A soil container 12 feet in diameter and 4 feet deep was constructed around the root ball of a 92-foot Douglas-fir tree in a naturally regenerated stand. The weighing mechanism, consisting of 550 feet of
2.5-inch butyl rubber tubing filled with water connected to a standpipe,
was placed under the...
Karyotype analyses have been madeon only two on the six recognized species in the genus Pseudotsuga, Douglas-fir (P. menziesii) and bigcone Douglas-fir (P. macrocarpa). In this
study, a comparison was made between the karyotypes of Douglas-fir and Formosan Douglas-fir (P. wiloniana). The basic chromosome number of the Formosan Douglas-fir was...
A practical demonstration of a method for
rating forest stands as to their probability of
defoliation by the Douglas-fir tussock moth
using aerial photographs and available cruise
data was done in the Palouse Ranger District,
Clearwater National Forest, Idaho.
A nonlinear computer program, RISK, was used to
identify significant independent...
The objective of this study was to assess the effects of
forest management intensity on long-term productivity of Pacific
Northwest Douglas-fir forests. The components of management intensity
included rotation length, timber utilization standard (whole
tree or bole only), method of slash treatment (remove/burn or leave)
and fertilization practice (urea nitrogen...
Black bears (Ursus americanus) in western Oregon and Washington peel bark from conifers in early spring to forage on the sugar-rich phloem and cambial tissues. This provides important energy at a time when similarly attractive forage is scarce. Bears often damage Douglas-fir (Pseudotsuga menziesii) trees in stands that are intensively...
After three-quarters of a century of introduction of 152 conifer and broadleaf species,
no promising candidate exotic was found for the Douglas-fir region. Growth curves
spanning 50 years or longer are figured for many species. Firs, pines, larches, spruces,
hemlocks, and cedars originating in northwestern North America had superior growth...
A rapid and efficient procedure that required no partitioning was developed for the purification of abscisic acid (AbA) from the needles of Douglas-fir seedlings. Extracted needle pigments were removed by a
PVP column and the eluted AbA was concentrated on a DEAE column. The AbA was eluted from the DEAE...
To understand the effect of human-induced stresses on forests, there is a need for a method to separate effects of imposed stress from effects of natural climate stress. I developed an approach to predict forest response to climate stress using as indicators stable carbon isotopes in tree foliage and growth-rings....
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...