Improved accessibility in remote noble fir (Abies procera Rehd.) stands and the
realization of the value of noble fir wood have led to increased pressure to enter and
actively manage noble fir stands in Oregon and Washington. This study examined the
incidence of infection and decay caused by Heterobasidion annosum...
A series of studies, in three western Oregon Douglas-fir plantations, was conducted to understand the physiological impacts of Swiss needle cast on Douglas-fir physiology. Four aspects of the disease complex were investigated: fungal colonization and assessment, plant-water relations, carbon assimilation and interaction with climate. Several techniques were developed and used...
Western white pine historically dominated northern Idaho’s forested landscape and was the Inland Empire’s most economically important tree. White pine blister rust, caused by the exotic fungus Cronartium ribicola, played a principal role in the decline of western white pine. The pathogen causes branch and bole cankers, which usually girdle...
Root rot caused by Armillariella mellea creates roughly circular
disease centers of infected dead and dying trees in the younggrowth
ponderosa pine forest under study. Research objectives concerning
chemical control of the disease were: 1) to test the
effectiveness of certain chemicals in protecting living pines adjacent
to disease centers...
A series of studies and replicated field sites were implemented in the Oregon Coast Range within Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) sapling plantations infected with varying levels of Swiss needle cast (SNC) caused by the fungus, Phaeocryptopus gaeumannii (Rhode) Petrak (PG). This research was conducted to understand the effects of...
Root disease fungi attack and destroy the tree’s root system, resulting in growth loss, decay, death, or wind throw of infected trees. Trees with root disease also are more susceptible to pests, especially bark beetles. On the other hand, root diseases are a component of the forest ecosystem and play...
Commercial thinning operations can result in damage to residual stems. A literature review revealed that little was known about the effects of residual logging wounds with regard to rotation-age commercial conifers, particularly Douglas-fir. An experiment to examine fungal colonization of Douglas-fir following logging damage showed that while damage was significant...
Breeding Port-Orford-cedar for resistance to Phytophthora lateralis, a causal agent of root disease, begins by screening, through artificial inoculation, phenotypically resistant trees selected from natural stands. The successful program selected tolerant or resistant POC parent trees for the purpose of disease management. Candidate resistant POCs were used in my dissertation...
