This study was directed to improve our understanding of the ecology of Swiss needle
cast (SNC) of Douglas-fir, a disease that produces extensive damage to forests and
plantation in the coastal region of Oregon and Washington. A disease prediction model
for the coastal area of Oregon was built by establishing...
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...
Understory species associations and their association with tree species were examined on three intensively studied stands. We studied the chronosequence of understory species associated with different aged singleleaf pinyon (Pinus monophylla Torr. and Frem.) trees. Mid- to late pinyon-juniper understory succession was found to be more spatial than floristic in...
This study was undertaken to determine the
effects of different chilling treatments during the dormant
season upon growth of Douglas-fir seedlings0 In
addition it was planned to determine whether seedlings
native to various geographic areas differ in their chilling
The hypotheses were advanced, based on previous
studies, that chilling...
Hypersensitive response-like (HR-like) needle reactions to infection by the white pine blister rust pathogen, Cronartium ribicola, have been reported for several species of five needle pines native to western North America. The best-studied examples are in Pinus monticola and P. lambertiana. In these species a "needle spot" phenotype has been...
The genus Lopidea Uhler is revised for America north of
Mexico. The relationship of Lopidea to other orthotyline
genera is discussed and it is proposed that the genus
Ilnacora Reuter is the sister group of Lopidea.
Forty-eight species of Lopidea are recognized in North
America, one of which is described...
Coast redwood (Sequoia sempervirens) (D. Don) Endl. is a host for Phytophthora ramorum but it was unclear if the pathogen represents a significant disease risk to this tree species. In this study the susceptibility of coast redwood seedlings and the likelihood of sporulation on redwood were examined. Two methods were...