Hemlock dwarf mistletoe (Arceuthobium tsugense subsp. tsugense) is an arboreal, hemiparasitic plant that principally parasitizes western hemlock (Tsuga heterophylla). Hemlock dwarf mistletoe exerts a profound influence on infected trees that can drastically change the structure of the tree crown due to reduced growth, top dieback, branch deformation and death, resulting...
Lodgepole pine (Pinus contorta) forests are widely distributed throughout western North America. However, the lodgepole pine forests of central Oregon are ecologically unique to the region, with a mixed severity fire regime, low cone serotiny, and their occasional presence as a climax species. Most of the research conducted regarding the...
Swiss needle cast (SNC) is a foliage disease of Douglas-fir caused by Nothophaeocryptopus gaeumannii, an Ascomycete fungus (Mycosphaerellaceae) that causes growth reductions in Douglas-fir plantations across the Pacific Northwest. Epidemiology of the fungus is generally well known in plantation trees, but the relationship between disease expression and foliage nutrition and...
Douglas-fir (Pseudotsuga menziesii) is a commercially and ecologically important tree species native to western North America. The foliar pathogens Phaeocryptopus gaeumannii, the causal agent of Swiss Needle Cast, and Rhabdocline species, the causal agents of Rhabdocline needle cast, are two important pathogens specific to Douglas-fir. These pathogens are highly influenced...
Changes to disturbance regimes resulting from shifts in forest management practices have created novel landscape conditions in the Pacific Northwest (PNW). I analyzed the implications of changes to landscape conditions caused by forest management for the spread of a native root disease: black stain root disease (BSRD) of Douglas-fir. BSRD...
Red fir (Abies magnifica) is a high elevation conifer generally growing between an altitude of 1,400 and 2,700 meters. In California, red fir grows in the Sierra Nevada, the Klamath Mountains, the eastern edges of the northern Californian Coast Ranges, and in the southern Cascades. Red fir commonly grows in...