INTRODUCTION 



The singleleaf pinyon (Pinus monophylla) -Utah juniper (Juniperus osteosperma) 

 woodland of the Great Basin has had a long history of use; but because of the noncom- 

 mercial status of the two species, there has been little research on their silvical 

 characteristics. Reveal (1944) reported on the stand and tree characteristics of 

 singleleaf pinyon and Utah juniper in the Pine Nut Range in western Nevada. Herman 

 (1953, 1956) studied the phenology and growth characteristics of Utah juniper in central 

 Arizona. Daniel and others (1966) made an extensive study of pinyon- juniper woodlands 

 in Utah, Arizona, northwestern New Mexico, western Colorado, and eastern Nevada, but 

 they dealt lightly with tree growth rates. 



Other species of pinyon and juniper have received more attention than singleleaf 

 pinyon and Utah juniper. Howell (1940) studied the growth and yield of Colorado pinyon 

 (Pinus edulis) , one-seed juniper {Juniperus monospevma) , and Rocky Mountain juniper 

 (J. saopulorum) in New Mexico and Arizona. The silvical characteristics of Colorado 

 pinyon, Rocky Mountain juniper, and western juniper (J", occidentalis) were summarized 

 in Agricultural Handbook No. 271 (Fowells 1965) . 



As the demand for firewood and other pinyon- juniper products continues to increase, 

 the harvesting of these trees can be expected to increase dramatically, and more spec- 

 ific information will be needed for productive management of pinyon- juniper woodlands. 

 In 1977, we began a study to obtain silvical information on singleleaf pinyon and Utah 

 juniper. A secondary objective of the study has been to obtain data on intensively 

 measured plots to provide standards for checking the accuracy of sampling methods that 

 have been or will be developed for studying or inventorying pinyon- juniper stands. 



This paper contains the results of the first year of study in a predominantly 

 pinyon woodland in the Sweetwater Mountains along the California-Nevada border. Single- 

 leaf pinyon growing in these mountains were studied to determine their rates of height 

 and diameter growth in relation to tree age and competitive position, the basal area 

 increment patterns of these pinyon stands, and the rates of wood, foliage, and above- 

 ground biomass increments of both individual trees and stands. Similar data will be 

 obtained on other pinyon- juniper woodlands in the Great Basin during the course of this 

 project. 



STUDY AREA AND PLOT DESCRIPTIONS 



This study was made in a pinyon firewood sale area on the Bridgeport Ranger 

 District, Toiyabe National Forest. The area is approximately 12 miles north of Bridge- 

 port, California, between Green Creek and Frying Pan Creek on the east slope of the 

 Sweetwater Mountains. Three plots--Green Creek, Cattle Trough, and Monte Cristo--were 

 established in the study area; the aspect, slope, elevation, and percentage of over- 

 story cover of each plot are presented in table 1. All three plots are on stony soils 

 derived from rhyolitic colluvium. The stands at Green Creek were younger than those 

 at Cattle Trough, but the oldest trees were found at Monte Cristo (table 2) . 



There has been a great deal of mining activity in the Sweetwater area and most of 

 the stands are second- growth, dating from cuttings that furnished fuel and timber to 

 the miners in the early 1860's (Wilson 1941). The absence of stumps in the area raises 

 some question as to the past cutting, but Lord (1883) reported that Chinese laborers 

 followed the woodcutters, pulling up the stumps, roots, and shrubs from the cutover 

 hills. 



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