This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Unfortunately, there is an error in the first sentence of the section ''Introduction'' in the ori... more Unfortunately, there is an error in the first sentence of the section ''Introduction'' in the original publication of the article. The value ''960 million km 2 '' is incorrect and should be ''9.6 million km 2 .'' The correct sentence should read as: ''China is one of the largest countries in the world; it has a 9.6 million km 2 land area and a population of 1.3 billion.'' The online version of the original article can be found under
LANDIS is a landscape decision support tool that models spatial relationships to help managers an... more LANDIS is a landscape decision support tool that models spatial relationships to help managers and planners examine the large-scale, long-term, cumulative effects of succession, harvesting, wildfire, prescribed fire, insects, and disease. It can operate on forest landscapes from a few thousand to a few million acres in extent. Fire modeling capabilities in LANDIS are detailed, but intuitive. Modeled fires kill trees based on the fire intensity and each tree species' fire tolerance, and spatially explicit ignition probability maps can be incorporated but are not required. As the LANDIS model runs through many annual or 10year iterations, it illustrates how and where forest vegetation is expected to change in response to succession, fire, harvesting, and other disturbances. LANDIS output can be mapped, summarized, and linked to other attributes of interest, such as wildlife habitat suitability. Although it is possible to run the LANDIS model using generic or default values, the real benefits come when the model is calibrated to reflect the unique conditions associated with a specific forest ecosystem. Applications of LANDIS include analyses of fire regimes, separately or in combination with harvesting, on the Mark Twain National Forest (Missouri), the Hoosier National Forest (Indiana), and the Chequamegon-Nicolet National Forest (Wisconsin). These analyses can guide the selection of long-term management alternatives for forested landscapes. LANDIS has also proven useful in more theoretical investigations that compare long-term effects of alternative fire regimes on the expected direction and rate of tree species composition change across an array of ecological land types.
Aim: Population dynamics and disturbances have often been simplified or ignored when predicting r... more Aim: Population dynamics and disturbances have often been simplified or ignored when predicting regional-scale tree species distributions in response to climate change in current climate-distribution models (e.g., niche and biophysical process models). We determined the relative importance of population dynamics, tree harvest, climate change, and their interaction in affecting tree species distribution changes. Location: Central Hardwood Forest Region of the United States. Major taxa studied: Tree species. Methods: We used a forest dynamic model, LANDIS PRO that accounted for population dynamics, tree harvest, and climate change to predict tree species' distributions at 270 m resolution from 2000 to 2300. We quantified the relative importance of these factors using a repeated measures analysis of variance. We further investigated the effects of each factor on changes in species distributions by summarizing extinction and colonization rates. Results: On average, population dynamics was the most important factor affecting tree species distribution changes. Tree harvest was more important than climate change by 2100 whereas climate change was more important than harvest by 2300. By end of the 21 st century, most tree species expanded their distributions irrespective of any climate or harvest scenario. By 2300, most northern, some southern, and most widely distributed species contracted their distributions while most southern species, some widely distributed species, and few northern species expanded their distributions under warmer climates with tree harvest. Harvest accelerated or ameliorated the contractions and expansions for species that were negatively or positively affected by climate change. Main conclusions: Our results suggest that population dynamics and tree harvest can be more important than climate change and thus should be explicitly included when predicting future tree species' distributions. Understanding the underlying mechanisms that drive tree species distributions will enable better predictions of tree species distributions under climate change.
Background/Question/Methods Oak decline has impacted Midwestern-upland oak-hickory forests, parti... more Background/Question/Methods Oak decline has impacted Midwestern-upland oak-hickory forests, particularly species in the red oak group (Quercus Section Lobatae) across the Ozark Highlands of Missouri, Arkansas and Oklahoma. Drought is a common inciting factor in oak decline, while advanced tree age is considered a predisposing factor, and opportunistic organisms such as armillaria root fungi and opportunistic insects are believed to contribute to oak decline. Declining trees are initially indicated by foliage wilt and browning followed by progressive branch dieback. If crown dieback continues trees can die. The objective of this study was to analyze oak mortality by species group and inventory year to illustrate the general spatial and temporal trends of oak decline and mortality by using the 1999-2010 Forest Inventory and Analysis (FIA) annualized data from plots in the Ozark Highlands of Arkansas and Missouri landscape. Results/Conclusions Of the species groups examined in this stu...
Wetlands in the mid-and high-latitudes are particularly vulnerable to environmental changes and h... more Wetlands in the mid-and high-latitudes are particularly vulnerable to environmental changes and have declined dramatically in recent decades. Climate change and human activities are arguably the most important factors driving wetland distribution changes which will have important implications for wetland ecological functions and services. We analyzed the importance of driving variables for wetland distribution and investigated the relative importance of climatic factors and human activity factors in driving historical wetland distribution changes. We predicted wetland distribution changes under climate change and human activities over the 21st century using the Random Forest model in a mid-and high-latitude region of Northeast China. Climate change scenarios included three Representative Concentration Pathways (RCPs) based on five general circulation models (GCMs) downloaded from the Coupled Model Intercomparison Project, Phase 5 (CMIP5). The three scenarios (RCP 2.6, RCP 4.5, and RCP 8.5) predicted radiative forcing to peak at 2.6, 4.5, and 8.5 W/m 2 by the 2100s, respectively. Our results showed that the variables with high importance scores were agricultural population proportion, warmness index, distance to water body, coldness index, and annual mean precipitation; climatic variables were given higher importance scores than human activity variables on average. Average predicted wetland area among three emission scenarios were 340,000 ha, 123,000 ha, and 113,000 ha for the 2040s, 2070s, and 2100s, respectively. Average change percent in predicted wetland area among three periods was greatest under the RCP 8.5 emission scenario followed by RCP 4.5 and RCP 2.6 emission scenarios, which were 78%, 64%, and 55%, respectively. Losses in predicted wetland distribution were generally around agricultural lands and expanded continually from the north to the whole region over time, while the gains were mostly associated with grasslands and water in the most southern region. In conclusion, climatic factors had larger effects than human activity factors on historical wetland distribution changes and wetland distributions were predicted to decline remarkably over time under climate change scenarios. Our findings have important implications for wetland resource management and restoration because predictions of future wetland changes are needed for wetlands management planning.
At the forest landscape/region level, based on annual Forest Inventory and Analysis plot data fro... more At the forest landscape/region level, based on annual Forest Inventory and Analysis plot data from 1999 to 2010, oak decline and mortality trends for major oak species (groups) were examined in the Ozark Highlands of Arkansas and Missouri. Oak decline has elevated cumulative mortality of red oak species to between 11 and 15 percent in terms of relative density and basal area of standing dead oak trees, respectively. These values are three to five times higher than for white oak group and non-oak species. Oak decline and associated escalating mortality have occurred primarily in red oak species while the white oak group has maintained a relatively stable mortality rate that is comparable to non-oak species. Cross-correlation analyses indicate that mortality in the red
Human activities have altered disturbance patterns in many parts of world, but there is no quanti... more Human activities have altered disturbance patterns in many parts of world, but there is no quantitative information on patterns and trends of forest disturbance regimes in China. We applied a spectral-temporal segmentation approach over all available Landsat data to map individual disturbance patches and characterize the patterns and trends in disturbance rate, size, frequency, and severity across China's forests. From 1986 to 2020, about 39.7% of China's forests were disturbed with an annual rate of 1.16 ± 0.41% yr −1. The disturbance decreased at a rate of −390 ± 142 km 2 yr −1 , primarily driven by the effective implementation of forest protection policy since 2000s. The rate, frequency, and size of disturbance generally intensified in Southeast, but weakened in Northeast China. Our high-quality, spatially explicit disturbance map provides an essential data layer to understand the landscape-scale drivers of forest dynamics and functions for important but less understood pan-temperate forest regions.
Temperate forests regrowing from historical land use and land cover change in the eastern US serv... more Temperate forests regrowing from historical land use and land cover change in the eastern US serve as carbon (C) sinks. Environmental drivers have been significantly altered (e.g. rising atmospheric CO2concentration, warmer temperature, and elevated nitrogen (N) deposition) and will have a wide range of impacts on future forest C sinks. However, the interactions among these environmental drivers are unclear and their effects are subject to uncertainty. We assessed the combined and interactive effects of rising CO2concentration, climate change (temperature, precipitation), and N deposition on forest aboveground net primary production (ANPP) and their relative contribution to ANPP changes of a temperate forest in the eastern US. We used a process-based ecosystem model PnET-day to simulate coupled cycles of C, water, and N of forest ecosystems. We found that (1) climate change exerted negative effects on ANPP (−0.250 kg C m−2yr−1) whereas rising CO2and N deposition enhanced ANPP (+0.25...
Most temperate forests in U.S. are recovering from heavy exploitation and are in intermediate suc... more Most temperate forests in U.S. are recovering from heavy exploitation and are in intermediate successional stages where partial tree harvest is the primary disturbance. Changes in regional forest composition in response to climate change are often predicted for plant functional types using biophysical process models. These models usually simplify the simulation of succession and harvest and may not consider important species‐specific demographic processes driving forests changes. We determined the relative importance of succession, harvest, and climate change to forest composition changes in a 125‐million ha area of the Central Hardwood Forest Region of U.S. We used a forest landscape modeling approach to project changes in density and basal area of 23 tree species due to succession, harvest, and four climate scenarios from 2000 to 2300. On average, succession, harvest, and climate change explained 78, 17, and 1% of the variation in species importance values (IV) at 2050, respective...
Oak decline was the focus of the last Oak Symposium in 2002. Since then, in the Ozark Highlands a... more Oak decline was the focus of the last Oak Symposium in 2002. Since then, in the Ozark Highlands and considering the red oak group alone, more than 60 percent of the forest has been severely impacted by oak decline. This is a synthesis of our past 15 years of research into oak decline. Our methods included inventories and/or modeling at seedling, forest stand, landscape, and regional scales. Within 1 year of decline onset, a stand scale study showed the number of standing dead northern red oak (Quercus rubra L.) trees increased by 55 percent (P-value = 0.029). Within the Ozark Highlands, 3.6 million ha of the red oak group [(Quercus Section Lobatae): includes northern red oak (Q. rubra L.), black oak (Q. velutina Lam.), scarlet oak (Q. coccinea Muenchh.), blackjack oak (Q. marilandica Munchh.) and southern red oak (Q. falcate Michx.)], 0.4 million ha of white oak (e.g., Quercus alba L., Quercus stellata) and 0.28 million ha of non-oak group forests had severe decline between 2006 to 2010. While model simulations across a 0.43-million ha area of the Ozark National Forest through the next century predict reduction of potential oak decline sites from 45 percent to 20 percent if historic fire frequencies are re-established. However, simulations by harvesting alone resulted in only a 3-percent reduction of high risk sites over doing nothing. Based on the combined results of these studies, our recommendations to reduce the impact of oak decline within oak decline susceptible forests include managing physiological age of susceptible trees, favoring decline resistant species, and prescribed fire.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Unfortunately, there is an error in the first sentence of the section ''Introduction'' in the ori... more Unfortunately, there is an error in the first sentence of the section ''Introduction'' in the original publication of the article. The value ''960 million km 2 '' is incorrect and should be ''9.6 million km 2 .'' The correct sentence should read as: ''China is one of the largest countries in the world; it has a 9.6 million km 2 land area and a population of 1.3 billion.'' The online version of the original article can be found under
LANDIS is a landscape decision support tool that models spatial relationships to help managers an... more LANDIS is a landscape decision support tool that models spatial relationships to help managers and planners examine the large-scale, long-term, cumulative effects of succession, harvesting, wildfire, prescribed fire, insects, and disease. It can operate on forest landscapes from a few thousand to a few million acres in extent. Fire modeling capabilities in LANDIS are detailed, but intuitive. Modeled fires kill trees based on the fire intensity and each tree species' fire tolerance, and spatially explicit ignition probability maps can be incorporated but are not required. As the LANDIS model runs through many annual or 10year iterations, it illustrates how and where forest vegetation is expected to change in response to succession, fire, harvesting, and other disturbances. LANDIS output can be mapped, summarized, and linked to other attributes of interest, such as wildlife habitat suitability. Although it is possible to run the LANDIS model using generic or default values, the real benefits come when the model is calibrated to reflect the unique conditions associated with a specific forest ecosystem. Applications of LANDIS include analyses of fire regimes, separately or in combination with harvesting, on the Mark Twain National Forest (Missouri), the Hoosier National Forest (Indiana), and the Chequamegon-Nicolet National Forest (Wisconsin). These analyses can guide the selection of long-term management alternatives for forested landscapes. LANDIS has also proven useful in more theoretical investigations that compare long-term effects of alternative fire regimes on the expected direction and rate of tree species composition change across an array of ecological land types.
Aim: Population dynamics and disturbances have often been simplified or ignored when predicting r... more Aim: Population dynamics and disturbances have often been simplified or ignored when predicting regional-scale tree species distributions in response to climate change in current climate-distribution models (e.g., niche and biophysical process models). We determined the relative importance of population dynamics, tree harvest, climate change, and their interaction in affecting tree species distribution changes. Location: Central Hardwood Forest Region of the United States. Major taxa studied: Tree species. Methods: We used a forest dynamic model, LANDIS PRO that accounted for population dynamics, tree harvest, and climate change to predict tree species' distributions at 270 m resolution from 2000 to 2300. We quantified the relative importance of these factors using a repeated measures analysis of variance. We further investigated the effects of each factor on changes in species distributions by summarizing extinction and colonization rates. Results: On average, population dynamics was the most important factor affecting tree species distribution changes. Tree harvest was more important than climate change by 2100 whereas climate change was more important than harvest by 2300. By end of the 21 st century, most tree species expanded their distributions irrespective of any climate or harvest scenario. By 2300, most northern, some southern, and most widely distributed species contracted their distributions while most southern species, some widely distributed species, and few northern species expanded their distributions under warmer climates with tree harvest. Harvest accelerated or ameliorated the contractions and expansions for species that were negatively or positively affected by climate change. Main conclusions: Our results suggest that population dynamics and tree harvest can be more important than climate change and thus should be explicitly included when predicting future tree species' distributions. Understanding the underlying mechanisms that drive tree species distributions will enable better predictions of tree species distributions under climate change.
Background/Question/Methods Oak decline has impacted Midwestern-upland oak-hickory forests, parti... more Background/Question/Methods Oak decline has impacted Midwestern-upland oak-hickory forests, particularly species in the red oak group (Quercus Section Lobatae) across the Ozark Highlands of Missouri, Arkansas and Oklahoma. Drought is a common inciting factor in oak decline, while advanced tree age is considered a predisposing factor, and opportunistic organisms such as armillaria root fungi and opportunistic insects are believed to contribute to oak decline. Declining trees are initially indicated by foliage wilt and browning followed by progressive branch dieback. If crown dieback continues trees can die. The objective of this study was to analyze oak mortality by species group and inventory year to illustrate the general spatial and temporal trends of oak decline and mortality by using the 1999-2010 Forest Inventory and Analysis (FIA) annualized data from plots in the Ozark Highlands of Arkansas and Missouri landscape. Results/Conclusions Of the species groups examined in this stu...
Wetlands in the mid-and high-latitudes are particularly vulnerable to environmental changes and h... more Wetlands in the mid-and high-latitudes are particularly vulnerable to environmental changes and have declined dramatically in recent decades. Climate change and human activities are arguably the most important factors driving wetland distribution changes which will have important implications for wetland ecological functions and services. We analyzed the importance of driving variables for wetland distribution and investigated the relative importance of climatic factors and human activity factors in driving historical wetland distribution changes. We predicted wetland distribution changes under climate change and human activities over the 21st century using the Random Forest model in a mid-and high-latitude region of Northeast China. Climate change scenarios included three Representative Concentration Pathways (RCPs) based on five general circulation models (GCMs) downloaded from the Coupled Model Intercomparison Project, Phase 5 (CMIP5). The three scenarios (RCP 2.6, RCP 4.5, and RCP 8.5) predicted radiative forcing to peak at 2.6, 4.5, and 8.5 W/m 2 by the 2100s, respectively. Our results showed that the variables with high importance scores were agricultural population proportion, warmness index, distance to water body, coldness index, and annual mean precipitation; climatic variables were given higher importance scores than human activity variables on average. Average predicted wetland area among three emission scenarios were 340,000 ha, 123,000 ha, and 113,000 ha for the 2040s, 2070s, and 2100s, respectively. Average change percent in predicted wetland area among three periods was greatest under the RCP 8.5 emission scenario followed by RCP 4.5 and RCP 2.6 emission scenarios, which were 78%, 64%, and 55%, respectively. Losses in predicted wetland distribution were generally around agricultural lands and expanded continually from the north to the whole region over time, while the gains were mostly associated with grasslands and water in the most southern region. In conclusion, climatic factors had larger effects than human activity factors on historical wetland distribution changes and wetland distributions were predicted to decline remarkably over time under climate change scenarios. Our findings have important implications for wetland resource management and restoration because predictions of future wetland changes are needed for wetlands management planning.
At the forest landscape/region level, based on annual Forest Inventory and Analysis plot data fro... more At the forest landscape/region level, based on annual Forest Inventory and Analysis plot data from 1999 to 2010, oak decline and mortality trends for major oak species (groups) were examined in the Ozark Highlands of Arkansas and Missouri. Oak decline has elevated cumulative mortality of red oak species to between 11 and 15 percent in terms of relative density and basal area of standing dead oak trees, respectively. These values are three to five times higher than for white oak group and non-oak species. Oak decline and associated escalating mortality have occurred primarily in red oak species while the white oak group has maintained a relatively stable mortality rate that is comparable to non-oak species. Cross-correlation analyses indicate that mortality in the red
Human activities have altered disturbance patterns in many parts of world, but there is no quanti... more Human activities have altered disturbance patterns in many parts of world, but there is no quantitative information on patterns and trends of forest disturbance regimes in China. We applied a spectral-temporal segmentation approach over all available Landsat data to map individual disturbance patches and characterize the patterns and trends in disturbance rate, size, frequency, and severity across China's forests. From 1986 to 2020, about 39.7% of China's forests were disturbed with an annual rate of 1.16 ± 0.41% yr −1. The disturbance decreased at a rate of −390 ± 142 km 2 yr −1 , primarily driven by the effective implementation of forest protection policy since 2000s. The rate, frequency, and size of disturbance generally intensified in Southeast, but weakened in Northeast China. Our high-quality, spatially explicit disturbance map provides an essential data layer to understand the landscape-scale drivers of forest dynamics and functions for important but less understood pan-temperate forest regions.
Temperate forests regrowing from historical land use and land cover change in the eastern US serv... more Temperate forests regrowing from historical land use and land cover change in the eastern US serve as carbon (C) sinks. Environmental drivers have been significantly altered (e.g. rising atmospheric CO2concentration, warmer temperature, and elevated nitrogen (N) deposition) and will have a wide range of impacts on future forest C sinks. However, the interactions among these environmental drivers are unclear and their effects are subject to uncertainty. We assessed the combined and interactive effects of rising CO2concentration, climate change (temperature, precipitation), and N deposition on forest aboveground net primary production (ANPP) and their relative contribution to ANPP changes of a temperate forest in the eastern US. We used a process-based ecosystem model PnET-day to simulate coupled cycles of C, water, and N of forest ecosystems. We found that (1) climate change exerted negative effects on ANPP (−0.250 kg C m−2yr−1) whereas rising CO2and N deposition enhanced ANPP (+0.25...
Most temperate forests in U.S. are recovering from heavy exploitation and are in intermediate suc... more Most temperate forests in U.S. are recovering from heavy exploitation and are in intermediate successional stages where partial tree harvest is the primary disturbance. Changes in regional forest composition in response to climate change are often predicted for plant functional types using biophysical process models. These models usually simplify the simulation of succession and harvest and may not consider important species‐specific demographic processes driving forests changes. We determined the relative importance of succession, harvest, and climate change to forest composition changes in a 125‐million ha area of the Central Hardwood Forest Region of U.S. We used a forest landscape modeling approach to project changes in density and basal area of 23 tree species due to succession, harvest, and four climate scenarios from 2000 to 2300. On average, succession, harvest, and climate change explained 78, 17, and 1% of the variation in species importance values (IV) at 2050, respective...
Oak decline was the focus of the last Oak Symposium in 2002. Since then, in the Ozark Highlands a... more Oak decline was the focus of the last Oak Symposium in 2002. Since then, in the Ozark Highlands and considering the red oak group alone, more than 60 percent of the forest has been severely impacted by oak decline. This is a synthesis of our past 15 years of research into oak decline. Our methods included inventories and/or modeling at seedling, forest stand, landscape, and regional scales. Within 1 year of decline onset, a stand scale study showed the number of standing dead northern red oak (Quercus rubra L.) trees increased by 55 percent (P-value = 0.029). Within the Ozark Highlands, 3.6 million ha of the red oak group [(Quercus Section Lobatae): includes northern red oak (Q. rubra L.), black oak (Q. velutina Lam.), scarlet oak (Q. coccinea Muenchh.), blackjack oak (Q. marilandica Munchh.) and southern red oak (Q. falcate Michx.)], 0.4 million ha of white oak (e.g., Quercus alba L., Quercus stellata) and 0.28 million ha of non-oak group forests had severe decline between 2006 to 2010. While model simulations across a 0.43-million ha area of the Ozark National Forest through the next century predict reduction of potential oak decline sites from 45 percent to 20 percent if historic fire frequencies are re-established. However, simulations by harvesting alone resulted in only a 3-percent reduction of high risk sites over doing nothing. Based on the combined results of these studies, our recommendations to reduce the impact of oak decline within oak decline susceptible forests include managing physiological age of susceptible trees, favoring decline resistant species, and prescribed fire.
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