Projects

This is a collaborative project with Jim Speer, Margot Kaye, Grant Harley, Chris Gentry, and Bryan Black. I serve as co-organizer and instructor for NADEF.

Summary: The North American Dendroecological Fieldweek (NADEF), is an annual ten-day field-based activity that teaches the tools of dendrochronology, provides networking opportunities for students and professionals, and expands the benefits of dendrochronological records to forest managers. Support for NADEF will catalyze new activities focusing on understanding the mechanisms behind the increases in global forest mortality, which has become more widespread than has been documented in preceding centuries. Understanding the mechanisms behind this forest mortality is critical for the development of intelligent, timely, and science-driven management responses to these mortality events. The field weeks will provide professional development for approximately 120 participants over a three-year period while educating participants about management information needed to sustain these forests. The field week will continue its strong record for broadening gender and ethnic diversity among scholars in dendrochronology. Opportunities for undergraduate scholarships will be provided to students from underrepresented groups, and graduate research fellowships will help educate and train students in professional presentation of the findings from the field weeks.

NADEF has a 25-year history of bringing together a diverse group of scholars to learn cutting-edge dendrochronology science for the continuous improvement of research in the forestry sciences and the better management of forest resources. For this series of field weeks, participants will engage in five research projects that will focus on completing a fire history, insect-outbreak reconstructions, climate reconstructions, analyses of stand-age structure across an elevational gradient, and sclerochronology, which is the examination of annual rings in bony structures such as those found in clams and the ear bones of fish. Field week researchers will use innovative research techniques to examine quantitative wood anatomy (the examination of individual cells of growth in the tree rings) along with stable isotopes to tease apart relationships among climate, fire, and insect outbreaks on forest mortality. These research activities help participants to better understand the direction that these forests are naturally trending so that future conditions for these forests can be predicted more accurately and more effective forest management strategies can be implemented. Beyond these learning experiences, the field weeks provide networking opportunities for students and professionals and expand the benefits of dendrochronological records to forest managers.

Publications:

Rinaldi, B., Maxwell, R.S., Callahan, T., Brice, R., and Heeter, K. 2021. Climate and ecological disturbance analysis of Engelmann spruce and Douglas fir in the Greater Yellowstone Ecosystem. Trees, Forests, and People 3: 100053. https://doi.org/10.1016/j.tfp.2020.100053

Abstract: Tree‐ring reconstructions of streamflow are uncommon in the eastern United States compared with the western United States. Although the east has not experienced severe drought on the scale of the west over the last 100 years, multiyear droughts have stressed the water management systems throughout the east. Here, we reconstruct mean May–September streamflow of three rivers serving population centers in the northeast (Beaver Kill River serving New York, NY), mid‐Atlantic (Potomac River serving Washington, DC), and southeast (Flint River serving Atlanta, GA) to demonstrate the efficacy of reconstructing streamflow in the eastern United States. Then, we conducted an interbasin comparison to identify periods of common variability and examined the influence of the North Atlantic subtropical high on reconstructed streamflow. Our models explained 40–61% of the variance in the instrumental record and passed verification tests in all basins during the period 1675–2000 CE. Droughts and pluvials showed some synchrony across all basins, but the mid‐Atlantic region acted as a hinge, sometimes behaving more like the northeast, and other times like the southeast. Climatic analyses suggest a relationship exists between the North Atlantic subtropical high and reconstructed streamflow that influences the probability of drought and pluvial events. Given the many factors influencing tree growth in closed‐canopy systems, we have shown that careful standardization of individual tree‐ring series, nested regression models, and the use of multiple species can produce robust proxies of streamflow across the eastern seaboard.

Update: In collaboration with Dr. Grant Harley (University of and Dr. Justin Maxwell (Indiana University), we are beginning to build a network of temperature sensitive tree-ring chronologies using the proxy blue light intensity. For more details, see the publication below. We continue to build our a network of streamflow and hydroclimate reconstructions using our growing set of old-growth chronologies. Additionally, I am working with PhD candidate Laura Smith (University of Tennessee) to build streamflow and precipitation reconstructions for the Tennessee Valley Authority.

Publications:

Harley, G.L., Heeter, K.J., Maxwell, J.T., Rayback, S.A., Maxwell, R.S., Reinemann, T.E.P., and Taylor, A.H. 2020. Towards broad-scale, long-term temperature reconstructions for Eastern North America. International Journal of Climatology. https://doi.org/10.1002/joc.6910

Maxwell, R.S., Harley, G.L., Maxwell, J.T., Rayback, S.A., Pederson, N., Cook, E.R., Barclay, D.J., and Li, W. 2017. An interbasin comparison of tree-ring reconstructed streamflow in the eastern United States. Hydrological Processes 31: 2381-2394. https://doi.org/10.1002/hyp.11188

Data Sets:

Maxwell, R.S., Harley, G.L., Maxwell, J.T., Rayback, S.A., Pederson, N., Cook, E.R., Barclay, D.J., and Li, W. 2019. Streamflow reconstructions for the Beaverkill River, Potomac River, and Flint River. https://www.ncdc.noaa.gov/paleo/study/27370.

This is a collaborative project with colleagues at Penn State (Soumaya Belmecheri, Alan Taylor, and Ken Davis). Soumaya and I birthed this project as postdocs and it has become an exciting new adventure. There's one publication in review and more on the way.

Summary: Terrestrial ecosystems are a key component of the global carbon cycle and a better understanding of their role in carbon cycle dynamics is needed to project the future carbon cycle. Current ecosystem carbon cycle models give highly variable projections for the response of the terrestrial carbon cycle to changing climate. Constraining ecosystem carbon-budget projections is an important issue given the interest in managing forests to increase the strength of the carbon sink to mitigate anthropogenic carbon emissions. Spatially explicit data on forest ecosystem productivity and net carbon exchange between the forest and atmosphere that span multi-decadal to centennial time periods, are needed to constrain model parameters and to evaluate model performance. But, such records are sparse. Current observational and remotely sensed data are limited to the last few decades, and tree-ring width records have shown relatively poor correlation with contemporary net carbon flux measurements. In this research project, the investigators postulate that carbon isotopes in tree-rings represent a proxy of forest ecosystem productivity and net carbon exchange between forests and the atmosphere. This hypothesis is based on carbon isotope theory and carbon isotope measurements from tree rings located in the footprint of an eddy covariance carbon dioxide flux tower. This project will test two related hypotheses. The first is that carbon isotopes in tree rings provide a good estimate of forest productivity and net ecosystem carbon exchange. This will be determined by comparing isotope measurements from trees with measurements from nearby long-running eddy-covariance flux towers. The second hypothesis will investigate whether the temporal variability of the carbon isotope record in the tree ring records representing forest productivity and ecosystem exchange are coherent between two flux towers separated by several hundred kilometers. This will be determined by sampling tree rings at nine sites between two flux towers and analyzing the spatial coherence of the tree-ring isotope record and several other climate and forest productivity variables across the sites. If the hypotheses are supported, a network of ecosystem-specific records of forest ecosystem productivity and net carbon exchange could be established to parameterize the next generation of earth system and carbon cycle models. The science education impact of this project will extend beyond the university by developing learning modules for use in secondary schools that service underrepresented groups using an established NSF GK-12 project at Penn State.

This project will determine if carbon isotopes in tree rings record the exchange of carbon dioxide between forests and the atmosphere. Contemporary forest-atmosphere exchange measurements are only available for approximately twenty years, making it difficult to test models used to project the carbon budget of forests and other ecosystems into the future and to determine their likely contribution to future climate change. This project will demonstrate the potential of using carbon isotopes in tree rings to estimate forest productivity and net carbon storage by forests over time periods of a century or more at local to regional scales. More accurate estimates of regional century-scale forest productivity and net carbon storage will inform climate and carbon management-related policy decisions regarding carbon sequestration efforts to mitigate anthropogenic carbon emissions.

Publications:

Belmecheri, S., Maxwell, R.S., Taylor, A.H., Davis, K.J., Guerieri, R., Moore, D.J., and Rayback, S.A. 2021. Precipitation alters the CO2 effect on water-use efficiency of temperate forests. Global Change Biology. https://doi.org/10.1111/gcb.15491

Maxwell, R.S., Belmecheri, S., Taylor, A.H., Davis, K.J., and Ocheltree, T.W. 2020. Carbon isotope ratios in tree rings respond differently to climatic variations than tree-ring width in a mesic temperate forest. Agricultural and Forest Meteorology 288-289: 108014. https://doi.org/10.1016/j.agrformet.2020.108014

Belmecheri, S., Maxwell, R.S., Taylor, A.H., Davis, K.J., Freeman, K.H., and Munger, W.J. 2014. Tree­ring δ13C as a proxy of gross primary productivity in a North American forest. Environmental Research Letters 9, 074011. https://doi.org/10.1088/1748-9326/9/7/074011

Data Sets:

Maxwell, R.S., Belmecheri, S., and Taylor, A.H. 2020. Carbon isotope ratios in tree rings respond differently to climatic variations than tree-ring width in a mesic temperate forest. Agricultural and Forest Meteorology 288-289: 108014.

https://www.ncdc.noaa.gov/paleo-search/study/32279 https://www.ncdc.noaa.gov/paleo-search/study/32272

https://www.ncdc.noaa.gov/paleo-search/study/32274 https://www.ncdc.noaa.gov/paleo-search/study/32275

https://www.ncdc.noaa.gov/paleo-search/study/32273 https://www.ncdc.noaa.gov/paleo-search/study/32276

https://www.ncdc.noaa.gov/paleo-search/study/32277 https://www.ncdc.noaa.gov/paleo-search/study/32278

https://www.ncdc.noaa.gov/paleo-search/study/32280 https://www.ncdc.noaa.gov/paleo-search/study/32281

Tom Saladyga (Concord University) and I have been working on a host of dendrochronology projects for many years in Central Appalachia. We have studies investigating the growth response to disturbance and climate analysis in old-growth forests, collaborations with the National Park Service, and worked on fire history as well.

Publications:

Saladyga, T. and Maxwell, R.S. 2021. A multi-century fire history from the Potomac Highlands of West Virginia. Southeastern Geographer 61: 258-278. https://doi.org/10.1353/sgo.2021.0019

Saladyga, T. and Maxwell, R.S., and Perles, S.J. 2020. Landscape-scale tree growth dynamics at three southern West Virginia national parks. Natural Resource Report NPS/ERMN/NRR—2020/2123. National Park Service. Fort Collins, CO. https://irma.nps.gov/Datastore/DownloadFile/641815.

Saladyga, T. and Maxwell, R.S. 2015. Temporal variability in climate response of eastern hemlock in the central Appalachian region. Southeastern Geographer 55: 145­-165.

Data Sets:

Saladyga, T. and Maxwell, R.S. 2012. Pipestem Resort State Park – Tsuga canadensis Tree-Ring Chronology - ITRDB WV006. https://www.ncdc.noaa.gov/paleo/study/16829.

I worked on this project as a postdoctoral scholar at Penn State University with Alan Taylor. Alan and I collaborated with Carl Skinner and Hugh Safford of the US Forest Service. The project culminated in a half-day workshop with at the Lake Tahoe Basin Management Unit headquarters where I presented to forest managers and other stakeholders. The project resulted in two manuscripts with two more in the works.

Abstract: Forest conditions prior to extensive land clearing are often used as a point-of-reference by ecologists and resource managers for characterizing the historical range of variability in forest conditions shaped by intact disturbance regimes. Quantitative data on forest reference conditions can be developed from forest surveys and reconstructions using dendroecology; however, these methods lack the spatial resolution needed for landscape management. In this paper, we combine predictive vegetation mapping methods with reference forest conditions inferred from early forest surveys, dendroecology, and fire simulation models to develop landscape scale reference conditions for forest structure, forest fuels, fire frequency, and fire behavior using the Lake Tahoe Basin, California as an example.

The dendroecological reconstruction method used for the Lake Tahoe Basin forests was not sensitive to variation in decomposition rates suggesting that our method provided robust estimates of reference period forest characteristics. The cluster analysis procedure identified five forest structure types (White Fir, Jeffrey Pine, Red Fir, Lodgepole Pine, and Subalpine) and 15 subtypes. Each forest type had a characteristic composition, density, and basal area. Our random forests approach to classifying and mapping the spatial distribution of the five dominant reference forest structure types resulted in 51.5% classification accuracy using 14 physiographic and climatic variables. The random forests model to identify subtypes within each forest group had an average percent correct classification of 47.8%. The random forests model for fire intervals explained 67% of the variance in the point fire return interval estimates from fire-scarred trees. Estimates of reference period fuels modeled from stand structure suggested moderate fuel loads for reference forests. The predicted potential fire type for forest subtypes under extreme weather was surface fire except for Red Fir and the Lodgepole Pine subtypes with potential for crown fire. By characterizing the reference forest composition, structure, and disturbance frequency with a range of variability, managers can develop a forested landscape more resilient to changes in disturbance regime and climate. Although our approach was developed for the Lake Tahoe Basin, California, it could be applied to a wide range of forest landscapes to identify forest reference conditions.

Publications:

Maxwell, R.S., Taylor, A.H., Skinner, C.N., Safford, H.S., Isaacs, R., Airey, C., and Young, A. 2014. Landscape scale modeling of reference period forest structure and fire behavior conditions on heavily­logged lands. Ecosphere 5:art32. https://doi.org/10.1890/ES13-00294.1

Taylor, A.H., Vandervlugt, A.M., Maxwell, R.S., Beaty, R.M., Airey, C., and Skinner, C.N. 2014. Changes in forest structure, fuels and potential fire behavior since 1873 in the Lake Tahoe Basin, USA. Applied Vegetation Science: 17: 17­31. https://doi.org/10.1111/avsc.12049

Maxwell, R.S., Taylor, A.H., Skinner, C.N., and Safford, H.S. 2012. Identifying spatially explicit reference conditions for forest landscapes in the Lake Tahoe Basin, USA. Project Report. US Forest Service. South Lake Tahoe, CA. https://www.fs.fed.us/psw/partnerships/tahoescience/documents/p020_FinalReportTaylor2012.pdf

Ah, the dissertation. The all consuming dissertation. Here's the climate reconstruction component but this project has a host of ecological implications including finding the oldest living eastern redcedar at 725+ years and still going. Results were presented at conferences and at the Interstate Commission on the Potomac River Basin. Data are available at the TreeFlow website that host tree-ring reconstructions of streamflow data. I'm still working on streamflow work for the eastern US. Hopefully, more to come in the next year.

Abstract: Mean May–September Potomac River streamflow was reconstructed from 950–2001 using a network of tree ring chronologies (n ¼ 27) representing multiple species. We chose a nested principal components reconstruction method to maximize use of available chronologies backward in time. Explained variance during the period of calibration ranged from 20% to 53% depending on the number and species of chronologies available in each 25 year time step. The model was verified by two goodness of fit tests, the coefficient of efficiency (CE) and the reduction of error statistic (RE). The RE and CE never fell below zero, suggesting the model had explanatory power over the entire period of reconstruction. Beta weights indicated a loss of explained variance during the 1550–1700 period that we hypothesize was caused by the reduction in total number of predictor chronologies and loss of important predictor species. Thus, the reconstruction is strongest from 1700–2001. Frequency, intensity, and duration of drought and pluvial events were examined to aid water resource managers. We found that the instrumental period did not represent adequately the full range of annual to multidecadal variability present in the reconstruction. Our reconstruction of mean May–September Potomac River streamflow was a significant improvement over the Cook and Jacoby (1983) reconstruction because it expanded the seasonal window, lengthened the record by 780 years, and better replicated the mean and variance of the instrumental record. By capitalizing on variable phenologies and tree growth responses to climate, multispecies reconstructions may provide significantly more information about past hydroclimate, especially in regions with low aridity and high tree species diversity.

Abstract: This paper presents a multicentury reconstruction of May precipitation (1200–1997) for the mid-Atlantic region of the United States. The reconstruction is based on the first principal component (PC1) of two millennial-length Juniperus virginiana L. (eastern red cedar) tree-ring chronologies collected from rocky, limestone sites in the Ridge and Valley province of West Virginia.A split-calibration linear regression model accounted for 27% of the adjusted variance in the instrumental record and was stable through time. The model was verified by the reduction of error (RE 5 0.21) and coefficient of efficiency (CE 50.20) statistics. Multidecadal changes in precipitation were common throughout the reconstruction, and wetter than median conditions and drier than median conditions occurred during the medieval climate anomaly (1200–1300) and the Little Ice Age (1550–1650), respectively. The full reconstruction contained evidence of interannual and decadal variability; however, the twentieth century recorded the greatest number of decadal extreme wet and dry periods. A comparison of the May precipitation reconstruction to other regional reconstructions [Potomac River,Maryland, streamflow(Cook and Jacoby); Virginia/NorthCarolina July Palmer hydrologic drought index (PHDI; Stahle et al.);Missouri July PHDI (Cleaveland and Stahle); and White River, Arkansas, streamflow (Cleaveland)] showed that the eastern U.S. decadal drought and pluvial events extended into the mid-Atlantic region. A positive correlation between PC1 and the winter North Atlantic Oscillation (NAO) index and comparisons of smoothed May precipitation and the NAO (Luterbacher et al.) indicated that J. virginiana’s response to May precipitation was mediated by winter temperature.

Publications:

Maxwell, R.S., Hessl, A.E., Cook, E.R., and Buckley, B.M. 2012. A multicentury reconstruction of May precipitation for the Mid­Atlantic Region using Juniperus virginiana tree rings. Journal of Climate 25(3): 1045­1056. https://doi.org/10.1175/JCLI-D-11-00017.1

Maxwell, R.S., Wixom, J.A., and Hessl, A.E. 2011. A comparison of two techniques for measuring and crossdating tree rings. Dendrochronologia 29: 237­243. https://doi.org/10.1016/j.dendro.2010.12.002

Maxwell, R.S., Hessl, A.E., Cook, E.R., and Pederson, N. 2011. A multi­species tree­ring reconstruction of Potomac River streamflow (950­2001). Water Resources Research 47: W05512. https://doi.org/10.1029/2010WR010019

Data Sets:

Maxwell, R.S., Hessl, A.E., Cook, E.R., and Buckley, B.M. 2012. US Mid-Atlantic Region 800 Year May Precipitation Reconstruction. https://www.ncdc.noaa.gov/paleo/study/12425.

Maxwell, R.S., Hessl, A.E., Cook, E.R., and Pederson, N. 2011. Potomac River 1000 Year May-September Streamflow Reconstruction. https://www.ncdc.noaa.gov/paleo/study/12424.

Maxwell, R.S., Hessl, A.E., Cook, E.R., and Buckley, B.M. 2019. Smokehole Canyon – Juniperus virginiana Tree-Ring Chronology – ITRDB WV014. https://www.ncdc.noaa.gov/paleo-search/study/27619.

For this project, I collected some of the pilot data as a graduate student (funded by the American Center for Mongolian Studies) leading up to the NSF proposal by my PhD adviser Amy Hessl. Hope to do more in Mongolia in time.

Abstract: Rising temperatures are expected to increase wildfire activity in many regions of the world. Over the last 60 years in Mongolia, mean annual temperatures have increased ,28C and the recorded frequency and spatial extent of forest and steppe fires have increased. Few long records of fire history exist to place these recent changes in a historical perspective. The purpose of this paper is to report on fire history research from three sites in central Mongolia and to highlight the potential of this region as a test case for understanding the relationships between climate change, fire and land use. We collected partial cross-sections from fire-scarred trees and stumps at each site using a targeted sampling approach. All three sites had long histories of fire ranging from 280 to 450 years. Mean Weibull fire return intervals varied from 7 to 16 years. Fire scars at one protected-area site were nearly absent after 1760, likely owing to changes in land use. There is limited synchrony in fire occurrence across sites, suggesting that fire occurrence, at least at annual time scales, might be influenced by local processes (grazing, human ignitions, other land-use factors) as well as regional processes like climate. Additional data are being collected to further test hypotheses regarding climate change, land use and fire.

Publications:

Hessl, A.E., Ariya, U., Brown, P., Byambasuren, O., Green, T. Jacoby, G., Sutherland, E., Nachin, B., Maxwell, R.S., Pederson, N., De Grandpre, L., Saladyga, T., and Tardif, J.C. 2012. Reconstructing fire history in central Mongolia from tree rings. International Journal of Wildland Fire 21(1): 86­92. https://doi.org/10.1071/WF10108

Data Sets:

Hessl, A.E., Ariya, U., Brown, P.M., Byambasuren, O., Green, T., Jacoby, G.C., Sutherland, E.K., Nachin, B., Maxwell, R.S., Pedersen, N., De Grandpre, L., Saladyga, T., Tardif, J.C., Oyunbilig, E., Ser-Od, B., and Biligbaatar, B. 2012. Bogd Mountain Fire History Chronology - IMPD MNBOG001. https://www.ncdc.noaa.gov/paleo/study/22488.

Hessl, A.E., Ariya, U., Brown, P.M., Byambasuren, O., Green, T., Jacoby, G.C., Sutherland, E.K., Nachin, B., Maxwell, R.S., Pedersen, N., De Grandpre, L., Saladyga, T., Tardif, J.C., Oyunbilig, E., Ser-Od, B., and Biligbaatar, B. 2012. Forest Research Center Fire History Chronology - IMPD MNFRC001. https://www.ncdc.noaa.gov/paleo/study/22491.

Hessl, A.E., Ariya, U., Brown, P.M., Byambasuren, O., Green, T., Jacoby, G.C., Sutherland, E.K., Nachin, B., Maxwell, R.S., Pedersen, N., De Grandpre, L., Saladyga, T., Tardif, J.C., Oyunbilig, E., Ser-Od, B., and Biligbaatar, B. 2012. Tujin Nars Fire History Chronology- IMPD MNTUN001. https://www.ncdc.noaa.gov/paleo/study/22493.

This is how a became a master....of forest ecology. Of course, I had help from my advisor, Ray Hicks. Ray is now emeritus at West Virginia University but a walk in the wood with him was an education.

Summary: In 2003, the National Park Service (NPS) at New River Gorge National River (NERI) hosted a workshop to identify significant forest issues, resources, and processes occurring within the park (National Park Service 2003b). Several forest communities of concern were identified by the panel of scientists and resource managers. One such community, the rimrock pine forest lining the rim of the gorge, was chosen due to the importance of the community to wildlife and recreation. The rimrock pines also were thought to be a historically significant feature of the northern section of the gorge as evidenced by historic photographs from the 1940s and 1950s. The panel suggested an investigation be conducted to better understand the establishment and maintenance of the rimrock pine forest.

The workshop was followed by the Natural Resource Assessment for New River Gorge National River (Mahan 2004). In this report, Mahan provided information on the current status and significance of, threats to, and gaps in knowledge about the natural resources at NERI. The rimrock pine community was identified again as a valued resource that may be in decline due to lack of disturbance. Vanderhorst (2001) reported that plant communities including the rimrock pines, old fields, seeps, and herbaceous wetlands occupy approximately 1% of the land area at NERI. Despite the small area forested by rimrock communities they have been deemed valuable by the NPS and warrant further research.

The Natural Resource Assessment has served as a primer for the development of a new General Management Plan (GMP) for the park. Suggested management recommendations for the rimrock pine community include forest health monitoring, dendro-chronological analysis, and forest restoration through the use of prescribed burning. The GMP is presently under revision; however, management of niche communities may require research before implementation of management and restoration activities. Thus, both qualitative and quantitative descriptions of the rimrock are crucial to the preservation of this resource for the use of wildlife and the enjoyment of future generations of park visitors.

The study was designed to meet the following research objectives of the NPS:

Objective 1. An inventory and description of all strata of vegetation was conducted to evaluate the current stand condition including species composition, stand structure, vigor, and potential for regeneration. Understanding the current condition of the rimrock community is necessary to establish whether or not the ecosystem is in the desired state which will affect future management decisions regarding these valued habitat and recreation areas.

Objective 2. A dendroecological analysis of Virginia pine, as well as other dominant species present in the rimrock community, was used to determine the age structure, growth trends, and disturbance regime (i.e., fire history) of the forest. This investigation required the collection of increment cores from live canopy trees and cross sections from fire-scarred Virginia pines.

Objective 3. An array of historic evidence was collected and reviewed to aid in the interpretation of the current condition of the rimrock forest and to determine the historic range of the Virginia pine forest type. Materials such as past land use records, mining activities, and historic maps andvphotographs were essential in the development of a clearer understanding of the establishment and maintenance of the rimrock community.

Publications:

Maxwell, R.S. and Hicks, R.R. 2010. Fire history of a rimrock pine community at New River Gorge National River, West Virginia. Natural Areas Journal 30(3): 305­311. https://doi.org/10.3375/043.030.0311

Maxwell, R.S. and Hicks, R.R. 2007. Rimrock pine communities at New River Gorge National River, West Virginia. Technical Report NPS/NER/NRTR—2007/081. National Park Service, Department of the Interior. Philadelphia, PA. https://irma.nps.gov/DataStore/DownloadFile/152647

Data Sets:

Maxwell, R.S. and Hicks, R.R. 2007. New River Gorge National River Fire History Chronology - IMPD USNRG001. https://www.ncdc.noaa.gov/paleo/study/8472.

Maxwell, R.S. and Hicks, R.R. 2007. New River Gorge National River – Pinus virginiana Tree-Ring Chronology - ITRDB WV004. https://www.ncdc.noaa.gov/paleo/study/8530.