Treesearch

For as long as logs have been exported from the Pacific Northwest, they seem to have been worth more offshore than in the domestic market. Five reasons for the export premium are the inconvenience of trade, quality, extra "haul and hassle," continuity in export arrangements, and export embargoes. A large and increasing differential remains between export and domestic prices for comparable logs in high grades. Logs of lower quality do not seem to have a dual price structure, and there appears to be a declining premium for logs overall. Year-to-year fluctuations in the premium can be...

The involvement of porcupines, Erethizon dorsatum (L.), in the ecology of Colorado tick fever (CTF) virus in Rocky Mountain National Park was investigated from 1975 to 1977. Porcupine dens and feeding activity were found mostly on rocky knolls or on south-facing slopes within open stands of the montane coniferous forest, and 20 adult porcupines were trapped or captured by hand at those locations. An average of 24.6 ± 5.4 adult Dermacentor andersoni Stiles ticks were found per animal (annual range, 17.5-31.4 ticks). The minimum CTF virus infection rate of the ticks removed from porcupines...

Twelve species of bats occur in Douglas-fir forests of the Pacific Northwest, of which nine are known to roost in tree cavities, bark crevices, or foliage, and several are closely associated with old-growth forests. Thus bat populations may be detrimentally affected by forest management practices involving the removal of large, old trees and snags. We review the life history characteristics and habitat relations of bats in the Pacific Northwest and provide information useful in managing forests for the persistence of native bat populations.

Tree seedling studies, covering a wide range of experimental conditions in pollutant treatment, species, facilities, and exposure regimes, have become commonplace in forestry research for assessing the actual and potential environmental effects of air pollutants on forest ecosystems. While assuring a wide breadth of scientific information, sufficient consideration has not been given to either the comparability of such population studies or to their appropriate inference. Th e populations of seedlings for which seedling experiments have inference, including the limitations in national or...

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...

Several hundred Rocky Mountain elk (Cervus elaphus nelsoni V. Bailey) and Rocky Mountain mule deer (Odocoileus hemionus hemionus Rafinesque) inhabit a fenced, 25,000-acre enclosure at the Starkey Experimental Forest and Range in the Blue Mountains of northeast Oregon. Research there requires handling most of these animals each winter. In addition, 33 elk calves have been captured and raised for research. Protocols for care and handling of deer and elk are described. Legal requirements for the operation of facilities and research within the enclosure also are discussed.

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.