Treesearch

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).

The results of a statewide inventory of California's hardwood resources are presented. This is the first comprehensive inventory with tree and stand measurements ever conducted in the extensive oak woodlands. In timberland areas where hardwoods had been previously inventoried, improved procedures and volume equations developed specifically for the major California hardwood species were used in the new inventory. Included are details on area and volume of hardwoods by ownership; growth and mortality of hardwoods on timberland; hardwood tree cutting on timberland and woodland; the extent of...

The yield-table projection method for modeling the development of regional timber inventories is outlined, and its application to softwood timber types in the Southern United States is described. Problems of simulating forest management practices and natural succession are discussed. A computer model that projects softwood timber inventories using yield-table projection and stand regeneration using a Markovian probability structure is presented. The methodology and projections of this model are compared with alternative approaches to predicting future timber inventories in this region.

Pruning of coast Douglas-fir was evaluated; recent product recovery information for pruned and unpruned logs for both sawn and peeled products was used. Dimensions of pruned and unpruned trees were simulated with the Douglas-fir stand simulator (DFSIM). Results are presented for a range of sites, ages at time of pruning, ages at time of harvest, product prices, and interest rates, and for both fertilized and unfertilized regimes.

This report presents an assessment of macronutrients and their distribution within highly stocked, stagnant stands of mixed conifers on the Quilcene Ranger District, Olympic National Forest, northwest Washington. These stands consisted of predominantly three species: western hemlock (Tsuga heterophylla (Raf.) Sarg.), coast Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii), and western redcedar (Thuja plicata Donn ex D. Don). Preliminary investigation suggests that the living crown contains a small portion of the nutrient capital on the site. Extracting this material from...

Provisional seed zones and breeding zones were developed for sugar pine (Pinus lambertiana Dougl.) in southwestern Oregon. Zones are based on a map of genetic variation patterns obtained by evaluating genotypes of trees from 142 locations in the region. Genotypes controlling growth vigor and growth rhythm were assessed in a common garden. Within southwestern Oregon, two zones are recommended for low elevations (740 and 1172 m).

No significant increases in annual water yield were shown for three small watersheds in northeastern Oregon after shelterwood cutting (30-percent canopy removal, 50-percent basal area removal) and clearcutting. Average maximum air temperature increased after harvest and average minimum air temperature decreased by up to 2.6 °C. Both maximum and minimum water temperatures decreased slightly in two streams as compared with the control stream. Wind passage and velocities increased dramatically with removal of the forest cover. Both snow depth and snowpack water content increased in clearcuttings.