Eleven series of untreated posts, 33 series of nonpressuretreated posts, and 13 series of pressure-treated posts remain in test. Series in which all posts have failed now number 34 for untreated, and 18 for nonpressure-treated. Causes of failures since 1949 were: fungi, 77 per cent of failures; fungi and termites,...
To test the effects of kiln-drying on strength properties of Douglas fir and western hemlock, temperatures to 230 F, conditions for equilibrium moisture contents of 6 percent and 12 percent, and prolonged heating were investigated.
Prolonged heating and choice of conditions for 6 percent or 12 percent equilibrium moisture content...
Two intermediate cuttings were made in a Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) stand on the Wilark forest management research area in northwestern Oregon. Age of trees in the stand varied from 47 to 62 years at the first cutting. Crawler tractors were used in both extractions. In the first cutting,...
Germination and survival of Douglas-fir on seedbeds of unburned,
lightly burned, and severely burned soil, charcoal, litter, and sawdust,
exposed to 100, 75, and 25 percent of full light, were studied on a
south-facing clearcutting in the Coast range of Oregon.
Irrespective of exposure to light, germination was best on...
Survival and growth during three years at 8 out-planting areas are reported for Douglas-fir from 14 sources of seed. Early survival was highest near Nimpkish on Vancouver Island. At most plantations, trees from the local seed source grew as well as did those from the best three sources. Trees from...
Planting techniques, size and age of seedlings, and protection
against animals were investigated for their influence on survival of
ponderosa pine at two sites in southern Oregon. Caging and mulching
with paper were the most effective measures for reducing mortality.
Preliminary trials prior to large-scale planting were recommended for
determining...
Correlation was sought between abundance of mycorrhizae on
Douglas-fir seedlings and their survival in field plantations.
One possible indication of dormancy desirable for lifting from
nursery beds could be the varying seasonal abundance of ectotrophic
mycorrhizae on roots of seedlings. No direct correlation between percentage
of mycorrhizae and survival in...
The effect of lifting Douglas-fir seedlings from the nursery bed
and replanting them, either immediately or after storage at 2 C for
periods up to six weeks, was investigated through a series of experiments
conducted in controlled-environment chambers and under field
conditions. Seedlings lifted prior to December, or after buds...