R. D. Graham

Preventing and Stopping Internal Decay of Douglas Fir Poles

and between different logs would appear to be the largest obstacle which has to be overcome in developing such a mathematical description. The results described in this paper and other similar data should,, however, lead to a better understanding of the factors affecting the impregnation of wood and hopefully to either improvements in existing processes or to the development of altogether new processes.

Identity and distribution of Basidiomycotina colonizing Douglas fir poles during three years of air-seasoning

Douglas fir pole sections exposed at four air-seasoning sites in the Pacific Northwest were extensively sampled for Basidiomycotina each year for 3 yr. Poles were rapidly colonized by a variety of Basidiomycotina, but four taxa tended to dominate. Two of these, Antrodia carbonica and Postia placenta, are also important in deterioration of Douglas fir poles in service, while Stereum sanguinolentum is found in wounds on live Douglas fir trees and Peniophora (sensu stricto) spp. are colonizers of woody debris. A. carbonica and P. placenta predominantly colonized the heartwood at the ends and upper halves of the pole sections, whereas Peniophora spp. and S. sanguinolentum were uniformly distributed throughout the pole sections in the sapwood. Although the frequency of isolation of the four fungi varied among sites, colonization patterns were consistent.

Fumigant protection of untreated Douglas-fir posts

Sodium n-methyldithiocarbamate, chloropicrin, and methylisothiocyanate were tested for their ability to protect untreated Douglas-fir posts from decay and insect attack. Removal of increment cores for culturing and bioassays indicated that fumigants slowed, but did not prevent, Basidiomycete colonization. All posts contained surface decay after 4 years and termite attack after 10 years of exposure in ground contact. Pilodyn tests indicated that mechanical properties of all posts also declined, regardless of treatment, although MIT-treated posts declined least. The results suggest that fumigant treatment cannot completely protect non-pressure-treated Douglas-fir from decay but may be useful for low-stress applications, such as for fence posts. Fumigant treatment is not a substitute for proper pressure treatment where service conditions are severe.