Abstract:

The incidence and severity of black stain root disease (BSRD) were evaluated in a two-stage sample of 500 precommercial-aged Douglas-fir plantations on 5 Resource Areas of the Medford District, Bureau of Land Management. Black stain was widely distributed throughout the western half of the District. Nearly 19% of the susceptible-aged (10- to 30-yr-old) plantations were infected with black stain, but mortality losses were low. In both the extensive and intensive surveys, BSRD was more often distributed in precommercially thinned than unthinned plantations. Black stain occurred with significantly greater frequency adjacent to roads and major skid trails than in the main body of plantations. Roadside strips displayed significantly more injured trees and recent soil disturbance than the main body of plantations. BSRD incidence was high in comparison with other root diseases, but there was minimal impact to precommercial stand management. Low disease severity is somewhat unique among managed forests within this area of known high BSRD hazard. The lack of widespread damage from BSRD was associated with a lack of extensive tractor yarding and an apparent lack of precommercial thinning. Forest managers within high BSRD hazard areas can maintain low mortality levels by minimizing site disturbance and tree injury associated with timber harvesting, road building, and road maintenance activities and by timing precommercial thinning to avoid vector insect emergence and flight periods. Increased disturbance and injury to precommercial-aged stands will likely result in increased disease. West. J. Appl. For. 16(3):127–135.

Keywords: Thinning; Leptographium wageneri; tractor yarding; environmental management; forest; forest management; forest resources; forestry; forestry research; forestry science; natural resources; natural resource management

Document Type: Miscellaneous

Affiliations: 1: USDA Forest Service, Southwest Oregon Technical Center, J. Herbert Stone Nursery, 2606 Old Stage Road, Central Point, OR, 97502 2: USDI Bureau of Land Management, Medford District 3040 Biddle Road, Medford, OR, 97504