Treesearch

An understanding of fire spread is important to the development of improved methods and systems for the control of free burning fires. Gaining knowledge about fire spread in forest fuels is complex because many variables are involved and because we still lack full understanding of the interaction of these variables. The research reported here involves studies of fire spread in natural forest fuels in which the characteristics of the fuel and the weather environment were controlled.

The purpose of this study was to determine the effects of various intensities of grazing upon roots and root systems of plants native to the ponderosa pine zone of the Colorado Front Range. It was designed to ascertain the root characteristics of certain species of the plant community and any changes in root distribution induced by 17 years of moderate and heavy grazing by cattle. The cumulative effects of such grazing are also illustrated.

This paper indicates a method of judging range condition of grassland areas in the ponderosa pine forest of the Colorado Front Range based on relative herbage production of desirable forage species. The loop method of Parker (1951) is now widely used in range management. Data obtained by the method include measurements of vegetation (cover index, composition, and vigor) and soils and erosion (bare ground and litter). Vigor is represented by leaf-height measurements of the major forage species. Guides for using these data for estimating range condition and trend in range condition on many...

A method of exposing root systems of individual plants or plant communities has been developed and used successfully at the Manitou Experimental Forest in Colorado. Called the nail-board method, it incorporates techniques used by Pavlychenko (1937), Weaver and Darland (1949), and especially adapts those of de Roo (1957). Soil monoliths containing root samples are excavated in a nail-studded frame. The nails retain the roots in their natural positions while the soil is washed away. The method proved effective in sampling root systems of native ranges and should be adaptable to crop plants.

Two tables prepared for use with the National Fire-Danger Rating System replace 10 tables previously used with the Model-8 Fire-Danger Rating System. They provide for the conversion of Spread Index values at various altitudes, aspects, and times of day. A rate of spread table facilitates converting Spread Index values to chains per hour of perimeter increase for various fuel types and slope steepness.

Field personnel in all forest fire protection agencies need some simple but reasonably accurate method for evaluating severity of the fire season as it progresses and of comparing severity of the current season with that of preceding fire seasons. This paper proposes use of records of average fuel moisture percentages cumulated continuously for 5-day periods throughout successive fire seasons. Records for all seasons must start on the same calendar day. Beginning and closing dates should be selected so as to enable complete recording of buildup to and recovery from the peak of each...

The study of the interesting agaric family, Gomphidiaceae, was undertaken in 1958. Since that time collections have been made and examined from Idaho, Washington, Oregon, Montana, and the Upper and Lower Peninsulas of Michigan. Collections from New Hampshire failed to yield any specimens in this genus. All but three of the North American species have been studied from fresh material. In addition, the help of Dave Largent in sending fresh material via air mail from California is acknowledged. A large number of collections of dried material were examined at the University of Michigan...

One of the most troublesome groups of the Boletaceae, as far as the recognition of taxa is concerned, has been the group generally known as the section Viscipelles of Boletus in the older literature. This group represented a "gray area" between Boletinus on the one hand and Boletus sensu lato on the other. However, attempts to distinguish species in Suillus were frustrating not so much because of the difficulty of recognizing them in nature by the ordinary characters used to distinguish species and varieties in the fleshy fungi generally, but because of the difficulty of interpreting the...

Diseases are a major concern to forest managers throughout the lodgepole pine type. In many areas, diseases constitute the primary management problem. As might be expected for a tree that has a distribution from Baja California, Mexico to the Yukon and from the Pacific to the Dakotas, the diseases of chief concern vary in different parts of the tree's range. For this reason I would like to give first a capitulation of some of the common diseases of lodgepole pine; then I will discuss those of major importance and see what can be done about controlling them.

The productive capacity or site quality of an area enters into nearly every phase of forest management from regeneration to final harvest. No standards or measures of site quality have been developed specifically for ponderosa pine in the Southwest, which handicaps the forest manager. The major objective of the present study was to develop the basic site-index curves for young-growth ponderosa pine by means of which a relative growth capacity may be assigned to each forest condition in the forests of Arizona. Secondary objectives were to test the applicability of suggested mensurational...