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• 1. [Article] Divergent Carbon Dynamics under Climate Change in Forests with Diverse Soils, Tree Species, and Land Use Histories

  Accounting for both climate change and natural disturbances—which typically result in greenhouse gas emissions—is necessary to begin managing forest carbon sequestration. Gaining a complete understanding ...

  Citation × Citation Citation Abstract Copy Title: Divergent Carbon Dynamics under Climate Change in Forests with Diverse Soils, Tree Species, and Land Use Histories Author: Scheller, Robert M., Kretchun, Alec M., Van Tuyl, Steve, Clark, Kenneth L., Lucash, Melissa S., Hom, John Year: 2012 Accounting for both climate change and natural disturbances—which typically result in greenhouse gas emissions—is necessary to begin managing forest carbon sequestration. Gaining a complete understanding of forest carbon dynamics is, however, challenging in systems characterized by historic over-utilization, diverse soils and tree species, and frequent disturbance. In order to elucidate the cascading effects of potential climate change on such systems, we projected forest carbon dynamics, including soil carbon changes, and shifts in tree species composition as a consequence of wildfires and climate change in the New Jersey pine barrens (NJPB) over the next 100 years. To do so, we used the LANDIS-II succession and disturbance model combined with the CENTURY soil model. The model was calibrated and validated using data from three eddy flux towers and the available empirical or literature data. Our results suggest that climate change will not appreciably increase fire sizes and intensity. The recovery of C stocks following substantial disturbances at the turn of the 20th century will play a limited but important role in this system. In areas characterized by high soil water holding capacity, reduced soil moisture may lead to lower total C and these forests may switch from being carbon sinks to becoming carbon neutral towards the latter part of the 21st century. In contrast, other areas characterized by lower soil water holding capacity and drought tolerant species are projected to experience relatively little change over the next 100 years. Across all soil types, however, the regeneration of many key tree species may decline leading to longer-term (beyond 2100) risks to forest C. These divergent responses were largely a function of the dominant tree species, and their respective temperature and soil moisture tolerances, and soil water holding capacity. In summary, the system is initially C conservative but by the end of the 21st century, there is increasing risk of de-stabilization due to declining growth and regeneration. Title: Divergent Carbon Dynamics under Climate Change in Forests with Diverse Soils, Tree Species, and Land Use Histories Author: Scheller, Robert M., Kretchun, Alec M., Van Tuyl, Steve, Clark, Kenneth L., Lucash, Melissa S., Hom, John Year: 2012 Accounting for both climate change and natural disturbances—which typically result in greenhouse gas emissions—is necessary to begin managing forest carbon sequestration. Gaining a complete understanding of forest carbon dynamics is, however, challenging in systems characterized by historic over-utilization, diverse soils and tree species, and frequent disturbance. In order to elucidate the cascading effects of potential climate change on such systems, we projected forest carbon dynamics, including soil carbon changes, and shifts in tree species composition as a consequence of wildfires and climate change in the New Jersey pine barrens (NJPB) over the next 100 years. To do so, we used the LANDIS-II succession and disturbance model combined with the CENTURY soil model. The model was calibrated and validated using data from three eddy flux towers and the available empirical or literature data. Our results suggest that climate change will not appreciably increase fire sizes and intensity. The recovery of C stocks following substantial disturbances at the turn of the 20th century will play a limited but important role in this system. In areas characterized by high soil water holding capacity, reduced soil moisture may lead to lower total C and these forests may switch from being carbon sinks to becoming carbon neutral towards the latter part of the 21st century. In contrast, other areas characterized by lower soil water holding capacity and drought tolerant species are projected to experience relatively little change over the next 100 years. Across all soil types, however, the regeneration of many key tree species may decline leading to longer-term (beyond 2100) risks to forest C. These divergent responses were largely a function of the dominant tree species, and their respective temperature and soil moisture tolerances, and soil water holding capacity. In summary, the system is initially C conservative but by the end of the 21st century, there is increasing risk of de-stabilization due to declining growth and regeneration. Close

• 2. [Article] Foliar Nutrient Concentrations Related to Soil Sources Across a Range of Sites in the Northeastern United States

  Understanding the supply of nutrients from various soil sources and the sensitivity of tree species to soil nutrient availability is critical for predicting the effects of declines in base cations due ...

  Citation × Citation Citation Abstract Copy Title: Foliar Nutrient Concentrations Related to Soil Sources Across a Range of Sites in the Northeastern United States Author: Lucash, Melissa S., Yanai, Ruth D., Blum, Joel D., Park, B. B. Year: 2011 Understanding the supply of nutrients from various soil sources and the sensitivity of tree species to soil nutrient availability is critical for predicting the effects of declines in base cations due to acid rain and forest harvesting on forest health and productivity. We collected soil samples from 19 sites in the northeastern United States, chemically analyzed them using a sequential extraction procedure, and compared them to the chemical composition of foliage of the dominant tree species. Concentrations of Ca and Mg in foliage were correlated with exchangeable Ca and Mg concentrations in the upper mineral soil; for most tree species they were also correlated to acid-extractable Ca and Mg in the parent material (C horizon). Foliar P was better correlated with soil P in the upper mineral soil than in the C horizon, while foliar AI was insensitive to soil AI concentrations. In five sites in New Hampshire, the Ca/Sr of foliage was consistent with that of the Oie horizon, after taking the reported discrimination of Ca over Sr into account. In sites in New York, without an Oie horizon, the Ca/Sr of foliage was too high to be explained by any of the soil pools. A comparison of Ca/Sr ratios of foliage among species at common sites showed oak (Quercus spp.) to have higher Ca/Sr ratios than sugar maple (Acer saccharum Marsh.), birch (Betula spp.), red maple (A. rubrum L.) and beech (Fagus spp.). The interpretation of soil Ca sources from Ca/Sr ratios is complicated at sites where a single horizon does not dominate the source. Title: Foliar Nutrient Concentrations Related to Soil Sources Across a Range of Sites in the Northeastern United States Author: Lucash, Melissa S., Yanai, Ruth D., Blum, Joel D., Park, B. B. Year: 2011 Understanding the supply of nutrients from various soil sources and the sensitivity of tree species to soil nutrient availability is critical for predicting the effects of declines in base cations due to acid rain and forest harvesting on forest health and productivity. We collected soil samples from 19 sites in the northeastern United States, chemically analyzed them using a sequential extraction procedure, and compared them to the chemical composition of foliage of the dominant tree species. Concentrations of Ca and Mg in foliage were correlated with exchangeable Ca and Mg concentrations in the upper mineral soil; for most tree species they were also correlated to acid-extractable Ca and Mg in the parent material (C horizon). Foliar P was better correlated with soil P in the upper mineral soil than in the C horizon, while foliar AI was insensitive to soil AI concentrations. In five sites in New Hampshire, the Ca/Sr of foliage was consistent with that of the Oie horizon, after taking the reported discrimination of Ca over Sr into account. In sites in New York, without an Oie horizon, the Ca/Sr of foliage was too high to be explained by any of the soil pools. A comparison of Ca/Sr ratios of foliage among species at common sites showed oak (Quercus spp.) to have higher Ca/Sr ratios than sugar maple (Acer saccharum Marsh.), birch (Betula spp.), red maple (A. rubrum L.) and beech (Fagus spp.). The interpretation of soil Ca sources from Ca/Sr ratios is complicated at sites where a single horizon does not dominate the source. Close

• 3. [Article] Quantifying Resilience of Multiple Ecosystem Services and Biodiversity in a Temperate Forest Landscape

  Resilience is increasingly being considered as a new paradigm of forest management among scientists, practitioners, and policymakers. However, metrics of resilience to environmental change are lacking. ...

  Citation × Citation Citation Abstract Copy Title: Quantifying Resilience of Multiple Ecosystem Services and Biodiversity in a Temperate Forest Landscape Author: Cantarello, Elena, Newton, Adrian C., Martin, Phillip A., Evans, Paul M., Gosal, Arjan, Lucash, Melissa S. Year: 2017 Resilience is increasingly being considered as a new paradigm of forest management among scientists, practitioners, and policymakers. However, metrics of resilience to environmental change are lacking. Faced with novel disturbances, forests may be able to sustain existing ecosystem services and biodiversity by exhibiting resilience, or alternatively these attributes may undergo either a linear or nonlinear decline. Here we provide a novel quantitative approach for assessing forest resilience that focuses on three components of resilience, namely resistance, recovery, and net change, using a spatially explicit model of forest dynamics. Under the pulse set scenarios, we explored the resilience of nine ecosystem services and four biodiversity measures following a one-off disturbance applied to an increasing percentage of forest area. Under the pulse + press set scenarios, the six disturbance intensities explored during the pulse set were followed by a continuous disturbance. We detected thresholds in net change under pulse + press scenarios for the majority of the ecosystem services and biodiversity measures, which started to decline sharply when disturbance affected >40% of the landscape. Thresholds in net change were not observed under the pulse scenarios, with the exception of timber volume and ground flora species richness. Thresholds were most pronounced for aboveground biomass, timber volume with respect to the ecosystem services, and ectomycorrhizal fungi and ground flora species richness with respect to the biodiversity measures. Synthesis and applications. The approach presented here illustrates how the multidimensionality of stability research in ecology can be addressed and how forest resilience can be estimated in practice. Managers should adopt specific management actions to support each of the three components of resilience separately, as these may respond differently to disturbance. In addition, management interventions aiming to deliver resilience should incorporate an assessment of both pulse and press disturbances to ensure detection of threshold responses to disturbance, so that appropriate management interventions can be identified. Title: Quantifying Resilience of Multiple Ecosystem Services and Biodiversity in a Temperate Forest Landscape Author: Cantarello, Elena, Newton, Adrian C., Martin, Phillip A., Evans, Paul M., Gosal, Arjan, Lucash, Melissa S. Year: 2017 Resilience is increasingly being considered as a new paradigm of forest management among scientists, practitioners, and policymakers. However, metrics of resilience to environmental change are lacking. Faced with novel disturbances, forests may be able to sustain existing ecosystem services and biodiversity by exhibiting resilience, or alternatively these attributes may undergo either a linear or nonlinear decline. Here we provide a novel quantitative approach for assessing forest resilience that focuses on three components of resilience, namely resistance, recovery, and net change, using a spatially explicit model of forest dynamics. Under the pulse set scenarios, we explored the resilience of nine ecosystem services and four biodiversity measures following a one-off disturbance applied to an increasing percentage of forest area. Under the pulse + press set scenarios, the six disturbance intensities explored during the pulse set were followed by a continuous disturbance. We detected thresholds in net change under pulse + press scenarios for the majority of the ecosystem services and biodiversity measures, which started to decline sharply when disturbance affected >40% of the landscape. Thresholds in net change were not observed under the pulse scenarios, with the exception of timber volume and ground flora species richness. Thresholds were most pronounced for aboveground biomass, timber volume with respect to the ecosystem services, and ectomycorrhizal fungi and ground flora species richness with respect to the biodiversity measures. Synthesis and applications. The approach presented here illustrates how the multidimensionality of stability research in ecology can be addressed and how forest resilience can be estimated in practice. Managers should adopt specific management actions to support each of the three components of resilience separately, as these may respond differently to disturbance. In addition, management interventions aiming to deliver resilience should incorporate an assessment of both pulse and press disturbances to ensure detection of threshold responses to disturbance, so that appropriate management interventions can be identified. Close

• 4. [Article] Multimodel Simulations of Forest Harvesting Effects on Long-Term Productivity and CN Cycling in Aspen Forests

  The effects of forest management on soil carbon (C) and nitrogen (N) dynamics vary by harvest type and species. We simulated long-term effects of bole-only harvesting of aspen (Populus tremuloides) on ...

  Citation × Citation Citation Abstract Copy Title: Multimodel Simulations of Forest Harvesting Effects on Long-Term Productivity and CN Cycling in Aspen Forests Author: Wang, Fugui, Mladenoff, David J., Forrester, Jodi A., Blanco, Juan A., Scheller, Robert M., Peckham, Scott D., Keough, Cindy, Lucash, Melissa S. Year: 2014 The effects of forest management on soil carbon (C) and nitrogen (N) dynamics vary by harvest type and species. We simulated long-term effects of bole-only harvesting of aspen (Populus tremuloides) on stand productivity and interaction of CN cycles with a multiple model approach. Five models, Biome-BGC, CENTURY, FORECAST, LANDIS-II with Century-based soil dynamics, and PnET-CN, were run for 350 years with seven harvesting events on nutrient-poor, sandy soils representing northwestern Wisconsin, USA. Twenty CN state and flux variables were summarized from the models' outputs, and statistically analyzed using ordination and variance analysis methods. The multiple models' averages suggest that bole-only harvest would not significantly affect long-term site productivity of aspen, though declines in soil organic matter and soil N were significant. Along with direct N removal by harvesting, extensive leaching after harvesting before canopy closure was another major cause of N depletion. These five models were notably different in output values of the 20 variables examined, although there were some similarities for certain variables. PnET-CN produced unique results for every variable, and CENTURY showed fewer outliers and similar temporal patterns to the mean of all models. In general, this study demonstrated that when there are no site-specific data for fine-scale calibration and evaluation of a single model, the multiple model approach may be a more robust approach for long-term simulations. In addition, multi-modeling may also improve the calibration and evaluation of an individual model. Title: Multimodel Simulations of Forest Harvesting Effects on Long-Term Productivity and CN Cycling in Aspen Forests Author: Wang, Fugui, Mladenoff, David J., Forrester, Jodi A., Blanco, Juan A., Scheller, Robert M., Peckham, Scott D., Keough, Cindy, Lucash, Melissa S. Year: 2014 The effects of forest management on soil carbon (C) and nitrogen (N) dynamics vary by harvest type and species. We simulated long-term effects of bole-only harvesting of aspen (Populus tremuloides) on stand productivity and interaction of CN cycles with a multiple model approach. Five models, Biome-BGC, CENTURY, FORECAST, LANDIS-II with Century-based soil dynamics, and PnET-CN, were run for 350 years with seven harvesting events on nutrient-poor, sandy soils representing northwestern Wisconsin, USA. Twenty CN state and flux variables were summarized from the models' outputs, and statistically analyzed using ordination and variance analysis methods. The multiple models' averages suggest that bole-only harvest would not significantly affect long-term site productivity of aspen, though declines in soil organic matter and soil N were significant. Along with direct N removal by harvesting, extensive leaching after harvesting before canopy closure was another major cause of N depletion. These five models were notably different in output values of the 20 variables examined, although there were some similarities for certain variables. PnET-CN produced unique results for every variable, and CENTURY showed fewer outliers and similar temporal patterns to the mean of all models. In general, this study demonstrated that when there are no site-specific data for fine-scale calibration and evaluation of a single model, the multiple model approach may be a more robust approach for long-term simulations. In addition, multi-modeling may also improve the calibration and evaluation of an individual model. Close