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Log weights were estimated from the product of Huber's cubic volume formula and green density. Tags showing estimated log weights were attached to logs in the field, and the weights were tallied into a single load weight as logs were assembled for aerial yarding. Accuracy of the estimated load weights was evaluated by comparing the predicted with the actual load weights as measured with scales in a helicopter. A total of 110 loads were evaluated. The load weights were accurate (about 10-percent error), and the method was easily applied under difficult logging conditions. The number of...

We present a technique, based on microhistological analysis of fecal pellets, for quantifying the diets of forest rodents. This technique provides for the simultaneous recording of fungal spores and vascular plant material. Fecal samples should be freeze dried, weighed, and rehydrated with distilled water. We recommend a minimum sampling intensity of 50 fields of view for each of three slides per sample. Absolute and relative percentage of frequencies per sample can then be calculated.

Fishery scientists and managers are interested in obtaining information about downstream movements of fish species for biological and economic reasons. Different types of nets and traps have been used for this purpose with only partial success. The floating, self-cleaning downstream migrant trap described here proved successful for sampling several salmoniform and cypriniform species. The trap functions effectively for several streamflow ranges and handles small floating debris without loss of efficiency. Data from these floating traps show a range of trapping efficiency from 5.0 to 46.6...

Wildlife-habitat models are increasing in abundance, diversity, and use, but symptoms of failure are evident in their application, including misuse, disuse, failure to test, and litigation. Reasons for failure often relate to the different purposes managers and researchers have for using the models to predict and to aid understanding. This paper examines these two purposes and the nature of problems or failures in model application. A five-step approach toward solution is presented: (1) recognize the problem, (2) nurture modeling teams, (3) match purpose with test, (4) confront basic...

The growth response after 20 years from an initial spacing study established in a ponderosa pine (Pinus ponderosa Dougl. ex Laws.) and lodgepole pine (Pinus contorta Dougl. ex Loud.) plantation was measured in central Oregon. The study was designed to compare the growth rates of pure ponderosa pine, pure lodgepole pine, and a 50-percent mixture of each species planted at 6-, 9-, 12-, 15-, and 18-foot spacings. Diameter growth of pure ponderosa pine was greater than that of pure lodgepole pine at all spacings, although pure lodgepole grew faster in height than pure ponderosa. Growth of the...

Thirty grand fir (Abies grandis (Dougl. ex D. Don) Lindl.) trees were artificially inoculated with the fungal symbiont, Trichosporium symbioticum Wright, to simulate attack by the fir engraver beetle, Scolytus ventralis LeConte. Fifteen months after treatment, secondary resin production, necrotic lesion formation, and percentage of wounds with T. symbioticum were determined in relation to tree vigor and inoculation density. Resin production was significantly greater in high-vigor trees but was not affected by inoculation density or degree of fungal colonization. Lesions from inoculated...

Provides current information on lumber and plywood production and prices; employment in the forest industries; international trade in logs, lumber, and plywood; volume and average prices of stumpage sold by public agencies; and other related items.

Bats represent the second most diverse group of mammals inhabiting the western slopes of the Cascade Range in southern Washington and the Oregon Coast Range. Bat populations may well be sensitive to changes in forest age, structure, or distribution, but their nocturnal habits and high mobility render the study of the habitat requirements of bats problematical. Unlike most other groups of vertebrates, bats are difficult to either observe or capture, and survey methods are poorly known. This paper reviews techniques for surveying bat populations and presents the methodology used in the...

A stochastic model useful in simulating daily maximum and minimum temperature and precipitation developed by Bruhn and others has been adapted for use in the western spruce budworm modeling system. This document describes how to use the weather model and illustrates some aspects of its behavior.

Fishery managers are currently spending millions of dollars per year on habitat enhancement for anadromous salmonids but often do not have the tools needed to ensure success. An analysis of factors limiting production of salmonids in streams must be completed before any habitat-enhancement program is begun. This paper outlines the first formal procedure for identifying physical habitats limiting production of coho salmon.