This study was conducted to investigate why root disease centers east of the
Cascade crest tend to be larger in diameter and more abundant than their counterparts to
the west, within subalpine forest stands of central Oregon. The trend in a 290 km² study
area appeared opposite of what was...
Previous studies have indicated that roots from five tree species (Picea sitchensis, Tsuga heterophylla, Pseudotsuga menziesii, Pinus ponderosa, and Pinus contorta) decompose at different rates across an environmental gradient in Oregon. Measurements of wood chemistry from each tree species as well as moisture and
temperature from each location do not...
White and grand fir are both valuable components of the mixed-conifer stand structure managed for late-successional reserves in central Oregon. However, they are often short-lived species because of high susceptibility to root diseases, defoliating insects, bark beetles, and wildfire. This study focuses on the effects of root diseases caused by...
DNA markers that detect polymorphisms within and between two biological species of the coniferous laminated-root-rot fungus Phellinus weirii were developed and used to
measure the amount and distribution of genetic variation. In a preliminary survey, total cellular DNA from 3 Douglas-fir-type isolates and 3 cedar-type isolates was digested with 12...
The primary cause of "early dying" disease of potatoes in
Oregon is Verticillium dahliae; however, Colletotrichum atramentarium,
Erwinia carotovora subsp. carotovora (Ecc) and E. carotovora
subsp. atroseptica (Eca) are also commonly isolated from
diseased plants. Therefore, field and greenhouse studies were
initiated to determine the relative involvement of each pathogen,...
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...
