"In 1954, Dr. Helge Irgens-Moller initiated a rangewide collection of seed and seedlings of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco). Nearly 700 trees or stands were sampled in 10 western states, Canada, and Mexico. From 1957 to 1971, 639 of these collections were planted in the Hospital Tract Rangewide Source Archive...
Large inelastic strain occurs inside a piece of lumber during drying. The strain consists of several components such as elastic, plastic, creep, shrinkage and mechano-sorptive effect. The mechanical behavior of the whole board during drying is determined by the behavior of individual strain components and their interactions. Whereas limited investigations...
Cold hardiness and phenology are important adaptive
traits for perennial plant species in temperate climates.
Timing of growth, dormancy, and associated cold acclimation
and deacclimation represents a delicate balance between
maximizing growth under favorable conditions and minimizing
frost damage under unfavorable conditions. Geographic
patterns of genetic variation in adaptive traits,...
Aphids are a widespread family of plant pests, whose abilities to suppress shoot
and root growth are well documented for many terrestrial plants. Only a few studies have
been conducted on conifer aphids of the genus Cinara. Cinara pseudotsugae are known
to attack Douglas-fir seedlings, an important crop in the...
Two-year old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings from two seed lots of different predicted hardiness levels were grown in two separate nurseries. Seedlings were lifted every four weeks from early October 1991 through March 1992 and exposed to controlled freezing temperatures. Fluorescence emissions of the seedlings were measured prior...
Fusarium spp. are among the most important pathogens of Douglas-fir
(Pseudotsuga menziesii) seedlings in bareroot nurseries. Currently the most effective
disease control method is soil fumigation with methyl bromide. As methyl bromide is
phased out, however, other disease management strategies may become more important.
We explored two alternative approaches to...
Five different test methods to determine the parallel-to-grain shear
strength of Douglas-fir structural lumber were compared. Four methods
assessed the shear strength of lumber sections having a full nominal two by
four inch cross-section. These were: three-point bending, four-point bending,
five-point bending, and torsion. The fifth method was the ASTM...
Basamid^R (3,5-dimethy1-1,3,5,2H-tetrahydrothiadiazine-
2-thione) is a crystalline powder used as a soil sterilant.
This fumigant acts in soil by decomposing to methylisothiocyanate
(MITC), the primary active ingredient, as well as
hydrogen sulfide, methylamine, and formaldehyde. In wood,
Basamid decomposes too slowly to be efficacious against
decay fungi unless amended with various...