The goal of the Duke Hollow (DH) PRISM site is to create a demonstration project showing that a few people can manage invasive plants on a scale of several hundred acres. The commitment of the landowners to continue monitoring the forest and avoid weed resurgence has been crucial to the success of the project. Positive feedback from witnessing the forest become an inviting place to walk again has been a major incentive driving the work forward.
The forest in DH (located in Clarke County, Virginia) was largely cleared for farming during the 1800s. Today, there is still an original log cabin (ca. 1800) and attached frame house (ca. 1915) at the center of a clearing. Dr. Sanford Rosenthal bought a large part of this area as a family get-away in 1943. The forest regrew as most of the settlements were abandoned by WWII. The Appalachian Trail (AT) was re-routed through the property in the early 1980s. The Barbehenn family inherited and expanded the DH property to include an additional 175 acres (totaling 275 acres after the easement of land for the Appalachian Trail corridor).
An Ecological Challenge
The large clearing around the DH cabin has long attracted birds and the invasive plants that they spread. These include bittersweet, wineberry, Japanese honeysuckle, privet, multiflora rose, and Japanese barberry. Following the advice of the USDA in the early 1970s, Russian olive was planted, and it also spread up and down the hollow. With the death of hundreds of elm and ash trees, the DH forest is now riddled with small light gaps. Invasive plants are often the first species to take advantage of these gaps, again seeded there by birds. The thickets that have developed in the light are impenetrable even to deer and act as productive refuges for invasive plants. Though they are native, species of grapes and greenbriers are also major components of these thickets. Grapevines have been especially damaging to tree saplings, entwining them and preventing their vertical growth, and, as a result, impeding forest regeneration. Not coincidentally, these are also bird-dispersed species. The DH creek is a natural light gap (and bird flyway), and it was heavily colonized by invasive plant species.
Work on removing invasive plants began with periodic efforts around the homesite in the 1990s but has increased to a year-round effort by Ray Barbehenn (a retired ecologist). Effective strategies to control most of the weeds have been worked out. Primarily, this has involved cutting plants below ground level with loppers to eliminate re-sprouting. Seasonal priorities have been based on eradicating plants before they produce fruit. With the more recent invasion of species such as Japanese stiltgrass, small amounts of herbicides have been required. Extensive thicket-clearing has allowed people to efficiently search through the forest to defend the area from recolonization by invasive plants. Finally, with work expanding out onto the neighboring properties, the sources of seed being brought into DH by birds are now being curtailed.
Future plans include planting saplings in deer-proof enclosures to speed up reforestation, reducing the deer population, as well as enlisting help from neighboring landowners. Work to control invasive plants along the A.T. corridor is just beginning, spearheaded by the Potomac Appalachian Trail Club