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...
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....
Information about forest substrate respiration, nitrogenase activity and
mineralizable nitrogen may be incorporated into carbon and nitrogen budgets that comprise an important element of forest management planning. In this study, substrate respiration, nitrogenase activity and mineralizable nitrogen were measured in two western Oregon Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] stands within...
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...
I studied species' abundances and habitat relationships
of breeding and winter birds in commercially thinned and
unthinned Douglas-fir (Pseudotsuga menziesii) stands from May
1989 to June 1991. The study was conducted in 40- to 55-year old
stands in the Central Oregon Coast Ranges and the
Tillamook State Forest. Total abundance...
Previous studies of bird communities in the mid-Willamette Valley, Oregon, indicated that Oregon white oak (Ouercus garryana) stands supported more cavity-using bird
species than sympatric stands of Douglas-fir (Pseudotsuga menziesii). Mature Oregon oak stands are being harvested and few are regenerating. I compared cavity availability for hole-using fauna among 10...
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...