VTechWorks
VTechWorks provides global access to Virginia Tech scholarship, including journal articles, books, theses, dissertations, conference papers, slide presentations, technical reports, working papers, administrative documents, videos, images, and more by faculty, students, and staff. Faculty can deposit items to VTechWorks from Elements, including journal articles covered by the University open access policy. Email vtechworks@vt.edu for help.
Open Access Policy
Virginia Tech's open access policy enables researchers to deposit the accepted version of scholarly articles with no embargo.
Theses and Dissertations
Virginia Tech was first in the world to require ETDs in 1997, and continues to add scans of older theses and dissertations.
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More than 50 freely available and openly licensed textbooks are among our most downloaded items.
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Recent Submissions
Virginia Tech Annual Financial Report, 2024-2025
(Virginia Tech, 2025)
This is the annual financial report for Virginia Tech in 2024-2025.
CNRE News, Winter 2024/2025
(Virginia Tech, 2025)
The College of Natural Resources and Environment news magazine includes timely news about the departments and much more going on in the College.
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.
Interfacial Photogating of Graphene Field-Effect Transistor for Photosensory Biomolecular Detection
Howe, Leslie; Wang, Yifei; Ellepola, Kalani H.; Ho, Vinh X.; Dohmen, Rosalie L.; Pinto, Marlo M.; Hoff, Wouter D.; Cooney, Michael P.; Vinh, Nguyen Q. (Wiley-VCH, 2025-05)
The photogating effect, induced by a light-driven gate voltage, modulates the potential energy of the active channel in field-effect transistors, leading to a high photoconductive gain of these devices. The effect is particularly pronounced in low-dimensional structures, especially in graphene field-effect transistors. Along with unusual optical and electrical properties, graphene with ultra-high carrier mobility and a highly sensitive surface generates a strong photogating effect in the structure, making it an excellent element for detecting light-sensitive biomolecules. In this work, graphene field-effect transistor biosensors is demonstrated for the rapid detection of photoactive yellow protein in an aqueous solution under optical illumination. The devices exhibit millisecond-scale response times and achieve a detection limit below 5.8 fM under blue-light excitation, consistent with the absorption characteristics of the protein. The photogating effect in graphene field-effect transistors provides a promising approach for developing high-performance, light-sensitive biosensors for biomolecular detection applications.