Treesearch

A fully illustrated key is presented for identifying genera of oribatid mites known from or suspected of occurring in the Pacific Northwest. The manual includes an introduction detailing sampling methodology; an illustrated glossary of all terminology used; two color plates of all taxa from the H. J. Andrews Experimental Forest; a diagrammatic key to the 16 major groups of adult oribatids; illustrations to aid in quick recognition of the 16 adult groups; keys to all adult genera; and a diagrammatic key to the major types of immature oribatid mites with local species illustrated. The text...

Four plausible sets of stumpage supply and demand equations were developed and estimated; the demand equation was the same for each set, although the supply equation differed. The supply specifications varied from the model of regional excess demand in which National Forest harvest levels were assumed fixed to a more realistic model in which the harvest on the National Forests depended on current Federal timber sales, uncut-volume-under-contract, and stumpage price. Each set of equations was estimated with annual time-series data for Montana to test the effect of changing supply specificati...

A statewide inventory of shrubs in chaparral and on timberland and woodland in California is presented, and the relevance of shrubs to resource management is discussed. Shrub types (excluding coastal sage and Great Basin and desert shrubs) cover about 10 million acres, 73 percent of which is chaparral. Chamise is the most widespread type in chaparral (51 percent of total area). Critically flammable chaparral stands cover an estimated 1 million acres, much of which is in heavily populated southern California. More than 2 million additional acres are on the threshold of the critically...

The need for and the evaluation of elk-habitat evaluation models are reviewed, and a state-of-the-art example is presented that incorporates distribution of elk-habitat use related to distance from cover/forage edges, distance from roads, cover quality, and forage quantity and quality.

The 2412-hectare Mount Prindle Research Natural Area is located in central Alaska on the border of the Steese National Conservation Area and White Mountains National Recreation Area. It is managed by the U.S. Department of the Interior, Bureau of Land Management, Steese-White Mountains District. Mount Prindle was selected as a Research Natural Area (RNA) because it contains outstanding examples of solifluction lobes; habitat for wheatear (a small thrushlike bird), caribou, and Dall sheep; the yellow-flowered mustard Draba paysonii, which is uncommon in Alaska; a diversity of alpine plant...

Interspecific crosses of Abies religiosa (HBK.) Schlecht. & Cham. (oyamel) with Abies concolor (Gord. & Glend.) Lindle. ex Hildebr. var. concolor (white fir) and Abies magnifica A. Murr. (California red fir) were undertaken to explore the relationships between these species. The cross with A. magnifica produced no germinable seed, but many sound seeds were produced from the cross with A. concolor. These were sown in the nursery in 1968 and outplanted in 1970. In 1983, morphological characteristics of seven putative hybrids were compated with those of teh A. concolor seed parent, herbarium...

Scribner board-foot, merchantable cubic-foot, and total cubic-foot volume equations were derived from fall, buck, and scale data for 441 trees at 78 locations in the Susitna River basin, Alaska. Tree species included white and black spruce, paper birch, black cottonwood, and quaking aspen.

The current annual twigs of unbrowsed Barclay willow (Salix barclayi Anderss.) grow as gently tapering cylinders. Consequently, the distal half of the twig has only 33 to 41 percent of the total weight. Longer twigs have proportionally less weight in the distal end. The total weight of an unbrowsed twig can be estimated by simple regression of weight on an independent variable that approximates the volume of the twig (diameter of the twig immediately above the most recent bud scar times total length of the twig). Simple regression can also be used to estimate the weight of twig removed by...

Twenty-year postoutbreak growth was compared in thinned and unthinned, severely defoliated stands. Basal area of unthinned white fir has declined 37 percent and pine basal area has increased 32 percent since 1964. The stand thinned in 1960 has the lowest basal area in the study area, but the greatest tree growth before and after the outbreak. All defoliated fir are growing significantly faster during the 16 years after the outbreak compared to before the outbreak. Thinned stands, even though not resistant to defoliation, may be able to recover more rapidly and to a much greater magnitude...

After three growing seasons, young Douglas-fir trees in plots of various sizes that had been totally cleared of nonconifer vegetation were larger than trees in plots that had been partially cleared or not cleared at all. On the Bybee unit (Illinois Valley Ranger District, Siskiyou National Forest), height and diameter differences were highly significant between treatments. Diameter differences between the treatments were highly significant on the Squaw unit (Illinois Valley Ranger District, Siskiyou National Forest).