Treesearch

Procedures are given forest estimating weights of potential residue from Douglas- fir and western hemlock created by forest management activities west of the summit of the Cascade Range. Preliminary estimates are given for six other species. The weight tables are in pounds per tree and pounds per square foot of basal area for a 6- or 8- inch unmerchantable tip. The estimates are also separated into material of: 3-inch diameter and total weight. The tabular weights include foliage, live and dead branchwood, and unmerchantable tip.

There have been 18 species-group names proposed for Nearctic conifer-feeding moths in the genus Choristoneura. Of these, houstonana (Grote) and its synonym, retana (Walsingham), apply to Cupressaceae-feeding populations now assigned to Cudonigera Obraztsov & Powell. The remaining species are Pinaceae-feeders, mostly members of two series: (1) the Fumiferana complex, associated with spruces and firs (subfamily Abietoideae) and considered to consist of 5 allopatric species (with three synonyms); and (2) the Lambert ianacomplex, feeding on pines (subfamily Pinoideae) and consisting of two...

Dwarf mistletoes in the Pacific Northwest infect true firs, larch, pine, Douglas-fir, and hemlock. Forty-one percent of all stands east of the crest of the Cascade Range and 10 percent of west-side stands are infected. General characteristics of dwarf mistletoe are discussed including mortality and growth losses rate of spread within a tree and within stands. Relation of site class and growth loss and the effect of management activities.

For nearly 50 years, effluents from pulp and paper mills have been known to be toxic to fish and other aquatic animals. Lethal concentrations have been determined for several species of fish and other organisms. Many factors- -such as water temperature, age of fish, and additional stresses—affect the ability of fish to withstand pollution. Kraft mill wastes are generally more toxic than sulfite wastes. The high biological oxygen demand of sulfite wastes is often more serious than the chemical toxicity of the effluents. Studies on the effect of kraft effluents on invertebrates show...

In the absence of prices for nonmarketed outdoor recreational services provided by public agencies, it is not possible to do a complete benefit cost analysis for proposed facilities for recreation. Good information on the cost of providing recreational services to the public is nonetheless important. This paper provides a step-by-step procedure that recreation planners can use to estimate the cost per user-day for proposed recreational facilities.

The 10-year growth of a 55-year-old, even-aged western larch (Larix occidentalis Nutt.) stand after it was thinned from above and below to a wide range of stocking levels was measured in eastern Oregon. Basal area and volume growth increased as stand density increased for both thinning methods. Despite heavy infestations of the larch casebearer during the last 4 years, diameter growth was greater in the second 5-year period than the first, but height growth was reduced considerably because of top dieback. Thinning from above reduced net volume growth because of mortality caused by windthrow...

The tri-tube cryogenic gravel sampler has been improved, and accessories have been developed that increase its reliability and safety of operation, reduce core extraction time, and allow accurate partitioning of cores into subsamples. The improved tri-tube sampler is one of the most versatile and efficient substrate sampling tools yet developed.

The population response of the northern red-backed vole (Clethrionomys rutilus) to a differentially cut white spruce (Picea glauca) forest 30 km southwest of Fairbanks, Alaska, was monitored by simultaneous livetrapping in a clearcut, in a partially cut or shelterwood area, and in an area of uncut forest. During the first summer after logging, vole density was similar in the shelterwood and uncut forest, but lower in the clearcut. Breeding occurred in all areas, and only overwintering females had litters. Movement between areas was minimal. Populations in all areas were similar in age and...

A possibly new species or subspecies of larch bud moth of the genus Zeiraphera, closely related to Z. improbana (Walker), was found associated with tamarack, Larix laricina (Du Roi) K. Koch, stands in interior Alaska. An outbreak occurred during 1975 and 1976 over an area of 240 000 ha (590,000 acres). Adult moths were mottled grayish in appearance. First instars emerged from the overwintering egg stage from mid to late May and began feeding as soon as the tamarack buds began to unfold. Pupation, adult emergence, and oviposition occurred from mid-June to mid-July and there was one generatio...

With some exceptions, the substitution of national forest timber for exported private timber is forbidden by regulations. Certain firms may use a limited amount of national forest timber as replacement for exported private timber, however, in accordance with their pattern of purchases and exports from 1971 through 1973. About 359 million board feet of national forest timber could be used annually as replacement for exported private timber by this provision; in 1977, about 102 million board feet was used in this fashion. About 81 percent of the replacement volume was from national forests...