Treesearch

A predictive technique using a simple linear regression was developed to forecast the midcrown density of small tussock moth larvae from estimates of cocoon density in the previous generation. The regression estimator was derived from field samples of cocoons and larvae taken from a wide range of nonoutbreak tussock moth populations. The accuracy of the predictions was demonstrated on an operational basis in an independent tussock moth outbreak.

Variation in diameter, height, and stem volume of 57-year-old Douglas-fir(Pseudotsuga menziesii var. menziesii (Mirb.) Franco) was related to distance of these trees from a 27 m wide strip in the same Douglas-fir plantation that had been interplanted with red alder (Alnus rubra Bong.). Within the interplanted strip and despite its greater total stand density, bole volume of dominant and codominant Douglas-fir averaged 1.27 m 3 compared with 0.55, 0.45, 0.46, or 0.49 m 3 in trees 15, 30, 45, or 60 m, respectively, from the edge of the mixed stand. Some positive influence of nitrogen-fixing...

Inexpensive camera systems have been successfully used to detect the occurrence of martens, fishers, and other wildlife species. The use of cameras is becoming widespread, and we give suggestions for standardizing techniques so that comparisons of data can occur across the geographic range of the target species. Details are given on equipment needs, setting up the stations, checking and recording, summarizing data, and research needs.

Foliage was collected from paired Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco) trees characterized as either "resistant" or "susceptible" western spruce budworm (Choristoneura occidentalis Freeman (Lepidoptera: Tortricidae) attack. Resistant trees produced more foliage monoterpenes and broke bud 7 to 10 days earlier than susceptible trees.

A satellite meeting of the 10th Forestry World Congress focused on the methods used for forest sector analysis and their applications in both developed and developing countries. The results of that meeting are summarized, and a general approach for forest sector modeling is proposed. The approach includes models derived from the existing literature and can be used as a structure for applying forest sector analysis in developing countries.

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...