THE IMPACTS OF DRIVERS OF GLOBAL CLIMATE AND LAND-USE CHANGES ON FORESTS IN THE EASTERN US

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 1016433
• Project Start Date: Aug 1, 2018
• Project End Date: Jun 30, 2023
• Program Code: [(N/A)]- (N/A)

Project Director
Abrams, MA.

Recipient Organization
PENNSYLVANIA STATE UNIVERSITY
208 MUELLER LABORATORY
UNIVERSITY PARK,PA 16802

Performing Department
Ecosystem Science & Management

Non Technical Summary
The world's climate is warming in ways not seen for several thousand years.The post-1850 increases in greenhouse gases and abrupt global warming are clearly affecting tree physiology and many other ecosystem processes, and provide vast research opportunities for tree physiologists and other environmental scientists. These topics are now the dominant focus worldwide, but have the potential, in our opinion, to minimize the role of other important factors, particularly among those who are intent on finding climate signals. Human populations and their role as a disturbing agent in ecosystems have also changed dramatically along with the recent changes in climate. Comprehending past and future impacts of climate change on vegetation requires more complete understanding of the human-climate-vegetation dynamic. Vegetation models should include changes in disturbance regimes, and not rely solely on climate change or bigeochemical factors. New research endeavors that combine multidisciplinary data, as outlined in this article, in other locales and with other disciplines should greatly increase our understanding of global change impacts as we move further into the twenty-first century.

Animal Health Component

50%

Research Effort Categories

Basic

50%

Applied

50%

Developmental

0%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
123	0620	1070	100%

Knowledge Area
123 - Management and Sustainability of Forest Resources;

Subject Of Investigation
0620 - Broadleaf forests of the North;

Field Of Science
1070 - Ecology;

Keywords

climate change

land-use

forests

distrubance

anthropogenic

fire

Goals / Objectives
This project will address global change impacts on forests and the drivers responsible for those changes. Global change, including climate change and land-use impacts, as a scientific topic has risen to epic proportions, with real and surmised impacts covering all aspects of life (ecological, economic, and social). Long-publicized predictions of climate-change effects on vegetation are now starting to reveal themselves, particularly at high altitudes and latitudes where subtle changes in temperature are greatly magnified in glacier retraction, permafrost thaw, and tree-line shifts. However, at certain locations, vegetation change has lagged in part due to ecological inertia (entrenchment due to plant longevity, plasticity, and resilience). Confounding things further is that climate change (changes in precipitation, temperature, and weather patterns) has not been uniform, but varies from region to region, thus affecting vegetation communities and attendant plants differently. A number of other anthropogenic disturbances have also impacted vegetation immediately preceding and concurrent with recent climate change (past ≈150 yrs), some of which had profound and long-lasting effects. In total, present-day vegetation represents an amalgamation of all these phenomena to various degrees. To gain a sense of relative importance among the principal change factors, we will research and quantify the effects of climate and land-use history on forest dynamics using tree-census data in various locations in the eastern US. We will employ a methodology in which tree ecophysiological attributes coupled with changes in species composition and dominance to serve as a unifying template for interpretation of global change impacts.Big accelerations of learning and scientific advances often take place when science of one field is merged with another. This type of interdisciplinary research involves the integration of different tools, skill sets, knowledge, and problem solving approaches from complementary disciplines to explore new areas of science. In recent years, we have been working to expand the knowledge of climate change, human impacts and land-use legacies by merging the fields of tree physiology and vegetation dynamics. This came forth from the realization that the distribution and dominance of each tree species corresponds to an ecophysiological expression and that long-term change in forest composition is directly relatable to the underlying physiological attributes of component species. This analysis can provide a more robust assessment of the role and impacts of the most important drivers of forest dynamics, namely climate change and land-use history. This method also elucidates ecophysiological changes at the forest type and forest biome level by capitalizing on extensive and long-term forest survey records.The specific goals and objectives of this research included:1. Characterizing of the ecophysiological attributes of the major tree species in various study areas in the eastern US. (Abrams)2. Obtaining long-term records of forest dynamics and growth data for contrasting sites in all locations. (Abrams and Kaye)3. Relating forest dynamics (changes in species composition and dominance) and growth (tree diameter changes) to the drivers (land-use and climate) of those changes. (Abrams and Kaye)4. Determining the causal factors (e.g., climate versus disturbance and others) for this change in ecophysiology and how it varies by site and region, with a special emphasis in drought vulnerability in the US. (Abrams and Kaye)

Project Methods
Our approach involves categorizing tree species/genera into temperature, shade tolerance (intolerant, intermediate and tolerant) and pyrogenicity classes based on their known life history and physiological characteristics. Temperature classes were established using actual temperature. Tree species were sorted by the average temperature within their ecological range (US distribution) and divided into four temperature classes. To assess level of disturbance, tree genera were categorized by shade tolerance (intolerant, intermediate and tolerant) and pyrogenicity (pyrophilic and pyrophobic). Tree survey data from pre-European settlement and present-day were tallied by temperature (cold, cool, warm and hot), shade tolerance (intolerant, intermediate and tolerant) and pyrogenicity (pyrophilic and pyrophobic), and change percentages were calculated for each class. For the purpose of this research, we expanded the ecophysiological classes to include drought tolerance and tree longevity. We chose three longevity classes, short-lived (<100 years), intermediate-lived (100-250 years) and long-lived (>250 years) based on the range and distribution of the typical age of mortality for major eastern US tree species. These classifications were applied to 190 tree-census datasets that compared pre-European settlement (original land survey data dating back to the 1600s) and current vegetation conditions in the eastern USA expressed as percent changes in the abundance (relative density or importance value) of arboreal vegetation (Nowacki and Abrams 2015). Importance value is typically calculated by combining or averaging species' relative frequency, density and dominance (basal area). Here, we expanded this comparative analysis to five ecophysiological categories as a more robust set to relate compositional changes to known climate (temperature and drought) or disturbance (land-use) phenomena. Dr. Kaye addresses the role of lithology in forest composition, growth, and productivity by combining forest inventory data with reconstructed forest growth to untangle the relative roles of bedrock, climate, and land-use history in forest dynamics. This portion of the project focuses on eastern deciduous forests in North America, and uses the same framework of ecophysiological classifications of tree species to identify their sensitivity to shale and sandstone bedrocks specifically.

Progress 10/01/19 to 09/30/20

Outputs
Target Audience:Forest managers, natural resource managers, global change ecologist, national and international conservation organizations Changes/Problems:Because of the Covid pandemic the amount of field research and travel has been limited in 2020, which has impacted our data collection ability. What opportunities for training and professional development has the project provided?Our research has provided training and professional development for many graduates at Penn State and other universities involved in a dendrochronology field week training led by Dr. Margot Kaye. Forests in the mid-Atlantic and western US regions were used for ecological and climate change impact studies. How have the results been disseminated to communities of interest?Talks at professional meetings and seminars and publications, manager workshops, attending and leading field trips (Abrams and Kaye). These included professional trips to China, India, and Japan over the last year by Dr. Marc Abrams. What do you plan to do during the next reporting period to accomplish the goals?1. Additional research characterizing the ecological attributes of the major tree species in various study areas in the eastern US in relation to climate change vulnerability(Abrams) 2. Additional work on long-term records of forest dynamics and growth data for contrasting sites in all locations(Abrams and Kaye) 3. Relating forest dynamics (changes in species composition and dominance) and growth (tree diameter changes) to the global change drivers (land-use and climate) in relation to climate stressors(Abrams and Kaye) 4. Continue determining the factors (e.g., climate versus disturbance and others) for this change in functional ecology and how it varies by site and region, with a special emphasis in climate vulnerability in the US(Abrams and Kaye) 5. Evaluate impacts of land use and climate change on hardwood and conifer forests in the northeast and mid- Atlantic regions

Impacts
What was accomplished under these goals? Our research multifaceted goals of documenting global changes suggest that both anthropogenic disturbances and climate change are having a very pronounced impact onarea forests composition and tree growth (Goals 1 and 2). We found differential impacts depending on forest type and region in a manner that varied across the Tension Zone Line (Goal 3). Northern regions with intensive disturbance regimes resulted in the ubiquitous loss of conifers and large increases of Acer, Populus, and Quercus in the northern hardwood type. Further south, a decline in fire since the 1930s in the central hardwoods has resulted in Acer increases; and associated mesophication in Quercus-Pinus systems are ongoing (Goal 4). This also represented an increase in slow growing maple compared with faster growing oak and pine (the goal of documenting spatial and temporal variation in tree growth(Kaye;Goal 2). This led to significant warm to cool shifts in temperature class where cool-adapted Acer saccharum increased and temperature neutral changes where warm-adapted Acer rubrum increased. In both cases, these shifts were attributed to fire suppression rather than climate change (Goal 4). Eastern US forests have also experienced intensive deer browsing; that is, limitedhardwood regeneration will remain in climate disequilibrium into the foreseeable future (the goal of documenting the most important drivers of forest change, including the impacts of deer browsing(Abrams; Goal 3 and 4). Nevertheless, these forests are experiencing significant densification from both preferred and non-preferred deer browse tree species. Overall, the results of our study suggest that altered disturbance regimes rather than climate had the greatest influence on vegetation composition and dynamics in the eastern United States over multiple centuries. However, the impact of climate on tree growth is evident (Kaye; Goal 2). Land-use change often trumped or negated the impacts of warming climate, and needs greater recognition in climate change discussions, scenarios, and model interpretations (Goals 1-4). Prior to European settlement, much of the eastern use reflected anIndigenous landscape from Native American land-use practices, especially burning, rather than a climatic climax landscape.

Publications

• Type: Journal Articles Status: Published Year Published: 2020 Citation: Umeki, K., M. D. Abrams, K. Toyama and E. Nabeshima. 2020. A model for longitudinal data sets relating wind-damage probability to biotic and abiotic factors: a Bayesian approach. Forest Systems, doi.org/10.5424/fs/2019282-15200, 12 pages
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Hanberry BB, Abrams MD, Arthur MA and Varner JM (2020) Reviewing Fire, Climate, Deer, and Foundation Species as Drivers of Historically Open Oak and Pine Forests and Transition to Closed Forests. Frontiers of Forest Global Change 3:56. doi: 10.3389/ffgc.2020.00056, 12 pages
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Abrams, M. D. and G. J. Nowacki. 2020. Native American imprint in palaeoecology. Nature Sustainability, https://doi.org/10.1038/s41893-020-0578-6
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Abrams, M. D. 2020. Don't Downplay the Role of Indigenous People in Molding the Ecological Landscape. Scientific American August 5, 2020. https://www.scientificamerican.com/article/dont-downplay-the-role-of-indigenous-people-in-molding-the-ecological-landscape/
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Maynard-Bean, E., M.W. Kaye, E.E. Burkhart, & T. Wagner, 2020. Citizen scientists record novel leaf phenology of invasive shrubs in eastern U.S. forests. Biological Invasions, DOI: 10.1007/s10530-020-02326-1
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Smeglin Y.H., K.J. Davis, Y. Shi, D.M. Eissenstat, J.P. Kaye, M.W. Kaye, 2020. Observing and Simulating Spatial Variations of Forest Carbon Stocks in Complex Terrain. Journal of Geophysical Research: Biogeosciences 125:e2019JG005160.
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Zachary D. M., H. Wu, K. Zipp, C.L. Dems, E. Smithwick, M.W. Kaye, P. Newman, A. Zhao & A. Taylor, 2020. Hunter and non-hunter perceptions of costs, benefits, and likelihood of outcomes of prescribed fire in the Mid-Atlantic region. Society & Natural Resource, DOI: 10.1080/08941920.2020.1780359.

Progress 10/01/18 to 09/30/19

Outputs
Target Audience:Forest managers, natural resource managers, global change ecologist, conservation organizations Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Mature and old-growth hardwood and conifer forests in the mid-Atlantic region were used for ecological and climate change impact studies. In one project, 60-70 trees in each forest across all species and diameter classes were recorded for size and age. In another study, tree growth was reconstructed from over 1000 trees and over 20 species across a climate gradient in the central Appalachians. These data were used to assess the impacts of competition, forest succession, and global change factors on forest dynamics. Historical land use, forest succession, forest composition, and competition among trees were assessed as factors influencing tree growth, while climate variability plays a secondary role. How have the results been disseminated to communities of interest?Talks at professional meetings and seminars and publications, manager workshops What do you plan to do during the next reporting period to accomplish the goals? Continue characterizing of the ecophysiological attributes of the major tree species in various study areas in the eastern US. (Abrams) Additional work on long-term records of forest dynamics and growth data for contrasting sites in all locations. (Abrams and Kaye) Relating forest dynamics (changes in species composition and dominance) and growth (tree diameter changes) to the drivers (land-use and climate) of those changes. (Abrams and Kaye) Continue determining the causal factors (e.g., climate versus disturbance and others) for this change in ecophysiology and how it varies by site and region, with a special emphasis in drought vulnerability in the US. (Abrams and Kaye) Evaluate impacts of land use and climate change onhardwood and conifer forests in the northeast and mid- Atlantic regions.

Impacts
What was accomplished under these goals? Our findings over the last year suggest that natural and anthropogenic disturbance, including insects, pathogens and deep browsing, are having a very pronounced impact are area forests composition (Goal 1). The impact of climate was seen more at the level of tree ring growth, which varied in response to both disturbance and climate variation (Goal 2). Nevertheless, forest dynamic and growth varied differentially across the different forest types of the eastern US (Goal 3). To the north, intensive and expansive early European disturbance resulted in the ubiquitous loss of conifers and large increases of Acer, Populus, and Quercus in northern hardwoods, whereas to the south, these disturbances perpetuated the dominance of Quercus in central hardwoods (Goal 1). Acer increases and associated mesophication in Quercus-Pinus systems were delayed until mid-20th century fire suppression. This also represented an increase in slow growing maple compared with faster growing oak and pine (the goal of documenting spatial and temporal variation in tree growth). This led to significant warm to cool shifts in temperature class where cool-adapted Acer saccharum increased and temperature neutral changes where warm-adapted Acer rubrum increased (Goal 1). In both cases, these shifts were attributed to fire suppression rather than climate change. Deer browsing impacts were pronounced in that they suppressed the expansion of favored species, such as oak, hickory and cedar, and facilitated the expansion of less desired browse tree such as red maple. Nevertheless, forests of the eastern US are suffering from a densification problem, despite high deer browsing pressure, and this is further limiting the recruitment of light demanding trees (Goal 3). Because mesophication is ongoing, eastern US forests formed during the catastrophic disturbance era followed by fire suppression will remain in climate disequilibrium into the foreseeable future (the goal of documenting the most important drivers of forest change, including the impacts of deer browsing). Overall, the results of our research over the last year suggest that altered disturbance regimes are having the greatest influence on vegetation composition and dynamics in the eastern United States. Land-use changes exceed the impacts of warming climate, and needs greater recognition in climate change discussions, scenarios, and model interpretations (Goal 4). Nevertheless, forests of the eastern US remain vulnerable to future climate change if a furthering of warmth and drought occurs within the Biome

Publications

• Type: Journal Articles Status: Published Year Published: 2018 Citation: Hanberry, B. B. and M. D. Abrams. 2018. Recognizing loss of open forest ecosystems by tree densification and land use intensification in the Midwestern United States. Regional Environmental Change 18: doi.org/10.1007/s10113-018-1299-5. 10 pages
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Hanberry, B. B., M. D. Abrams & J. D. White. 2019. Is increased precipitation during the 20th century statistically or ecologically significant in the eastern US? Journal of Land Use Science 13: 259268. DOI: 10.1080/1747423X.2018.1519606
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Abrams, M. D. and S. E. Johnson. 2019. Witness tree records for the early Colonial period (1623-1700) of eastern Virginia. American Midland Naturalist 181:128135.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Abrams, M. D. and G. J. Nowacki. 2019. Global change impacts on forest and fire dynamics using paleoecology and tree census data for eastern North America. Annals of Forest Science DOI: 10.1007/s13595-018-0790-y, 23 pages
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Hanberry, B. B. and M. D. Abrams. 2019. Does deer density impact tree stocking level in forests of the eastern U.S.? Ecological Processes https://doi.org/10.1186/s13717-019-0185-5. 12 pages
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Maynard-Bean, E. and M.W. Kaye, 2019. Invasive shrub removal benefits native plants in an eastern deciduous forest of North America. Invasive Plant Science and Management 12: 3-10.
• Type: Journal Articles Status: Published Year Published: 2018 Citation: Brubaker, K. M., Q.K. Johnson, and M.W. Kaye, 2018. Spatial patterns of tree and shrub biomass in a deciduous forest using leaf-off and leaf-on lidar. Canadian Journal of Forest Research 48: 1020-1033.
• Type: Journal Articles Status: Under Review Year Published: 2019 Citation: Reed, W and M.W. Kaye, Bedrock type drives forest carbon storage and uptake across the mid-Atlantic Appalachian Ridge and Valley, U.S.A. Submitted to Forest Ecology and Management.
• Type: Theses/Dissertations Status: Accepted Year Published: 2019 Citation: Igniting Change: Measuring Prescribed Fire Effects in a Central Pennsylvania Hardwood Forest

Progress 08/01/18 to 09/30/18

Outputs
Target Audience:Forest managers, natural resource managers, global change ecologist, conservation organizations Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Mature and old-growth hardwood and conifer forests in the mid-Atlantic region were used for ecological and climate change impact studies. In one project, 60-70 trees in each forest across all species and diameter classes were recorded for size and age. In another study, tree growth was reconstructed from over 1000 trees and over 20 species across a climate gradient in the central Appalachians. These data were used to assess the impacts of competition, forest succession, and global change factors on forest dynamics. Historical land use, forest succession, forest composition, and competition among trees were assessed as factors influencing tree growth, while climate variability plays a secondary role. How have the results been disseminated to communities of interest?Talks at professional meetings and seminars. What do you plan to do during the next reporting period to accomplish the goals? Characterizing of the ecophysiological attributes of the major tree species in various study areas in the eastern US. (Abrams) Obtaining long-term records of forest dynamics and growth data for contrasting sites in all locations. (Abrams and Kaye) Relating forest dynamics (changes in species composition and dominance) and growth (tree diameter changes) to the drivers (land-use and climate) of those changes. (Abrams and Kaye) Determining the causal factors (e.g., climate versus disturbance and others) for this change in ecophysiology and how it varies by site and region, with a special emphasis in drought vulnerability in the US. (Abrams and Kaye) Evaluate impacts of land use and climate change on hardwood and conifer forests in the northeast and mid- Atlantic regions.

Impacts
What was accomplished under these goals? Our initial findings (the goals of documenting changes in forest composition and growth) suggest that post-European settlement disturbances are having a very pronounced impact are area forests composition and tree growth, more so than regional climate, but in a manner that varied across the Tension Zone Line. To the north, intensive and expansive early European disturbance resulted in the ubiquitous loss of conifers and large increases of Acer, Populus, and Quercus in northern hardwoods, whereas to the south, these disturbances perpetuated the dominance of Quercus in central hardwoods. Acer increases and associated mesophication in Quercus-Pinus systems were delayed until mid-20th century fire suppression. This also represented an increase in slow growing maple compared with faster growing oak and pine (the goal of documenting spatial and temporal variation in tree growth). This led to significant warm to cool shifts in temperature class where cool-adapted Acer saccharum increased and temperature neutral changes where warm-adapted Acer rubrum increased. In both cases, these shifts were attributed to fire suppression rather than climate change. Because mesophication is ongoing, eastern US forests formed during the catastrophic disturbance era followed by fire suppression and intensive deer browsing will remain in climate disequilibrium into the foreseeable future (the goal of documenting the most important drivers of forest change, including the impacts of deer browsing). Overall, the results of our study suggest that altered disturbance regimes rather than climate had the greatest influence on vegetation composition and dynamics in the eastern United States over multiple centuries. Land-use change often trumped or negated the impacts of warming climate, and needs greater recognition in climate change discussions, scenarios, and model interpretations.

Publications