Effects of Prescribed Burning, Mechanical, and Chemical Treatments to Curtail Rhododendron Dominance and Reduce Urban Interface Fuel Loads

Rosebay rhododendron (Rhododendron maximum L.) is an ericaceous shrub commonly found in riparian areas of the Appalachian Mountains. After more than a century of fire exclusion in the U.S., the distribution of R. maximum and its dominance of forest understories have increased. Rhododendron expansion has caused a decline in overstory tree regeneration and the potential for dangerous fuel conditions around suburban structures near the wildlandurban interface. In this study, treatments involving prescribed fire, mechanical cutting, and herbicide applications were applied to R. maximum-dominated forests in southwestern Virginia to determine what effect seven different silvicultural treatments had on (1) controlling of R. maximum as a forest weed; (2) fuel loading inside of a R. maximum thicket; and (3) treatment costs. Due primarily to less than ideal moisture conditions, a single prescribed burn was relatively ineffective in reducing overall fuel loading and causing immediate R. maximum mortality. However, prescribed fire reduced litter layers and caused delayed mortality on R. maximum stems three years following treatment. Mechanical cutting treatments were successful in reducing R. maximum basal area per acre and caused a drastic shift in the stem size class distribution. But cutting also resulted in heavy sprouting and increased fuel loading. When applied alone, herbicide applications were successful in controlling only the smallest diameter