David S. deCalesta

White-tailed deer impact on the vegetation dynamics of a northern hardwood forest

Considerable controversy has arisen over the management of white-tailed deer in eastern landscapes where there is evidence of damage to forest vegetation, crops, and wildlife habitat attributable to deer. We examined the impact of 4, 8, 15, and 25 deer/ km 2 on herbaceous layer abundance and tree seedling density, height development, species composition, and diversity for 10 yr in a repeated-measures randomized-complete-block experiment at four replicate cherry-maple forest sites in northwestern Pennsylvania, USA. At each 65-ha site, deer were placed in 13- or 26-ha fenced enclosures in which the landscape composition and forage production of a forest managed on a 100-yr rotation was simulated by clear-cutting 10% of each area and thinning 30%. Vegetation was sampled 0-1, 3, 5, and 10 yr after treatment (YAT). We analyzed vegetative treatment responses separately in each silvicultural treatment. Time was an important factor mediating responses at all deer densities. Rubus spp. abundance in all silvicultural treatments and the density of striped maple (STM) in clearcuts and birch (BI), American beech (AB), and red maple (RM) in thinnings showed negative trends with increasing deer density. As deer density increased, we found negative linear trends in the height of BI, RM, and AB in clearcuts; in the height of AB, RM, and STM in thinnings; and in the height of AB and RM in uncut stands. Species richness showed a negative linear trend with increasing deer density in all silvicultural treatments. Conversely, species avoided by deer or resilient to deer browsing increased with in- creasing deer density. Percent cover of ferns, grasses, and sedges showed positive linear trends with deer density in clearcuts and in thinnings. The percentage of plots dominated by black cherry (BC) increased with increasing deer density in cut and uncut stands. The net result of increased deer impact was an altered trajectory of vegetation development dominated by species avoided by deer or resilient to deer browsing. Negative effects on vegetation became significant at deer impact levels well below those observed in many eastern forests. Moreover, species not browsed or resilient to browsing may have indirect effects on vegetation development through plant-plant interactions and on wildlife habitat quality for small mammals, birds, and deer. Managing these impacts is important as pressures to harvest and fragment eastern forests accelerate.

NED-1: integrated analyses for forest stewardship decisions

NED is a collective term for a set of software intended to help resource managers develop goals, assess current and potential conditions, and produce sustainable management plans for forest properties. The software tools are being developed by the USDA Forest Service, Northeastern and Southern Research Stations, in cooperation with many other collaborators. NED-1 is a Windows-based program that helps analyze forest inventory data from the perspective of various resources on management areas as large as several thousand hectares. Resources addressed include visual quality, ecology, forest health, timber, water, and wildlife. NED-1 evaluates the degree to which an individual stand or an entire management unit may provide the conditions required to accomplish specific goals. NED-1 users select from a variety of reports, including tabular data summaries, general narratives, and goal-specific analyses. An extensive hypertext system provides information about the resource goals, the desired conditions that support achieving those goals, and related data used to analyze the actual condition of the forest, as well as detailed information about the program itself and the rules and formulas used to produce the analyses. The software is constructed in C++ using an application framework; the inferencing component that handles the rule bases uses Prolog.

Deer and diversity in Allegheny hardwood forests: managing an unlikely challenge

High white-tailed deer (Odocoileus virginianus) density and interfering vegetation were identified as factors affecting the regeneration of hardwood forests in the Allegheny National Forest and surrounding forests in northwestern Pennsylvania. Research was designed by Forest Service scientists to quantify these effects. A high degree of interest in the impact of these effects on the diversity of forest resources led to additional research. Scientists, natural resource managers, and private timber interests used the research findings on the impacts of deer and interfering vegetation on regeneration and diversity to produce newsletters, tours, symposia, and to make presentations to groups of legislators, environmentalists and other influential segments of the public. This combined research-educational effort has been associated with the enactment of hunting regulations designed to reduce deer density and for registration and continued use of herbicides to control interfering vegetation. Both actions have the potential to increase the diversity of songbirds and woody and herbaceous vegetation in forest lands. The challenge is to sustain directed management of deer density and interfering vegetation until these factors are controlled to the point where they no longer negatively impact the diversity of forest resources.