Treesearch

A simulation model was developed to estimate postfire changes in the production and value of grazing lands in the Northern Rocky Mountain-Intermountain region. Ecological information and management decisions were used to simulate expected changes in production and value after wildfire in six major rangeland types: permanent forested range (ponderosa pine), transitory range (Douglas-fir, larch, lodgepole pine, western white pine), mountain grassland, sagebrush, pinyon-juniper, and western hardwoods. Changes varied widely in quantity and duration among the range types. The largest decrease...

A cost-aggregation approach has been developed for determining the cost of Fire Management Inputs (FMls)-the direct fireline production units (personnel and equipment) used in initial attack and large-fire suppression activities. All components contributing to an FMI are identified, computed, and summed to estimate hourly costs. This approach can be applied to any FMI by any organization with fire protection responsibility. Significant cost differences were found not only among the three State fire organizations studied, but among the three administrative regions within the Forest Service....

Selected crown and bole characteristics were predictor variables in growth classification equations developed for California red fir, Shasta red fir, and white fir in northern California. Individual firs were classified on the basis of percent basal area increment (PCTBAI ) as Class 1 (≤ 1 pct), Class 2 (> 1 pct and ≤ 3 pct), or Class 3 (> 3 pct). Data from increment borings indicated that the equations accurately classified about 75 percent of trees at least 4 inches (10 cm) in diameter-at-breast-height (d.b.h. ), except those firs in stands seriously disturbed within the previous decade...

Automatic discrete sample pumping systems used to monitor water quality should deliver to storage all materials pumped in a given cycle. If they do not, successive samples will be contaminated, a severe problem with highly variable suspended sediment concentrations in small streams. The cross-contamination characteristics of two small commonly used portable pumping samplers are compared to each other and to reference measurements under conditions of sudden and severe changes in suspended sediment concentrations. The pressure-vacuum sampler showed greater cross contamination, especially...

Local volume tables for Pacific madrone (Arbutus menziesii Pursh), tanoak (Lithocarpus densifiorus [Hook. & Am.] Rehd.), and California black oak (Quercus kelloggii Newb.), developed from data recorded by an optical dendrometer, are presented by 1-inch diameter classes in the range of 3 to 30 inches. Cubic volume tables are given for each species to treetop. and to a 4-inch diameter top. For Scribner board-foot volume. a similar table to a 4-inch top is provided. The tables apply to trees in the northern Sierra Nevada and, possibly, in the southern Cascade Range where site quality generally...

Abstract - A depth proportional intake boom for portable pumping samplers was used to collect suspended sediment samples in two coastal streams for three winters. The boom pivots on the stream bed while a float on the downstream end allows debris to depress the boom and pass without becoming trapped. This equipment modifies point sampling by maintaining the intake nozzle at the same proportion of water depth regardless of stage. Data taken by pumping samplers with intakes mounted on the boom were compared with depth integrated hand samples. Pumped samples showed higher concentrations then...

In the young-mature mixed-conifer and hardwood forests of north-central California, a dense and persistent hardwood understory competes with the conifers for space, nutrients, and water. Clear-cutting with intensive site preparation often is the most appropriate silvicultural regeneration method. This report, the result of 20 years of research on the Challenge Experimental Forest in Yuba County, California, evaluates one approach to clearcutting. Topics discussed are broadcast burning, windrow and burning, seedfall, rodents, woody shrubs, seedling stocking, and early growth of conifers....