Treesearch

A set of four visual inventories are proposed. They are designed to document scenic resources for varied scales of application, from regional and general to local and specific. The Northern Great Plains is used as a case study. Scenic analysis and identification of criteria extend earlier work. The inventory is based on (1) study of previously developed landscape analysis methods and their terminology; (2) examination of high altitude imagery and topographic maps as sources of visual information; and (3) field observations in the Northern Great Plains. Criteria include visual characteristic...

The California Department of Forestry's Team Teaching Fire Prevention Program consists of small-group discussions, slides or films, and a visit by Smokey Bear to school classrooms. In a survey, teachers and principals who had experienced the program responded favorably to it. The conduct by team members also received approval. The limited criticisms of the Program centered around apparent deviations from the established format. In a separate study, students exposed to the Program scored higher in tests of their under-standing of fire prevention principles than did those who had not been...

Existing systems for estimating site index of ponderosa pine (Pinus ponderosa Laws.) do not apply well to California stands where stocking is controlled. A more suitable system has been developed using trends in natural height growth, derived from stem analysis of dominant trees in California. This site index system produces polymorphic patterns of height development to 80 years of age. Using a second system, site index can be predicted in stands where dominants have reached a breast-height age of at least 4 years but have not attained a height of 20 feet. Accuracy of estimates by this...

The Forest and Rangeland Renewable Resources Planning Act of 1974 directs the Secretary of Agriculture to prepare an assessment of the nation's renewable resources and a program that will assure an adequate future supply of these resources. Responsibility for this work is assigned to the Forest Service. An inter-university symposium was held in 1976 to evaluate the first Assessment and Program. The workshop reports and the preparatory studies are summarized here, along with policy recommendations proposed.

In sexually reproducing plant species, the prevailing breeding system is of enormous importance in determining the patterns of group variation and subsequent race and species formation. The breeding system regulates the limits of the breeding population and the extent to which hybridization occurs. The breeding system in a species is governed by certain reproductive isolating mechanisms, which may be effective at many levels. One level at which isolation is operative is the interaction of pistil and pollen. In this case, pollen may be preferentially inhibited from germinating or growing in...

The molecular weight distribution of a linear homologous polymer is usually obtained empirically for any particular sample. Sample-to-sample comparisons are made in terms of the weight- or number-average molecular weights and graphic displays of the distribution curves. Such treatment generally precludes data interpretations in which a distribution can be described in terms of differing proportions of mixed populations. However, a statistical continuous univariate distribution function such as the Weibull can be applied to the molecular weight distributions measured for cellulose nitrate...

Even before weight loss in the low-temperature pyrolysis of cellulose becomes significant, the average degree of polymerization of the partially pyrolyzed samples drops sharply. The gel permeation chromatograms of nitrated derivatives of the samples can be described in terms of a small number of mixed size populations—each component fitted within reasonable limits by a Weibull distribution function. The modal value of each component is taken as an integral multiple of a "macromonomer" of nominal degree of polymerization 228.4. Thus, the data are consistent with a model in which the...

In Mediterranean climates, the shrubby plant cover and the coniferous forest above it are vulnerable to frequent large fires. The fuelbreak, a strip of land in a strategic area-such as a ridgetop-where fuel modification and often type conversion can be accomplished, is an approach to fire suppression being widely applied in the Western United States, particularly California. The fuelbreak concept and fuel modification practices have been developed extensively since the 1950's. Fuelbreak system planning is integral to land-use and fire control planning. Fuel modification practices include...

Dwarf mistletoe had no noticeable effect on trunk taper of young, dominant and codominant red firs 4 to 22 inches (10.2 to 55.9 cm) d.b.h. Also, taper was not influenced by live crown ratio of infected and uninfected trees. Trees less than 7 inches d.b.h. had significantly more taper than larger trees, irrespective of dwarf mistletoe.

The technique proposed allows interpolation of data recorded at unevenly spaced sites to a regular grid or to other sites. Known data are interpolated to an initial guess field grid of unevenly spaced rows and columns by a simple distance weighting procedure. The initial guess field is then adjusted by using a parabolic leapfrog correction and the known data. The final output is then generated by use of cubic spline interpolation on the adjusted grid. Application to test and actual data showed acceptably low root-mean-square error.