CAPACITY OF SURFACE AND INTERNAL GROUNDLINE TREATMENTS TO PROTECT UNTREATED DOUGLAS-FIR POSTS

The capacity of groundline preservative pastes and fumigants to protec t untreated Douglas-fir pole sections was evaluated over a 10-year per iod. Culturing of increment cores and closed-tube bioassays indicate t hat combinations of preservative pastes and fumigants applied at the g roundline provide reasonable protection to the groundline zone, but do not completely protect the aboveground zone. In the absence of an oil -treated shell, rapid fumigant loss occurs, which suggests that more f requent fumigant applications may be necessary to protect untreated wo od.