Treesearch

To assess the adequacy of a permanent-plot data base for estimating growth and yield, one first needs to know how the plots in the data base are distributed in relation to the population they are presumed to represent. The distribution of permanent plots to study forest growth in the Inland Empire (northeastern Washington, northern Idaho, and western Montana) is displayed using a method that relates the permanent plots to the land base. The permanent plots are quantified into classes defined using inventory data that describe the land base. Five stand attributes are used to define the...

Maintaining permanent plot data with different sampling designs over long periods within an organization, and sharing such information between organizations, requires that common standards be used. A data structure for the description of the sampling design within a stand is proposed. It is composed of just those variables and their relationships needed to compile stand attributes and their variances. The data structure is able to incorporate changes in design that commonly occur through the life of a set of permanent plots. Using the data structure, seven actual or proposed designs, from...

Seventy-seven seedling populations of Douglas-fir (Pseudotsuga menziesii var. glauca) sampled from near the Continental Divide in Idaho and Montana exhibited pronounced genetic differences when compared in three common environments. Differentiation involved several traits that are components of an annual developmental cycle that must be completed within a growing season of finite length. Consequently, the elevational and geographic clines of genetic variation tend to parallel variation in the length of the growing season at the seed source. Such clines suggest that maladaptation in...

A pandora moth outbreak in Arizona was studied from 1979 to 1985 to determine the moth's life cycle, densities, and distribution of life stages, larval and adult behavior, effects of the defoliation, sampling procedures, importance of biotic mortality factors, and the effectiveness of insecticides. This report summarizes the available published and unpublished information on the outbreak.

The stem profile model of Max and Burkhart (1976) is conditioned for dbh and a second upper stem measurement. This model was applied to a loblolly pine data set using diameter outside bark at 5.3m (i.e., height of 17.3 foot Girard form class) as the second upper stem measurement, and then compared to the original, unconditioned model. Variance of residuals was reduced; however, bias was approximately the same for both the conditioned and unconditioned models. Benchmark prediction problems, which reflect common multiproduct utilization criteria for southern pines, were used to judge the...

This vegetation classification is based upon existing community structure and composition in the aspen-dominated forests of the Intermountain Region of the Forest Service. The 56 community types occur within eight tree-cover types. A diagnostic key using indicator species facilitates field identification of the community types. Vegetational composition, productivity, and successional status are included. Tables provide detailed comparisons of community types. The classification and descriptions are based upon field data from over 2,100 aspen stands scattered over southeastern Idaho,...

Although growth and yield models have been used to update forest inventories for large regions, such models poorly predict cover changes from land use conversions, regeneration, and harvest. These changes could be monitored directly for large areas using remote sensing, which can be expensive, or estimates made by agricultural agencies, which are not detailed for condition of timberlands. The Kalman filter, which is a flexible statistical estimator, might increase statistical efficiency and produce annual estimates of cover by combining such direct monitoring with past knowledge (i.e.,...

Three trapping techniques for small mammals were used in 47 study stands in northern California and southern Oregon and resulted in different capture frequencies by the different techniques. In addition, the abundances of mammals derived from the different techniques produced vegetation association models which were often quite different. Only the California redbacked vole (Clethrionomys californicus) showed any association with stand age, and no species had any marked associations with the moisture regime of the stands or the geographical regions.

Eight-year tree growth of western larch (Larix occidentalis) and Douglas-fir (Pseudotsuga menziesii) was measured following prescribed underburning on burned and control plots in western Montana. Western larch on bun.ed plots had reduced radial growth in the first year following fire but increased growth in the next 7 years. Douglas-fir had similar growth on burned and unburned plots. Growth was not reduced by low levels of crown scorch or cambial injury. Stand basal area growth was less on burned plots due to high fire-caused mortality.

Mortality was determined in a stand of Douglas-fir 8 years after 20 plots were treated with light surface fires. Logistic regression was used to model long-term mortality as functions of morphological variables measured shortly after burning. Independent variables were diameter at breast height, height of needle scorch, percentage of the prefire crown volume scorched, season of burn, and the number of quadrants with dead cambium at 1.4 m bole height. Mortality increased with increasing scorch height, percent crown scorch, and dead cambium. It decreased with larger diameter. The best...