; Kiendler-Scharr, A.; Pajunoja, A.; Virtanen, A.; Krechmer, J.; Canagaratna, M. R.; Thompson, S.; Yatavelli, R. L. N.; Stark, H.; Worsnop, D. R.; Martin, S. T.; Farmer, D.; Brown, S. S.; Jimenez, J. L.

    2015-12-01

    A major field campaign (Southern Oxidant and Aerosol Study, SOAS) was conducted in summer 2013 in a forested area in Centreville Supersite, AL (SEARCH network) in the southeast U.S. To investigate secondary organic aerosol (SOA) formation from biogenic volatile organic compounds (BVOCs), 3 oxidation flow reactors (OFR) were used to expose ambient air to oxidants and their output was analyzed by state-of-the-art gas and aerosol instruments including a High-Resolution Aerosol Mass Spectrometer (HR-AMS), a HR Proton-Transfer Reaction Time-of-Flight Mass Spectrometer (PTR-TOFMS), and Two HR-TOF Chemical Ionization Mass Spectrometers (HRToF-CIMS). Ambient air was exposed 24/7 to variable concentrations of each of the 3 main atmospheric oxidants (OH, NO3 radicals and O3) to investigate the oxidation of BVOCs (including isoprene derived epoxydiols, IEPOX) and SOA formation and aging. Effective OH exposures up to 1×1013 molec cm-3 s were achieved, equivalent to over a month of aging in the atmosphere. Multiple oxidation products from isoprene and monoterpenes including small gas-phase acids were observed in OH OFR. High SOA formation of up to 12 μg m-3 above ambient concentrations of 5 μg m-3 was observed under intermediate OH exposures, while very high OH exposures led to destruction of ~30% of ambient OA, indicating shifting contributions of functionalization vs. fragmentation, consistent with results from urban and terpene-dominated environments. The highest SOA enhancements were 3-4 times higher than ambient OA. More SOA is typically formed during nighttime when terpenes are higher and photochemistry is absent, and less during daytime when isoprene is higher, although the IEPOX pathway is suppressed in the OFR. SOA is also observed after exposure of ambient air to O3 or NO3, although the amounts and oxidation levels were lower than for OH. Formation of organic nitrates in the NO3 reaction will also be discussed.A major field campaign (Southern Oxidant and Aerosol

  7. Potential of VIIRS Time Series Data for Aiding the USDA Forest Service Early Warning System for Forest Health Threats: A Gypsy Moth Defoliation Case Study

    NASA Technical Reports Server (NTRS)

    Spruce, Joseph P.; Ryan, Robert E.; Smoot, James; Kuper, Phillip; Prados, Donald; Russell, Jeffrey; Ross, Kenton; Gasser, Gerald; Sader, Steven; McKellip, Rodney

    2007-01-01

    This report details one of three experiments performed during FY 2007 for the NASA RPC (Rapid Prototyping Capability) at Stennis Space Center. This RPC experiment assesses the potential of VIIRS (Visible/Infrared Imager/Radiometer Suite) and MODIS (Moderate Resolution Imaging Spectroradiometer) data for detecting and monitoring forest defoliation from the non-native Eurasian gypsy moth (Lymantria dispar). The intent of the RPC experiment was to assess the degree to which VIIRS data can provide forest disturbance monitoring information as an input to a forest threat EWS (Early Warning System) as compared to the level of information that can be obtained from MODIS data. The USDA Forest Service (USFS) plans to use MODIS products for generating broad-scaled, regional monitoring products as input to an EWS for forest health threat assessment. NASA SSC is helping the USFS to evaluate and integrate currently available satellite remote sensing technologies and data products for the EWS, including the use of MODIS products for regional monitoring of forest disturbance. Gypsy moth defoliation of the mid-Appalachian highland region was selected as a case study. Gypsy moth is one of eight major forest insect threats listed in the Healthy Forest Restoration Act (HFRA) of 2003; the gypsy moth threatens eastern U.S. hardwood forests, which are also a concern highlighted in the HFRA of 2003. This region was selected for the project because extensive gypsy moth defoliation occurred there over multiple years during the MODIS operational period. This RPC experiment is relevant to several nationally important mapping applications, including agricultural efficiency, coastal management, ecological forecasting, disaster management, and carbon management. In this experiment, MODIS data and VIIRS data simulated from MODIS were assessed for their ability to contribute broad, regional geospatial information on gypsy moth defoliation. Landsat and ASTER (Advanced Spaceborne Thermal Emission

  8. Changes in soil carbon stocks after a conversion from secondary forest to rubber - a case study for Xishuangbanna prefecture, Southwest China

    NASA Astrophysics Data System (ADS)

    de Blecourt, M.; Brumme, R.; Veldkamp, E.

    2012-04-01

    Since the 1950's rapid deforestation is taking place in Xishuangbanna prefecture, a border region in Southwest China. Deforestation is mainly related to the increase of rubber plantations, the forest area was decreased by 28% (370,494 ha) while the area in rubber plantations increased by 194,151 ha (increase of 90%) between 1976 and 2003. Besides rubber plantations forest areas have mainly been replaced by shrublands, and shifting cultivation. The aim of this study is to quantify changes in soil carbon stocks after a conversion from secondary forest to rubber. The study site has a size of 3600 ha and was located in Xishuangbanna prefecture, Southwest China. We selected 11 rubber plantation sites with ages ranging from 5 to 46 years old and paired each rubber plantation site with a secondary forest site. The sites have a size of 20 x 20m and were carefully selected to ensure that the paired sites have similar topographic and soil characteristics and only differ in the recent land use history. At each site we measured soil carbon concentration and stocks up to 120 cm's depth, furthermore we measured soil characteristics (soil pH, bulk density, exchangeable cations), biophysical parameters (slope, aspect, altitude, estimates of aboveground biomass and forest floor) and recorded management related parameters (land use age, harvesting, burning history). The specific questions addressed in this study are: i) What is the amount of change in soil carbon concentration and stocks after a conversion from forest to rubber for respectively the cumulative soil pedon and the individual soil depth intervals? ii) Which predictor variables considering soil characteristics, biophysical factors and management related parameters can be used to predict the changes in soil carbon stocks following this land use conversion? Preliminary results show that soil carbon stocks up to 120 cm depth were significantly lower in rubber plantations compared to their reference site (P = 0.009), with a

  9. Predators, Prey and Habitat Structure: Can Key Conservation Areas and Early Signs of Population Collapse Be Detected in Neotropical Forests?

    PubMed Central

    de Thoisy, Benoit; Fayad, Ibrahim; Clément, Luc; Barrioz, Sébastien; Poirier, Eddy; Gond, Valéry

    2016-01-01

    Tropical forests with a low human population and absence of large-scale deforestation provide unique opportunities to study successful conservation strategies, which should be based on adequate monitoring tools. This study explored the conservation status of a large predator, the jaguar, considered an indicator of the maintenance of how well ecological processes are maintained. We implemented an original integrative approach, exploring successive ecosystem status proxies, from habitats and responses to threats of predators and their prey, to canopy structure and forest biomass. Niche modeling allowed identification of more suitable habitats, significantly related to canopy height and forest biomass. Capture/recapture methods showed that jaguar density was higher in habitats identified as more suitable by the niche model. Surveys of ungulates, large rodents and birds also showed higher density where jaguars were more abundant. Although jaguar density does not allow early detection of overall vertebrate community collapse, a decrease in the abundance of large terrestrial birds was noted as good first evidence of disturbance. The most promising tool comes from easily acquired LiDAR data and radar images: a decrease in canopy roughness was closely associated with the disturbance of forests and associated decreasing vertebrate biomass. This mixed approach, focusing on an apex predator, ecological modeling and remote-sensing information, not only helps detect early population declines in large mammals, but is also useful to discuss the relevance of large predators as indicators and the efficiency of conservation measures. It can also be easily extrapolated and adapted in a timely manner, since important open-source data are increasingly available and relevant for large-scale and real-time monitoring of biodiversity. PMID:27828993

  10. Predators, Prey and Habitat Structure: Can Key Conservation Areas and Early Signs of Population Collapse Be Detected in Neotropical Forests?

    PubMed

    de Thoisy, Benoit; Fayad, Ibrahim; Clément, Luc; Barrioz, Sébastien; Poirier, Eddy; Gond, Valéry

    2016-01-01

    Tropical forests with a low human population and absence of large-scale deforestation provide unique opportunities to study successful conservation strategies, which should be based on adequate monitoring tools. This study explored the conservation status of a large predator, the jaguar, considered an indicator of the maintenance of how well ecological processes are maintained. We implemented an original integrative approach, exploring successive ecosystem status proxies, from habitats and responses to threats of predators and their prey, to canopy structure and forest biomass. Niche modeling allowed identification of more suitable habitats, significantly related to canopy height and forest biomass. Capture/recapture methods showed that jaguar density was higher in habitats identified as more suitable by the niche model. Surveys of ungulates, large rodents and birds also showed higher density where jaguars were more abundant. Although jaguar density does not allow early detection of overall vertebrate community collapse, a decrease in the abundance of large terrestrial birds was noted as good first evidence of disturbance. The most promising tool comes from easily acquired LiDAR data and radar images: a decrease in canopy roughness was closely associated with the disturbance of forests and associated decreasing vertebrate biomass. This mixed approach, focusing on an apex predator, ecological modeling and remote-sensing information, not only helps detect early population declines in large mammals, but is also useful to discuss the relevance of large predators as indicators and the efficiency of conservation measures. It can also be easily extrapolated and adapted in a timely manner, since important open-source data are increasingly available and relevant for large-scale and real-time monitoring of biodiversity.

  11. Legacy of Pre-Disturbance Spatial Pattern Determines Early Structural Diversity following Severe Disturbance in Montane Spruce Forests

    PubMed Central

    Bače, Radek; Svoboda, Miroslav; Janda, Pavel; Morrissey, Robert C.; Wild, Jan; Clear, Jennifer L.; Čada, Vojtěch; Donato, Daniel C.

    2015-01-01

    Background Severe canopy-removing disturbances are native to many temperate forests and radically alter stand structure, but biotic legacies (surviving elements or patterns) can lend continuity to ecosystem function after such events. Poorly understood is the degree to which the structural complexity of an old-growth forest carries over to the next stand. We asked how pre-disturbance spatial pattern acts as a legacy to influence post-disturbance stand structure, and how this legacy influences the structural diversity within the early-seral stand. Methods Two stem-mapped one-hectare forest plots in the Czech Republic experienced a severe bark beetle outbreak, thus providing before-and-after data on spatial patterns in live and dead trees, crown projections, down logs, and herb cover. Results Post-disturbance stands were dominated by an advanced regeneration layer present before the disturbance. Both major species, Norway spruce (Picea abies) and rowan (Sorbus aucuparia), were strongly self-aggregated and also clustered to former canopy trees, pre-disturbance snags, stumps and logs, suggesting positive overstory to understory neighbourhood effects. Thus, although the disturbance dramatically reduced the stand’s height profile with ~100% mortality of the canopy layer, the spatial structure of post-disturbance stands still closely reflected the pre-disturbance structure. The former upper tree layer influenced advanced regeneration through microsite and light limitation. Under formerly dense canopies, regeneration density was high but relatively homogeneous in height; while in former small gaps with greater herb cover, regeneration density was lower but with greater heterogeneity in heights. Conclusion These findings suggest that pre-disturbance spatial patterns of forests can persist through severe canopy-removing disturbance, and determine the spatial structure of the succeeding stand. Such patterns constitute a subtle but key legacy effect, promoting structural

  12. Avian species richness in relation to intensive forest management practices in early seral tree plantations.

    PubMed

    Jones, Jay E; Kroll, Andrew J; Giovanini, Jack; Duke, Steven D; Ellis, Tana M; Betts, Matthew G

    2012-01-01

    Managers of landscapes dedicated to forest commodity production require information about how practices influence biological diversity. Individual species and communities may be threatened if management practices truncate or simplify forest age classes that are essential for reproduction and survival. For instance, the degradation and loss of complex diverse forest in young age classes have been associated with declines in forest-associated Neotropical migrant bird populations in the Pacific Northwest, USA. These declines may be exacerbated by intensive forest management practices that reduce hardwood and broadleaf shrub cover in order to promote growth of economically valuable tree species in plantations. We used a Bayesian hierarchical model to evaluate relationships between avian species richness and vegetation variables that reflect stand management intensity (primarily via herbicide application) on 212 tree plantations in the Coast Range, Oregon, USA. Specifically, we estimated the influence of broadleaf hardwood vegetation cover, which is reduced through herbicide applications, on bird species richness and individual species occupancy. Our model accounted for imperfect detection. We used average predictive comparisons to quantify the degree of association between vegetation variables and species richness. Both conifer and hardwood cover were positively associated with total species richness, suggesting that these components of forest stand composition may be important predictors of alpha diversity. Estimates of species richness were 35-80% lower when imperfect detection was ignored (depending on covariate values), a result that has critical implications for previous efforts that have examined relationships between forest composition and species richness. Our results revealed that individual and community responses were positively associated with both conifer and hardwood cover. In our system, patterns of bird community assembly appear to be associated with

  13. Conspecific Leaf Litter-Mediated Effect of Conspecific Adult Neighborhood on Early-Stage Seedling Survival in A Subtropical Forest

    NASA Astrophysics Data System (ADS)

    Liu, Heming; Shen, Guochun; Ma, Zunping; Yang, Qingsong; Xia, Jianyang; Fang, Xiaofeng; Wang, Xihua

    2016-11-01

    Conspecific adults have strong negative effect on the survival of nearby early-stage seedlings and thus can promote species coexistence by providing space for the regeneration of heterospecifics. The leaf litter fall from the conspecific adults, and it could mediate this conspecific negative adult effect. However, field evidence for such effect of conspecific leaf litter remains absent. In this study, we used generalized linear mixed models to assess the effects of conspecific leaf litter on the early-stage seedling survival of four dominant species (Machilus leptophylla, Litsea elongate, Acer pubinerve and Distylium myricoides) in early-stage seedlings in a subtropical evergreen broad-leaved forest in eastern China. Our results consistently showed that the conspecific leaf litter of three species negatively affected the seedling survival. Meanwhile, the traditional conspecific adult neighborhood indices failed to detect this negative conspecific adult effect. Our study revealed that the accumulation of conspecific leaf litter around adults can largely reduce the survival rate of nearby seedlings. Ignoring it could result in underestimation of the importance of negative density dependence and negative species interactions in the natural forest communities.

  14. Conspecific Leaf Litter-Mediated Effect of Conspecific Adult Neighborhood on Early-Stage Seedling Survival in A Subtropical Forest

    PubMed Central

    Liu, Heming; Shen, Guochun; Ma, Zunping; Yang, Qingsong; Xia, Jianyang; Fang, Xiaofeng; Wang, Xihua

    2016-01-01

    Conspecific adults have strong negative effect on the survival of nearby early-stage seedlings and thus can promote species coexistence by providing space for the regeneration of heterospecifics. The leaf litter fall from the conspecific adults, and it could mediate this conspecific negative adult effect. However, field evidence for such effect of conspecific leaf litter remains absent. In this study, we used generalized linear mixed models to assess the effects of conspecific leaf litter on the early-stage seedling survival of four dominant species (Machilus leptophylla, Litsea elongate, Acer pubinerve and Distylium myricoides) in early-stage seedlings in a subtropical evergreen broad-leaved forest in eastern China. Our results consistently showed that the conspecific leaf litter of three species negatively affected the seedling survival. Meanwhile, the traditional conspecific adult neighborhood indices failed to detect this negative conspecific adult effect. Our study revealed that the accumulation of conspecific leaf litter around adults can largely reduce the survival rate of nearby seedlings. Ignoring it could result in underestimation of the importance of negative density dependence and negative species interactions in the natural forest communities. PMID:27886275

  15. Early postoperative parathormone sampling and prognosis after total parathyroidectomy in secondary hyperparathyroidism.

    PubMed

    Nascimento, Climério Pereira do; Brescia, Marília D'Elboux Guimarães; Custódio, Melani Ribeiro; Massoni, Ledo Mazzei; Silveira, André Albuquerque; Goldenstein, Patrícia Taschner; Arap, Sérgio Samir; Jorgetti, Vanda; Moyses, Rosa Maria Affonso; Montenegro, Fábio Luiz de Menezes

    2017-04-27

    There is possibility of a supernumerary hyperplastic parathyroid gland in dialysis patients after total parathyroidectomy and autograft in dialysis patients. To test if the early postoperative measure of parathyroid hormone (PTH) can identify persistent hyperparathyroidism. A prospective cohort of dialysis patients submitted to parathyroidectomy had PTH measured up to one week after operation. The absolute value and the relative decrease were analyzed according to clinical outcome of satisfactory control of secondary hyperparathyroidism or persistence. Of 51 cases, preoperative PTH varied from 425 to 6,964 pg/mL (median 2,103 pg/mL). Postoperatively, PTH was undetectable in 28 cases (54.9%). In eight individuals (15.7%) the PTH was lower than 16 pg/mL, in 10 (19.6%) the PTH values were between 16 and 87pg/mL, and in five (9.8%), PTH was higher than 87 pg/mL. Undetectable PTH was more common in patients with preoperative PTH below the median (p = 0.0002). There was a significant correlation between preoperative PTH and early postoperative PTH (Spearman R = 0.42, p = 0.002). A relative decrease superior to 95% was associated to satisfactory clinical outcome. A relative decrease less than 80% was associated to persistent disease, despite initial postoperative hypocalcemia. Measurement of PTH in the first days after parathyroidectomy in dialysis patients may suggest good clinical outcome if a decrease of at least 95% of the preoperative value is observed. Less than 80% PTH decrease is highly suggestive of residual hyperfunctioning parathyroid tissue with persistent hyperparathyroidism, and an early reintervention may be considered. Em pacientes renais crônicos dialíticos submetidos à paratireoidectomia total com autoenxerto, existe a possibilidade de uma glândula paratireoide hiperplásica residual. Verificar se a medida pós-operatória precoce do hormônio da paratireoide (PTH) após paratireoidectomia total com autoenxerto é útil para indicar uma gl

  16. Early identification of secondary brain damage in subarachnoid hemorrhage: a role for glial fibrillary acidic protein.

    PubMed

    Petzold, Axel; Keir, Geoffrey; Kerr, Mary; Kay, Andrew; Kitchen, Neil; Smith, Martin; Thompson, Edward J

    2006-07-01

    Secondary ischaemic deficit adversely affects outcome in patients with subarachnoid hemorrhage (SAH). Astrocytes are vulnerable to ischemia, releasing glial fibrillary acidic protein (GFAP) when challenged. In this study, we followed nine patients with SAH who underwent extra-ventricular drainage for the management of secondary hydrocephalus. Cerebrospinal fluid (CSF) was collected daily for up to 14 days. CSF GFAP was quantified using a standard ELISA. In the patients, we found that the CSF GFAP values were pathologically elevated in 83/89 (93%) of the CSF samples. The levels were highest on day 1 (median = 47.64 ng/mL) and decreased to 11.19 ng/mL on day 3, leveling out at approximately 1 ng/mL after 10 days. In non-survivors, a secondary rise of GFAP levels became significant during the high-risk period for vasospasm, with median levels of 21.76 ng/mL compared to 2.62 ng/mL in the survivors (p = 0.037) on day 6. This study suggests that CSF GFAP levels are of prognostic value in SAH. Additionally, the difference in the slope of GFAP levels between survivors (rapid wash-out) and non-survivors (secondary peaks) may allow difierentiation between primary brain injury from secondary brain damage due to delayed cerebral ischaemia.

  17. SITHON: A Wireless Network of in Situ Optical Cameras Applied to the Early Detection-Notification-Monitoring of Forest Fires

    PubMed Central

    Tsiourlis, Georgios; Andreadakis, Stamatis; Konstantinidis, Pavlos

    2009-01-01

    The SITHON system, a fully wireless optical imaging system, integrating a network of in-situ optical cameras linking to a multi-layer GIS database operated by Control Operating Centres, has been developed in response to the need for early detection, notification and monitoring of forest fires. This article presents in detail the architecture and the components of SITHON, and demonstrates the first encouraging results of an experimental test with small controlled fires over Sithonia Peninsula in Northern Greece. The system has already been scheduled to be installed in some fire prone areas of Greece. PMID:22408536

  18. Perception of body image in early adolescence. An investigation in secondary schools.

    PubMed

    Juli, Maria Rosaria

    2017-09-01

    The clinical evidence shows that the onset of eating disorders is increasing in the prepubescent phase or even in childhood. Already starting from the prepubescence the certainties related to the body start to unwind and the individual is encouraged to build new ones, based both on the anatomic transformation of his/her own body and on the social expectation according to the identity. The onset of a Eating Disorders is normally between 13 and 25 years, but in the last years we recorded a lowering in the onset threshold to an age between 11 and 13 years, with some earlier cases at 7 years (Franzoni et al. 2012). Many theories consider body dissatisfaction as the immediate antecedent to the development of this eating disorder. Different studies have confirmed that a strong concern for physical appearance could sometimes precede an eating disorder (Cuzzolaro 2004). The alteration of the body image is the major predictive factor for the relapse, the patients themselves refer that it is one of the major obstacles for the realization of a lasting recovering. In the following study one hundred kids between 10 and 15 years old, without any Eating Disorders diagnosis, have been tested to evaluate whether if already from this age there is a concern about body image starting at this age, the fear of gaining weight and the desire to be slimmer. It is known, indeed, that these factors, if significantly present in a subject, can turn into predictive factors of a psychopathology. We need to build our body image over time; changing our percertion of reality can change also what we see, in particular the body image we strive for changes (Bianchini 2008). 100 teenagers split in 53 females and 47 males aged between 10 and 14 years, randomly picked in the secondary school. The results of the study show that in the age between 10 and 15 years the concern for the body shape is already present, without difference between the genders. Although 45% of the sample is underweight, the Figure

  19. Arbuscular mycorrhizal fungi increased early growth of two nontimber forest product species Dyera polyphylla and Aquilaria filaria under greenhouse conditions.

    PubMed

    Turjaman, Maman; Tamai, Yutaka; Santoso, Erdy; Osaki, Mitsuru; Tawaraya, Keitaro

    2006-10-01

    Nontimber forest products (NTFPs) represent an important source of income to millions of people in tropical forest regions, but some NTFP species have decreased in number and become endangered due to overexploitation. There is increasing concern that the planting stocks of Dyera polyphylla and Aquilaria filaria are not sufficient to sustain the yield of NTFPs and promote forest conservation. The objective of this study was to determine the effect of two arbuscular mycorrhizal (AM) fungi, Glomus clarum and Gigaspora decipiens, on the early growth of two NTFP species, D. polyphylla and A. filaria, under greenhouse conditions. The seedlings of both species were inoculated with G. clarum or G. decipiens, or uninoculated (control) under greenhouse conditions. Percentage of AM colonization, plant growth, survival rate, and nitrogen (N) and phosphorus (P) concentrations were measured after 180 days of growth. The percentage of AM colonization of D. polyphylla and A. filaria ranged from 87 to 93% and from 22 to 39%, respectively. Colonization by G. clarum and G. decipiens increased plant height, diameter, and shoot and root dry weights. Shoot N and P concentrations of the seedlings were increased by AM colonization by as much as 70-153% and 135-360%, respectively. Survival rates were higher in the AM-colonized seedlings at 180 days after transplantation than in the control seedlings. The results suggest that AM fungi can accelerate the establishment of the planting stocks of D. polyphylla and A. filaria, thereby promoting their conservation ecologically and sustaining the production of these NTFPs economically.

  20. Soil-atmosphere exchange of nitrous oxide, nitric oxide, and methane under secondary succession of pasture to forest in the Atlantic lowlands of Costa Rica

    SciTech Connect

    Keller, M.; Reiners, W.A.

    1994-12-01

    We investigated changes in soil-atmosphere flux of CH{sub 4}, N{sub 2}O, and NO resulting from the succession of pasture to forest in the Atlantic lowlands of Costa Rica. We studied a dozen sites intensively for over one year in order to measure rates and to understand controlling mechanisms for gas exchange. CH{sub 4} flux was controlled primarily by soil moisture content. Soil consumption of atmospheric CH{sub 4} was greatest when soils were relatively dry. Forest soils consumed CH{sub 4} while pasture soils which had poor drainage generally produced CH{sub 4}. The seasonal pattern of N{sub 2}O emissions from forest soils was related exponentially to soil water-filled pore space. Annual average N{sub 2}O emissions correlated with soil exchangeable NO{sub 3}{sup -} concentrations. Soil-atmosphere NO flux was greatest when soils were relatively dry. We found the largest NO emissions from abandoned pasture sites. Combining these data with those from another study in the Atlantic lowlands of Costa Rica that focused on deforestation, we present a 50-year chronosequence of trace gas emissions that extends from natural conditions, through disturbance and natural recovery. The soil-atmosphere fluxes of CH{sub 4} and N{sub 2}O and NO may be restored to predisturbance rates during secondary succession. The changes in trace gas emissions following deforestation, through pasture use and secondary succession, may be explained conceptually through reference to two major controlling factors, nitrogen availability and soil-atmosphere diffusive exchange of gases as it is influenced by soil moisture content and soil compaction. 59 refs., 6 figs., 3 tabs.

  1. 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

    The dynamic, bi-directional exchange of trace chemical species between forests and the atmosphere has important impacts on both the forest ecosystem and atmospheric composition, with potentially profound consequences on air quality, climate and global ecosystem functioning. Forests are a dominant source of biogenic volatile organic compound (BVOC) emissions into the earth's atmosphere and thus play an important role in the formation of secondary organic aerosol (SOA). To arrive at a better scientific understanding of the complex chemical and physical processes of forest-atmosphere exchange and provide a platform for robust analysis of field measurements of these processes, a process-level, multiphase model of the atmospheric chemistry and physics of forest canopies is being developed. This model, the Atmospheric Chemistry and Canopy Exchange Simulation System (ACCESS) is being used to investigate various aspects of forest-atmosphere exchange and chemistry including gas, aqueous and aerosol phases. ACCESS currently includes processes accounting for the emission of BVOCs from the canopy, turbulent vertical transport within and above the canopy and throughout the height of the planetary boundary layer, detailed chemical reactions, mixing with the background atmosphere and bi-directional exchange between the atmosphere and the canopy and the forest floor. The Walker Branch Watershed (WBW) is a dedicated ecosystem research area on the U. S. Department of Energy's Oak Ridge Reservation in eastern Tennessee. The 97.5 ha watershed has been the site of long-term ecosystem and atmospheric research activities since the mid-1960's. A flux tower located within the watershed (35°57'30"N, 84°17'15"W; 365 m above mean sea level) and 10 km southwest of Oak Ridge, Tennessee, has served as a focal point for previous atmospheric turbulence and chemical flux measurements and the canopy morphology of the forest surrounding the flux tower has been extensively documented. The forest is

  2. Early Estimates of Public Elementary and Secondary Education Statistics: School Year 2000-2001.

    ERIC Educational Resources Information Center

    McDowell, Lena

    2001-01-01

    Provides current-year estimates of selected key statistics for public elementary and secondary schools. Data from the National Center for Education Statistics Common Core of Data indicate enrollment, numbers of teachers, student/teacher ratios, high school graduates, and education revenues and expenditures. (Author/SLD)

  3. Motivational Trajectories for Early Language Learning across the Primary-Secondary School Transition

    ERIC Educational Resources Information Center

    Graham, Suzanne; Courtney, Louise; Tonkyn, Alan; Marinis, Theodoros

    2016-01-01

    The transition from primary to secondary school is an area of concern across a range of curriculum subjects and this is no less so for foreign language learning. Indeed problems with transition have been identified in England as an important barrier to the introduction of language learning to the primary school curriculum, with implications for…

  4. Motivational Trajectories for Early Language Learning across the Primary-Secondary School Transition

    ERIC Educational Resources Information Center

    Graham, Suzanne; Courtney, Louise; Tonkyn, Alan; Marinis, Theodoros

    2016-01-01

    The transition from primary to secondary school is an area of concern across a range of curriculum subjects and this is no less so for foreign language learning. Indeed problems with transition have been identified in England as an important barrier to the introduction of language learning to the primary school curriculum, with implications for…

  5. Accelerating the Mathematics Learning of Low Socio-Economic Status Junior Secondary Students: An Early Report

    ERIC Educational Resources Information Center

    Cooper, Tom; Nutchey, David; Grant, Edlyn

    2013-01-01

    The "Accelerating the Mathematics Learning of Low Socio-Economic Status Junior Secondary Students" project aims to address the issues faced by very underperforming mathematics students as they enter high school. Its aim is to accelerate learning of mathematics through a vertical curriculum to enable students to access Year 10 mathematics…

  6. Early Childhood Education: A Model for 21st Century Secondary Education

    ERIC Educational Resources Information Center

    Berndt, Rene

    2012-01-01

    As the designer of primary and secondary educational facilities, the author has become familiar with educational thinkers such as Sir Kenneth Robinson, Peter Senge, Ewan McIntosh, Daniel Pink and Howard Gardner--each promoting an approach based on system-thinking, self-directed exploration and multidimensional, interactive learning. In 2009, he…

  7. Early Childhood Education: A Model for 21st Century Secondary Education

    ERIC Educational Resources Information Center

    Berndt, Rene

    2012-01-01

    As the designer of primary and secondary educational facilities, the author has become familiar with educational thinkers such as Sir Kenneth Robinson, Peter Senge, Ewan McIntosh, Daniel Pink and Howard Gardner--each promoting an approach based on system-thinking, self-directed exploration and multidimensional, interactive learning. In 2009, he…

  8. Rapid responses of the prairie-forest ecotone to early Holocene aridity in mid-continental North America

    NASA Astrophysics Data System (ADS)

    Williams, John W.; Shuman, Bryan; Bartlein, Patrick J.

    2009-04-01

    The prairie-forest transition in midcontinental North America is a major physiognomic boundary, and its shifts during the Holocene are a classic example of climate-driven ecotonal dynamics. Recent work suggests asymmetrical Holocene behavior, with a relatively rapid early Holocene deforestation and more gradual reforestation later in the Holocene. This paper presents a new synthesis of the Holocene history of the Great Plains prairie-forest ecotone in the north-central US and central Canada that updates prior mapping efforts and systematically assesses rates of change. Changes in percent woody cover (%WC) are inferred from fossil pollen records, using the modern analog technique and surface-sediment pollen samples cross-referenced against remotely sensed observations. For contemporary pollen samples from the Great Plains, %WC linearly correlates to percent arboreal pollen (%AP), but regression parameters vary interregionally. At present, %AP is consistently higher than %WC, because of high background levels of arboreal pollen. Holocene maps of the eastern prairie-forest ecotone agree with prior maps, showing a rapid decrease in %WC and eastward prairie advance between 10,000 and 8000 ka (1 ka = 1000 calibrated years before present), a maximum eastward position of the ecotone from 7 to 6 ka, and increased %WC and westward prairie retreat after 6 ka. Ecotone position is ambiguous in Iowa and southeastern Minnesota, due to a scarcity of modern analogs for early-Holocene samples with high Ulmus abundances and for samples from alluvial sediments. The northern prairie-forest ecotone was positioned in central Saskatchewan between 12 and 10 ka, stabilized from 10 to 6 ka despite decreases in %WC at some sites, then moved south after 6 ka. In both east and north, ecotonal movements are consistent with a dry early Holocene and increasing moisture availability after 6 ka. Sites near the ecotone consistently show an asymmetric pattern of abrupt early Holocene deforestation

  9. Ecosystem feedbacks and nitrogen fixation in boreal forests.

    PubMed

    DeLuca, Thomas H; Zackrisson, Olle; Gundale, Michael J; Nilsson, Marie-Charlotte

    2008-05-30

    Biological feedback mechanisms regulate fundamental ecosystem processes and potentially regulate ecosystem productivity. To date, no studies have documented the down-regulation of terrestrial nitrogen (N) fixation via an ecosystem-level feedback mechanism. Herein, we demonstrate such a feedback in boreal forests. Rapid cycling of N in early secondary succession forests yielded greater throughfall N deposition, which in turn decreased N fixation by cyanobacterial associates in feather moss carpets that reside on the forest floor. The forest canopy exerts a tight control on biotic N input at a period of high productivity.

  10. Early Red Spruce Restoration Research by the Appalachian Forest Experiment Station, 1922–1954

    Treesearch

    James S. Rentch; Thomas M. Schuler

    2017-01-01

    This photograph (Fig. 1), taken in June of 1923 by E.S. Ship, depicts a red spruce (Picea rubens) stand with advanced reproduction near the summit of Mount Mitchell in the Pisgah National Forest of North Carolina. According to Hopkins (1899), the original extent of red spruce encompassed as much as 1,500,000 ac in the southern Appalachians; by 1895...

  11. Early stump sprouting after clearcutting in a northern Missouri bottomland hardwood forest

    Treesearch

    Matthew G. Olson; Benjamin O. Knapp

    2017-01-01

    Midwestern bottomland hardwood forests are often composed of species that are capable of sprouting vigorously, yet relatively little is known about sprout development within these mixed-species systems. This study describes stump sprouting of midwestern bottomland hardwood species in the first 3 growing seasons after a clearcutting with reserves (∼2.0 m2...

  12. Properties of native plant communities do not determine exotic success during early forest succession

    Treesearch

    Aldo Compagnoni; Charles B. Halpern

    2009-01-01

    Considerable research has been devoted to understanding how plant invasions are influenced by properties of the native community and to the traits of exotic species that contribute to successful invasion. Studies of invasibility are common in successionally stable grasslands, but rare in recently disturbed or seral forests. We used 16 years of species richness and...

  13. Persistent effects of fire severity on early successional forests in interior Alaska

    Treesearch

    Aditi Shenoy; Jill F. Johnstone; Eric S. Kasischke; Knut. Kielland

    2011-01-01

    There has been a recent increase in the frequency and extent of wildfires in interior Alaska, and this trend is predicted to continue under a warming climate. Although less well documented, corresponding increases in fire severity are expected. Previous research from boreal forests in Alaska and western Canada indicate that severe fire promotes the recruitment of...

  14. Early results from a pilot test of planting small American chesnut seedlings under a forest canopy

    Treesearch

    W. Henry McNab; Steven Patch; A. Amelia Nutter

    2003-01-01

    Successful development of American chestnut (Castanea dentata) hybrids that are resistant to chestnut blight (Cryphonectria parasitica) will require information about methods for effective and economical reintroduction of this species in forests of the southern Appalachian Mountains (Boucher 2000) American chestnut regenerates...

  15. Modeling early forest succession following clear-cutting in western Oregon.

    Treesearch

    Zhiqiang Yang; Warren B. Cohen; Mark E. Harmon

    2005-01-01

    In the Pacific Northwest, the process of conifer development after stand-replacing disturbance has important implications for many forest processes (e.g., carbon storage, nutrient cycling, and biodiversity). This paper examines conifer development in the Coast Range Province and Western Cascades Province of Oregon using repeat interpretation of historic aerial...

  16. Early Stump Sprout Development after Two Levels of Harvest in a Midwestern Bottomland Hardwood Forest

    Treesearch

    Benjamin O. Knapp; Matthew G. Olson; Daniel C. Dey

    2017-01-01

    Sprouting is an important source of regeneration for hardwood trees but has not been studied extensively in bottomland hardwood forests. We quantified the sprouting responses of 11 bottomland hardwood species or species groups after two levels of overstory harvest, including clearcutting with reserves (CCR) (residual basal area ∼2.0 m2/ha) and...

  17. Disturbance history and stand dynamics in secondary and old-growth forests of the Southern Appalachain Mountains, USA

    Treesearch

    Sarah M. Butler; Alan S. White; Katherine J. Elliott; Robert S. Seymour

    2014-01-01

    Understanding the patterns of past disturbance allows further insight into the complex composition, structure, and function of current and future forests, which is increasingly important in a world where disturbance characteristics are changing. Our objectives were to define disturbance causes, rates (percent disturbance per decade), magnitudes and frequency (time...

  18. Indigenous Knowledge Informing Management of Tropical Forests: The Link between Rhythms in Plant Secondary Chemistry and Lunar Cycles.

    Treesearch

    Kristiina A. Vogt; Karen H. Beard; Shira Hammann; Jennifer O’Hara Palmiotto; Daniel J. Vogt; Frederick N. Scatena; Brooke P. Hecht

    2002-01-01

    This research used knowledge of the indigenous practice of timing nontimber forest product harvest with the full moon to demonstrate that chemicals controlling the decomposition rate of foliage fluctuate with the lunar cycle and may have developed as a result of plant-herbivore interactions. Indigenous knowledge suggests that leaves harvested during the full moon are...

  19. Potential of VIIRS Data for Regional Monitoring of Gypsy Moth Defoliation: Implications for Forest Threat Early Warning System

    NASA Technical Reports Server (NTRS)

    Spruce, Joseph P.; Ryan, Robert E.; Smoot, James C.; Prados, Donald; McKellip, Rodney; Sader. Steven A.; Gasser, Jerry; May, George; Hargrove, William

    2007-01-01

    A NASA RPC (Rapid Prototyping Capability) experiment was conducted to assess the potential of VIIRS (Visible/Infrared Imager/Radiometer Suite) data for monitoring non-native gypsy moth (Lymantria dispar) defoliation of forests. This experiment compares defoliation detection products computed from simulated VIIRS and from MODIS (Moderate Resolution Imaging Spectroradiometer) time series products as potential inputs to a forest threat EWS (Early Warning System) being developed for the USFS (USDA Forest Service). Gypsy moth causes extensive defoliation of broadleaved forests in the United States and is specifically identified in the Healthy Forest Restoration Act (HFRA) of 2003. The HFRA mandates development of a national forest threat EWS. This system is being built by the USFS and NASA is aiding integration of needed satellite data products into this system, including MODIS products. This RPC experiment enabled the MODIS follow-on, VIIRS, to be evaluated as a data source for EWS forest monitoring products. The experiment included 1) assessment of MODIS-simulated VIIRS NDVI products, and 2) evaluation of gypsy moth defoliation mapping products from MODIS-simulated VIIRS and from MODIS NDVI time series data. This experiment employed MODIS data collected over the approximately 15 million acre mid-Appalachian Highlands during the annual peak defoliation time frame (approximately June 10 through July 27) during 2000-2006. NASA Stennis Application Research Toolbox software was used to produce MODIS-simulated VIIRS data and NASA Stennis Time Series Product Tool software was employed to process MODIS and MODIS-simulated VIIRS time series data scaled to planetary reflectance. MODIS-simulated VIIRS data was assessed through comparison to Hyperion-simulated VIIRS data using data collected during gypsy moth defoliation. Hyperion-simulated MODIS data showed a high correlation with actual MODIS data (NDVI R2 of 0.877 and RMSE of 0.023). MODIS-simulated VIIRS data for the same

  20. The effect of local and landscape-level characteristics on the abundance of forest birds in early-successional habitats during the post-fledging season in western Massachusetts.

    PubMed

    Labbe, Michelle A; King, David I

    2014-01-01

    Many species of mature forest-nesting birds ("forest birds") undergo a pronounced shift in habitat use during the post-fledging period and move from their forest nesting sites into areas of early-successional vegetation. Mortality is high during this period, thus understanding the resource requirements of post-fledging birds has implications for conservation. Efforts to identify predictors of abundance of forest birds in patches of early-successional habitats have so far been equivocal, yet these previous studies have primarily focused on contiguously forested landscapes and the potential for landscape-scale influences in more fragmented and modified landscapes is largely unknown. Landscape composition can have a strong influence on the abundance and productivity of forest birds during the nesting period, and could therefore affect the number of forest birds in the landscape available to colonize early-successional habitats during the post-fledging period. Therefore, the inclusion of landscape characteristics should increase the explanatory power of models of forest bird abundance in early-successional habitat patches during the post-fledging period. We examined forest bird abundance and body condition in relation to landscape and habitat characteristics of 15 early-successional sites during the post-fledging season in Massachusetts. The abundance of forest birds was influenced by within-patch habitat characteristics, however the explanatory power of these models was significantly increased by the inclusion of landscape fragmentation and the abundance of forest birds in adjacent forest during the nesting period for some species and age groups. Our findings show that including factors beyond the patch scale can explain additional variation in the abundance of forest birds in early-successional habitats during the post-fledging period. We conclude that landscape composition should be considered when siting early-successional habitat to maximize its benefit to forest

  1. Progress in the development of a S-RETGEM-based detector for an early forest fire warning system

    NASA Astrophysics Data System (ADS)

    Charpak, G.; Benaben, P.; Breuil, P.; Martinengo, P.; Nappi, E.; Peskov, V.

    2009-12-01

    We present a prototype of a Strip Resistive Thick GEM (S-RETGEM) photosensitive gaseous detector filled with Ne and ethylferrocene (EF) vapours at a total pressure of 1 atm for an early forest fire detection system. Measurements show that it is one hundred times more sensitive than the best commercial ultraviolet (UV) flame detectors; and therefore, it is able to reliably detect a flame of ~ 1.5 × 1.5 × 1.5 m3 at a distance of about 1 km. An additional and unique feature of this detector is its imaging capability, which in combination with other techniques, may significantly reduce false fire alarms rate when operating in an automatic mode. Preliminary results conducted with air-filled photosensitive gaseous detectors are also presented. The main advantages of this approach include both the simplicity of manufacturing and affordability of construction materials such as plastics and glues specifically reducing detector production cost. The sensitivity of these air-filled detectors at certain conditions may be as high as those filled with Ne and EF. Long-term tests of such sealed detectors indicate a significant progress in this direction. We believe that our detectors utilized in addition to other flame and smoke sensors will exceptionally increase the capability to detect forest fire at a very early stage of development. Our future efforts will be focused on attempts to commercialize such detectors utilizing our aforementioned findings.

  2. Role of Sarcoplasmic Reticulum Calcium in Development of Secondary Calcium Rise and Early Afterdepolarizations in Long QT Syndrome Rabbit Model

    PubMed Central

    Chang, Po-Cheng; Wo, Hung-Ta; Lee, Hui-Ling; Lin, Shien-Fong; Wen, Ming-Shien; Chu, Yen; Yeh, San-Jou; Chou, Chung-Chuan

    2015-01-01

    Background L-type calcium current reactivation plays an important role in development of early afterdepolarizations (EADs) and torsades de pointes (TdP). Secondary intracellular calcium (Cai) rise is associated with initiation of EADs. Objective To test whether inhibition of sarcoplasmic reticulum (SR) Ca2+ cycling suppresses secondary Cai rise and genesis of EADs. Methods Langendorff perfusion and dual voltage and Cai optical mapping were conducted in 10 rabbit hearts. Atrioventricular block (AVB) was created by radiofrequency ablation. After baseline studies, E4031, SR Ca2+ cycling inhibitors (ryanodine plus thapsigargin) and nifedipine were then administrated subsequently, and the protocols were repeated. Results At baseline, there was no spontaneous or pacing-induced TdP. After E4031 administration, action potential duration (APD) was significantly prolonged and the amplitude of secondary Cai rise was enhanced, and 7 (70%) rabbits developed spontaneous or pacing-induced TdP. In the presence of ryanodine plus thapsigargin, TdP inducibility was significantly reduced (2 hearts, 20%, p = 0.03). Although APD was significantly prolonged (from 298 ± 30 ms to 457 ± 75 ms at pacing cycle length of 1000 m, p = 0.007) by ryanodine plus thapsigargin, the secondary Cai rise was suppressed (from 8.8 ± 2.6% to 1.2 ± 0.9%, p = 0.02). Nifedipine inhibited TdP inducibility in all rabbit hearts. Conclusion In this AVB and long QT rabbit model, inhibition of SR Ca2+ cycyling reduces the inducibility of TdP. The mechanism might be suppression of secondary Cai rise and genesis of EADs. PMID:25875599

  3. Commercial multicopter unmanned aircraft system as a tool for early stage forest survey after wind damage

    NASA Astrophysics Data System (ADS)

    Mokros, Martin; Vybostok, Jozef; Merganic, Jan; Tomastik, Julian; Cernava, Juraj

    2017-04-01

    In recent years unmanned aircraft systems (UAS) are objects of research in many areas. This trend can be seen also in forest research where researchers are focusing on height, diameter and tree crown measurements, monitoring of forest fire, forest gaps and health condition. Our research is focusing on the use of UAS for detecting areas disturbed by wind and deriving the volume of fallen trees for management purposes. This information is crucial after the wind damage happened. We used DJI Phantom 2 Vision+ and acquired the imagery of one forest stand (5.7 ha). The UAS is a quadcopter "all in one" solution. It has a built-in camera with gimbal and a remote controller. The camera is controlled through the application (android/ios). The built-in camera has an image resolution of 4384×3288 (14 megapixels). We have placed five crosses within the plot to be able to georeference the point cloud from UAS. Their positions were measured by Topcon Hiper GGD survey-grade GNSS receiver. We measured the border of damaged area by four different GNSS devices - GeoExplorer 6000, Trimble Nomad, Garmin GPSMAP 60 CSx and by smartphone Sony Xperia X. To process images from UAS we used Agisoft Photoscan Professional, while ArcGIS 10.2 was used to calculate and compare the areas . From the UAS point cloud we calculated DTM and DSM and deducted them. The areas where the difference was close to zero (-0.2 to 0.2) were signed as potentially wind damage areas. Then we filtered the areas that were not signed correctly (for example routes). The calculated area from UAS was 2.66 ha, GeoExplorer 6000 was 2.20 ha, Nomad was 2.06 ha, Garmin was 2.21 ha and from Xperia was the area 2.24 ha. The differences between UAS and GPS devices vary from 0.42 ha to 0.6 ha. The differences were mostly caused by inability to detect small spots of fallen trees on UAS data. These small spots are difficult to measure by GPS devices because the signal is very poor under tree crowns and also it is difficult to find

  4. Early detection of drug use and bullying in secondary school children by using a three-dimensional simulation program.

    PubMed

    Carmona Torres, José A; Cangas, Adolfo J; García, Gustavo R; Langer, Alvaro I; Zárate, Roberto

    2012-01-01

    The current study analyzes the psychometric properties of an innovative three-dimensional (3D) simulation program, entitled Mii-School (MS), designed for the early detection of drug use and bullying in Secondary School children. This computer program showed adequate reliability and construct validity. The factorial structure, as well as the explanatory weight of the different factors, is presented. In addition, the results of a parallel version in paper and pencil format are also presented and compared with those of the computerized version (i.e., MS). There was a statistically significant difference between the two formats in the total (i.e., combined) sore of risk. When drug use and bullying were separately analyzed, differences were found only with regard to drug use. The relevance of these results as well as the suitability of this type of 3D instrument for the early detection of risky behaviors in young people are discussed.

  5. Influences of Forest Tree Species and Early Spring Temperature on Surface-Atmosphere Transfers of Water and Carbon in the Northeastern U.S.

    NASA Astrophysics Data System (ADS)

    Hadley, J. L.; Kuzeja, P.; Mulcahy, T.; Singh, S.

    2008-12-01

    Influences of Forest Tree Species and Early Spring Temperature on Surface-Atmosphere Transfers of Water and Carbon in the Northeastern U.S. Julian Hadley, Paul Kuzeja, Safina Singh and Thomas Mulcahy Transfers of water vapor from terrestrial ecosystems to the atmosphere affect regional hydrology, weather and climate over short time scales, and forest-atmosphere CO2 exchange affects global climate over long timescales. To better understand these effects for forests dominated by two very different tree species, we measured forest-atmosphere water vapor and CO2 transfers by the eddy flux technique to at two sites in central Massachusetts USA for three years. Average annual evapotranspiration (ET) for a young deciduous forest dominated by red oak (Quercus rubra L., the most abundant tree species in the area), was about 430 mm or 25 percent greater than for a coniferous forest dominated by 100 to 230 year old eastern hemlock (Tsuga canadensis L.). The difference in ET was most pronounced in July and August when the deciduous forest lost about 50 percent more water by ET in the average year (192 mm for oak forest versus 130 mm for hemlock). These data indicate that if deciduous trees with similar physiology to red oak replace hemlocks, summertime ET will increase while summer streamflow, soil water content and the extent of year- round wetlands will decrease. Increased summertime ET should also lead to slightly higher regional atmospheric humidity and precipitation. Hemlock-to-deciduous forest conversion has occurred from North Carolina to southern New England and is continuing northward as a lethal insect pest, the hemlock woolly adelgid (Adelges tsugae Annand) continues to kill hemlocks. Average annual carbon storage for the old hemlock forest in our study was about 3.3 Mg C/ha, nearly equal to the average for the deciduous forest, 3.5 Mg C/ha. This calls into question ecological theory that predicts large declines in the rate of carbon uptake for old forests, and

  6. Indigenous knowledge informing management of tropical forests: the link between rhythms in plant secondary chemistry and lunar cycles.

    PubMed

    Vogt, Kristiina A; Beard, Karen H; Hammann, Shira; Palmiotto, Jennifer O'Hara; Vogt, Daniel J; Scatena, Frederick N; Hecht, Brooke P

    2002-09-01

    This research used knowledge of the indigenous practice of timing nontimber forest product harvest with the full moon to demonstrate that chemicals controlling the decomposition rate of foliage fluctuate with the lunar cycle and may have developed as a result of plant-herbivore interactions. Indigenous knowledge suggests that leaves harvested during the full moon are more durable. Palm leaves harvested during the full moon had higher total C, hemicellulose, complex C and lower Ca concentrations. These chemical changes should make palm leaves less susceptible to herbivory and more durable when harvested during the full moon. This study proposes a mechanism by which plants in the tropics minimize foliage herbivory and influence the decomposition rates of senesced leaves and their durability, especially during the full moon. This research supports the need to use natural life cycles in managing forests and provides a scientific basis for an indigenous community's harvesting practice.

  7. Variability in early height growth rate of forest trees: implications for retrospective studies of stand dynamics

    Treesearch

    Brain J. Palik; Kurt S. Pregitzer

    1995-01-01

    Retrospective studies of forest stand dynamics may rely on estimates of tree ages. In some of these studies, trees are aged near the stem base, while in other studies trees may be aged at breast height. An age correction may be added to breast-height ages in an attempt to account for average time to reach breast height and thus provide better estimates of total ages....

  8. The effect of local and landscape-level characteristics on the abundance of forest birds in early-successional habitats during the post-fledging season in western Massachusetts

    Treesearch

    Michelle A. Labbe; David I. King; Tim A. Mousseau

    2014-01-01

    Many species of mature forest-nesting birds ("forest birds") undergo a pronounced shift in habitat use during the post-fledging period and move from their forest nesting sites into areas of early-successional vegetation. Mortality is high during this period, thus understanding the resource requirements of post-fledging birds has implications for conservation...

  9. Nitrogen and phosphorus addition impact soil N₂O emission in a secondary tropical forest of South China.

    PubMed

    Wang, Faming; Li, Jian; Wang, Xiaoli; Zhang, Wei; Zou, Bi; Neher, Deborah A; Li, Zhian

    2014-07-08

    Nutrient availability greatly regulates ecosystem processes and functions of tropical forests. However, few studies have explored impacts of N addition (aN), P addition (aP) and N × P interaction on tropical forests N₂O fluxes. We established an N and P addition experiment in a tropical forest to test whether: (1) N addition would increase N₂O emission and nitrification, and (2) P addition would increase N₂O emission and N transformations. Nitrogen and P addition had no effect on N mineralization and nitrification. Soil microbial biomass was increased following P addition in wet seasons. aN increased 39% N₂O emission as compared to control (43.3 μgN₂O-N m(-2)h(-1)). aP did not increase N₂O emission. Overall, N₂O emission was 60% greater for aNP relative to the control, but significant difference was observed only in wet seasons, when N₂O emission was 78% greater for aNP relative to the control. Our results suggested that increasing N deposition will enhance soil N₂O emission, and there would be N × P interaction on N₂O emission in wet seasons. Given elevated N deposition in future, P addition in this tropical soil will stimulate soil microbial activities in wet seasons, which will further enhance soil N₂O emission.

  10. Nitrogen and phosphorus addition impact soil N2O emission in a secondary tropical forest of South China

    PubMed Central

    Wang, Faming; Li, Jian; Wang, Xiaoli; Zhang, Wei; Zou, Bi; Neher, Deborah A.; Li, Zhian

    2014-01-01

    Nutrient availability greatly regulates ecosystem processes and functions of tropical forests. However, few studies have explored impacts of N addition (aN), P addition (aP) and N×P interaction on tropical forests N2O fluxes. We established an N and P addition experiment in a tropical forest to test whether: (1) N addition would increase N2O emission and nitrification, and (2) P addition would increase N2O emission and N transformations. Nitrogen and P addition had no effect on N mineralization and nitrification. Soil microbial biomass was increased following P addition in wet seasons. aN increased 39% N2O emission as compared to control (43.3 μgN2O-N m−2h−1). aP did not increase N2O emission. Overall, N2O emission was 60% greater for aNP relative to the control, but significant difference was observed only in wet seasons, when N2O emission was 78% greater for aNP relative to the control. Our results suggested that increasing N deposition will enhance soil N2O emission, and there would be N×P interaction on N2O emission in wet seasons. Given elevated N deposition in future, P addition in this tropical soil will stimulate soil microbial activities in wet seasons, which will further enhance soil N2O emission. PMID:25001013

  11. Characterization of xylan in the early stages of secondary cell wall formation in tobacco bright yellow-2 cells.

    PubMed

    Ishii, Tadashi; Matsuoka, Keita; Ono, Hiroshi; Ohnishi-Kameyama, Mayumi; Yaoi, Katsuro; Nakano, Yoshimi; Ohtani, Misato; Demura, Taku; Iwai, Hiroaki; Satoh, Shinobu

    2017-11-15

    The major polysaccharides present in the primary and secondary walls surrounding plant cells have been well characterized. However, our knowledge of the early stages of secondary wall formation is limited. To address this, cell walls were isolated from differentiating xylem vessel elements of tobacco bright yellow-2 (BY-2) cells induced by VASCULAR-RELATED NAC-DOMAIN7 (VND7). The walls of induced VND7-VP16-GR BY-2 cells consisted of cellulose, pectic polysaccharides, hemicelluloses, and lignin, and contained more xylan and cellulose compared with non-transformed BY-2 and uninduced VND7-VP16-GR BY-2 cells. A reducing end sequence of xylan containing rhamnose and galaturonic acid- residues is present in the walls of induced, uninduced, and non-transformed BY-2 cells. Glucuronic acid residues in xylan from walls of induced cells are O-methylated, while those of xylan in non-transformed BY-2 and uninduced cells are not. Our results show that xylan changes in chemical structure and amounts during the early stages of xylem differentiation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Management of secondary hemorrhage from early graft failure in military extremity wounds.

    PubMed

    Greer, Lauren T; Patel, Bhavin; Via, Katherine C; Bowman, Jonathan N; Weber, Michael A; Fox, Charles J

    2012-10-01

    Secondary hemorrhage after a dehisced vascular reconstruction is a dreaded complication, yet few reports describe the initial management and outcome of casualties with ruptured grafts from military wounds. We aimed to report a single-center experience of graft ruptures after evacuation of casualties to a tertiary hospital in the continental United States. Trauma records of US combat casualties were retrospectively reviewed from April 2005 to August 2007. Casualties who underwent an extremity vascular reconstruction in Iraq or Afghanistan and experienced a ruptured graft were included. Ten graft ruptures (mean time, 14 days) occurred during the study period. All casualties were males with penetrating injuries by secondary blast effects (5, 50%) or gunshot wounds (5, 50%). Mean age and Injury Severity Score were 28.2 years (range, 20-41 years) and 21.1 (range 10-32), respectively. Repairs were performed on the superficial femoral (4, 40%), popliteal (2, 20%), brachial (1, 10%), axillary (1, 10%), iliac (1, 10%), and common femoral (1, 10%) arteries using reversed saphenous vein grafts (10, 100%). Initial management included control of hemorrhage and extra-anatomic reconstruction with a vein graft (4), prosthetic graft (4), end-to-end anatomosis (1), or primary amputation (1). Secondary complications in those 10 limbs requiring reintervention included 4 thrombotic graft failures (40%), and 1 transfemoral amputation from a graft infection. Ruptures were frequently associated with long-bone fractures (6, 60%), large soft tissue open wounds (5, 50%) and infection (7, 70%). At a mean follow-up of 37 months, the amputation rate in this series was 30%, with an amputation-free survival of 70%. Contaminated military wounds with bony fractures may predispose a graft of any type (vein or prosthetic) to anastomotic dehiscence. Wounds must be carefully debrided, and when grafts cannot be covered with viable muscle, they should be routed around the zone of injury. Therapeutic

  13. Early secondary gingivo-alveolo-plasty in the treatment of unilateral cleft lip and palate patients: 20 years experience.

    PubMed

    Meazzini, Maria Costanza; Rossetti, Giulia; Garattini, Giovanna; Semb, Gunvor; Brusati, Roberto

    2010-04-01

    Since 1988, the Milano surgical protocol has included lip, nose and soft palate repair at 6-9 months of age and closure of the hard palate at 18-36 months together with an Early Secondary Gingivo-Alveolo-Plasty (ESGAP). Prior to 1988 the alveolar cleft was repaired in a third step by bone grafting at 9-11 years of age. The goal of this study was to evaluate the long-term maxillary growth in unilateral cleft lip and palate (UCLP) patients who have undergone ESGAP. Alveolar ossification after ESGAP was also studied in the permanent dentition. Growth assessment was carried out comparing lateral X-ray cephalograms of a UCLP ESGAP sample (15 consecutive patients with a mean age of 18.2 +/-1.2 years) and of the UCLP bone graft sample (10 consecutive patients with a mean age of 18.7 +/-1.1 years) and a sample from the Oslo cleft lip and palate (CLP) centre sample (15 patients with a mean age of 18.1 +/-0.8 years). Alveolar ossification in the sample which had undergone ESGAP was evaluated through a sample of panoramic X-rays of UCLP in the permanent dentition. Alveolar bridging was assessed using a modified Bergland's scoring system. From the results it seems that ESGAP allows for an excellent alveolar ossification, but patients show an inhibition of maxillary growth compared with the secondary bone graft group and with the Oslo group. Although ESGAP allows for early repair of the alveolus together with palate repair, thus eliminating in all patients the need for secondary bone grafting, it seems to have an inhibiting influence on maxillary growth which increases the need for Le Fort I osteotomies. It is however fair to recall, that, even with an adjunctive Le Fort I osteotomy, ESGAP enables the total number of operations to be reduced to three, instead of most European protocols (4-5 procedures).

  14. A Step towards Clerical Preferment: Secondary School Teachers' Careers in Early Modern Sweden

    ERIC Educational Resources Information Center

    Lindmark, Daniel

    2004-01-01

    This article investigates the function served by embarking on a teaching career in the Latin school system for recruitment to the clergy in early modern Sweden. The study is restricted to the eighty-nine teachers serving at Pitea Grammar School in Northern Sweden in the period from 1650 to 1849. The investigation pays considerable attention to the…

  15. The Crucible of Classroom Practice: Alchemy and Early Professional Learning in Secondary English Teaching

    ERIC Educational Resources Information Center

    Gannon, Susanne

    2012-01-01

    This paper explores the metaphor of the classroom as a "crucible" for early professional learning where beginning teachers forge professional identities in complex, unpredictable, paradoxical, affectively and physically potent contexts of practice. It works into the dissonances and contradictions of the micro-narratives embedded in the…

  16. The Crucible of Classroom Practice: Alchemy and Early Professional Learning in Secondary English Teaching

    ERIC Educational Resources Information Center

    Gannon, Susanne

    2012-01-01

    This paper explores the metaphor of the classroom as a "crucible" for early professional learning where beginning teachers forge professional identities in complex, unpredictable, paradoxical, affectively and physically potent contexts of practice. It works into the dissonances and contradictions of the micro-narratives embedded in the…

  17. Supporting Optimal Child Development through Early Head Start and Head Start Programs: Reflections on Secondary Data Analyses of FACES and EHSREP

    ERIC Educational Resources Information Center

    Chazan-Cohen, Rachel; Halle, Tamara G.; Barton, Lauren R.; Winsler, Adam

    2012-01-01

    We are delighted to reflect on the 10 papers highlighted in this important special issue of "Early Childhood Research Quarterly" devoted to recent secondary data analyses of the FACES and EHSREP datasets. First, we provide some background on Head Start research and give an overview of the large-scale Head Start and Early Head Start…

  18. Supporting Optimal Child Development through Early Head Start and Head Start Programs: Reflections on Secondary Data Analyses of FACES and EHSREP

    ERIC Educational Resources Information Center

    Chazan-Cohen, Rachel; Halle, Tamara G.; Barton, Lauren R.; Winsler, Adam

    2012-01-01

    We are delighted to reflect on the 10 papers highlighted in this important special issue of "Early Childhood Research Quarterly" devoted to recent secondary data analyses of the FACES and EHSREP datasets. First, we provide some background on Head Start research and give an overview of the large-scale Head Start and Early Head Start…

  19. Early snowmelt decreases ablation period carbon uptake in a high elevation, subalpine forest, Niwot Ridge, Colorado, USA

    NASA Astrophysics Data System (ADS)

    Winchell, T. S.; Molotch, N. P.; Barnard, D. M.

    2015-12-01

    The snow ablation period is a time of great potential for carbon uptake in high-elevation, subalpine forests. During this period, water availability associated with snowmelt promotes photosynthetic carbon uptake, while snow cover diminishes carbon losses from soil respiration. Although the ablation period can be as short as two weeks, as much as 30% of the total seasonal carbon uptake can occur during this period. Varying ablation period dynamics, however, can result in varying rates of carbon uptake during this integral uptake period. We use fifteen years of observational climate flux and snow water equivalent (SWE) data for a subalpine forest in the Colorado Rocky Mountains to analyze carbon uptake trends during the annual ablation period. Specifically, we focus on how the timing of peak SWE affects carbon uptake during the ablation period. We find that when the snowmelt period occurs one month earlier than average, the forest experiences an ablation period mean air temperature of 2.7° C, approximately 5° C colder than an ablation period that occurs one month later than average. This early, colder atmospheric condition leads to daytime carbon uptake rates that are 2.5 gC/m2/day less than the later, warmer period, which results in 47 gC/m2 less ablation period carbon uptake. As most climate models project peak SWE to occur earlier under various warming scenarios, we can expect to see a trend of less carbon uptake during future ablation periods. We expect to see a decrease in total growing season carbon uptake if the post-snowmelt period is unable to compensate for the decrease in ablation period carbon uptake.

  20. Being in a safe and thus secure place, the core of early labour: A secondary analysis in a Swedish context.

    PubMed

    Carlsson, Ing-Marie

    2016-01-01

    Early labour is the very first phase of the labour process and is considered to be a period of time when no professional attendance is needed. However there is a high frequency of women who seek care at the delivery wards during this phase. When a woman is admitted to the delivery ward, one role for midwives is to determine whether the woman is in established labour or not. If the woman is assessed as being in early labour she will probably then be advised to return home. This recommendation is made due to past research that found that the longer a woman is in hospital the higher the risk for complications for her and her child. Women have described how this situation leaves them in a vulnerable situation where their preferences are not always met and where they are not always included in the decision-making process. The aim of this study was to generate a theory based on where a woman chooses to be during the early labour process and to increase our understanding about how experiences can differ from place to place. The method was a secondary analysis with grounded theory. The data used in the analysis was from two qualitative interview studies and 37 transcripts. The findings revealed a substantive theory that women needed to be in a safe and thus secure place during early labour. This theory also describes the interplay between how women ascribed their meaning of childbirth as either a natural live event or a medical one, how this influenced where they wanted to be during early labour, and how that chosen place influenced their experiences of labour and birth.

  1. Being in a safe and thus secure place, the core of early labour: A secondary analysis in a Swedish context.

    PubMed

    Carlsson, Ing-Marie

    2016-01-01

    Background Early labour is the very first phase of the labour process and is considered to be a period of time when no professional attendance is needed. However there is a high frequency of women who seek care at the delivery wards during this phase. When a woman is admitted to the delivery ward, one role for midwives is to determine whether the woman is in established labour or not. If the woman is assessed as being in early labour she will probably then be advised to return home. This recommendation is made due to past research that found that the longer a woman is in hospital the higher the risk for complications for her and her child. Women have described how this situation leaves them in a vulnerable situation where their preferences are not always met and where they are not always included in the decision-making process. Aim The aim of this study was to generate a theory based on where a woman chooses to be during the early labour process and to increase our understanding about how experiences can differ from place to place. Methods The method was a secondary analysis with grounded theory. The data used in the analysis was from two qualitative interview studies and 37 transcripts. Conclusion The findings revealed a substantive theory that women needed to be in a safe and thus secure place during early labour. This theory also describes the interplay between how women ascribed their meaning of childbirth as either a natural live event or a medical one, how this influenced where they wanted to be during early labour, and how that chosen place influenced their experiences of labour and birth.

  2. Being in a safe and thus secure place, the core of early labour: A secondary analysis in a Swedish context

    PubMed Central

    Carlsson, Ing-Marie

    2016-01-01

    Background Early labour is the very first phase of the labour process and is considered to be a period of time when no professional attendance is needed. However there is a high frequency of women who seek care at the delivery wards during this phase. When a woman is admitted to the delivery ward, one role for midwives is to determine whether the woman is in established labour or not. If the woman is assessed as being in early labour she will probably then be advised to return home. This recommendation is made due to past research that found that the longer a woman is in hospital the higher the risk for complications for her and her child. Women have described how this situation leaves them in a vulnerable situation where their preferences are not always met and where they are not always included in the decision-making process. Aim The aim of this study was to generate a theory based on where a woman chooses to be during the early labour process and to increase our understanding about how experiences can differ from place to place. Methods The method was a secondary analysis with grounded theory. The data used in the analysis was from two qualitative interview studies and 37 transcripts. Conclusion The findings revealed a substantive theory that women needed to be in a safe and thus secure place during early labour. This theory also describes the interplay between how women ascribed their meaning of childbirth as either a natural live event or a medical one, how this influenced where they wanted to be during early labour, and how that chosen place influenced their experiences of labour and birth. PMID:27172510

  3. Strong resilience of soil respiration components to drought-induced die-off resulting in forest secondary succession.

    PubMed

    Barba, Josep; Curiel Yuste, Jorge; Poyatos, Rafael; Janssens, Ivan A; Lloret, Francisco

    2016-09-01

    How forests cope with drought-induced perturbations and how the dependence of soil respiration on environmental and biological drivers is affected in a warming and drying context are becoming key questions. The aims of this study were to determine whether drought-induced die-off and forest succession were reflected in soil respiration and its components and to determine the influence of climate on the soil respiration components. We used the mesh exclusion method to study seasonal variations in soil respiration (R S) and its components: heterotrophic (R H) and autotrophic (R A) [further split into fine root (R R) and mycorrhizal respiration (R M)] in a mixed Mediterranean forest where Scots pine (Pinus sylvestris L.) is undergoing a drought-induced die-off and is being replaced by holm oak (Quercus ilex L.). Drought-induced pine die-off was not reflected in R S nor in its components, which denotes a high functional resilience of the plant and soil system to pine die-off. However, the succession from Scots pine to holm oak resulted in a reduction of R H and thus in an important decrease of total respiration (R S was 36 % lower in holm oaks than in non-defoliated pines). Furthermore, R S and all its components were strongly regulated by soil water content-and-temperature interaction. Since Scots pine die-off and Quercus species colonization seems to be widely occurring at the driest limit of the Scots pine distribution, the functional resilience of the soil system over die-off and the decrease of R S from Scots pine to holm oak could have direct consequences for the C balance of these ecosystems.

  4. Remote sensing leaf water stress in coffee (Coffea arabica) using secondary effects of water absorption and random forests

    NASA Astrophysics Data System (ADS)

    Chemura, Abel; Mutanga, Onisimo; Dube, Timothy

    2017-08-01

    Water management is an important component in agriculture, particularly for perennial tree crops such as coffee. Proper detection and monitoring of water stress therefore plays an important role not only in mitigating the associated adverse impacts on crop growth and productivity but also in reducing expensive and environmentally unsustainable irrigation practices. Current methods for water stress detection in coffee production mainly involve monitoring plant physiological characteristics and soil conditions. In this study, we tested the ability of selected wavebands in the VIS/NIR range to predict plant water content (PWC) in coffee using the random forest algorithm. An experiment was set up such that coffee plants were exposed to different levels of water stress and reflectance and plant water content measured. In selecting appropriate parameters, cross-correlation identified 11 wavebands, reflectance difference identified 16 and reflectance sensitivity identified 22 variables related to PWC. Only three wavebands (485 nm, 670 nm and 885 nm) were identified by at least two methods as significant. The selected wavebands were trained (n = 36) and tested on independent data (n = 24) after being integrated into the random forest algorithm to predict coffee PWC. The results showed that the reflectance sensitivity selected bands performed the best in water stress detection (r = 0.87, RMSE = 4.91% and pBias = 0.9%), when compared to reflectance difference (r = 0.79, RMSE = 6.19 and pBias = 2.5%) and cross-correlation selected wavebands (r = 0.75, RMSE = 6.52 and pBias = 1.6). These results indicate that it is possible to reliably predict PWC using wavebands in the VIS/NIR range that correspond with many of the available multispectral scanners using random forests and further research at field and landscape scale is required to operationalize these findings.

  5. The Dictyostelium MAPK ERK1 is phosphorylated in a secondary response to early developmental signaling.

    PubMed

    Schwebs, David J; Hadwiger, Jeffrey A

    2015-01-01

    Previous reports have suggested that the two mitogen-activated protein kinases (MAPKs) in Dictyostelium discoideum, ERK1 and ERK2, can be directly activated in response to external cAMP even though these MAPKs play different roles in the developmental life cycle. To better characterize MAPK regulation, the levels of phosphorylated MAPKs were analyzed in response to external signals. Only ERK2 was rapidly phosphorylated in response to the chemoattractants, cAMP and folate. In contrast, the phosphorylation of ERK1 occurred as a secondary or indirect response to these stimuli and this phosphorylation was enhanced by cell-cell interactions, suggesting that other external signals can activate ERK1. The phosphorylation of ERK1 or ERK2 did not require the function of the other MAPK in these responses. Folate stimulation of a chimeric population of erk1- and gα4- cells revealed that the phosphorylation of ERK1 could be mediated through an intercellular signal other than folate. Loss of ERK1 function suppressed the developmental delay and the deficiency in anterior cell localization associated with gα5- mutants suggesting that ERK1 function can be down regulated through Gα5 subunit-mediated signaling. However, no major changes in the phosphorylation of ERK1 were observed in gα5- cells suggesting that the Gα5 subunit signaling pathway does not regulate the phosphorylation of ERK1. These findings suggest that the activation of ERK1 occurs as a secondary response to chemoattractants and that other cell-cell signaling mechanisms contribute to this activation. Gα5 subunit signaling can down regulate ERK1 function to promote prestalk cell development but not through major changes to the level of phosphorylated ERK1.

  6. Tree rings provide early warning signals of jack pine mortality across a moisture gradient in the southern boreal forest

    NASA Astrophysics Data System (ADS)

    Mamet, S. D.; Chun, K. P.; Metsaranta, J. M.; Barr, A. G.; Johnstone, J. F.

    2015-08-01

    Recent declines in productivity and tree survival have been widely observed in boreal forests. We used early warning signals (EWS) in tree ring data to anticipate premature mortality in jack pine (Pinus banksiana)—an extensive and dominant species occurring across the moisture-limited southern boreal forest in North America. We sampled tree rings from 113 living and 84 dead trees in three soil moisture regimes (subxeric, submesic, subhygric) in central Saskatchewan, Canada. We reconstructed annual increments of tree basal area to investigate (1) whether we could detect EWS related to mortality of individual trees, and (2) how water availability and tree growth history may explain the mortality warning signs. EWS were evident as punctuated changes in growth patterns prior to transition to an alternative state of reduced growth before dying. This transition was likely triggered by a combination of severe drought and insect outbreak. Higher moisture availability associated with a soil moisture gradient did not appear to reduce tree sensitivity to stress-induced mortality. Our results suggest tree rings offer considerable potential for detecting critical transitions in tree growth, which are linked to premature mortality.

  7. A comparison of species composition and community assemblage of secondary forests between the birch and pine-oak belts in the mid-altitude zone of the Qinling Mountains, China

    PubMed Central

    Chai, Zongzheng

    2016-01-01

    The mid-altitude zone of the Qinling Mountains in China was once dominated by birch and pine-oak belts but are now mainly covered by secondary growth following large-scale deforestation. Assessing the recovery and sustainability of these forests is essential for their management and restoration. We investigated and compared the tree species composition and community assemblages of secondary forests of the birch and pine-oak belts in the Huoditang forest region of the Qinling Mountains after identical natural recoveries. Both types of belts had rich species compositions and similar floristic components but clearly different community structures. Tree diversity was significantly higher for the birch than the pine-oak belt. Niche and neutral processes simultaneously influenced the species distribution and community dynamics of the belts, and these forests were able to maintain stable development during natural recoveries. The conservation and management of these forests should receive more attention to protect biodiversity and the forest resources in the Qinling Mountains. PMID:27123377

  8. A comparison of species composition and community assemblage of secondary forests between the birch and pine-oak belts in the mid-altitude zone of the Qinling Mountains, China.

    PubMed

    Chai, Zongzheng; Wang, Dexiang

    2016-01-01

    The mid-altitude zone of the Qinling Mountains in China was once dominated by birch and pine-oak belts but are now mainly covered by secondary growth following large-scale deforestation. Assessing the recovery and sustainability of these forests is essential for their management and restoration. We investigated and compared the tree species composition and community assemblages of secondary forests of the birch and pine-oak belts in the Huoditang forest region of the Qinling Mountains after identical natural recoveries. Both types of belts had rich species compositions and similar floristic components but clearly different community structures. Tree diversity was significantly higher for the birch than the pine-oak belt. Niche and neutral processes simultaneously influenced the species distribution and community dynamics of the belts, and these forests were able to maintain stable development during natural recoveries. The conservation and management of these forests should receive more attention to protect biodiversity and the forest resources in the Qinling Mountains.

  9. QLF monitoring of therapies for early secondary caries arrestment and remineralization

    NASA Astrophysics Data System (ADS)

    Fontana, Margherita; Gonzalez-Cabezas, Carlos; Stookey, George K.

    2000-03-01

    Secondary caries (SC) is the most common reason for restoration failure. The purpose of this study was to evaluate the Quantitative Light-Induced Fluorescence (QLF) method for monitoring therapies to inhibit SC progression. Forty-eight human teeth with resin restorations were demineralized for 4 days in a microbial caries model. Half of each specimen was then covered with an acid-resistant varnish to maintain the baseline lesion, and treated (group 1: non-treated control; group 2: chlorhexidine varnish for 24 h; group 3: fluoride varnish for 24 h; group 4: APF topical fluoride gel for 4 min), prior to being demineralized for 4 more days. Specimens were analyzed by QLF, sectioned, stained with Rhodamine B, and analyzed with a confocal microscope (CLSM) for lesion depth. The QLF results indicated that the control group was significantly (p less than 0.05) different (i.e., lesions progressed) from groups treated with fluoride (groups 3 and 4; lesions remineralized). All other group comparisons were not significantly different. Results obtained from CLSM analysis were similar to the ones obtained with QLF, except that lesions in group 2 were significantly deeper than the ones in the fluoride groups. Results suggest that the QLF method has a clear potential for monitoring remineralizing therapies for SC.

  10. Fire decreases arthropod abundance but increases diversity: early and late season prescribed fire effects in a Sierra Nevada mixed-conifer forest

    Treesearch

    Scott M. Ferrenberg; Dylan W. Schwilk; Eric E. Knapp; Eric Groth; Jon E. Keeley

    2006-01-01

    Prior to fire suppression in the 20th century, the mixed-conifer forests of the Sierra Nevada, California, U.S.A., historically burned in frequent fires that typically occurred during the late summer and early fall. Fire managers have been attempting to restore natural ecosystem processes through prescription burning, and have often favored burning during the fall in...

  11. Fanconi Syndrome Secondary to Deferasirox in Diamond-Blackfan Anemia: Case Series and Recommendations for Early Diagnosis.

    PubMed

    Papneja, Koyelle; Bhatt, Mihir D; Kirby-Allen, Melanie; Arora, Steven; Wiernikowski, John T; Athale, Uma H

    2016-08-01

    Deferasirox is an oral iron chelator used to treat patients with transfusion-related iron overload. We report, from two institutions, two children with Diamond-Blackfan anemia who developed Fanconi syndrome secondary to deferasirox administration, along with a review of the literature. The current recommendation for the laboratory monitoring of patients receiving deferasirox does not include serum electrolytes or urine analysis. Thus, despite routine clinic visits and bloodwork, these two patients presented with life-threatening electrolyte abnormalities requiring hospitalization. Hence, we propose the inclusion of serum electrolytes and urine analysis as part of routine monitoring to facilitate the early diagnosis of Fanconi syndrome in the context of high doses of deferasirox therapy. © 2016 Wiley Periodicals, Inc.

  12. Effects of Chronic Sleep Restriction during Early Adolescence on the Adult Pattern of Connectivity of Mouse Secondary Motor Cortex123

    PubMed Central

    Billeh, Yazan N.; Bernard, Amy; de Vivo, Luisa; Honjoh, Sakiko; Mihalas, Stefan; Ng, Lydia; Koch, Christof

    2016-01-01

    Abstract Cortical circuits mature in stages, from early synaptogenesis and synaptic pruning to late synaptic refinement, resulting in the adult anatomical connection matrix. Because the mature matrix is largely fixed, genetic or environmental factors interfering with its establishment can have irreversible effects. Sleep disruption is rarely considered among those factors, and previous studies have focused on very young animals and the acute effects of sleep deprivation on neuronal morphology and cortical plasticity. Adolescence is a sensitive time for brain remodeling, yet whether chronic sleep restriction (CSR) during adolescence has long-term effects on brain connectivity remains unclear. We used viral-mediated axonal labeling and serial two-photon tomography to measure brain-wide projections from secondary motor cortex (MOs), a high-order area with diffuse projections. For each MOs target, we calculated the projection fraction, a combined measure of passing fibers and axonal terminals normalized for the size of each target. We found no homogeneous differences in MOs projection fraction between mice subjected to 5 days of CSR during early adolescence (P25–P30, ≥50% decrease in daily sleep, n=14) and siblings that slept undisturbed (n=14). Machine learning algorithms, however, classified animals at significantly above chance levels, indicating that differences between the two groups exist, but are subtle and heterogeneous. Thus, sleep disruption in early adolescence may affect adult brain connectivity. However, because our method relies on a global measure of projection density and was not previously used to measure connectivity changes due to behavioral manipulations, definitive conclusions on the long-term structural effects of early CSR require additional experiments. PMID:27351022

  13. Modelling primary and secondary growth processes in plants: a summary of the methodology and new data from an early lignophyte.

    PubMed Central

    Speck, Thomas; Rowe, Nick P

    2003-01-01

    A mathematical method, based on polar coordinates that allow modelling of primary and secondary growth processes in stems of extant and fossil plants, is summarized and its potential is discussed in comparison with numerical methods using digitizing tablets or electronic image analysing systems. As an example, the modelling of tissue distribution in the internode of an extant sphenopsid (Equisetum hyemale) is presented. In the second half of the paper we present new data of a functional analysis of stem structure and biomechanics of the early lignophyte Tetraxylopteris schmidtii (Middle Devonian) using the polar coordinate method for modelling the tissue distribution in stems of different ontogenetic age. Calculations of the mechanical properties of the stems, based on the modelling of the tissue arrangement, indicate that there is no increase in structural bending modulus throughout the entire development of the plant. The oldest ontogenetic stage has a significantly smaller bending elastic modulus than the intermediate ontogenetic stage, a 'mechanical signal', which is not consistent with a self-supporting growth form. These results, and the ontogenetic variations of the contributions of different stem tissues to the flexural stiffness of the entire stem, are discussed in the evolutionary context of cambial secondary growth. PMID:14561338

  14. Persistent Effects of Fire Severity on Early Successional Forests in Interior Alaska

    NASA Technical Reports Server (NTRS)

    Shenoy, Aditi; Johnstone, Jill F.; Kasischke, Eric S.; Kielland, Knut

    2011-01-01

    There has been a recent increase in the frequency and extent of wildfires in interior Alaska, and this trend is predicted to continue under a warming climate. Although less well documented, corresponding increases in fire severity are expected. Previous research from boreal forests in Alaska and western Canada indicate that severe fire promotes the recruitment of deciduous tree species and decreases the relative abundance of black spruce (Picea mariana) immediately after fire. Here we extend these observations by (1) examining changes in patterns of aspen and spruce density and biomass that occurred during the first two decades of post-fire succession, and (2) comparing patterns of tree composition in relation to variations in post-fire organic layer depth in four burned black spruce forests in interior Alaska after 10-20 years of succession.Wefound that initial effects of fire severity on recruitment and establishment of aspen and black spruce were maintained by subsequent effects of organic layer depth and initial plant biomass on plant growth during post-fire succession. The proportional contribution of aspen (Populus tremuloides) to total stand biomass remained above 90% during the first and second decades of succession in severely burned sites, while in lightly burned sites the proportional contribution of aspen was reduced due to a 40- fold increase in spruce biomass in these sites. Relationships between organic layer depth and stem density and biomass were consistently negative for aspen, and positive or neutral for black spruce in all four burns. Our results suggest that initial effects of post-fire organic layer depths on deciduous recruitment are likely to translate into a prolonged phase of deciduous dominance during post-fire succession in severely burned stands. This shift in vegetation distribution has important implications for climate-albedo feedbacks, future fire regime, wildlife habitat quality and natural resources for indigenous subsistence

  15. Persistent Effects of Fire Severity on Early Successional Forests in Interior Alaska

    NASA Technical Reports Server (NTRS)

    Shenoy, Aditi; Johnstone, Jill F.; Kasischke, Eric S.; Kielland, Knut

    2011-01-01

    There has been a recent increase in the frequency and extent of wildfires in interior Alaska, and this trend is predicted to continue under a warming climate. Although less well documented, corresponding increases in fire severity are expected. Previous research from boreal forests in Alaska and western Canada indicate that severe fire promotes the recruitment of deciduous tree species and decreases the relative abundance of black spruce (Picea mariana) immediately after fire. Here we extend these observations by (1) examining changes in patterns of aspen and spruce density and biomass that occurred during the first two decades of post-fire succession, and (2) comparing patterns of tree composition in relation to variations in post-fire organic layer depth in four burned black spruce forests in interior Alaska after 10-20 years of succession.Wefound that initial effects of fire severity on recruitment and establishment of aspen and black spruce were maintained by subsequent effects of organic layer depth and initial plant biomass on plant growth during post-fire succession. The proportional contribution of aspen (Populus tremuloides) to total stand biomass remained above 90% during the first and second decades of succession in severely burned sites, while in lightly burned sites the proportional contribution of aspen was reduced due to a 40- fold increase in spruce biomass in these sites. Relationships between organic layer depth and stem density and biomass were consistently negative for aspen, and positive or neutral for black spruce in all four burns. Our results suggest that initial effects of post-fire organic layer depths on deciduous recruitment are likely to translate into a prolonged phase of deciduous dominance during post-fire succession in severely burned stands. This shift in vegetation distribution has important implications for climate-albedo feedbacks, future fire regime, wildlife habitat quality and natural resources for indigenous subsistence

  16. Primary and secondary effects of climate variability on carbon and water exchange in a managed subalpine Eucalyptus forest.

    NASA Astrophysics Data System (ADS)

    van Gorsel, Eva; Berni, Jose. A. J.; Briggs, Peter; Cabello-Leblic, Arancha; Chasmer, Laura; Cleugh, Helen A.; Hacker, Joerg; Hantson, Stijn; Haverd, Vanessa; Hughes, Dale; Hopkinson, Chris; Keith, Heather; Kljun, Natascha; Leuning, Ray; Yebra, Marta; Zegelin, Steve

    2013-04-01

    Climate variability and change, ecosystem disturbance and land management operate over a large range of temporal and spatial scales and lead to variability in carbon and water fluxes. Diagnosing the climate controls over these fluxes is not simple but key to improving prediction and understanding of water and carbon cycle-climate interactions. We use a novel technique to investigate the variability of the fluxes from daily to multiannual timescales. We rank direct controlling factors of climate on water use and carbon uptake (changes in radiation, temperature, humidity) and indirect factors (disturbance triggered by changes in climate conditions). Direct climate impacts depend on the time scale under consideration but are generally strongest on the annual time scale. To investigate the spatio-temporal variability caused by disturbance we use NDVI and albedo. They provide information on status and dynamics of the vegetation and we find that the whole area within Bago State Forest that was classified as native Eucalyptus forest (305.05 km2) was affected by a disturbance by insect attack. This disturbance affected tree species differently, led to a reduced photosynthetically active leaf area, reduced canopy conductance and hence photosynthetic capacity. The reduced net carbon uptake of the trees was evident as reduced biomass increment and increased mortality was observed. Net ecosystem exchange measurements at the Tumbarumba flux tower indicate that the ecosystem turned from a generally strong carbon sink to a source. We further find that the coherence between albedo and carbon and water exchange is strong on annual and multi-annual time scales. At a multi-annual time scale, carbon and water fluxes are coherent with the multivariate El Niño index.

  17. Early Cambrian Relief Sandstone, Officer basin, south Australia - An example of secondary porosity development

    SciTech Connect

    Gaugham, C.J.; Warren, J.K. )

    1990-05-01

    The Lower Cambrian Relief Sandstone has been drilled and cored at seven locations in the eastern Officer basin, central Australia. Core, well log, petrographic, and x-ray diffraction analyses have been used to subdivide the Relief Sandstone into stratigraphic units and individual depositional environments, and to determined controlling factors on known reservoir distribution and quality. Interest in the Relief Sandstone as a potential economic oil-bearing sandstone is supported by excellent reservoir quality (up to 26.5% porosity and 4,839 md permeability). Potential source rocks are found above, below and interfingering with the Relief Sandstone. There are several occurrences of live oil bleeding from vugs and fractures in a stratigraphically higher carbonate. Traces of oil in the Relief sands and the presence of live oil in relatively close proximity suggests that the Relief Sandstone could host an economic oil accumulation. The majority of the Relief Sandstone was deposited in eolian or braided fluvial environments, with some alluvial fan sedimentation in the east, and tidal- to shallow-marine deposition in the west. Distribution of reservoir-quality sands is bimodal. In the east porosity and permeability for the most part are very poor to average. In the west, porosity and permeability are generally good to excellent. The bulk of the economic porosity is secondary, a result of dissolution of cement and matrix, with minor porosity from leaching of grains. The lower reservoir quality in the east is due to diagenesis associated with compaction and authigenic illite. Grain packing with suturing and silica overgrowths have reduced primary porosity to noneconomic levels. Permeability has been reduced by these processes and by the blocking of pore throats with authigenic illite. In the west, the porosity and permeability are high and generally due to dissolution of clay cement and primary matrix.

  18. Vaccination Enhances Early Immune Responses in White Shrimp Litopenaeus vannamei after Secondary Exposure to Vibrio alginolyticus

    PubMed Central

    Lin, Yong-Chin; Chen, Jiann-Chu; Morni, Wan Zabidii W.; Putra, Dedi Fazriansyah; Huang, Chien-Lun; Li, Chang-Che; Hsieh, Jen-Fang

    2013-01-01

    Background Recent work suggested that the presence of specific memory or some form of adaptive immunity occurs in insects and shrimp. Hypervariable pattern recognition molecules, known as Down syndrome cell adhesion molecules, are able to mount specific recognition, and immune priming in invertebrates. In the present study, we attempted to understand the immune response pattern of white shrimp Litopenaeus vannamei which received primary (PE) and secondary exposure (SE) to Vibrio alginolyticus. Methodology Immune parameters and proliferation of haematopoietic tissues (HPTs) of shrimp which had received PE and SE to V. alginolyticus were measured. In the PE trial, the immune parameters and proliferation of HPTs of shrimp that received heat-killed V. alginolyticus (HVa) and formalin-inactivated V. alginolyticus (FVa) were measured. Mortality, immune parameters and proliferation of HPTs of 7-day-HVa-PE shrimp (shrimp that received primary exposure to HVa after 7 days) and 7-day-FVa-PE shrimp (shrimp that received primary exposure to FVa after 7 days) following SE to live V. alginolyticus (LVa) were measured. Phagocytic activity and clearance efficiency were examined for the 7∼35-day-HVa-PE and FVa-PE shrimp. Results HVa-receiving shrimp showed an earlier increase in the immune response on day 1, whereas FVa-receiving shrimp showed a late increase in the immune response on day 5. The 7-day-FVa-PE shrimp showed enhancement of immunity when encountering SE to LVa, whereas 7-day-HVa-PE shrimp showed a minor enhancement in immunity. 7-day-FVa-PE shrimp showed higher proliferation and an HPT mitotic index. Both phagocytic activity and clearance maintained higher for both HVa-PE and FVa-PE shrimp after 28 days. Conclusions HVa- and FVa-receiving shrimp showed the bacteria agglutinated prior to being phagocytised. FVa functions as a vaccine, whereas HVa functions as an inducer and can be used as an immune adjuvant. A combined mixture of FVa and HVa can serve as a

  19. Spatial distribution patterns of ammonia-oxidizing archaea abundance in subtropical forests at early and late successional stages

    PubMed Central

    Chen, Jie; Zhang, Hui; Liu, Wei; Lian, Juyu; Ye, Wanhui; Shen, Weijun

    2015-01-01

    Characterizing the spatial distribution patterns of soil microorganisms is helpful in understanding the biogeochemical processes they perform, but has been less studied relative to those of macroorganisms. In this study, we investigated and compared the spatially explicit distribution patterns of ammonia-oxidizing archaea (AOA) abundance and the influential factors between an early (ES) and a late successional (LS) subtropical forest stand. The average AOA abundance, vegetational attributes, and soil nutrient contents were mostly greater in the LS than the ES stand (P = 0.085 or smaller), but their spatial variations were more pronounced in the ES than the LS stand. The spatial distribution patches of AOA abundance were smaller and more irregular in the ES stand (patch size <50 m) than in the LS stand (patch size about 120 m). Edaphic and vegetational variables contributed more to the spatial variations of AOA abundance for the ES (9.3%) stand than for LS stand, whereas spatial variables (MEMs) were the main contributors (62%) for the LS stand. These results suggest that environmental filtering likely influence the spatial distribution of AOA abundance at early successional stage more than that at late successional stage, while spatial dispersal is dominant at late successional stage. PMID:26565069

  20. γδ T cells as early sensors of tissue damage and mediators of secondary neurodegeneration

    PubMed Central

    Gelderblom, Mathias; Arunachalam, Priyadharshini; Magnus, Tim

    2014-01-01

    Spontaneous or medically induced reperfusion occurs in up to 70% of patients within 24 h after cerebral ischemia. Reperfusion of ischemic brain tissue can augment the inflammatory response that causes additional injury. Recently, T cells have been shown to be an essential part of the post-ischemic tissue damage, and especially IL-17 secreting T cells have been implicated in the pathogenesis of a variety of inflammatory reactions in the brain. After stroke, it seems that the innate γδ T cells are the main IL-17 producing cells and that the γδ T cell activation constitutes an early and mainly damaging immune response in stroke. Effector mechanism of γδ T cell derived IL-17 in the ischemic brain include the induction of metalloproteinases, proinflammatory cytokines and neutrophil attracting chemokines, leading to a further amplification of the detrimental inflammatory response. In this review, we will give an overview on the concepts of γδ T cells and IL-17 in stroke pathophysiology and on their potential importance for human disease conditions. PMID:25414640

  1. Biological soil crusts reduce soil erosion in early successional subtropical forests in PR China

    NASA Astrophysics Data System (ADS)

    Seitz, Steffen; Goebes, Philipp; Käppeler, Kathrin; Nebel, Martin; Webber, Carla; Scholten, Thomas

    2016-04-01

    Biological soil crusts (BSCs) have major influences on terrestrial ecosystems and play significant functional roles in soil systems, such as accelerating soil formation, changing water flows or enhancing soil stability. By that, they have the potential to protect soil surfaces against erosive forces by wind or water. However, the effect of BSCs on erosion processes is rarely mentioned in literature and most of the work done focused on arid and semi-arid environments. Furthermore, compared to the structure and function of BSCs, less attention was paid to their temporal and topographical distribution. This study aims to investigate the influence of BSCs on initial soil erosion, and their topographical development over time in initial subtropical forest ecosystems. Therefore, measurements have been conducted within a biodiversity and ecosystem functioning experiment (BEF China) near Xingangshan, Jiangxi Province, PR China. Interrill erosion was measured on 220 microscale run-off plots (ROPs, 0.4 m × 0.4 m) and the occurrence, distribution and development of BSCs within the measuring setup were recorded. BSC cover in each ROP was determined photogrammetrically in four time steps (autumn 2011, summer 2012, summer 2013 and summer 2014). BSC species were identified by morphological characteristics and classified to higher taxonomic levels. Higher BSC cover led to reduced sediment discharge and runoff volume due to its protection against splash energy, the adherence of soil particles and enhanced infiltration. Canopy ground cover and leaf area index had a positive effect on the development of BSC cover at this initial stage of the forest ecosystem. Moreover, BSC cover decreased with increasing slope, as we presume that developing BSCs are washed away more easily at steep gradients. Elevation and aspect did not show an influence. BSCs in this study were moss-dominated and 26 different moos species were found. Mean BSC cover on ROPs was 14 % in the 3rd year of the tree

  2. Chemical epigenetics alters the secondary metabolite composition of guttate excreted by an atlantic-forest-soil-derived Penicillium citreonigrum.

    PubMed

    Wang, Xiaoru; Sena Filho, José G; Hoover, Ashley R; King, Jarrod B; Ellis, Trevor K; Powell, Douglas R; Cichewicz, Robert H

    2010-05-28

    Chemical epigenetic manipulation of Penicillium citreonigrum led to profound changes in the secondary metabolite profile of its guttate. While guttate from control cultures exhibited a relatively simple assemblage of secondary metabolites, the guttate collected from cultures treated with 50 muM 5-azacytidine (a DNA methyltransferase inhibitor) was highly enriched in compounds representing at least three distinct biosynthetic families. The metabolites obtained from the fungus included six azaphilones (sclerotiorin (1), sclerotioramine (6), ochrephilone (2), dechloroisochromophilone III (3), dechloroisochromophilone IV (4), and 6-((3E,5E)-5,7-dimethyl-2-methylenenona-3,5-dienyl)-2,4-dihydroxy-3-methylbenzaldehyde (5)), pencolide (7), and two new meroterpenes (atlantinones A and B (9 and 10, respectively)). While pencolide was detected in the exudates of both control and 5-azacytidine-treated cultures, all of the other natural products were found exclusively in the guttates of the epigenetically modified fungus. All of the metabolites from the P. citreonigrum guttate were tested for antimicrobial activity in a disk diffusion assay. Both sclerotiorin and sclerotioramine caused modest inhibition of Staphylococcus epidermidis growth; however, only sclerotioramine was active against a panel of Candida strains.

  3. Chemical Epigenetics Alters the Secondary Metabolite Composition of Guttate Excreted by an Atlantic-Forest-Soil-Derived Penicillium citreonigrum

    PubMed Central

    Wang, Xiaoru; Filho, José G. Sena; Hoover, Ashley R.; King, Jarrod B.; Ellis, Trevor K.; Powell, Douglas R.; Cichewicz, Robert H.

    2010-01-01

    Chemical epigenetic manipulation of Penicillium citreonigrum led to profound changes in the secondary metabolite profile of its guttate. While guttate from control cultures exhibited a relatively simple assemblage of secondary metabolites, the guttate collected from cultures treated with 50 μM 5-azacytidine (a DNA methyltransferase inhibitor) were highly enriched in compounds representing at least three distinct biosynthetic families. The metabolites obtained from the fungus included six azaphilones (sclerotiorin (1), sclerotioramine (6), ochrephilone (2), dechloroisochromophilone III (3), dechloroisochromophilone IV (4), and 6-((3E,5E)-5,7-dimethyl-2-methylenenona-3,5-dienyl)-2,4-dihydroxy-3-methylbenzaldehyde (5)), pencolide (7), and two new meroterpenes (atlantinones A and B (9 and 10, respectively)). While pencolide was detected in the exudates of both control and 5-azacytidine-treated cultures, all of the other natural products were found exclusively in the guttates of the epigenetically modified fungus. All of the metabolites from the P. citreonigrum guttate were tested for antimicrobial activity in a disk diffusion assay. Both sclerotiorin and sclerotioramine caused modest inhibition of Staphylococcus epidermidis growth; however, only sclerotioramine was active against a panel of Candida strains. PMID:20450206

  4. Pediatric paraganglioma: an early manifestation of an adult disease secondary to germline mutations.

    PubMed

    Mora, Jaume; Cascón, Alberto; Robledo, Mercedes; Catala, Albert

    2006-11-01

    Paraganglioma (PGL) and phaeochromocytoma (PCC) are chemotherapy and radiation-resistant neuroendocrine tumors that arise from sympathetic tissue, and rarely occur in children. PCC may be associated with predisposing (germline) conditions like the multiple endocrine neoplasia type 2 (MEN2; OMIM 164761), von Hippel-Lindau syndrome (VHL; OMIM 193300), and rarely neurofibromatosis type 1 syndrome (NF1; OMIM 162200) and multiple endocrine neoplasia type 1 (MEN1; OMIM 131100). PGL, on the other hand, may be related to predisposing germline conditions like the familial PGL syndrome and the NF1 syndrome. In adult studies, one of the highest predisposing factors for germline mutation among patients presenting apparently sporadic PCC/PGL was their age at presentation. The aim of this study was to determine the rate of germline mutations among the rare patients presenting with sporadic PGL during childhood. In this study, we report the genetic analysis for predisposing conditions for the only three PGL cases retrospectively identified at our pediatric institution in the last 20 years. None had NF1 clinical associated lesions. Mutation screening of genes associated to VHL (VHL), MEN (RET), and familial PGL (SDH-B, -C, and -D) showed that all cases had germline deletions in the SDHB gene. We report a novel mutation, c.778 del C. Importantly, several non-symptomatic relatives were found to be carriers, thus ensuring them a clinical follow-up. According to our findings, PGL presenting during childhood represents an early manifestation of an adult disease caused by predisposing germline mutations. These results underline the importance of genetic studies in pediatric PGLs. (c) 2005 Wiley-Liss, Inc.

  5. Fire decreases arthropod abundance but increases diversity: Early and late season prescribed fire effects in a Sierra Nevada mixed-conifer forest

    USGS Publications Warehouse

    Ferrenberg, Scott; Schwilk, Dylan W.; Knapp, Eric E.; Groth, Eric; Keeley, Jon E.

    2006-01-01

    Prior to fire suppression in the 20th century, the mixed-conifer forests of the Sierra Nevada, California, U.S.A., historically burned in frequent fires that typically occurred during the late summer and early fall. Fire managers have been attempting to restore natural ecosystem processes through prescription burning, and have often favored burning during the fall in order to mimic historical fire regimes. Increasingly, however, prescription burning is also being done during the late spring and early summer in order to expand the window of opportunity for needed fuel reduction burning. The effect of prescribed fires outside of the historical fire season on forest arthropods is not known. The objective of this study was to compare the short-term effects of prescribed fires ignited in the early and late fire season on forest floor arthropods. Arthropod abundance and diversity were assessed using pitfall trapping in replicated burn units in Sequoia National Park, California. Overall, abundance of arthropods was lower in the burn treatments than in the unburned control. However, diversity tended to be greater in the burn treatments. Fire also altered the relative abundances of arthropod feeding guilds. No significant differences in arthropod community structure were found between early and late season burn treatments. Instead, changes in the arthropod community appeared to be driven largely by changes in fuel loading, vegetation, and habitat heterogeneity, all of which differed more between the burned and unburned treatments than between early and late season burn treatments.

  6. Ice storm damage and early recovery in an old-growth forest.

    PubMed

    Duguay, S M; Arii, K; Hooper, M; Lechowicz, M J

    2001-01-01

    We quantified the damage caused by a major ice storm to individual trees in two 1-ha permanent plots located at Mont St. Hilaire in southwestern Québec, Canada. The storm, which occurred in January 1998, is the worst on record in eastern North America; glaze ice on the order of 80-100 mm accumulated at our study site. All but 3% of the trees (DBH > or = 10 cm) lost at least some crown branches, and 35% lost more than half their crown. Damage to trees increased in the order: Tsuga canadensis, Betula alleghaniensis, Ostrya virginiana, Acer saccharum, Fagus grandifolia, Quercus rubra, Betula papyrifera, Acer rubrum, Tilia americana, and Fraxinus americana. Only 22% of the saplings and small trees (4 cm < DBH < 10 cm) escaped being broken or pinned to the ground by falling material. Levels of damage generally were greater in an exposed ridge top forest than in a cove protected from wind. By August 1999 only 53% of the trees had new shoots developing from the trunk or broken branches; among the more dominant canopy trees, Fagus grandifolia had the least sprouting and Acer saccharum and Quercus rubra the most. We anticipate and will monitor both significant turnover in the tree community and some shift in composition of the canopy dominants.

  7. Exotic species as modifiers of ecosystem processes: Litter decomposition in native and invaded secondary forests of NW Argentina

    NASA Astrophysics Data System (ADS)

    Aragón, Roxana; Montti, Lia; Ayup, María Marta; Fernández, Romina

    2014-01-01

    Invasions of exotic tree species can cause profound changes in community composition and structure, and may even cause legacy effect on nutrient cycling via litter production. In this study, we compared leaf litter decomposition of two invasive exotic trees (Ligustrum lucidum and Morus sp.) and two dominant native trees (Cinnamomum porphyria and Cupania vernalis) in native and invaded (Ligustrum-dominated) forest stands in NW Argentina. We measured leaf attributes and environmental characteristics in invaded and native stands to isolate the effects of litter quality and habitat characteristics. Species differed in their decomposition rates and, as predicted by the different species colonization status (pioneer vs. late successional), exotic species decayed more rapidly than native ones. Invasion by L. lucidum modified environmental attributes by reducing soil humidity. Decomposition constants (k) tended to be slightly lower (-5%) for all species in invaded stands. High SLA, low tensile strength, and low C:N of Morus sp. distinguish this species from the native ones and explain its higher decomposition rate. Contrary to our expectations, L. lucidum leaf attributes were similar to those of native species. Decomposition rates also differed between the two exotic species (35% higher in Morus sp.), presumably due to leaf attributes and colonization status. Given the high decomposition rate of L. lucidum litter (more than 6 times that of natives) we expect an acceleration of nutrient circulation at ecosystem level in Ligustrum-dominated stands. This may occur in spite of the modified environmental conditions that are associated with L. lucidum invasion.

  8. 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.

  9. First open field measurements with a portable CO2 lidar/dial system for early forest fires detection

    NASA Astrophysics Data System (ADS)

    Gaudio, Pasquale; Gelfusa, Michela; Lupelli, Ivan; Malizia, Andrea; Moretti, Alessandro; Richetta, Maria; Serafini, Camilla; Bellecci, Carlo

    2011-11-01

    Lidar and dial are well established methods to explore the atmosphere. Different groups have already shown experimentally the possibility to measure the density variation of aerosol and particulate in the atmosphere due to plumes emitted in forest fires with this kind of systems. The aim of the present work is to demonstrate the capabilities of our mobile Lidar system, based on a CO2 laser, to detect forest fires and minimizing false alarms. For this purpose, our system can be operated in both lidar and dial configurations in sequence. The first Lidar measurement is performed to evaluate the variation of the local density into the atmosphere, using a nonabsorption water wavelength 10R18 (10.571 μm). If the returned signal reports a backscattering peak, the presence of a fire is probable. To confirm this hypothesis, a second dial measurement is carried out to reveal a second component emitted during the combustion process. The chosen second component is water vapour, which is, as it is well-known, largely produced during the first combustion stage. Measuring the water concentration peak after the detection of the aerosol density increment (referred to the standard mean atmospheric value) represents a good method to reduce false alarms with a dial system. In order to test this methodology, a first set of measurements has been performed in a field near the Engineering Faculty of the University of Rome "Tor Vergata". A quite small controlled-fire has been lighted into a box at a distance of about one kilometre from the system. The data acquired at the two wavelengths (10R18 and 10R20) have been averaged on 100 elastic backscattered Lidar signals. The first results confirm the effectiveness of the measurement strategy for reducing the number of false alarm preserving the early detection.

  10. A comparative assessment of land cover dynamics of three protected forest areas in tropical eastern Africa.

    PubMed

    Lung, Tobias; Schaab, Gertrud

    2010-02-01

    Processes of deforestation, known to threaten tropical forest biodiversity, have not yet been studied sufficiently in East Africa. To shed light on the patterns and causes of human influences on protected forest ecosystems, comparisons of different study areas regarding land cover dynamics and potential drivers are needed. We analyze the development of land cover since the early 1970s for three protected East African rainforests and their surrounding farmlands and assess the relationship between the observed changes in the context of the protection status of the forests. Processing of Landsat satellite imagery of eight or seven time steps in regular intervals results in 12 land cover classes for the Kakamega-Nandi forests (Kenya) and Budongo Forest (Uganda) whereas ten are distinguished for Mabira Forest (Uganda). The overall classification accuracy assessed for the year 2001 or 2003 is similarly high for all three study areas (81% to 85%). The time series reveal that, despite their protection status, Kakamega-Nandi forests and Mabira Forest experienced major forest decrease, the first a continuous forest loss of 31% between 1972/1973 and 2001, the latter an abrupt loss of 24% in the late 1970s/early 1980s. For both forests, the temporally dense time series show short-term fluctuations in forest classes (e.g., areas of forest regrowth since the 1980s or exotic secondary bushland species from the 1990s onwards). Although selectively logged, Budongo Forest shows a much more stable forest cover extent. A visual overlay with population distribution for all three regions clearly indicates a relationship between forest loss and areas of high population density, suggesting population pressure as a main driver of deforestation. The revealed forest losses due to local and commercial exploitation further demonstrate that weak management impedes effective forest protection in East Africa.

  11. Organosulfates and Carboxylic Acids in Secondary Organic Aerosols in Coniferous Forests in Rocky Mountains (USA), Sierra Nevada Mountains (USA) and Northern Europe (Finland and Denmark)

    NASA Astrophysics Data System (ADS)

    Glasius, M.; Hansen, A. M. K.; Kristensen, K.; Kristensen, T. B.; Mccubbin, I. B.; Hallar, A. G.; Petäjä, T.; Surratt, J. D.; Worton, D. R.; Bilde, M.; Kulmala, M. T.; Goldstein, A. H.

    2014-12-01

    Levels and chemical composition of secondary organic aerosols affect their climate effects and properties. Organosulfates (OS) are formed through heterogeneous reactions involving oxidized sulfur compounds, primarily originating from anthropogenic sources. Availability of authentic standards have until now been an obstacle to quantitative investigations of OS in atmospheric aerosols. We have developed a new, facile method for synthesis and purification of OS standards. Here we have used 7 standards to quantify OS and nitrooxy organosulfates (NOS) observed in aerosols collected at four sites in coniferous forests in USA and Europe during spring or summer. The two American sites were Storm Peak Laboratory, Colorado (Rocky Mountains, elevation 3220 m a.s.l) and Sierra Nevada Mountains, California (as part of BEARPEX 2007 and 2009). The European sites were Hyytiälä Forest Station, Finland (in the boreal zone) and Silkeborg, Denmark (temperate forest). Aerosol filter samples were extracted and analyzed using a high performance liquid chromatograph coupled through an electrospray inlet to a quadrupole time-of-flight mass spectrometer (HPLC-QTOF-MS). We identified 11 carboxylic acids using authentic standards, while 16 different OS and 8 NOS were identified based on their molecular mass and MS fragmentation patterns, as well as comparison with available standards. OS were ubiquitous in the atmospheric aerosol samples, even at the high elevation mountain station. Levels of carboxylic acids from oxidation of monoterpenes were 8-25 ng m-3 at Silkeborg and Storm Peak Laboratory, while concentrations at the sites with strong regional monoterpene emissions (Sierra Nevada Mountains and Hyytiälä) were much higher (10-200 ng m-3). At all sites, the dominant group of OS were derived from isoprene (IEPOX) and related compounds, while OS of monoterpenes showed lower concentrations, except at Hyytiälä during periods of north-westerly winds when monoterpene OS were at similar or

  12. Lithium prevents early cytosolic calcium increase and secondary injurious calcium overload in glycolytically inhibited endothelial cells

    SciTech Connect

    Bosche, Bert; Schäfer, Matthias; Graf, Rudolf; Härtel, Frauke V.; Schäfer, Ute; Noll, Thomas

    2013-05-03

    Highlights: •We investigate free calcium as a central signalling element in endothelial cells. •Inhibition of glycolysis with 2-deoxy-D-glucose reduces cellular ATP. •This manoeuvre leads to a biphasic increase and overload of free calcium. •Pre-treatment with lithium for 24 h abolishes both phases of the calcium increase. •This provides a new strategy to protect endothelial calcium homeostasis and barrier function. -- Abstract: Cytosolic free calcium concentration ([Ca{sup 2+}]{sub i}) is a central signalling element for the maintenance of endothelial barrier function. Under physiological conditions, it is controlled within narrow limits. Metabolic inhibition during ischemia/reperfusion, however, induces [Ca{sup 2+}]{sub i} overload, which results in barrier failure. In a model of cultured porcine aortic endothelial monolayers (EC), we addressed the question of whether [Ca{sup 2+}]{sub i} overload can be prevented by lithium treatment. [Ca{sup 2+}]{sub i} and ATP were analysed using Fura-2 and HPLC, respectively. The combined inhibition of glycolytic and mitochondrial ATP synthesis by 2-desoxy-D-glucose (5 mM; 2-DG) plus sodium cyanide (5 mM; NaCN) caused a significant decrease in cellular ATP content (14 ± 1 nmol/mg protein vs. 18 ± 1 nmol/mg protein in the control, n = 6 culture dishes, P < 0.05), an increase in [Ca{sup 2+}]{sub i} (278 ± 24 nM vs. 71 ± 2 nM in the control, n = 60 cells, P < 0.05), and the formation of gaps between adjacent EC. These observations indicate that there is impaired barrier function at an early state of metabolic inhibition. Glycolytic inhibition alone by 10 mM 2-DG led to a similar decrease in ATP content (14 ± 2 nmol/mg vs. 18 ± 1 nmol/mg in the control, P < 0.05) with a delay of 5 min. The [Ca{sup 2+}]{sub i} response of EC was biphasic with a peak after 1 min (183 ± 6 nM vs. 71 ± 1 nM, n = 60 cells, P < 0.05) followed by a sustained increase in [Ca{sup 2+}]{sub i}. A 24-h pre-treatment with 10 mM of lithium

  13. Climate Change Impacts on Forest Succession and Future Productivity

    NASA Astrophysics Data System (ADS)

    Mohan, J. E.; Melillo, J. M.; Clark, J. S.; Schlesinger, W. H.

    2012-12-01

    Change in ecosystem carbon (C) dynamics with forest succession is a long-studied topic in ecology, and secondary forests currently comprise a significant proportion of the global land base. Although mature forests are generally more important for conserving species and habitats, early successional trees and stands typically have higher rates of productivity, including net ecosystem productivity (NEP), which represents carbon available for sequestration. Secondary forests undergoing successional development are thus major players in the current global carbon cycle, yet how forests will function in the future under warmer conditions with higher atmospheric carbon dioxide (CO2) concentrations is unknown. Future forest C dynamics will depend, in part, on future species composition. Data from "Forests of the Future" research in a number of global change experiments provide insights into how forests may look in terms of dominant species composition, and thus function, in a future world. Studies at Free-Air Carbon Dioxide (FACE) experiments at Duke Forest and other facilities, plus climate warming experiments such as those at the Harvard Forest, suggest a common underlying principle of vegetation responses to environmental manipulation: Namely, that shade-tolerant woody species associating with arbuscular mycorrhizal (AM) fungi show greater growth stimulation than ectomycorrhizal-associating (ECM) trees which are more common in temperate and boreal forests (Fig. 1 of relative growth rates standardized by pre-treatment rates). This may be due in part to the role of AM fungi in obtaining soil phosphorus and inorganic forms of nitrogen for plant associates. In combination, these results suggest a shift in future forest composition towards less-productive tree species that generally acquire atmospheric CO2 at lower annual rates, as well as a competitive advantage extended to woody vines such as poison ivy. Due to higher atmospheric CO2 and warmer temperatures, forests of the

  14. Early applied electric field stimulation attenuates secondary apoptotic responses and exerts neuroprotective effects in acute spinal cord injury of rats.

    PubMed

    Zhang, C; Zhang, G; Rong, W; Wang, A; Wu, C; Huo, X

    2015-04-16

    Injury potential, which refers to a direct current voltage between intact and injured nerve ends, is mainly caused by injury-induced Ca2+ influx. Our previous studies revealed that injury potential increased with the onset and severity of spinal cord injury (SCI), and an application of applied electric field stimulation (EFS) with the cathode distal to the lesion could delay and attenuate injury potential formation. As Ca2+ influx is also considered as a major trigger for secondary injury after SCI, we hypothesize that EFS would protect an injured spinal cord from secondary injury and consequently improve functional and pathological outcomes. In this study, rats were divided into three groups: (1) sham group, laminectomy only; (2) control group, subjected to SCI only; and (3) EFS group, received EFS immediately post-injury with the injury potential modulated to 0±0.5 mV by EFS. Functional recovery of the hind limbs was assessed using the Basso, Beattie, and Bresnahan (BBB) locomotor scale. Results revealed that EFS-treated rats exhibited significantly better locomotor function recovery. Luxol fast blue staining was performed to assess the spared myelin area. Immunofluorescence was used to observe the number of myelinated nerve fibers. Ultrastructural analysis was performed to evaluate the size of myelinated nerve fibers. Findings showed that the EFS group rats exhibited significantly less myelin loss and had larger and more myelinated nerve fibers than the control group rats in dorsal corticospinal tract (dCST) 8 weeks after SCI. Furthermore, we found that EFS inhibited the activation of calpain and caspase-3, as well as the expression of Bax, as detected by Western blot analysis. Moreover, EFS decreased cellular apoptosis, as measured by TUNEL, within 4 weeks post-injury. Results suggest that early EFS could significantly reduce spinal cord degeneration and improve functional and historical recovery. Furthermore, these neuroprotective effects may be related to

  15. Scatter-hoarding rodents as secondary seed dispersers of a frugivore-dispersed tree Scleropyrum wallichianum in a defaunated Xishuangbanna tropical forest, China.

    PubMed

    Cao, Lin; Xiao, Zhishu; Guo, Cong; Chen, Jin

    2011-09-01

    Local extinction or population decline of large frugivorous vertebrates as primary seed dispersers, caused by human disturbance and habitat change, might lead to dispersal limitation of many large-seeded fruit trees. However, it is not known whether or not scatter-hoarding rodents as secondary seed dispersers can help maintain natural regeneration (e.g. seed dispersal) of these frugivore-dispersed trees in the face of the functional reduction or loss of primary seed dispersers. In the present study, we investigated how scatter-hoarding rodents affect the fate of tagged seeds of a large-seeded fruit tree (Scleropyrum wallichianum Arnott, 1838, Santalaceae) from seed fall to seedling establishment in a heavily defaunated tropical forest in the Xishuangbanna region of Yunnan Province, in southwest China, in 2007 and 2008. Our results show that: (i) rodents removed nearly all S. wallichianum seeds in both years; (ii) a large proportion (2007, 75%; 2008, 67.5%) of the tagged seeds were cached individually in the surface soil or under leaf litters; (iii) dispersal distance of primary caches was further in 2007 (19.6 ± 14.6 m) than that in 2008 (14.1 ± 11.6 m), and distance increased as rodents recovered and moved seeds from primary caches into subsequent caching sites; and (iv) part of the cached seeds (2007, 3.2%; 2008, 2%) survived to the seedling stage each year. Our study suggests that by taking roles of both primary and secondary seed dispersers, scatter-hoarding rodents can play a significant role in maintaining seedling establishment of S. wallichianum, and are able to at least partly compensate for the loss of large frugivorous vertebrates in seed dispersal. © 2011 ISZS, Blackwell Publishing and IOZ/CAS.

  16. Fuel reduction and coarse woody debris dynamics with early season and late season prescribed fire in a Sierra Nevada mixed conifer forest

    USGS Publications Warehouse

    Knapp, E.E.; Keeley, J.E.; Ballenger, E.A.; Brennan, T.J.

    2005-01-01

    Fire exclusion has led to an unnatural accumulation and greater spatial continuity of organic material on the ground in many forests. This material serves both as potential fuel for forest fires and habitat for a large array of forest species. Managers must balance fuel reduction to reduce wildfire hazard with fuel retention targets to maintain other forest functions. This study reports fuel consumption and changes to coarse woody debris attributes with prescribed burns ignited under different fuel moisture conditions. Replicated early season burn, late season burn, and unburned control plots were established in old-growth mixed conifer forest in Sequoia National Park that had not experienced fire for more than 120 years. Early season burns were ignited during June 2002 when fuels were relatively moist, and late season burns were ignited during September/October 2001 when fuels were dry. Fuel loading and coarse woody debris abundance, cover, volume, and mass were evaluated prior to and after the burns. While both types of burns reduced fuel loading, early season burns consumed significantly less of the total dead and down organic matter than late season burns (67% versus 88%). This difference in fuel consumption between burning treatments was significant for most all woody fuel components evaluated, plus the litter and duff layers. Many logs were not entirely consumed - therefore the number of logs was not significantly changed by fire - but burning did reduce log length, cover, volume, and mass. Log cover, volume, and mass were reduced to a lesser extent by early season burns than late season burns, as a result of higher wood moisture levels. Early season burns also spread over less of the ground surface within the burn perimeter (73%) than late season burns (88%), and were significantly patchier. Organic material remaining after a fire can dam sediments and reduce erosion, while unburned patches may help mitigate the impact of fire on fire-sensitive species by

  17. Feeding behavior and nutrient intake in spiny forest-dwelling ring-tailed lemurs (Lemur catta) during early gestation and early to mid-lactation periods: compensating in a harsh environment.

    PubMed

    Gould, Lisa; Power, Michael L; Ellwanger, Nicholas; Rambeloarivony, Hajamanitra

    2011-07-01

    Strong resource seasonality in Madagascar has led to the evolution of female feeding priority and weaning synchrony in most lemur species. For these taxa, pregnancy/early lactation periods coincide with low food availability, and weaning of infants is timed with increased resources at the onset of the rainy season. Reproductive females experience high metabolic requirements, which they must accommodate, particularly when food resources are scarce. Female ring-tailed lemurs (Lemur catta) residing in spiny forest habitat must deal with resource scarcity, high temperatures (∼36-40°C) and little shade in early to mid-lactation periods. Considered "income breeders," these females must use resources obtained from the environment instead of relying on fat stores; thus, we expected they would differ from same-sized males in time spent on feeding and in the intake of food and nutrients. We investigated these variables in two groups (N = 11 and 12) of Lemur catta residing in spiny forest habitat during early gestation and early to mid-lactation periods. Focal animal data and food plant samples were collected, and plants were analyzed for protein, kcal, and fiber. We found no sex differences for any feeding or nutrient intake variable for the top five food species consumed. Females in early gestation spent more time feeding compared with early/mid-lactation. Physiological compensation for spiny forest-dwelling females may be tied to greater time spent resting compared with gallery forest conspecifics, consuming foods high in protein, calories, and water, reduced home range defense in a sparsely populated habitat, and for Lemur catta females in general, production of relatively dilute milk compared with many strepsirrhines.

  18. Monoterpene emissions from Beech ( Fagus sylvatica) in a French forest and impact on secondary pollutants formation at regional scale

    NASA Astrophysics Data System (ADS)

    Moukhtar, S.; Bessagnet, B.; Rouil, L.; Simon, V.

    Biogenic emissions from forest, crops, and grasslands are now considered major compounds in photochemical processes. Air quality analyses require more and more accurate input data, particularly emissions. Unfortunately, depending on the type of vegetation, these emissions are not always reliably defined. For example, Fagus sylvatica, which is a very abundant deciduous tree in France and in Europe, is a weak monoterpene emitter in the European inventory developed by Simpson et al. [1999. Journal of Geophysical Research 104, 8113-8152], but is a strong monoterpene emitter in Luchetta [1999. Caractérisation et quantification dans la basse atmosphère de composés organiques volatils biogéniques et anthropiques contribuant à la pollution de l'air. Ph.D. thesis, INPT Toulouse]. Beech ( F. sylvatica) emission potential has never been measured in France. This study investigates the isoprene and monoterpenes emission measurements from F. sylvatica in France during a research program INTERREG III in Fossé Rhénan, during May and June 2003. A dynamic cuvette method was used. Sabinene is the main monoterpene emitted, composing more than 90% of biogenic emissions. The remaining is composed of α-pinene, β-pinene and limonene. No isoprene emissions were detected. The monoterpene emissions from F. sylvatica are affected by temperature and photosynthetic active radiation (PAR). In order to describe monoterpene emissions, the "isoprene algorithm" developed by Guenther et al. [1991. Journal of Geophysical Research 26A, 10799-10808; 1993. Journal of Geophysical Research 98D, 12609-12617] has been used. With this algorithm, simulation results and observations agree fairly well. The standard emission rate ( T=303K and PAR=1000 μmol m -2 s -1) for total monoterpenes is 43.5 μg g dw-1 h -1. This classifies F. sylvatica as a strong monoterpene emitter. The European inventory [Simpson, et al., 1999. Journal of Geophysical Research 104, 8113-8152], which is the standard inventory of

  19. Collaborative Interaction in Turn-Taking: A Comparative Study of European Bilingual (CLIL) and Mainstream (MS) Foreign Language Learners in Early Secondary Education

    ERIC Educational Resources Information Center

    Moore, Pat

    2011-01-01

    This paper explores the emergence of collaborative interaction among early secondary learners in bilingual sections at state schools in Andalusia. These sections are organised in line with a content and language integrated learning (CLIL) approach. By transcribing and then analysing data from oral interviews conducted with randomly selected pairs…

  20. A Research-Informed Dialogic-Teaching Approach to Early Secondary School Mathematics and Science: The Pedagogical Design and Field Trial of the"epiSTEMe" Intervention

    ERIC Educational Resources Information Center

    Ruthven, Kenneth; Mercer, Neil; Taber, Keith S.; Guardia, Paula; Hofmann, Riikka; Ilie, Sonia; Luthman, Stefanie; Riga, Fran

    2017-01-01

    The "Effecting Principled Improvement in STEM Education" ["epiSTEMe"] project undertook pedagogical research aimed at improving pupil engagement and learning in early secondary school physical science and mathematics. Using principles identified as effective in the research literature and drawing on a range of existing…

  1. A Research-Informed Dialogic-Teaching Approach to Early Secondary School Mathematics and Science: The Pedagogical Design and Field Trial of the"epiSTEMe" Intervention

    ERIC Educational Resources Information Center

    Ruthven, Kenneth; Mercer, Neil; Taber, Keith S.; Guardia, Paula; Hofmann, Riikka; Ilie, Sonia; Luthman, Stefanie; Riga, Fran

    2017-01-01

    The "Effecting Principled Improvement in STEM Education" ["epiSTEMe"] project undertook pedagogical research aimed at improving pupil engagement and learning in early secondary school physical science and mathematics. Using principles identified as effective in the research literature and drawing on a range of existing…

  2. Home use of misoprostol for early medical abortion in a low resource setting: secondary analysis of a randomized controlled trial.

    PubMed

    Iyengar, Kirti; Klingberg-Allvin, Marie; Iyengar, Sharad D; Paul, Mandira; Essén, Birgitta; Gemzell-Danielsson, Kristina

    2016-02-01

    Although home use of misoprostol for early medical abortion is considered to be safe, effective and feasible, it has not become standard service delivery practice. The aim of this study was to compare the efficacy, safety, and acceptability of home use of misoprostol with clinic misoprostol in a low-resource setting. This was a secondary analysis of a randomized controlled trial conducted in six primary care clinics in India. Women seeking medical abortion within up to nine gestational weeks (n = 731) received mifepristone in the clinic and were allocated either to home or clinic administration of misoprostol. Follow-up contact was after 10-15 days. Of 731 participants, 73% were from rural areas and 55% had no formal education. Complete abortion rates in the home and clinic misoprostol groups were 94.2 and 94.4%, respectively. The rate of adverse events was similar in both groups (0.3%). A greater proportion of home users (90.2%) said that they would opt for misoprostol at home in the event of a future abortion compared with clinic users (79.7%) who would opt for misoprostol at the clinic in a similar situation (p = 0.0002). Ninety-six percent women using misoprostol at home or in the clinic were satisfied with their abortion experience. Home-use of misoprostol for early medical abortion is as effective and acceptable as clinic use, in low resource settings. Women should be offered a choice of this option regardless of distance of their residence from the clinic and communication facilities. © 2015 Nordic Federation of Societies of Obstetrics and Gynecology.

  3. Early subtropical forest growth is driven by community mean trait values and functional diversity rather than the abiotic environment

    PubMed Central

    Kröber, Wenzel; Li, Ying; Härdtle, Werner; Ma, Keping; Schmid, Bernhard; Schmidt, Karsten; Scholten, Thomas; Seidler, Gunnar; von Oheimb, Goddert; Welk, Erik; Wirth, Christian; Bruelheide, Helge

    2015-01-01

    While functional diversity (FD) has been shown to be positively related to a number of ecosystem functions including biomass production, it may have a much less pronounced effect than that of environmental factors or species-specific properties. Leaf and wood traits can be considered particularly relevant to tree growth, as they reflect a trade-off between resources invested into growth and persistence. Our study focussed on the degree to which early forest growth was driven by FD, the environment (11 variables characterizing abiotic habitat conditions), and community-weighted mean (CWM) values of species traits in the context of a large-scale tree diversity experiment (BEF-China). Growth rates of trees with respect to crown diameter were aggregated across 231 plots (hosting between one and 23 tree species) and related to environmental variables, FD, and CWM, the latter two of which were based on 41 plant functional traits. The effects of each of the three predictor groups were analyzed separately by mixed model optimization and jointly by variance partitioning. Numerous single traits predicted plot-level tree growth, both in the models based on CWMs and FD, but none of the environmental variables was able to predict tree growth. In the best models, environment and FD explained only 4 and 31% of variation in crown growth rates, respectively, while CWM trait values explained 42%. In total, the best models accounted for 51% of crown growth. The marginal role of the selected environmental variables was unexpected, given the high topographic heterogeneity and large size of the experiment, as was the significant impact of FD, demonstrating that positive diversity effects already occur during the early stages in tree plantations. PMID:26380685

  4. Prevalence of early initiation of breastfeeding and determinants of delayed initiation of breastfeeding: secondary analysis of the WHO Global Survey.

    PubMed

    Takahashi, Kenzo; Ganchimeg, Togoobaatar; Ota, Erika; Vogel, Joshua P; Souza, João Paulo; Laopaiboon, Malinee; Castro, Cynthia Pileggi; Jayaratne, Kapila; Ortiz-Panozo, Eduardo; Lumbiganon, Pisake; Mori, Rintaro

    2017-03-21

    Early initiation of breastfeeding (EIBF) within 1 hour of birth can decrease neonatal death. However, the prevalence of EIBF is approximately 50% in many developing countries, and data remains unavailable for some countries. We conducted a secondary analysis using the WHO Global Survey on Maternal and Perinatal Health to identify factors hampering EIBF. We described the coverage of EIBF among 373 health facilities for singleton neonates for whom breastfeeding was initiated after birth. Maternal and facility characteristics of EIBF were compared to those of breastfeeding >1 hour after birth, and multiple logistic regression analysis was performed. In total, 244,569 singleton live births without severe adverse outcomes were analysed. The EIBF prevalence varied widely among countries and ranged from 17.7% to 98.4% (average, 57.6%). There was less intra-country variation for BFI <24 hours. After adjustment, EIBF was significantly lower among women with complications during pregnancy and caesarean delivery. Globally, EIBF varied considerably across countries. Maternal complications during pregnancy, caesarean delivery and absence of postnatal/neonatal care guidelines at hospitals may affect EIBF. Our findings suggest that to better promote EIBF, special support for breastfeeding promotion is needed for women with complications during pregnancy and those who deliver by caesarean section.

  5. Prevalence of early initiation of breastfeeding and determinants of delayed initiation of breastfeeding: secondary analysis of the WHO Global Survey

    PubMed Central

    Takahashi, Kenzo; Ganchimeg, Togoobaatar; Ota, Erika; Vogel, Joshua P.; Souza, João Paulo; Laopaiboon, Malinee; Castro, Cynthia Pileggi; Jayaratne, Kapila; Ortiz-Panozo, Eduardo; Lumbiganon, Pisake; Mori, Rintaro

    2017-01-01

    Early initiation of breastfeeding (EIBF) within 1 hour of birth can decrease neonatal death. However, the prevalence of EIBF is approximately 50% in many developing countries, and data remains unavailable for some countries. We conducted a secondary analysis using the WHO Global Survey on Maternal and Perinatal Health to identify factors hampering EIBF. We described the coverage of EIBF among 373 health facilities for singleton neonates for whom breastfeeding was initiated after birth. Maternal and facility characteristics of EIBF were compared to those of breastfeeding >1 hour after birth, and multiple logistic regression analysis was performed. In total, 244,569 singleton live births without severe adverse outcomes were analysed. The EIBF prevalence varied widely among countries and ranged from 17.7% to 98.4% (average, 57.6%). There was less intra-country variation for BFI <24 hours. After adjustment, EIBF was significantly lower among women with complications during pregnancy and caesarean delivery. Globally, EIBF varied considerably across countries. Maternal complications during pregnancy, caesarean delivery and absence of postnatal/neonatal care guidelines at hospitals may affect EIBF. Our findings suggest that to better promote EIBF, special support for breastfeeding promotion is needed for women with complications during pregnancy and those who deliver by caesarean section. PMID:28322265

  6. A low vitamin D status at diagnosis is associated with an early conversion to secondary progressive multiple sclerosis.

    PubMed

    Muris, Anne-Hilde; Rolf, Linda; Broen, Kelly; Hupperts, Raymond; Damoiseaux, Jan; Smolders, Joost

    2016-11-01

    Low circulating 25-hydroxyvitamin D (25(OH)D) levels have been associated with an increased risk of relapses in relapsing remitting multiple sclerosis (RRMS), but an association with disability progression is uncertain. Lower 25(OH)D levels are found in secondary progressive MS (SPMS) when compared to RRMS. We hypothesized that a poor vitamin D status in RRMS is associated with an increased risk of conversion to SPMS. In a retrospective longitudinal study we measured 25(OH)D levels at the start of a 3-year follow-up, and analyzed whether these levels predict the risk of RRMS to SPMS conversion. In 338 RRMS patients, vitamin D status did not predict the 3-year risk of conversion to SPMS (n=51; OR 0.970; p=0.65). However, in diagnostic blood samples of SPMS patients with a relatively short RRMS duration (n=19) 25(OH)D levels were significantly lower (38nmol/L; Q1-Q3: 24-50) than in diagnostic samples of matched RRMS patients with no progression to SPMS ((n=38; 55nmol/L; Q1-Q3: 40-70) (p<0.01). These data indicate an association between a low vitamin D status at the start of RRMS and the early conversion to SPMS. Therefore, time to SPMS conversion is of interest as clinical measure in (follow-up of) clinical vitamin D supplementation studies. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. The Effect of Local and Landscape-Level Characteristics on the Abundance of Forest Birds in Early-Successional Habitats during the Post-Fledging Season in Western Massachusetts

    PubMed Central

    Labbe, Michelle A.; King, David I.

    2014-01-01

    Many species of mature forest-nesting birds (“forest birds”) undergo a pronounced shift in habitat use during the post-fledging period and move from their forest nesting sites into areas of early-successional vegetation. Mortality is high during this period, thus understanding the resource requirements of post-fledging birds has implications for conservation. Efforts to identify predictors of abundance of forest birds in patches of early-successional habitats have so far been equivocal, yet these previous studies have primarily focused on contiguously forested landscapes and the potential for landscape-scale influences in more fragmented and modified landscapes is largely unknown. Landscape composition can have a strong influence on the abundance and productivity of forest birds during the nesting period, and could therefore affect the number of forest birds in the landscape available to colonize early-successional habitats during the post-fledging period. Therefore, the inclusion of landscape characteristics should increase the explanatory power of models of forest bird abundance in early-successional habitat patches during the post-fledging period. We examined forest bird abundance and body condition in relation to landscape and habitat characteristics of 15 early-successional sites during the post-fledging season in Massachusetts. The abundance of forest birds was influenced by within-patch habitat characteristics, however the explanatory power of these models was significantly increased by the inclusion of landscape fragmentation and the abundance of forest birds in adjacent forest during the nesting period for some species and age groups. Our findings show that including factors beyond the patch scale can explain additional variation in the abundance of forest birds in early-successional habitats during the post-fledging period. We conclude that landscape composition should be considered when siting early-successional habitat to maximize its benefit to

  8. Early detection of emerging forest disease using dispersal estimation and ecological niche modeling.

    PubMed

    Meentemeyer, Ross K; Anacker, Brian L; Mark, Walter; Rizzo, David M

    2008-03-01

    Distinguishing the manner in which dispersal limitation and niche requirements control the spread of invasive pathogens is important for prediction and early detection of disease outbreaks. Here, we use niche modeling augmented by dispersal estimation to examine the degree to which local habitat conditions vs. force of infection predict invasion of Phytophthora ramorum, the causal agent of the emerging infectious tree disease sudden oak death. We sampled 890 field plots for the presence of P. ramorum over a three-year period (2003-2005) across a range of host and abiotic conditions with variable proximities to known infections in California, USA. We developed and validated generalized linear models of invasion probability to analyze the relative predictive power of 12 niche variables and a negative exponential dispersal kernel estimated by likelihood profiling. Models were developed incrementally each year (2003, 2003-2004, 2003-2005) to examine annual variability in model parameters and to create realistic scenarios for using models to predict future infections and to guide early-detection sampling. Overall, 78 new infections were observed up to 33.5 km from the nearest known site of infection, with slightly increasing rates of prevalence across time windows (2003, 6.5%; 2003-2004, 7.1%; 2003-2005, 9.6%). The pathogen was not detected in many field plots that contained susceptible host vegetation. The generalized linear modeling indicated that the probability of invasion is limited by both dispersal and niche constraints. Probability of invasion was positively related to precipitation and temperature in the wet season and the presence of the inoculum-producing foliar host Umbellularia californica and decreased exponentially with distance to inoculum sources. Models that incorporated niche and dispersal parameters best predicted the locations of new infections, with accuracies ranging from 0.86 to 0.90, suggesting that the modeling approach can be used to forecast

  9. Modeling the early-phase redistribution of radiocesium fallouts in an evergreen coniferous forest after Chernobyl and Fukushima accidents.

    PubMed

    Calmon, P; Gonze, M-A; Mourlon, Ch

    2015-10-01

    Following the Chernobyl accident, the scientific community gained numerous data on the transfer of radiocesium in European forest ecosystems, including information regarding the short-term redistribution of atmospheric fallout onto forest canopies. In the course of international programs, the French Institute for Radiological Protection and Nuclear Safety (IRSN) developed a forest model, named TREE4 (Transfer of Radionuclides and External Exposure in FORest systems), 15 years ago. Recently published papers on a Japanese evergreen coniferous forest contaminated by Fukushima radiocesium fallout provide interesting and quantitative data on radioactive mass fluxes measured within the forest in the months following the accident. The present study determined whether the approach adopted in the TREE4 model provides satisfactory results for Japanese forests or whether it requires adjustments. This study focused on the interception of airborne radiocesium by forest canopy, and the subsequent transfer to the forest floor through processes such as litterfall, throughfall, and stemflow, in the months following the accident. We demonstrated that TREE4 quite satisfactorily predicted the interception fraction (20%) and the canopy-to-soil transfer (70% of the total deposit in 5 months) in the Tochigi forest. This dynamics was similar to that observed in the Höglwald spruce forest. However, the unexpectedly high contribution of litterfall (31% in 5 months) in the Tochigi forest could not be reproduced in our simulations (2.5%). Possible reasons for this discrepancy are discussed; and sensitivity of the results to uncertainty in deposition conditions was analyzed. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Effects of the amount and composition of the forest floor on emergence and early establishment of loblolly pine seedlings

    Treesearch

    Michael G. Shelton

    1995-01-01

    Five forest floor weights (0, 10, 20, 30, and 40 MgJha), three forest floor compositions (pine, pine-hardwood, and hardwood), and two seed placements (forest floor and soil surface) were tested in a three-factorial. split-plot design with four incomplete, randomized blocks. The experiment was conducted in a nursery setting and used wooden frames to define 0.145-m

  11. Proactive restoration: planning, implementation, and early results of silvicultural strategies for increasing resilience against gypsy moth infestation in upland oak forests on the Daniel Boone National Forest, Kentucky

    Treesearch

    Callie Schweitzer; Stacy L. Clark; Kurt W. Gottschalk; Jeff Stringer; Robbie Sitzlar

    2014-01-01

    Determining targets in forest restoration is a complicated task that can be facilitated by cooperative partnerships. Too often restoration plans are implemented after adverse events that cause widespread tree mortality, such as drought or insect outbreaks, have occurred. Reactive management precludes the use of preemptive management techniques that can result in more...

  12. The Influence of Monoterpene and Isoprene Nitrates on the Chemistry and Phase State of Secondary Organic Aerosol in a Low-NOx Mixed Deciduous/Coniferous Forest

    NASA Astrophysics Data System (ADS)

    Slade, J. H., Jr.; Shepson, P. B.; Desrochers, S. J.; Harvey, R. M.; Wallace, W.; Bui, A.; Griffin, R. J.; Kavassalis, S.; Shi, Q.; Murphy, J. G.; Cook, R.; Connor, M.; Ault, A. P.; Pratt, K.; Alwe, H. D.; Millet, D. B.; Bertman, S. B.; Stevens, P. S.; Wennberg, P. O.; Boor, B.; Petrucci, G.

    2016-12-01

    Particle phase state plays a key role in secondary organic aerosol (SOA) growth, reactive uptake of gas-phase radicals, and condensed phase reactions, influencing atmospheric composition and clouds. While biogenic SOA derived from isoprene and monoterpene oxidation can exhibit glassy or highly viscous semisolid phase states depending on relative humidity, the lifetimes of important SOA precursors including organic nitrates (ON) can depend on the liquid water content (LWC) and particle acidity. Reactions such as acid-catalyzed hydrolysis of particulate ON (pON) are especially sensitive to changes in aerosol LWC. However, the role of particle phase state on the chemistry of pON, and the chemical transformations of pON on the phase of SOA are poorly understood. During the summer of 2016, as part of the PROPHET - Atmospheric Measurements of Oxidants in Summer (AMOS) field study in a northern Michigan mixed deciduous/coniferous forest, we investigated the production of isoprene (IN) and monoterpene nitrates (MTN) at the ground and canopy levels and their role in particle formation, growth, and phase using a combination of high-resolution chemical ionization and aerosol mass spectrometry techniques, size distribution measurements, and particle bounce factors (BF) using two electrical low pressure impactors operating in parallel. Preliminary derived BF suggest the particles may be in a liquid-like state similar to those measured in other high-humidity and isoprene-rich regions such as the Amazon and Southeastern US. However, maxima in BF are observed during periods of high pON, NO, and IN during the day and high NO2 and MTN at night. Some periods were marked with low pON followed by an increase in particulate organic sulfate (pOS), and decrease in BF. Based on these observations, we hypothesize that acid-catalyzed hydrolysis of pON from IN- and MTN-derived SOA may be driving the transition of pON to pOS, leading to a change in the phase state of SOA. Preliminary results

  13. Differentiating secondary from primary dengue using IgG to IgM ratio in early dengue: an observational hospital based clinico-serological study from North India.

    PubMed

    Changal, Khalid Hamid; Raina, Ab Hameed; Raina, Adnan; Raina, Manzoor; Bashir, Rehana; Latief, Muzamil; Mir, Tanveer; Changal, Qayum Hamid

    2016-11-28

    Secondary dengue causes more severe disease than the primary. Early on, it is important to differentiate the two. We tried to find important clinical and laboratory differences between the two for the purpose of early differentiation. One hundred fourteen patients confirmed on reverse transcriptase-polymerase chain reaction (RT PCR) were studied. On day 2 of illness IgM and IgG indices were studied for calculation of IgG/IgM ratio. A one-step immunochromatographic assay was used for classification of patients into primary and secondary dengue. Patient characteristics were also studied. Dengue serotype 1 was the most common found in 60.5% patients. 66.7% (76 patients) had secondary dengue. Secondary dengue cases had a higher mean temperature (101.56 ± 1.55 vs. 100.79 ± 1.25,°F, p 0.015), lower platelet counts (50.51 ± 38.91 vs. 100.45 ± 38.66, x 10(3)/micl, p <0.0001) and a significantly higher percentage of Dengue hemorrhagic fever/Dengue shock syndrome (38.2% vs. 2.6%, p <0.0001). In early phase of dengue NS1 and PCR were found to be better tests for diagnosis and later IgM is better. The IgG/IgM ratio of ≥ 1.10 had a sensitivity of 100%, specificity of 97.4% and accuracy of 67.5% in differentiating secondary from primary dengue. Early on in the clinical course, IgG/ IgM ratio can play an important role to differentiate the two. We found the ratio of ≥ 1.10 to be the best cut off for the same.

  14. Molecular evolution of rDNA in early diverging Metazoa: First comparative analysis and phylogenetic application of complete SSU rRNA secondary structures in Porifera

    PubMed Central

    2008-01-01

    Background The cytoplasmic ribosomal small subunit (SSU, 18S) ribosomal RNA (rRNA) is the most frequently-used gene for molecular phylogenetic studies. However, information regarding its secondary structure is neglected in most phylogenetic analyses. Incorporation of this information is essential in order to apply specific rRNA evolutionary models to overcome the problem of co-evolution of paired sites, which violates the basic assumption of the independent evolution of sites made by most phylogenetic methods. Information about secondary structure also supports the process of aligning rRNA sequences across taxa. Both aspects have been shown to increase the accuracy of phylogenetic reconstructions within various taxa. Here, we explore SSU rRNA secondary structures from the three extant classes of Phylum Porifera (Grant, 1836), a pivotal, but largely unresolved taxon of early branching Metazoa. This is the first phylogenetic study of poriferan SSU rRNA data to date that includes detailed comparative secondary structure information for all three sponge classes. Results We found base compositional and structural differences in SSU rRNA among Demospongiae, Hexactinellida (glass sponges) and Calcarea (calcareous sponges). We showed that analyses of primary rRNA sequences, including secondary structure-specific evolutionary models, in combination with reconstruction of the evolution of unusual structural features, reveal a substantial amount of additional information. Of special note was the finding that the gene tree topologies of marine haplosclerid demosponges, which are inconsistent with the current morphology-based classification, are supported by our reconstructed evolution of secondary structure features. Therefore, these features can provide alternative support for sequence-based topologies and give insights into the evolution of the molecule itself. To encourage and facilitate the application of rRNA models in phylogenetics of early metazoans, we present 52 SSU r

  15. Molecular evolution of rDNA in early diverging Metazoa: first comparative analysis and phylogenetic application of complete SSU rRNA secondary structures in Porifera.

    PubMed

    Voigt, Oliver; Erpenbeck, Dirk; Wörheide, Gert

    2008-02-27

    The cytoplasmic ribosomal small subunit (SSU, 18S) ribosomal RNA (rRNA) is the most frequently-used gene for molecular phylogenetic studies. However, information regarding its secondary structure is neglected in most phylogenetic analyses. Incorporation of this information is essential in order to apply specific rRNA evolutionary models to overcome the problem of co-evolution of paired sites, which violates the basic assumption of the independent evolution of sites made by most phylogenetic methods. Information about secondary structure also supports the process of aligning rRNA sequences across taxa. Both aspects have been shown to increase the accuracy of phylogenetic reconstructions within various taxa.Here, we explore SSU rRNA secondary structures from the three extant classes of Phylum Porifera (Grant, 1836), a pivotal, but largely unresolved taxon of early branching Metazoa. This is the first phylogenetic study of poriferan SSU rRNA data to date that includes detailed comparative secondary structure information for all three sponge classes. We found base compositional and structural differences in SSU rRNA among Demospongiae, Hexactinellida (glass sponges) and Calcarea (calcareous sponges). We showed that analyses of primary rRNA sequences, including secondary structure-specific evolutionary models, in combination with reconstruction of the evolution of unusual structural features, reveal a substantial amount of additional information. Of special note was the finding that the gene tree topologies of marine haplosclerid demosponges, which are inconsistent with the current morphology-based classification, are supported by our reconstructed evolution of secondary structure features. Therefore, these features can provide alternative support for sequence-based topologies and give insights into the evolution of the molecule itself. To encourage and facilitate the application of rRNA models in phylogenetics of early metazoans, we present 52 SSU rRNA secondary

  16. Functional capacities of human IgM memory B cells in early inflammatory responses and secondary germinal center reactions.

    PubMed

    Seifert, Marc; Przekopowitz, Martina; Taudien, Sarah; Lollies, Anna; Ronge, Viola; Drees, Britta; Lindemann, Monika; Hillen, Uwe; Engler, Harald; Singer, Bernhard B; Küppers, Ralf

    2015-02-10

    The generation and functions of human peripheral blood (PB) IgM(+)IgD(+)CD27(+) B lymphocytes with somatically mutated IgV genes are controversially discussed. We determined their differential gene expression to naive B cells and to IgM-only and IgG(+) memory B cells. This analysis revealed a high similarity of IgM(+)(IgD(+))CD27(+) and IgG(+) memory B cells but also pointed at distinct functional capacities of both subsets. In vitro analyses revealed a tendency of activated IgM(+)IgD(+)CD27(+) B cells to migrate to B-cell follicles and undergo germinal center (GC) B-cell differentiation, whereas activated IgG(+) memory B cells preferentially showed a plasma cell (PC) fate. This observation was supported by reverse regulation of B-cell lymphoma 6 and PR domain containing 1 and differential BTB and CNC homology 1, basic leucine zipper transcription factor 2 expression. Moreover, IgM(+)IgD(+)CD27(+) B lymphocytes preferentially responded to neutrophil-derived cytokines. Costimulation with catecholamines, carcinoembryonic antigen cell adhesion molecule 8 (CEACAM8), and IFN-γ caused differentiation of IgM(+)IgD(+)CD27(+) B cells into PCs, induced class switching to IgG2, and was reproducible in cocultures with neutrophils. In conclusion, this study substantiates memory B-cell characteristics of human IgM(+)IgD(+)CD27(+) B cells in that they share typical memory B-cell transcription patterns with IgG(+) post-GC B cells and show a faster and more vigorous restimulation potential, a hallmark of immune memory. Moreover, this work reveals a functional plasticity of human IgM memory B cells by showing their propensity to undergo secondary GC reactions upon reactivation, but also by their special role in early inflammation via interaction with immunomodulatory neutrophils.

  17. Functional capacities of human IgM memory B cells in early inflammatory responses and secondary germinal center reactions

    PubMed Central

    Seifert, Marc; Przekopowitz, Martina; Taudien, Sarah; Lollies, Anna; Ronge, Viola; Drees, Britta; Lindemann, Monika; Hillen, Uwe; Engler, Harald; Singer, Bernhard B.; Küppers, Ralf

    2015-01-01

    The generation and functions of human peripheral blood (PB) IgM+IgD+CD27+ B lymphocytes with somatically mutated IgV genes are controversially discussed. We determined their differential gene expression to naive B cells and to IgM-only and IgG+ memory B cells. This analysis revealed a high similarity of IgM+(IgD+)CD27+ and IgG+ memory B cells but also pointed at distinct functional capacities of both subsets. In vitro analyses revealed a tendency of activated IgM+IgD+CD27+ B cells to migrate to B-cell follicles and undergo germinal center (GC) B-cell differentiation, whereas activated IgG+ memory B cells preferentially showed a plasma cell (PC) fate. This observation was supported by reverse regulation of B-cell lymphoma 6 and PR domain containing 1 and differential BTB and CNC homology 1, basic leucine zipper transcription factor 2 expression. Moreover, IgM+IgD+CD27+ B lymphocytes preferentially responded to neutrophil-derived cytokines. Costimulation with catecholamines, carcinoembryonic antigen cell adhesion molecule 8 (CEACAM8), and IFN-γ caused differentiation of IgM+IgD+CD27+ B cells into PCs, induced class switching to IgG2, and was reproducible in cocultures with neutrophils. In conclusion, this study substantiates memory B-cell characteristics of human IgM+IgD+CD27+ B cells in that they share typical memory B-cell transcription patterns with IgG+ post-GC B cells and show a faster and more vigorous restimulation potential, a hallmark of immune memory. Moreover, this work reveals a functional plasticity of human IgM memory B cells by showing their propensity to undergo secondary GC reactions upon reactivation, but also by their special role in early inflammation via interaction with immunomodulatory neutrophils. PMID:25624468

  18. Characteristics related to early secondary amenorrhoea and pregnancy among women diagnosed with systemic lupus erythematosus: an analysis using the GOAL study

    PubMed Central

    Knight, Jessica H; Howards, Penelope P; Spencer, Jessica B; Tsagaris, Katina C; Lim, Sam S

    2016-01-01

    Objective Systemic lupus erythematosus (SLE) disproportionately affects women and often develops during their reproductive years. Research suggests that some women who receive cyclophosphamide as treatment for SLE experience earlier decline in menstrual function, but reproductive health among women with SLE who have not taken this drug is less well understood. This study aims to better understand the relation between SLE and reproduction by assessing early secondary amenorrhoea and pregnancy in women treated with and without cyclophosphamide from a population-based cohort with large numbers of African-Americans. Methods Female patients with SLE, ages 20–40 at time of diagnosis, who were 40 years or older at the time of the survey were included in this analysis (N=147). Participants in the Georgians Organized Against Lupus (GOAL) study were asked about their reproductive histories including early secondary amenorrhoea, defined as loss of menstruation before age 40. Results Women who were cyclophosphamide naïve had an increased prevalence of early secondary amenorrhoea compared with population estimates, 13–17% compared with 1–5%. Factors associated with early secondary amenorrhoea in women not treated with cyclophosphamide were marital status and receipt of a kidney transplant. Treatment with cyclophosphamide doubled the prevalence after adjustment for patient characteristics. Over 88% of women reported being pregnant at least once, and about 83% of these had a child, but the majority of pregnancies occurred before diagnosis. Conclusions SLE diagnosed in early adulthood may affect women's reproductive health even if they are not treated with cyclophosphamide. Better understanding of other factors related to reproductive health in this population will improve clinicians' and patients' abilities to make treatment and family planning decisions. PMID:27752335

  19. Potential application of gasification to recycle food waste and rehabilitate acidic soil from secondary forests on degraded land in Southeast Asia.

    PubMed

    Yang, Zhanyu; Koh, Shun Kai; Ng, Wei Cheng; Lim, Reuben C J; Tan, Hugh T W; Tong, Yen Wah; Dai, Yanjun; Chong, Clive; Wang, Chi-Hwa

    2016-05-01

    Gasification is recognized as a green technology as it can harness energy from biomass in the form of syngas without causing severe environmental impacts, yet produ