United States 

 Department of 

 Agriculture 



Forest Service 



Intermountain 

 Forest and Range 

 Experiment Station 



Research Paper 

 INT-273 



April 1981 



Biomass of 

 Singleleaf Pinyon 

 and Utah Juniper 



Elwood L. Miller, Richard O. Meeuwig, and 

 Jerry D. Budy 



INTRODUCTION 



The pinyon-juniper (p-j) woodland forest of the western 

 United States has a long history of use largely because of 

 the scarcity of timber in this region. For centuries this 

 woodland forest has provided people with nuts, fuelwood, 

 fenceposts, and poles (Fogg 1966). However, after the turn 

 of the century the importance of the p-j decreased 

 markedly mainly because of the availability of fossil 

 fuels, the decline in rural population, and the decrease in 

 mining. Although much of the research during the last 

 three decades was initiated to curtail or convert the p-j 

 (Box and others 1966), recent interest has focused on the 

 ecology, management, and potential use of this forest 

 resource (Aldon and Loring 1977; Springfield 1976; 

 Gifford and Busby 1975; Barger and Ffolliott 1972). Two 

 extensive p-j bibliographies were compiled by West and 

 others (1973) and by Aldon and Springfield (1973). 



The increased interest in p-j reveals the need for reliable 

 mensurational data. Although volume tables exist, they are 

 usually based on a small number of field measurements 

 often from a local area. During the late 1930's and early 

 1940's a number of workers developed volume tables based 

 on various tree variables. Howell (1937) found that crown 

 width and stump diameter best estimated volumes for one- 

 seed juniper in Arizona. Stump diameter and maximum 

 crown width were used to construct fuelwood volume 

 tables for one-seed and Rocky Mountain junipers (Howell 

 and Lexen 1939). Howell (1941) reported that differences 

 in volume for trees of similar stump diameter and crown 

 width were due to wide variations in tree form. Bradshaw 

 and Reveal (1943) developed tree classifications for 

 singleleaf pinyon and Utah juniper based on four maturity 

 classes. However, they still found wide variation in form of 

 trees in the same class. Blackburn (1967) developed six 

 age classes for both pinyon and juniper based on growth 

 ring counts, height, basal diameter, and outward 

 appearances. Reveal (1944) prepared volume tables for 

 singleleaf pinyon and Utah juniper based on diameter at 

 breast height (d.b.h.), tree height, and average crown 

 diameter measurements. 



Growth measurements on Utah juniper in Arizona were 

 made using tree height and stump diameter (Herman 1953). 

 Using the same trees, Myers (1962) later found no relation 

 between stump diameter and 20-year growth in height, 

 diameter, and volume. 



Aerial volume tables for pinyon-juniper stands were 

 developed using total height, average crown diameter, and 

 percent crown cover of the stand (Moessner 1962). Mason 

 and Hutchings (1967) estimated foliage yields of Utah 

 juniper based on crown diameter measurements. Storey 

 (1969) found that tree weights of singleleaf pinyon and 

 Utah juniper were closely correlated with maximum crown 

 diameter and average crown diameter. 



Although volume is the standard unit of measurement in 

 forestry, it is not satisfactory for noncommercial woodland 

 species such as pinyon and juniper, which lack a "mer- 

 chantable bole." In addition, various products have been 

 utilized from tree components other than the bole. 

 Biomass, or weight, as a unit of measurement appears more 

 reasonable in estimating the total quantity of usable wood 

 products available in the p-j woodland. Also, the 

 feasibility of whole-tree harvesting indicates a need for the 



aboveground biomass data. 



In the southern United States, biomass tables have been 

 developed for loblolly pine (Taras and Clark 1975), 

 shortleaf pine (Clark and Taras 1976), and longleaf pine 

 (Taras and Clark 1977). Crown biomass studies have been 

 conducted on lodgepole pine (Gary 1976) and on 11 

 species of Rocky Mountain conifers (Brown 1978). H. E. 

 Young (1976a) summarizes work from 62 forest biomass 

 studies. Numerous biomass studies are reported by the 

 Working Party on the Mensuration of the Forest Biomass 

 (IUFRO) in three volumes (Young 1976b, 1973, 1971). 

 Storey (1969) conducted the only study of tree weights 

 in the p-j woodland. Recently, a line-intersect method to 

 inventory cordwood in the p-j woodland was reported 

 (Meeuwig and others 1978). Clendenen (1979) developed 

 volume tables for p-j on the Carson National Forest in 

 northern New Mexico. 



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