Two methods attempting to stop marginal spread of a root disease center in Douglas-fir were evaluated within the Flathead Indian Reservation, Montana. The first method was to cut all living trees within a 1-chain strip outside the edge of the infestation. The second method was to uproot all trees for 1 chain outside the edge. Neither method appeared to effectively restrict marginal spread of root disease because black stain (Ceratocystis wageneri) was present in nonsymptomatic trees beyond the treated area. Accurate diagnosis of organisms involved in root disease is a prerequisite to successful silvicultural treatments.