Ongoing Research Activities

Floristic Diversity

The sustainability of natural resources and the protection of species diversity form central questions and goals of environmental scientists, yet policy makers and land managers often make decisions based on inadequate data.
Forested ecosystems throughout the world face increased demands from global and local economies, while also providing numerous ecological functions and serve as hotspots of biological diversity. The eastern deciduous forests of North America are no exception and are home to more species of trees than are found anywhere else in the United States. These forests have experienced dramatic changes over the past one hundred years because of the exclusion of fire, introductions of non-native species, decline of the American chestnut, and intensive tree harvests. Appalachian forests serve as the basis for many local economies through timber harvest and recreation opportunities. Research focused on how timber harvests and other silvicultural operations and changes in species composition affect diversity and functioning of eastern deciduous forests is needed because of the increased economic demand of the forest with a simultaneous increase in the desire to protect species diversity.

Using silvicultural treatments ranging in disturbance intensity, we are measuring the long-term response of the plant community (including all woody and herbaceous species) to silvicultural disturbances in the central Appalachian Mountains of Virginia and West Virginia. Specifically, our questions focus on mechanisms driving the diversity and composition of native species and the invasibility and persistence by non-native species in response to the disturbance gradient. By sampling permanently marked plots at various spatial scales, we are providing a database that will answer basic ecological questions about the response of plant communities and species invasions to disturbance, as well as practical information on which species are most vulnerable or robust to management options.

Distribution of Forest Nutrients

Nutrients are not distributed uniformly across the forest floor.  Traditionally, most soil samples analyzed for nutrient content are taken to avoid rotten stumps.  However, these stumps are abundant in the forest floor, are quickly colonized by tree roots, and are likely to be important sources of nutrients in regenerating stands.  Eric Sucre and Tom Fox of the Department of Forestry are using ground-penetrating radar to determine the location of rotting stumps and are analyzing nutrient content and root mass in and out of these stumps in order to better assess nutrient availability in forest stands.

Commercial Tree Regeneration

Regeneration of commercially important hardwood species is an important consideration in any silvicultural system.  Although all the treatments are designed to promote oak regeneration, they  may differ in their success.  Regeneration of commercial hardwoods and the overall floristic diversity increased following silvicultural treatments that disturbed the overstory and increased light reaching the forest floor.  In higher quality sites, however, oak is being outcompeted by faster growing species, regardless of treatment applied. Chad Atwood and Tom Fox in the Department of Forestry studying the importance of stump sprouts following the various silvicultural treatments to address these issues.

Forest salamanders

Terrestrial salamanders play important roles in energy and nutrient webs in forested ecosystems by regulating invertebrates, potentially affecting rates of decomposition of leaf litter, and providing sources of nutritious prey for birds, mammals, and other species.  Silvicultural systems can decrease salamander populations and thus may affect how ecosystems function.  The SASAB project has investigated the response of terrestrial salamanders to a range of silvicultural systems since 1994.  Silvicultural treatments that removed some portion of the overstory reduced salamander populations by 2-years post-treatment, and by years 8-12 populations have not yet rebounded to preharvest levels.  Current research is evaluating why populations of salamanders have not recovered.  Jessica Homyack and Carola Haas of the Department of Fisheries and Wildlife Sciences are examining whether the slow recovery of salamander populations may be explained by (1) lasting effects of silvicultural treatments to vegetation characteristics and prey availability, (2) lasting effects of silvicultural treatments on microclimates resulting in changes to energy budgets of individual salamanders, or (3) an inability for rapid population growth among species with low fecundity.  They are also collaborating with Eric Sucre and Tom Fox in the Department of Forestry to examine the ecological consequences of reduced salamander populations by manipulating densities of
red-backed salamanders in field mesocosms.