Experiments were conducted to determine if the plagiotropic
growth habit of rooted cuttings of Douglas-fir might result from a
system favoring the accumulation of indoleacetic acid in the adaxial
side of the shoot in response to vertical placement.
Actively growing excised branch terminals were subjected to
gravitational disorientation to determine...
The effect of lifting date and root-pruning treatments on
water potential, root regeneration, and shoot growth of six-month-old
and three-year-old Douglas-fir seedlings bare-root transplanted
into a growth chamber, and sawdust bed, respectively, was studied.
Root growth in six-month-old and three-year-old seedlings was
highest in February and August respectively. Survival was...
The relation of bud and cambial activity to root initiation and
elongation in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco)
stem cuttings was studied through two successive growth cycles.
Stem cuttings of current season's growth were taken periodically
from field-grown Douglas-fir trees to determine: (1) origin and
development of root initials; and...
A microscopic study was conducted on specific gravity wafers taken from standard tensile strength specimens of young growth Douglas-fir. Samples were studied to determine the effect of variables such as percent summerwood, fiber length and fibril angle on tensile strength of Douglas-fir. The sample specimens were picked so effects of...
• A technique for measuring in vitro respiration was investigated to understand why rates were higher than those reported in vivo and to elucidate trends within mature Pseudotsuga menziesii (Douglas‐fir) trees.
• Extracted increment cores were divided into 3–4 radial depths and a gas chromatograph was used to compare respiration...
Three methods--radial compression strength, color indicators of decay and micro-toughness, an examination of tracheid fracture patterns, were evaluated for detection of early decay and for application to field use. Three-eighth-inch diameter plugs 3/4-inch long, cut from the sapwood and heartwood of a Douglas-fir pole free of decay, were decayed by...