Source: PENNSYLVANIA STATE UNIVERSITY submitted to NRP
IMPACTS OF LAND-USE HISTORY, FIRE, DEER BROWSING AND GLOBAL CHANGE ON FOREST STRUCTURE AND FUNCTION IN THE EASTERN UNITED STATES.
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
MCINTIRE-STENNIS
Reporting Frequency
Annual
Accession No.
1000092
Grant No.
(N/A)
Cumulative Award Amt.
(N/A)
Proposal No.
(N/A)
Multistate No.
(N/A)
Project Start Date
Sep 17, 2013
Project End Date
Jun 30, 2018
Grant Year
(N/A)
Program Code
[(N/A)]- (N/A)
Recipient Organization
PENNSYLVANIA STATE UNIVERSITY
208 MUELLER LABORATORY
UNIVERSITY PARK,PA 16802
Performing Department
Ecosystem Science & Management
Non Technical Summary
One of the most fundamental approaches for evaluating the disturbance history of a stand is through the tree-ring science of dendrochronology. Calculation of releases is a powerful and unique tool in that it reflects both localized and stand-wide disturbances at a high temporal resolution. Mean fire intervals of 4-20 years have been reported for most oak forests in the eastern and central U.S. Oak species possess a suite of adaptations for fire and drought stress, but not for competing in a closed forest understory dominated by later successional species. Strong indirect evidence for this idea is found in the fact that when fire is suppressed in oak forests during the 20th century, they are rapidly invaded by later successional, fire sensitive species, such as maple, beech, birch, and blackgum. These species are now replacing oak and becoming dominant trees. We believe that the suppression of fire and the successional replacement of oak forests is a cause and effect relationship. Throughout the eastern U.S., interactions and feedback among climate, vegetation, soils and topography, large- and small-scale disturbances, anthropogenic factors, and wildlife impacts created an ecological dynamic for oak forests that can only be understood from a long-term, multifactor perspective. By studying the natural and cultural environment under which oak forests developed we may better understand the ecological requirements needed to manage and conserve our existing oak and pine communities.
Animal Health Component
50%
Research Effort Categories
Basic
50%
Applied
50%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
12306991070100%
Knowledge Area
123 - Management and Sustainability of Forest Resources;

Subject Of Investigation
0699 - Trees, forests, and forest products, general;

Field Of Science
1070 - Ecology;
Goals / Objectives
To examine the dendrochronology, community ecology, and historical development of mixed-oak and conifer dominated forests in the mid-Atlantic region. More specifically: 1. Compare and contrast the composition of forests in the eastern U.S. prior to European settlement in the 1700s with present-day forest composition. 2. Conduct a detailed analysis of the age structure and radial-growth dynamics (using tree rings) in a variety of mature and old-growth forests to access long-term stand dynamics and climatic variation in relation to ecological history and global change phenomenon. 3. Determine how the radial growth of individual tree species is being impact by climate change in different regions and sites in the eastern U.S. 4. Evaluate impacts of deer predation on tree regeneration in hardwood and conifer forests in the northeast and mid-Atlantic regions.
Project Methods
Mature and old-growth hardwood and conifer forests in the mid-Atlantic region will be used for dendroecological study. In each forest 60-70 trees across all species and diameter classes will be cored using increment bores. Age determinations for all cores will be made using a dissecting microscope. Cores from the oldest trees will be used to construct a growth chronology of the site spanning 200-400 years. These cores will be dried, mounted and sanded. Annual-growth increments will be measured to the nearest 0.01 mm with a tree-ring measuring device. After cross-dating using signature years, annual increments will be averaged to obtain a mean growth chronology for the one or two dominant tree species. A ring-width index will also be created for each tree chronology by dividing yearly mean measured growth values by the expected values obtained from linear regression (Fritts and Swetnam 1989). Annual growth increments will be measured for additional suitable tree cores for growth comparisons across other species and age classes. All tree cookies and increment cores from selected study areas will be dried, mounted, and sanded with increasingly finer sand paper. The samples will be examined for signature years for cross-dating purposes to help identify missing, partial, or false rings. After proper ages for all samples are verified, they will be examined for fire scars and the season of burning (dormant or growing). Tree rings on the samples will be measured for annual radial growth to the nearest 0.002 mm with the UniSlide "TA" Tree-Ring Measurement System (Velmex Inc.). Crossdating accuracy was verified using the program COFECHA in the International Tree-Ring Data Bank Program Library.

Progress 09/17/13 to 06/30/18

Outputs
Target Audience:Forest managers, natural resource managers, wildfire and prescribed fire managers,global change ecologist, conservation organizations, K-12 educators, educators in higher education Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Graduate and undergraduate students have been trained on the project to work in forest ecology, social sciences, dendrochronology, and Critical Zone science. Graduate students have had the opportunity to present their research to local, regional, national, and international audiences. They have published their research accomplishments in peer reviewed journals and participated in outreach events. M Kaye trained students (undergraduate, graduate), postdocs, professionals, educators in the field of dendrochrolonology as an annual instructor at the North American Dendroecological Fieldweek. How have the results been disseminated to communities of interest?Kaye and Abrams have participated in working groups, outreach events, and public communications to disseminate knowledge of global change impacts on eastern forests. They have been working with managers to identify ecological and societal roadblocks to implementing prescribed fire as a management tool, including focus groups and informational meetings in Pennsylvania and New Jersey with forest fire managers. They have been visiting K-12 schools to share knowledge in forestry, forest ecology, conservation, and natural history. Webinars have been provided, fore example to theNational Phenology Network. Forest ecology information has been shared with the Susquehanna Shale Hills Critical Zone Observatory. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Abrams and Kaye have focused on a broad range of factors affecting eastern deciduous forests. An emerging theme in their research is that the many drivers of forest dynamics such as climate, fire, and human land use, all interact such that no one factor can be considered in isolation. For example, the impacts of climate on eastern deciduous forests are highly mediated by interactions within the forest community. Specifically, the warmer and wetter climate predicted for Pennsylvania will positively affect native tree regeneration, but it will also positively affect other plant types that compete with tree regeneration. Similarly, the long-term radial growth of many dominant tree species is as affected by competition from other trees as much as by climate directly. In both cases, consideration of climate impacts on forests necessitates inclusion of other factors such as competition among species to accurately quantify and project future forest dynamics. In addition to climate, radial tree growth is also strongly affected by topographic position and bedrock. The highest rates of growth in oak-dominated forests of central Pennsylvania can be found on south aspects, within swales, and on shale-derived soils. Additionally, forests growing on shale bedrock compared to sandstone have higher carbon storage and species diversity. This knowledge informs forest conservation and management by identifying locations of the landscape with the highest potential for growth, carbon storage, and biodiversity. Abrams, along with his Ph. D student Greg Nowacki, was responsible for coining the term "mesophycation" that refers to species composition and microenvironmental changes in eastern deciduous forests due to human land use. Mesophyication is a major issue in forest management and this project has highlighted the drivers of that change. Forest managementtools such as prescribed fire can work against mesophycation, favoring more species such as oaks and hickories that have higher economic and ecological values compared tomesophytic species such as red maple. Research for this project has also brought to light the potential for climate and bedrock to affect tree growth, forest composition, and forest nutrient cycling, emphasizing the importance of these factors when making management decisions. Our project included and is relevant to interdisciplinary groups including foresters, geographers, geoscientists, hydrologists, social scientists, andanthropologists. Specific project accomplishments include: Completing a climate change simulation experiment to understand the effects of projected climate change on forest regeneration: Simulated climate change in a regenerating forest ecosystem showed that native tree species responded positively to warmer and wetter conditions, with increased growth and advanced phenology for all tree species regardless of their native latitudinal distribution. Experimental treatments accelerated nutrient cycling in the ecosystem, but caused a decline in soil microbial communities, perhaps from the stress of repeated wetting and drying cycles. This accomplishment relates to Objective 2 above by addressing the impacts of two global change factors, climate change and harvesting, on native forests. Completing a project on the long-term and large-scale impact of climate on growth of dominant forest tree species in the central Appalachians: Radial growth of tree species throughout the central Appalachians over the past two centuries has been driven by temperature, precipitation, and species interactions that are a legacy of forest harvesting over 100 years ago. This accomplishment directly addresses goals 2 and 3 of the project. Continue a long-term study of the impacts of invasive shrubs on native forest dynamics: As part of this initiative a citizen science campaign was started including over 100 volunteers in the eastern US through the National Phenology Network to study the leaf phenology of invasive plant species compared to native. Across the eastern US non-native invasive shrubs leaf out before native shrubs in the spring and maintain their leaves after native shrubs in the autumn. This is called extended leaf phenology and imparts advantage to invasive shrubs through resource acquisition during shoulder seasons that native shrubs rely on the forest understory. Invasive shrub removal benefits native species, including tree regeneration, shrubs, and herbaceous species.

Publications

  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Abrams, M. D. and M. Scheibel. 2013. A five-year record mast production and climate in contrasting mixed-oak-hickory forests on the Mashomack Preserve, Long Island, New York. Natural Areas Journal 33: 99-104.
  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Abrams, M. D. and S. E. Johnson. 2013. The impacts of mast year and prescribed fire on tree regeneration in oak forests at the Mohonk Preserve, eastern New York. Natural Areas Journal 33:427-434.
  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Abrams, M. D. and K. C. Steiner. 2013. Long-term seedling height growth and compositional changes following logging and wildfire in a central Pennsylvania oak forest. Castanea 78(4):256-265.
  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Abrams, M. D. 2013. The impact of mast years on seedling recruitment following canopy thinning and deer fencing in contrasting northeastern U.S. coastal forests. Journal of the Torrey Botanical Society 140: 379390.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Abrams, M. D., K. Umeki, C. Bouma, E. Nabeshima and K. Toyama. 2017. A dendroecological analysis of forest dynamics for old-growth Abies-Quercus-Tsuga on the Boso peninsula, southeastern Japan. Tree Ring Research 73: 5974.
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Averill, K. M., D. A. Mortensen, E. A. H. Smithwick, M. D. Abrams, et al. 2018. A regional assessment and review of native deer browsing impacts on plant invasion. AoB Plants (Annals of Botany) 10: doi.org/10.1093/aobpla/plx047. 23 pages
  • 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: 2013 Citation: Kulakowski, D., Kaye, M. W., & Kashian, D. M. (2013). Long-term aspen cover change in the western US. Forest ecology and management, 299, 52--59.
  • Type: Journal Articles Status: Published Year Published: 2013 Citation: McDaniel, M., Kaye, J., & Kaye, M. (2013). Increased temperature and precipitation had limited effects on soil extracellular enzyme activities in a post-harvest forest. Soil Biology and Biochemistry, 56, 90--98.
  • Type: Journal Articles Status: Published Year Published: 2014 Citation: McDaniel, M., Wagner, R., Rollinson, C., Kimball, B., Kaye, M., & Kaye, J. (2014). Microclimate and ecological threshold responses in a warming and wetting experiment following whole tree harvest. Theoretical and applied climatology, 116(1-2), 287--299.
  • Type: Journal Articles Status: Published Year Published: 2014 Citation: Kaye, M. W. & Wagner, R. J. (2014). Eastern deciduous tree seedlings advance spring phenology in response to experimental warming, but not wetting, treatments. Plant ecology, 215(5), 543--554.
  • Type: Journal Articles Status: Published Year Published: 2014 Citation: McDaniel, M., Kaye, J., & Kaye, M. (2014). Do hot moments become hotter under climate change? Soil nitrogen dynamics from a climate manipulation experiment in a post-harvest forest. Biogeochemistry, 121(2), 339--354.
  • Type: Journal Articles Status: Published Year Published: 2014 Citation: McDaniel, M., Kaye, J., Kaye, M., & Bruns, M. (2014). Climate change interactions affect soil carbon dioxide efflux and microbial functioning in a post-harvest forest. Oecologia, 174(4), 1437--1448.
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Brantley, S., Dibiase, R., Russo, T., Shi, Y., Lin, H., Davis, K., Kaye, M. W., Hill, L., Kaye, J. P., Neal, A., & others (2015). Designing a suite of measurements to understand the critical zone. Earth Surface Dynamics Discussions, 3, 1005--1059.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Smith, L. A., Eissenstat, D., & Kaye, M. W. (2016). Variability in aboveground carbon driven by slope aspect and curvature in an eastern deciduous forest, USA. Canadian Journal of Forest Research, 47(2), 149--158.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Kaye, M. W., & Hone, C. M. (2016). Removal of invasive shrubs alters light but not leaf litter inputs in a deciduous forest understory. Restoration Ecology, 24(5), 617--625.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Rollinson, C. R., Kaye, M. W., & Canham, C. D. (2016). Interspecific variation in growth responses to climate and competition of five eastern tree species. Ecology, 97(4), 1003--1011.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Sanchez-Salguero, Raul, Hevia, A., Camarero, J. J., Treydte, K., Frank, D., Crivellaro, A., Dominguez-Delmas, Marta, Hellman, L., Kaczka, R. J., Kaye, M. W., & others (2017). An intensive tree-ring experience: Connecting education and research during the 25th European Dendroecological Fieldweek (Asturias, Spain). Dendrochronologia, 42, 80--93.
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Heres, Ana-Maria, Kaye, M. W., Granda, E., Benavides, R., Lazaro-Nogal, Ana, Rubio-Casal, A. E., Valladares, F., & Yuste, J. C. (2018). Tree vigour influences secondary growth but not responsiveness to climatic variability in Holm oak. Dendrochronologia, 49, 68--76.
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: D'Orangeville, Loic, Maxwell, J., Kneeshaw, D., Pederson, N., Duchesne, L., Logan, T., Houle, D., Arseneault, D., Beier, C. M., Bishop, D. A., & others (2018). Drought timing and local climate determine the sensitivity of eastern temperate forests to drought. Global change biology.
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Harley, G. L., Baisan, C. H., Brown, P. M., Falk, D. A., Flatley, W. T., Grissino-Mayer, H. D., Hessl, A., Heyerdahl, E. K., Kaye, M. W., Lafon, C. W., & others (2018). Advancing dendrochronological studies of fire in the United States. Fire, 1(1), 11.
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Manning, D.R., Kaye, M.W., Perles, S.J., Mortensen, D.A., (2018). Short-Term Vegetation Responses Following Windthrow Disturbance on Preserved Forest Lands. Forests 9 (5), 278
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Brubaker, K.M, Johnson, Q.K., Kaye, M.W., (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 (9), 1020-1033


Progress 10/01/16 to 09/30/17

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?Graduate and undergraduate students have been trained on the project to work in forest ecology, social sciences, dendrochronology, and Critical Zone science. How have the results been disseminated to communities of interest?Kaye and Abrams have participated in working groups, outreach events, and public communications to disseminate knowledge of global change impacts on eastern forests. Additionally, Kaye has been working with managers to identify ecological and societal roadblocks to implementing prescribed fire as a management tool. What do you plan to do during the next reporting period to accomplish the goals?We will continue working on projects that identify dominant impacts on eastern forests, such land-use history, climate, fire, introduced pests and pathogens, and geology. Graduate and undergraduate students will continue to be trained through this project, and results will be shared through journal publications, outreach to stakeholders, and participation on working groups.

Impacts
What was accomplished under these goals? Abrams and Kaye have lead research programs that contribute to the conservation and management of eastern forests. Specific research projects include the effect of climate, human land-use, and geology on forest growth and composition. They have worked with interdisciplinary groups including geographers, geoscientists, hydrologists, social scientists, and anthropologists. The main research conducted by Abrams and Kaye over the last year has dealt with global change impacts on forests in the US, Europe and Asia. Global change, including climate change and land-use, has impacted nearly all aspects of life (ecological, economic, and social). Their research activities have included global change impacts at high altitudes and latitudes and remote locations where subtle changes in temperature are greatly magnified. This research as elucidated that climate change (including 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 anthropogenic disturbances that have also impacted vegetation immediately preceding and concurrent with recent climate change (past ≈100 yrs) have been studied. To gain a sense of relative importance among the principal change factors, research by Abrams and Kaye quantified tree ecophysiological attributes coupled with changes in species composition and dominance to serve as a unifying template for interpretation of global change impacts. In addition, they have looked at the effects of forest canopy windthrow on invasive plant species and found that land preserved may buffer the effects of invasive species in the years immediately following the disturbance. They have studied forest productivity and found large variability across topography, with the highest productivity in mixed oak stands occurring in swales of south-facing slopes. Furthermore, forest productivity is consistently higher on shale-derived sites than those on sandstone. This spatial variability in forest productivity rivals the effect of climate, and should therefore be considered when quantifying regional carbon budgets. They worked in a collaborative group with sociologists and geographers to identify potential barriers for managers to use prescribed fire in the mid-Atlantic. Big accelerations of learning and scientific advances often take place when science of one field is merged with another. The type of interdisciplinary research by Abrams and Kaye involves the integration of different tools, skill sets, knowledge, and problem solving approaches from complementary disciplines to explore new areas of science.

Publications

  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Bouma, C. L. and M. D. Abrams. 2017. Differential impacts of climate on tree rings across a topographic gradient. British Journal of Environment and Climate Change 7: 92-112.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Iavorivska L, EW Boyer, JW Grimm, MP Miller, DR DeWalle, KJ Davis, 2017. Variability of dissolved organic carbon in precipitation during storms at the Shale Hills Critical Zone Observatory. Hydrological Processes, available online DOI: 10.1002/hyp.11235.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Johnson, S. E and M. D. Abrams. 2017. The impact of Native American activity on vegetation and soil charcoal in the eastern U.S. Global Journal of Archaeology & Anthropology 1: 24-40.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Smith, LA, DM Eissenstat, and MW Kaye, 2017. Variability in aboveground carbon driven by slope aspect and curvature in an eastern deciduous forest, USA. Canadian Journal of Forest Research 47: 149158.


Progress 10/01/15 to 09/30/16

Outputs
Target Audience:Natural resources professionals and managers, and academic scientists 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 are major factors influencing tree growth, while climate variability plays a secondary role. Environmental scientists need to understand the natural range of variation in climate and its role in present and future changes, not only anthropogenic forcing. We must recognize that past land-use history has and will continue to play a very important role in the structure and function of forests, and the impacts of anthropogenic climate change remain unknown. How have the results been disseminated to communities of interest?Yes to scientific audience and land managers via publication and talks at professional meetings and seminars. What do you plan to do during the next reporting period to accomplish the goals?Continue with the objectives and goals of the project

Impacts
What was accomplished under these goals? European disturbance overrode 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 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 will remain in climate disequilibrium into the foreseeable future. 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. When fire is suppressed in oak forests during the 20th century, they are rapidly invaded by later successional, fire sensitive species, such as maple (Acer), beech (Fagus), birch (Betula), and black gum (Nyssa). These species are now replacing oak and becoming dominant trees. The suppression of fire and the successional replacement of oak forests is a cause and effect relationship. Our studies specifically address the fire and oak hypothesis, long-term burning studies in oak forests, and the direct dating of fire scars in old-growth oak forests to resolve some of the remaining issues about the ecological role of fire in the development of oak forests. Moreover, fire is not the only factor that has influenced the ecology of oak forests during the 20th century. The impacts of acid rain, elevated CO2, potential global warming, herbivory, and gypsy moth outbreaks were studied in relation to the decline in oak recruitment and increase in later successional tree species in eastern oak forest. Throughout the eastern U.S., interactions and feedback among climate, vegetation, soils and topography, large- and small- scale disturbances, anthropogenic factors, and wildlife impacts created an ecological dynamic for oak forests that can only be understood from a long-term, multifactor perspective. In relation to global change, most trees studied in the eastern U.S. are exhibiting increase growth (in terms of basal area increment) over the last 50 years. Post-European forest dynamics appear to be more related to changes in disturbance regime than climate change.

Publications

  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Abrams, M. D. and G. J. Nowacki. 2016. An interdisciplinary approach to better assess global change impacts and drought vulnerability on forest dynamics. Tree Physiology 36: 421-427; doi:10.1093/treephys/tpw005.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Abrams, M.D. 2016. Sowing the seeds of fire and oak in the eastern US: a tribute to Buell et al. 1954. Fire Ecology 12: 7?12. doi: 0.4996/fireecology.1202007.
  • Type: Book Chapters Status: Published Year Published: 2016 Citation: Abrams, M. D. 2016. The history of fire in eastern oak forests. In: Managing Oak Forests in the Eastern United States; editors P. D. Keyser, T. Fearer, T. C. A. Harper. CRC Press, New York, pages 7-17.


Progress 10/01/14 to 09/30/15

Outputs
Target Audience:global ecologists and forest managers 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 are major factors influencing tree growth, while climate variability plays a secondary role. Environmental scientists need to understand the natural range of variation in climate and its role in present and future changes, not only anthropogenic forcing. We must recognize that past land-use history has and will continue to play a very important role in the structure and function of forests, and the impacts of anthropogenic climate change remain unknown. How have the results been disseminated to communities of interest?To scientific audience and land managers via publication and talks at professional meetings and seminars What do you plan to do during the next reporting period to accomplish the goals?Continue with the objectives and goals of the project

Impacts
What was accomplished under these goals? European disturbance overrode 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 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 will remain in climate disequilibriu into the foreseeable future. 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. When fire is suppressed in oak forests during the 20th century, they are rapidly invaded by later successional, fire sensitive species, such as maple (Acer), beech (Fagus), birch (Betula), and black gum (Nyssa). These species are now replacing oak and becoming dominant trees. The suppression of fire and the successional replacement of oak forests is a cause and effect relationship. Our studies specifically address the fire and oak hypothesis, long-term burning studies in oak forests, and the direct dating of fire scars in old-growth oak forests to resolve some of the remaining issues about the ecological role of fire in the development of oak forests. Moreover, fire is not the only factor that has influenced the ecology of oak forests during the 20th century. The impacts of acid rain, elevated CO2, potential global warming, herbivory, and gypsy moth outbreaks were studied in relation to the decline in oak recruitment and increase in later successional tree species in eastern oak forest. Throughout the eastern U.S., interactions and feedback among climate, vegetation, soils and topography, large- and small- scale disturbances, anthropogenic factors, and wildlife impacts created an ecological dynamic for oak forests that can only be understood from a long-term, multifactor perspective. In relation to global change, most trees studied in the eastern U.S. are exhibiting increase growth (in terms of basal area increment) over the last 50 years. Post-European forest dynamics appear to be more related to changes in disturbance regime than climate change.

Publications

  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Nowacki, G. J. and M. D. Abrams. 2015. Is climate an important driver of post European vegetation change in the eastern U.S.? Global Change Biology 21: 314334, doi: 10.1111/gcb.12663
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Abrams, M. D. and G. J. Nowacki 2015. Large-scale catastrophic disturbance regimes can mask climate change impacts on vegetation. Global Change Biology doi: 10.1111/gcb.12828.
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Abrams, M. D. and G. J. Nowacki. 2015. Exploring the Early Anthropocene burning hypothesis and climate-fire anomalies for the eastern U.S. Journal of Sustainable Forestry34:3048.
  • Type: Journal Articles Status: Published Year Published: 2014 Citation: Rollinson, C.R. and M.W. Kaye, 2014. Modeling Temperature in Mountainous Ecoregions: Importance of Spatial Scale for Ecological Research. Climate research 64: 99-110.


Progress 10/01/13 to 09/30/14

Outputs
Target Audience: Global ecologists and forest mangers 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 are major factors influencing tree growth, while climate variability plays a secondary role. Environmental scientists need to understand the natural range of variation in climate and its role in present and future changes, not only anthropogenic forcing. We must recognize that past land-use history has and will continue to play a very important role in the structure and function of forests, and the impacts of anthropogenic climate change remain unknown. How have the results been disseminated to communities of interest? yes to scientific audience and land managers What do you plan to do during the next reporting period to accomplish the goals? continue with the objectives and goals of the project

Impacts
What was accomplished under these goals? When fire is suppressed in oak forests during the 20th century, they are rapidly invaded by later successional, fire sensitive species, such as maple (Acer), beech (Fagus), birch (Betula), and black gum (Nyssa). These species are now replacing oak and becoming dominant trees. The suppression of fire and the successional replacement of oak forests is a cause and effect relationship. Our studies specifically address the fire and oak hypothesis, long-term burning studies in oak forests, and the direct dating of fire scars in old-growth oak forests to resolve some of the remaining issues about the ecological role of fire in the development of oak forests. Moreover, fire is not the only factor that has influenced the ecology of oak forests during the 20th century. The impacts of acid rain, elevated CO2, potential global warming, herbivory, and gypsy moth outbreaks were studied in relation to the decline in oak recruitment and increase in later successional tree species in eastern oak forest. Throughout the eastern U.S., interactions and feedback among climate, vegetation, soils and topography, large- and small-scale disturbances, anthropogenic factors, and wildlife impacts created an ecological dynamic for oak forests that can only be understood from a long-term, multifactor perspective. In relation to global change, most trees studied in the eastern U.S. are exhibiting increase growth (in terms of basal area increment) over the last 50 years. Post-European forest dynamics appear to be more related to changes in disturbance regime than climate change.

Publications

  • Type: Journal Articles Status: Published Year Published: 2014 Citation: Abrams, MD and SE Johnson. 2014. Wildfire damage assessment of a young oak forest in Pennsylvania. Journal of Applied Fire Sciences 23: 91-104.
  • Type: Journal Articles Status: Published Year Published: 2014 Citation: Abrams, MD. and SE Johnson. 2014. Impacts of contrasting land-use history on forests and soils at Scotia Barrens, central Pennsylvania: Implications for altered and arrested vegetation development. Human Ecology 42:793799.
  • Type: Journal Articles Status: Published Year Published: 2014 Citation: Kaye, MW and RJ Wagner, 2014. Eastern deciduous tree seedlings advance spring phenology in response to experimental warming, but not wetting, treatments. Plant Ecology 215: 543-554.
  • Type: Journal Articles Status: Published Year Published: 2014 Citation: McDaniel, MD, JP Kaye, MW Kaye, and MA Bruns, 2014. Climate change interactions affect soil CO2 efflux and microbial functioning in a post-harvest forest. Oecologia 174:1437-1448.
  • Type: Journal Articles Status: Published Year Published: 2014 Citation: Nowacki, GJ and MD Abrams. 2014. Is climate an important driver of post European vegetation change in the eastern U.S.? Global Change Biology DOI 10. 1111/gcb.12663; 21 pages.
  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Silver, EJ, JH Speer, MW Kaye, NJ Reo, SW Wood, LF Howard, AK Anning, and HW Wilbur, 2013. Fire history and age structure of an oak-pine forest on Price Mountain, Virginia. Natural Areas Journal 33:440-446.


Progress 09/17/13 to 09/30/13

Outputs
Target Audience: Nothing Reported Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Nothing was accomplished so far as the project just started two weeks prior to the report due date.

Publications