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...
Agrobacterium tumefaciens and Agrobacteriwn rhizogenes, the causal agents of crown gall disease and hairy root disease, are known for their ability to transfer part of their
DNA (the T-DNA) from the bacterial tumor-inducing (Ti) plasmid to the genome of the
host plant. Interest has focused on these bacteria because they...
Armillaria (Fr. ex. Fr.) is a parasite whose pathogenicity
and role in forest ecosystems often depends upon the
physiological condition of the tree. Therefore, I tested the
frequency and severity of Armillaria ostoyae (Romagn.) Herink
infection among Abies grandis (Dougl.) Lindl., Larix
occidentalis Nutt., Pinus contorta var. latifolia (Engelm.),
Pinus...
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...
The root disease fungus Inonotus tomentosus, common in the old
growth boreal forests of British Columbia, poses a threat to the
health of second growth forests established on sites with a previous
history of root disease. Colonized stumps occur in groups of 1 to 6;
the groups are clumped within...
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...
