Physical Site Factors Influencing Annual Production of True Mountain Mahogany, Cercocarpus Montanus

Abstract

True mountain mahogany (Cercocarpus niontanus Raf.) is a widely distributed browse species of major importance in the western United States. The palatability is good to excellent for all classes of livestock and it is onie of the most valuable winter foods for deer and other herbivorous big game animals. Fundamental knowledge of the ecology of this browse plant is extremely limited. Increasing emphasis on the miiaintenance and manipulation of browse ranges requires that basic information be obtained oni the plants providing the forage. The purpose of this study was to determine the role of physical site factors which inifluence the annual production of true moulntain imahiogalny. The investigation was designed to identify the physical site factors significantly infIluencilng the annual production of true mlouniitaini mahograny, and to assess the relative importance of these factors. Site factors are commonly grouped into two primary classifications: living and non-living. The non-living factors may be divided into the broad categories of climate and physiography. This study is concerned with the physiographic factors relating to soil and topographv. For invaluable counsel aind directioni (lurirlg the study the author wishes to thanklik the following individuals: Dr. Lee E. Yeager, Leader, Colorado Cooperative Wildlife Research UTnit, Colorado State University; Dr. Harold WV. Steinihoff alnd Prof. Charles Terwilliger of the College of Forestry and Range Managemiienit, Colorado State University; Mr. E. H. Reid and Dr. Jacob L. Kovner, Clhief, Divisioni of Ra-nge Researchi alnd Mathematical Statistician, respectively, of the 1 Based on a thesis submitted to the Graduate School of Colorado State University, Fort Collins, Colorado. The investigation was sponsored, financed, and supervised by the Colorado Cooperative Wildlife Research Unit and the Colorado Game and Fish Department, Federal Aid Project W-101-R. Publication by permission of the Dean, Graduate School, Colorado State University. 2 Formerly graduate fellow, Colorado Cooperative Wildlife Research Unit; the Colorado Game and Fish Department, the Colorado State University, the Wildlife Management Institute, Washington, D. C., and the Bureau of Sport Fisheries and Wildlife, U. S. Fish and Wildlife Service, cooperating. Rocky Mountain Forest and Range Experiment Station; Dr. Elmer E. Remmenga, Director, Statistics Laboratory, Colorado State University; and Dr. John L. Retzer, Staff Assistant, Forest Soils, U. S. Forest Service, Washington, D. C.