Treesearch

Changes in family composition during nursery production were evaluated by following individual seeds and seedlings of 36 wind-pollinated Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) families sown in mixture in two operational nurseries in western Washington and Oregon. Families differed significantly in emergence and in percent of seedlings culled for being too small. However, differences were small enough that family composition was largely unaffected. The observed changes in family composition did not markedly reduce genetic diversity and did not affect the genetic...

A total of 53 upland mixed communities were sampled and classified into five community types: Populus tremuloides/Arctostaphylos uva-ursi, Populus tremuloides/Shepherdla canadensis, Betula papyrifera-Populus tremuloides/Viburnum edule, Betula papyrifera-Populus tremuloldes/Alnus crispa and Picea glauca-Betula papyrlfera/Hylocomlum splendens. Community types were described by distribution and physical environment, vegetation composition, structural features, and relation to previously described vegetation units.

Instar development is recorded for the Douglas-fir tussock moth (Orgyia pseudotsugata) for two different elevations in the Boise National Forest, Idaho, in 1991. The percentage of the population by instars is associated with accumulated degree-days after eclosion, which can be used to predict the proper timing for spray application. For all practical purposes, areas can be released for spraying when third instars are initially found.

An elk-proof fence was built in 1987 at the Starkey Experimental Forest and Range in northeast Oregon. The 25,000-acre research enclosure holds several hundred Rocky Mountain elk (Cervus elaphus nelsoni V. Bailey) and Rocky Mountain mule deer (Odocoileus hemionus hemionus Rafinesque) year round. The fence, constructed with high-tensile Tightlock woven wire from New Zealand, is 8 feet high and requires minimal maintenance. Tension curves in the wire, unique to Tightlock deer fence, make it elastic. Injury to animals is minimized by this inherent "shock absorbing action." Techniques for...

Catastrophes and manipulation of stocking levels are important determinants of stand development and the appearance of future forest landscapes. Managers need stocking level guides, particularly for sites incapable of supporting stocking levels presented in normal yield tables. Growth basal area (GBA) has been used by some managers in attempts to assess inherent differences in site occupancy but rarely has been related to Gingrich-type stocking guides. To take advantage of information currently available, we used some assumptions to relate GBA to stand density index (SDI) and then created...

Data from six western States provided 1,251 life tables representing western spruce budworm, Chodstoneura occidentalis Freeman. These data provided projection capabilities for defoliation and successive budworm densities, as well as a basis for comparing survival rates among the three principal North American needle-eating budworms (western and eastern spruce budworms, and the jack pine budworm). Several modifications are suggested in current methods for managing budworm-susceptible forests, and suggestions are provided for further studies on the budworm life systems.

Provisional seed zones and breeding zones were developed for Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) in the Siskiyou National Forest in southwestern Oregon. Zones were based on maps of genetic variation patterns obtained by evaluating genotypes of trees from 260 locations in the region. Genotypes controlling growth vigor and growth rhythm were assessed in a common garden. Within the Forest, three breeding blocks were recommended, with different numbers of elevational bands in each block: from 0 to 610 meters, from 611 to 838 meters, and then a series of bands 152 meters wide at...

The fire-adapted forests of the Blue Mountains are suffering from a forest health problem of catastrophic proportions. Contributing to the decline of forest health are such factors as the extensive harvesting of the western larch and ponderosa pine overstory during the 1900s, attempted exclusion of fire from a fire-dependent ecosystem, and the continuing drought. The composition of the forest at lower elevations has shifted from historically open-grown stands primarily of ponderosa pine and western larch to stands with dense understories of Douglas-fir and grand fir. Epidemic levels of...

Log exports have been restricted in British Columbia for over 100 years. The intent of the restriction is to use the timber in British Columbia to encourage development of forest industry, employment, and well-being in the Province. Logs have been exempted from the within-Province manufacturing rule at various times, in varying amounts, for different reasons, and by changing procedures. Although policy clearly restricts log exports, the effects are not simple. The timber industry benefits from both financial returns due to exporting and a restricted log market, while policy changes and...

The commercial harvest of edible forest fungi has mushroomed into a multimillion dollar industry with several thousand tons harvested annually. The development of this special forest product industry has raised considerable controversy about how this resource should be managed, especially on public lands. Concerns center around destruction of forest habitat by repeated entry and harvest, gradual loss of the mushroom resource by potential overharvest, conflict between recreational users and commercial harvesters, and regulation and monitoring of future harvests. A key to wisely managing the...