The sinuous flight behavior of male Douglas-fir tussock
moths, Orgyia pseudotsugata, (McD.), is characterized by
positive anemotaxis and positive chemoklinotaxis and varies
depending on distance from the pheromone source, population
density, and time of day. Visual cues play a minor role
in close-range orientation to a pheromone source, but
males...
Douglas-fir bark was extracted with n-hexane yielding a light colored, "wax-like" solid as the n-hexane soluble fraction. The chemical constituents of this n-hexane soluble fraction were partially resolved by column chromatography using Silica Gel G as stationary phase and chloroform-n-hexane (3:1 v/v) as developing solvent. Several bands were observed under...
Foresters in the Pacific Northwest are directing increasing effort into the management of young-growth forests. These foresters find themselves in a transition period in which they are beginning to develop the framework for managing young-growth forests while they continue to manage substantial reserves of old-growth timber. In this transition period,...
This study was divided into two parts. Part I was a quantitative description of some aspects of plant-water relations in Douglas-fir seedlings, and part II was tests of several techniques of screening selected families of Douglas-fir seedlings for drought resistance. Part I. During 20 mild summer days in 1976 at...
The young larvae of the Douglas-fir tussock moth (Orgyia pseudotsugata (McDunnough) (DFTM) are dependent on the new foliage of its ho'sts (Doug1as-fir, grand fir, white fir) for their food supply. The phenology of the DFTM and its hosts are synchronized, with
egg hatch and dispersal occurring one to three weeks...
Snags, standing dead trees, are used by many species of wildlife. Despite the importance of snags their basic ecology remains unknown.
Some forest management practices eliminate snags from the forest with a concomitant effect upon snag-dependent wildlife. My objective was to describe the density, spatial distribution, and physical character of...
Results reported here are from a large study designed to evaluate the effects of certain nursery procedures on subsequent survival of Douglas-fir seedlings. The effects of storage conditions and lifting dates were reported elsewhere (9). The determination of the optimum size of seedling for planting on different sites has been...
Although the Douglas-fir region of the northwestern United States and British Columbia is frequently considered to have a common silviculture, obstacles to successful regeneration of the species range from competing vegetation and mammals on the mesic sites to extreme drought and heat on the xeric southerly exposures in northern California...
The Dwight L. Phipps State Forest Nursery at Elkton annually supplies 22 million 2-0
Douglas-fir seedlings to Oregon land managers. Some managers report excellent success in
planting, but others report failures, particularly when planting late in the season. In some
instances poor survival seemed to be related to storage.
Physiological...
Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) is one of the world's most important and valuable timber trees. Its natural distribution in North America resembles an inverted V with uneven sides. From the apex in British Columbia, the western half extends along the Pacific mountain ranges into California for about 2,200 km...