Wildland fuel loading estimates along a gradient of forest cover types and landscape factors in Harpers Ferry National Historic Park, West Virginia and Rock Creek Park, Virginia, USA

Abstract

Wildland fuel loading estimates are utilized by natural resource managers today for a variety of reasons, including but not limited to the approximation of fire behavior and potential fire effects. Standing and dead trees, downed woody material, litter (Oi Horizon), and duff (Oe+Oa Horizons) contribute to fuel loading and fire risk. They also play a critical role in overall ecosystem health. Downed woody material contributes to carbon storage and nutrient cycling, and provides an important source of habitat heterogeneity for multiple insect, reptile, amphibian, and small mammalian species. Within the National Park Service, many managers of parks with high visitation rates have been asked if forests within their parks are in decline, or are at risk of decline, due to the number of standing and dead trees and the amount of downed and dead material on the forest floor. They have also vocalized concern about potential wildfire hazard in these forests. Studies of these essential ecosystem components in the eastern United States suggest that downed woody material, litter, and duff accumulation may be significantly related to landform and edaphic factors. Understanding these relationships may benefit park managers within the National Park Service. To address this concern at Rock Creek Park (located near Washington D.C.) and Harper's Ferry National Historical Park (WV), standing and dead trees, downed woody material, litter, and duff were inventoried May-August 2024. Aspect and percent dead basal area had no influence on DWM accumulation. Soil order and slope percentage exhibited varied influence. Cover type exhibited the most influence, with mesic mixed-hardwood stands having the least fuel mass and higher fuel mass in xeric oak/hickory stands, pine stands, and floodplain stands, respectively. The National Park Service may be aided in their management of these parks through this knowledge, and messaging to the public may be targeted to visitors that frequent portions of the parks featuring these cover types.