Scholarly Works, Forest Resources and Environmental Conservation

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Research articles, presentations, and other scholarship

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Synthesizing data products, mathematical models, and observational measurements for lake temperature forecasting
Holthuijzen, Maike; Gramacy, Robert; Carey, Cayelan; Higdon, Dave; Thomas, R. Quinn (2025-06-01)
We present a novel forecasting framework for lake water temperature, which is crucial for managing lake ecosystems and drinking water resources. The General Lake Model (GLM) has been previously used for this purpose, but, similar to many process-based simulation models, it: requires a large number of inputs, many of which are stochastic; presents challenges for uncertainty quantification (UQ); and can exhibit model bias. To address these issues, we propose a Gaussian process (GP) surrogate-based forecasting approach that efficiently handles large, high-dimensional data and accounts for input-dependent variability and systematic GLM bias. We validate the proposed approach and compare it with other forecasting methods, including a climatological model and raw GLM simulations. Our results demonstrate that our bias-corrected GP surrogate (GPBC) can outperform competing approaches in terms of forecast accuracy and UQ up to two weeks into the future.
Habitat suitability ensembles of genotype and disease resistance for Juglans cinerea to assist restoration efforts
Bascom, Carlisle S.; Conrad, Anna O.; Ebrahimi, Aziz; Jacobs, Douglass F.; Fearer, Carrie (Elsevier, 2026-07)
The environmental suitability of a particular organism is often a combination of local climatic factors, resource competition intensity, as well as pathogen and predator pressure. Pathogen pressure, or host resistance, is particularly important in host species severely impacted by disease. Variations in heritable pathogen resistance can lead to differences in apparent habitat suitability of resistant or susceptible subpopulations. In the case of the butternut tree (Juglans cinerea), habitat suitability is limited by genetic resistance to the non-native butternut canker disease (BCD) in addition to environmental factors. Further, butternut frequently crosses with the non-native, BCD-resistant, congenic Japanese walnut (Juglans ailantifolia) producing fertile hybrids. We sought to develop models of butternut or hybrid genotype and BCD resistance phenotypes that could inform conservation efforts. We combine two regression-based and three machine-learning based composite models to build a series of ensemble habitat suitability models of butternut and hybrid genotype, as well as butternut BCD resistance phenotype. Our ensembles highlight southern Indiana, western Kentucky, western Michigan, and much of New England as climatically suitable for BCD-resistant butternut. Meanwhile, much of the central Midwest and areas south of the Great Lakes are climatically suitable for hybrids. These ensembles can guide conservation efforts seeking to breed BCD-resistant butternut and hybrids by highlighting areas from which to source breeding stock or locate regeneration orchards.
Transit time modeling framework for predicting freshwater salinization in urban catchments
Bhide, Shantanu V.; Grant, Stanley B.; McGuire, Kevin J.; Prestegaard, Karen; Kaushal, Sujay S.; Sekellick, Andrew J.; Rippy, Megan A.; Schenk, Todd; Curtis, Shannon; Gomez-Velez, Jesus D.; Hotchkiss, Erin R.; Vikesland, Peter J.; Saksena, Siddharth (Elsevier, 2026-03)
The salinity of inland freshwaters is rising globally, particularly in urban watersheds where winter road deicers are widely applied. Attributing stream salinity dynamics to specific sources and transport pathways remains challenging due to episodic salt inputs, engineered drainage, and strong coupling between hydrology and subsurface storage. We present a modeling framework that couples climate-driven deicer build-up and wash-off with transient transit time distribution theory to simulate salt transport through drainage, interflow, and groundwater pathways. Applied to an urban watershed in Northern Virginia (USA), the model reproduces ten years of high-frequency stream salinity measurements across daily-to-decadal timescales. The calibrated model implies an average deicer application of 206 tonnes Cl yr−1, or roughly one 20 kg bag of rock salt person−1 yr−1 when normalized by the 20,000 people living in the watershed. In winter months, higher infiltration routes a large fraction of snowmelt and deicers into shallow subsurface pathways, enhancing vadose-zone and interflow contributions to stream salinity. Limited subsurface storage capacity and seasonal hydrologic turnover flush excess chloride from the vadose zone and groundwater during subsequent summer storms. By linking climate-driven deicer inputs, hydrologic connectivity, and stream water age, the framework provides a transferable basis for diagnosing and managing freshwater salinization in urban watersheds.
Genomic approaches to accelerate American chestnut restoration
Westbrook, Jared W.; Malukiewicz, Joanna; Zhang, Qian; Sreedasyam, Avinash; Jenkins, Jerry W.; Lakoba, Vasiliy; Fitzsimmons, Sara; Van Clief, Jamie; Collins, Kendra; Hoy, Stephen; Stark, Cassie; Graboski, Lake; Jenkins, Eric; Saielli, Thomas M.; Jarrett, Benjamin T.; Wigfield, Lucinda J.; Kerwien, Lauren M.; Wilbur, Ciera; Sandercock, Alexander M.; Craddock, J. Hill; Keriö, Susanna; Zhebentyayeva, Tetyana; Fan, Shenghua; Thomas, Austin M.; Abbott, Albert G.; Nelson, C. Dana; Xia, Xiaoxia; McKenna, James R.; Kell, Caleb; Williams, Melissa; Boston, LoriBeth; Plott, Christopher; Carle, Florian; Swatt, Jack; Ostroff, Jack; Jeffers, Steven N.; McKeever, Kathleen; Smith, Erica; Ellis, Thomas J.; James, Joseph B.; Sisco, Paul; Newhouse, Andrew; Carlson, Erik; Powell, William A.; Hebard, Frederick V.; Scrivani, John; Heverly, Caragh; Cipollini, Martin; Clark, Brian; Evans, Eric; Levine, Bruce; Carlson, John E.; Goodstein, David; Orebaugh, Jack; Yang, Zamin K.; Martin, Madhavi Z.; Tannous, Joanna; Rush, Tomás A.; Engle, Nancy L.; Tschaplinski, Timothy J.; Grimwood, Jane; Schmutz, Jeremy; Holliday, Jason A.; Lovell, John T. (American Association for the Advancement of Science, 2026-02)
More than a century after two introduced pathogens killed billions of American chestnut trees, introgression of resistance alleles from Chinese chestnuts has contributed to the recovery of self-sustaining populations. However, progress has been slow because of the complex genetic architecture of resistance. To better understand blight resistance, we compared reference genomes, gene expression responses, and stem metabolite profiles of the resistant Chinese and susceptible American chestnut species. To accelerate resistance breeding, we conducted large-scale phenotyping and genotyping in hybrids of these species. Simulation and inoculation experiments suggest that significant resistance gains are possible through selectively breeding trees with an average of 70 to 85% American chestnut ancestry. The resources developed in this work are foundational for breeding to create diverse restoration populations with sufficient disease resistance and competitive growth.
Urban Forest Management Plan: George Washington Memorial Parkway, Washington, D. C.
Heavers, Nathan; Kelsch, Paul J.; Wiseman, P. Eric (2024-12)
This report examines the urban forest of the George Washington Memorial Parkway (GWMP) and recommends management strategies and solutions to sustain the forest’s ecological integrity, its cultural significance, its recreational use, and its designed beauty. The GWMP urban forest is comprised of natural remnant woodlands and designed landscapes that extend along the parkway corridor, parallel to the Potomac River. This report specifically studies National Park Service (NPS) lands on the Virginia side of the river from the American Legion Bridge to Mount Vernon.
Urban and Community Forestry Economic Contribution in California in 2021
Parajuli, Rajan; Wiseman, P. Eric; Christensen, Brittany (2024-12-09)
Final presentation to sponsors and stakeholder about research conducted by multi-university team.
Certified Urban and Community Forester Credential Aims to Elevate the Profession and Grow SAF
Wiseman, P. Eric (Florida Urban Forestry Council, 2025-02-28)
Fairfax County’s Tree Canopy: Examining the Effects of Land Development Regulations on Tree Canopy Conservation
Wiseman, P. Eric; Keightley, Brian (2024-09-18)
Selecting and Managing Trees to Avoid Conflicts with Overhead Utility Lines
Wiseman, P. Eric; Fox, Laurie J.; Matiuk, Jonathan; Christensen, Brittany (Virginia Cooperative Extension, 2024-08-31)
Overview of appropriate trees for use under utility lines to avoid conflict and comply with height restrictions.
Household Firewood Use in Virginia and North Carolina: A Survey of Consumer Opinions and Activities
Wiseman, P. Eric; Schmitt-Harsh, Mikaela; Munsell, John F. (2021-10-03)
Experiential Learning and Service in the Campus Urban Forest
Wiseman, P. Eric (2025-04-14)
Evaluating Local Calibration Methods for Improving Diameter Growth Predictions in the Southern Variant, Forest Vegetation Simulator (FVS-Sn)
Cankaya, Ergin C.; Radtke, Philip J. (Springer Nature, 2025-10-06)
Local calibration methods were evaluated for diameter at breast height (dbh) growth predictions in 11 tree species in Virginia, USA, using a model form based on the Forest Vegetation Simulator Southern Variant (FVS-Sn) large tree dbh regression model. Data from 1090 remeasured forest inventory plots from the USDA Forest Service’s Forest Inventory and Analysis (FIA) database were used to calibrate FVS dbh growth predictions to local conditions and evaluate four calibration methods based on the following information: 1) median prediction errors calculated from locally observed dbh pairs before and after a five-year remeasurement period; 2) a random intercept estimated from locally observed dbh using mixed-effects regression; 3) a simple linear regression (SLR) model fitted to observed and predicted dbh at the local scale; and 4) an SLR model with regression through the origin. Calibration methods were assessed using leave-one-out cross-validation, comparing model predictions to observed dbh growth from withheld trees. Equivalence testing indicated median or regression-based local calibration methods achieved prediction-error tolerances over 5–7 year growth intervals as small as 0.11 cm (0.03 cm for two regression-based methods) for all species, whereas the random-intercept approach only achieved a minimum tolerance of 0.2 cm. Compared to uncalibrated models, local calibration substantially reduced prediction errors, demonstrating efficacy in increasing prediction accuracy, even with sparse FIA dbh growth data used for local-calibration.
The national Fire and Fire Surrogate study: Effects of fuel treatments in the western and eastern United States after 20 years
Bernal, Alexis A.; Stephens, Scott L.; Callaham, Mac A.; Collins, Brandon M.; Crotteau, Justin S.; Dickinson, Matthew B.; Hagan, Donald L.; Hedges, Rachelle; Hood, Sharon M.; Hutchinson, Todd F.; Taylor, Melanie K.; Coates, T. Adam (Wiley, 2025-02-12)
The national Fire and Fire Surrogate (FFS) study was initiated more than two decades ago with the goal of evaluating the ecological impacts of mechanical treatments and prescribed fire in different ecosystems across the United States. Since then, 4 of the original 12 sites remain active in managing and monitoring the original FFS study which provides a unique opportunity to look at the long-term effects of these treatments in different regions. These sites include California (Blodgett Forest Research Station), Montana (Lubrecht Experimental Forest), North Carolina (Green River Game Land), and Ohio (Ohio Hills). Although regions differed in ecosystem type (e.g., conifer- vs. hardwood-dominated), the overall goals of the FFS study were to promote desirable, fire-adapted species, reduce fire hazard, and improve understory diversity. Our study uses multivariate techniques to compare how these desired outcomes were maintained over the last 20 years and discusses whether we would modify the original treatments given what we know now. Our findings indicate that mechanical treatments and prescribed fire can promote desired tree species, mitigate potential fire behavior by reducing fuels and retaining larger-sized trees, decrease tree mortality, and stimulate regeneration—effects that are still apparent even after 20 years. However, we also found that maintaining desired outcomes was regionally specific with western sites (California and Montana) showing more desirable characteristics under mechanical treatments, while the eastern sites (North Carolina and Ohio) showed more desirable characteristics after prescribed burning. The beneficial effects of treatment were also more apparent in the long term when sites followed up with repeated treatments, which can be adapted to meet new objectives and conditions. These findings highlight the FFS study as an invaluable resource for research and provide evidence for meeting long-term restoration goals if treatments can be adapted to ecosystem type, be maintained by repeated treatments, and accommodate new goals by adapting treatments to changing conditions.
Reducing resilience debt: Mechanical felling and repeated prescribed fires may sustain eastern oak forests
Taylor, Melanie K.; Hagan, Donald L.; Coates, T. Adam; DeFeo, Julia A.; Callaham, Mac A. Jr.; Mohr, Helen H.; Waldrop, Thomas A.; Wurzburger, Nina (Wiley, 2025-10)
The misalignment of species adaptations with current environmental conditions can cause ecosystems to lose resilience, accumulate resilience debt, and transition to another state. Such a state change is evident in eastern North American broadleaf forests where dominant tree species are shifting from oaks (Quercus spp.) to mesophytic species such as maples (Acer spp.). The replacement of oaks is widespread and threatens the ecosystem services these forests provide, generating interest in using forest management to halt or reverse this change. The national Fire and Fire Surrogate (FFS) study was a large-scale study of forest management practices, and the Green River FFS site in western North Carolina (initiated in 2001) offers the opportunity to understand how management actions affect oak forest resilience. The Green River FFS site implemented three experimental treatments replicated across three spatial blocks: mechanical felling of saplings and ericaceous shrubs (Mech), prescribed fire (Fire), and a combination (Mech + Fire), which were compared to untreated controls (Control). Here, we used this long-running experiment to evaluate oak forest resilience by examining changes in overstory basal area and forest composition among overstory trees, saplings, and seedlings. We found that basal area increased in the Control and Mech treatments, was unchanged in the Fire treatment, and decreased in the Mech + Fire treatment as a result of mortality. Oak sapling abundances increased with reduced basal area, a pattern not found with the major mesophytic representative, maples. This suggests that oaks are well positioned to recruit to the overstory where basal area has decreased due to overstory mortality, and at the Green River FFS site, this was best achieved in the Mech + Fire treatment. Creating conditions where oak saplings have an advantage over maples requires the mortality of some overstory trees, including desirable oaks. Taken together, our findings suggest that the misalignment of oak traits and current environmental conditions has led to resilience debt, which may be reduced when management actions mimic a severe disturbance that results in the opening of the canopy. Thus, management actions that combine mechanical felling and repeated prescribed fires may promote sustained oak dominance in the future.
Principles for better environmental education field trips for early adolescent youth in the United States: an empirical study
Stern, Marc J.; Powell, Robert B.; Frensley, B. Troy; Anderson, Kelley C.; Kiewra, Lydia; Pownall, Malia; Schmitt, Talia; Thorpe, Emily G. (Routledge, 2025-05-12)
Which approaches lead to better outcomes for participants in environmental education (EE) field trips? This manuscript builds upon previous large-sample quantitative research that identified effective elements of single-day EE field trip programs for early adolescent youth across the USA. In this mixed-methods study, we observed 87 EE-focused school field trips in the USA and then surveyed youth participants immediately afterwards. We used the student surveys to quantitatively distinguish the top-performing quartile of programs from the bottom quartile. We then examined in-depth qualitative fieldnotes on each program in the top and bottom quartiles. Our analyses revealed six key principles that distinguished the programs with the most positive student outcomes from those with the least positive: (1) ensuring basic needs (physiological and safety) are met; (2) ensuring instructional clarity; (3) providing emotional support for students; (4) highlighting the novelty of the activities and setting; (5) maintaining or restoring student attention; and (6) providing a cohesive and thematic experience with clear purpose. There are many ways to embody the six principles. We share examples for each.
What Difference Can a Workshop Make? Lessons from an Evaluation of Eight Place-Based Climate Adaptation Workshops in the United States
Stern, Marc J.; Brousseau, Jennifer J.; O’Brien, Caleb (MDPI, 2025-12-24)
Place-based climate adaptation workshops are designed to help communities understand their climate-related vulnerabilities and plan adaptive actions in response. Through a series of surveys and interviews with participants, we examined the immediate and long-term impacts of eight place-based climate adaptation workshops in the United States. Six took place online due to COVID-19 restrictions; two took place in-person. All workshops positively enhanced declarative, procedural, and relational knowledge of participants and, to a lesser extent, their personal commitment to work on climate adaptation, optimism about climate adaptation in their communities, and perceptions of qualities of the network of actors engaged locally in climate adaptation. In-person workshops yielded somewhat stronger positive influences on relationship-building than online workshops. Most participants who responded to surveys 6 months to a year after the workshop reported that their workshop had a “minor” to “moderate” impact on stimulating meaningful adaptation actions in their area. Reported actions attributed to the workshops included the incorporation of climate adaptation into formal planning documents, the expansion of adaptation outreach, consideration of climate adaptation in day-to-day planning and decision-making in local government departments, and both successful and unsuccessful grant applications for projects and positions associated with climate adaptation. We describe the workshops’ design, as well as participant assessments of the value of different workshop components. We conclude with lessons learned for future effective workshop planning and design.
Carbon stock, fluxes, and partitioning in Pinus taeda plantations are affected by genetic variation and stand density in Southeast Brazil
Campoe, Otávio C.; Cordeiro, Natielle G.; Rojas, Gerardo; Albaugh, Timothy J.; Cook, Rachel L.; Rubilar, Rafael A.; Carter, David R.; Alvares, Clayton A.; Maier, Chris A. (2025-12-06)
Background: To understand how genetic variation among varieties and stand density affect carbon (C), we assessed C stocks, fluxes, and partitioning in Pinus taeda L. plantations in Southeast Brazil. We measured the annual C balance in two consecutive years (from 7 to 9 years after planting) in four different clonal varieties with distinct crown structures (C1-medium, C2-broad, C3-narrow, and C4-broad) and an OP (open-pollinated) family. From age 7 to 8 years, the C balance was assessed for all five varieties at a stand density of 1894 trees ha− 1. From age 8 to 9 years, the C balance was assessed for three varieties (C2, C3, and OP) at two stand densities (low density (LD): 613 trees ha− 1 and high density (HD): 1894 trees ha− 1). Results: At age 7–8, the total C stock (above- and belowground plus the litter layer) among varieties ranged from 168 Mg C ha− 1 (C3) to 186 Mg C m− 2 (C1), with the bole as the largest pool (68%). Aboveground net primary production (ANPP) ranged from 1.9 to 3.1 kg C m− 2 year− 1, and total belowground carbon flux (TBCF) from 2.0 to 2.9 kg C m− 2 year− 1. The partitioning of GPP (Gross Primary Production) to ANPP and TBCF reached a maximum value of 35% and 41%, respectively. At age 8–9 years, the C stock was greater in the HD stands than in the LD stands across all varieties. Overall, C stock reached between 103.5 and 184.6 Mg C ha− 1. ANPP under HD was 1.9 kg C m−² year−¹ compared with 0.62 kg C m−² year−¹ under LD. There were no significant differences in TBCF between the HD and LD stands. The partitioning of GPP to ANPP was lower and to TBCF was higher under LD compared with HD. Conclusion: Relationship between crown structure and the C stock, fluxes, and partitioning is not clear and should be used with caution for management prescriptions related to C sequestration. Also, no differences in the bole C stock and sequestration were found across varieties within the same planting density. Finally, the genetic variation among varieties and stand density significantly affected stand productivity, with stand density showing greater effect.
Spatial Decoupling of Biological and Geochemical Phosphorus Cycling in Podzolized Soils
Petticord, Daniel F.; Uveges, Benjamin T.; Boughton, Elizabeth H.; Strahm, Brian D.; Sparks, Jed P. (MDPI, 2025-10-16)
Phosphorus (P) is essential to life yet constrained by finite reserves, heterogeneous distribution, and strong chemical binding to soil minerals. Pedogenesis progressively alters the availability of P: in ‘young’ soils, P associated with Ca and Mg is relatively labile, while in ‘old’ soils, acidification and leaching deplete base cations, shifting P into organic matter and recalcitrant Al- and Fe-bound pools. Podzolized soils (Spodosols) provide a unique lens for studying this transition because podzolization vertically segregates these dynamics into distinct horizons. Organic cycling dominates the surface horizon, while downward translocation of Al, Fe, and humus creates a spodic horizon that immobilizes P through sorption and co-precipitation in amorphous organometal complexes. This spatial separation establishes two contrasting P pools—biologically dynamic surface P and mineral-stabilized deep P—that may be variably accessible to plants and microbes depending on depth, chemistry, and hydrology. We synthesize mechanisms of spodic P retention and liberation, including redox oscillations, ligand exchange, root exudation, and physical disturbance, and contrast these with strictly mineral-driven or biologically dominated systems. We further propose that podzols serve as natural experimental models for ecosystem aging, allowing researchers to explore how P cycling reorganizes as soils develop, how vertical stratification structures biotic strategies for nutrient acquisition, and how deep legacy P pools may be remobilized under environmental change. By framing podzols as a spatial analogue of long-term weathering, this paper identifies them as critical systems for advancing our understanding of nutrient limitation, biogeochemical cycling, and sustainable management of P in diverse ecosystems.
Regional differences in stem form between southern and northern red spruce (Picea rubens Sarg.) populations
Morrone, Steven; Green, Patrick Corey (Oxford University Press, 2024-04-06)
Red spruce (Picea rubens Sarg.) is a commercially and ecologically important conifer species that primarily exists at northern latitudes of eastern North America and extends southward following the Appalachian Mountains into North Carolina and Tennessee. Due to a warming climate and human-caused disturbances, only fragmented, sky-island populations remain at the highest peaks of the southern Appalachians where their habitat continues to be threatened. While they have been recognized for the rare wildlife habitat they provide in the region, these populations remain understudied. This work aimed to examine differences in stem form between the northern and southern populations of red spruce and to provide additional quantitative methods for managing red spruce stands through providing regionally fitted stem taper models. First, we examined differences in stem form using two methods: a sectional rate of change in diameter and a region variable added to the Model 02 taper model. The sectional taper comparison showed significant differences (P < .05) in taper rate throughout the stem that were most pronounced below breast height and above the midpoint. The nested model comparison also showed a significant difference after performing a likelihood ratio test. These results agreed that significant differences in stem form between the two populations exist and supported the idea that localized taper models would provide the best results. Next, we evaluated four stem taper models for their ability to predict upper stem diameters and total volume in southern Appalachian red spruce: a quadratic polynomial, a segmented, a variable exponent, and a geometric model. Fitting data came from a 1992 study across three southern Appalachian spruce-fir sites. Validation data came from a new dataset collected in 2022 at Unaka Mountain, Tennessee. Based on past studies and our results, we found that the Kozak (My last words on taper equations. For Chron 2004;80:507-15. https://doi.org/10.5558/tfc80507-4.) Model 02 variable exponent and the Max and Burkhart (Segmented polynomial regression applied to taper equations. For Sci 1976;22:283-9.) segmented polynomial models performed equally well. The choice of the final model should depend on the users' objectives and practical limitations (i.e. programming ability, availability of fitting data, error tolerance).
A Management Process for Improving the Resource and Social Sustainability of Camping: A Case Study in the US Desolation Wilderness
Marion, Jeffrey L.; Maretzki, Nathaniel (MDPI, 2025-11-16)
Protected area managers have long employed unregulated or dispersed camping policies that allow visitors to select and create campsites, frequently in flat areas where problems with campsite proliferation, expansion, severe resource impacts, social crowding, conflicts, and noise occur. This study fills a research gap by providing guidance based on recreation ecology studies and a US wilderness case study for evaluating and adopting a camping containment strategy in areas of higher use. Four efficient steps are described and illustrated involving campsite inventory, monitoring, and occupancy surveys, selection of preferred sustainable campsites, and implementation of a camping containment strategy and supporting practices. Case study findings are presented to illustrate the guidance and reveal the potential efficacy of implementing camping containment strategies that shift camping to preferred sustainable established or designated campsites as part of a visitor use adaptive management process. As demonstrated, such policies can accommodate heavy visitation with substantially reduced campsite numbers, aggregate area of camping impact, and an improved potential for higher quality social conditions.

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