This publication discusses the environmental requirements of needle diseases, their potential impact on tree vigor, when disease levels signal a problem, and what you can do to minimize damage.
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...
Forest managers of public lands in western Oregon and Washington have become increasingly interested in creating additional conifer cohorts in young, even-aged, second-growth Douglas-fir stands. The purpose of our research was to assess the establishment, survival, and growth of naturally-regenerated and underplanted conifers 10-13 years after overstory thinning and understory...
Containerized western larch, Douglas-fir, grand fir, subalpine fir, and ponderosa pine seedlings which displayed disease symptoms were sampled for presence of Fusarium spp. Seedlings from 33 seedlots within the Northern Region were sampled. Major types of diseases included post-emergence damping-off, root disease (late damping-off), and cotyledon blight. Fusarium oxysporum was...
Potential problem pests found were Armillaria root disease, pocket gopher, western pine shoot borer, and white pine blister rust. Early detection of problem pests allows management actions to be taken if needed to prevent serious impacts. Unit managers should check the areas periodically and call on pest management specialists to...
Isolates of Fusarium oxysporum, F. acuminatum, and F. sambucinum obtained from peat-vermiculite soil mixes were tested for pathogenicity on ponderosa pine, lodgepole pine, western larch, and blue spruce containerized seedlings and on germination of Scots pine and blue spruce seed. Ponderosa pine seedling were the least susceptible to killing by...
Insect damage was extensive to Douglas-fir, ponderosa pine, western white pine, and western larch cones at most seed production areas surveyed in 1979. From 70 to 100 percent of the cones from several collecting periods were injured. Moderate damage (40-70 percent of cones injured) occurred to Douglas-fir, ponderosa pine, western...
In spruce budworm damaged areas, height growth loss can be a major factor in stand development. This survey was confined to top-killed trees. Estimates on height growth loss or nontop-killed trees was not attempted. Although spruce did not have as high a percentage of trees top-killed as the true firs,...