United States

Department

of Agriculture

Forest Service

Intermountain

Forest and Range

Experimental Station

Research Paper

INT-273

April 1981

Biomass of

Singleleaf Pinyon

and Utah Juniper

Elwood L. Miller, Richard O. Meeuwig, and

Jerry D. Budy
THE AUTHORS 

ELWOOD L. MILLER is associate professor of forestry in 

the Division of Renewable Natural Resources, Max C. 

Fleischmann College of Agriculture, University of 

Nevada, Reno. He has a B.S.F. degree from Northern 

Arizona University, Flagstaff; an M.F. degree from 

Oregon State University, Corvallis; and a Ph.D. degree 

in forest ecology from Michigan State University, East 

Lansing. 

RICHARD 0. MEEUWIG is a research forester and leader of 

the l ntermountain Station's Pinyon-Juniper Ecology and 

Management research work unit at the Renewable 

Resources Center, University of Nevada, Reno. He 

has B.S. and M.S. degrees in forestry from the University 

of California, Berkeley, and a Ph.D. degree in soil 

physics from Utah State University, Logan. 

JERRY D. BUDY is assistant professor of forestry in the 

Division of Renewable Natural Resources, Max C. 

Fleischmann College of Agriculture, University of 

Nevada, Reno. He has a B.S. degree from the University 

of Wisconsin, Madison, and is completing requirements 

for a Ph.D. degree in forest hydrology at the University 

of Nevada, Reno. 

ACKNOWLEDGMENT 

Special thanks are due Clair Baldwin, Austin Ranger 

District, and Barry Davis, Bridgeport District of theToiyabe 

National Forest; John Wilcox, Ely District, and Garth 

Baxter, Wells District of the Humboldt National Forest for 

their cooperation in locating study sites and providing 

maps. 

RESEARCH SUMMARY 

Relationships between tree measurements and biomass 

of singleleaf pinyon (Pinus monophylla) and Utah juniper 

(Juniperus osteosperma) were investigated on 109 trees 

on 19 study sites in Nevada and eastern California. The 

resulting equations and tables provide a means for 

estimating the total aboveground biomass as well as the 

weights for the various size fractions by species. The 

tables can also be used to estimate the cordwood and 

slash resulting in a typical fuelwood harvesting operation. 

The entire aboveground biomass was separated into four 

size classes and weighed in the field. Cross-sectional 

disks and samples of twigs, foliage, and deadwood were 

used to determine the moisture contents of the various size 

fractions. The relationships between tree measurements 

and ovendry weights of the various size fractions were 

evaluated utilizing stepwise multiple regression techniques. Of the 13 tree measurements evaluated, stem 

diameter and average crown diameter were the most highly 

correlated with the ovendry weights. 

CONTENTS 

Page 

INTRODUCTION ................................... 1 

METHODS ......................................... 2 

Study Locations .................................. 2 

Field Techniques ................................. 2 

Tree Measurements.. ............................. 2 

Laboratory Analysis .............................. 3 

RESULTS .......................................... 3 

Total Tree Biomass.. ............................. 3 

Regression Analysis .............................. 5 

Equations ........................................ 5 

Weight Tables.. .................................. 6 

CONCLUSIONS .................................... 10 

PUBLICATIONS CITED.. ........................... 10 

APPENDIX A....................................... 12 

APPENDIX B....................................... 14 

APPENDIX C....................................... 16 
United States 

Department of 

Agriculture 

Forest Service 

Intermountain 

Forest end Range 

Research Paper 

I NT-273 

April 1981 

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 boring 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 oneseed 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 "merchantable bole.'Vn 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 (Tams 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 (Brawn 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 

(IUFRCB) 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. 
The study reported here was initiated largely because of 

the lack of a sufficient unit of measurement for making 

decisions on the potential use of p-j woodland resources. 

Because of the growth habit of p-j and its various potential 

wood products, biomass was selected as the unit of 

measurement to be evaluated and determined in this study. 

Objectives of the study were to: 

1. Develop prediction equations that use measureable, 

independent tree variables to estimate aboveground 

biomass as related to resource potentials and quantity 

of fuel. 

2. Obtain data for analysis of growth relations and site 

quality of pinyon-juniper in Nevada. 

METHODS 

Study Locations 

Study locations were selected from stands that facilitated 

access and tied in with other studies in the p-j. Although 

a majority of the study sites were in western Nevada, an 

east-west transect of sites was established across the 

central portion of the state. Analysis showed no significant 

difference between the western sites and the east-west 

transect sites. Thus, the study locations appear to be 

fairly representative of typical p-j woodlands found in 

Nevada. The geographic distribution, specific locations, 

and physiographic features of the 49 study sites are in 

appendix A. 

Sample paints were established at each study site. 

Points that showed evidence of recent fire, cutting, 

chaining, or other disturbance were avoided. Once a 

sample point was established at a site, the nearest tree of 

each species in each diameter class was sampled. The five 

diameter classes based on diameter at the root collar 

were: 

(I) <4 inches (<I0 cm) 

(2) 4-8 inches (10-20 cm) 

(3) 8-12 inches (20-30 cm) 

(4) 12-16 inches (30-40 cm) 

(5) >I6 inches ( >40 em). 

This selection method provides approximately equal 

coverage of all size classes in tP,a stand. 

Field Techniques 

For each sample tree selected, various crown variables 

were estimated and recorded. Before felling, the lower 

branches and most of the larger upper branches were cut 

flush to the main stem and placed on weighing tarps by size 

classes. After felling, the entire above-stump portion of 

the tree including all previously cut branches were 

separated into four classes and weighed using a load 

cell attached to a boom extended from the rear of a pickup. 

The four size classes weighed separately were: 

(1) > 3 inches (37.6 cm) diameter outside bark (d.o.b.1 

(2) 1-3 inches (2.5-7.6 cm) d.0.b. 

(3) < 1 inch (c2.5 cm) d.o.b. 

(4) deadwood--all diameters. 

Although all deadwood was weighed together, occular 

estimates of the percent in each of the size fractions was 

recorded. All tree weights of the above size classes were 

recorded to the nearest 1 pound using a digital meter. 

The proportions of foliage, twigs less than 0.25 inches 

(0.64 cm) and branches 0.25 to 1 inch (0.64 to 2.5 cm) were 

determined by subsampling approximately 10 percent of 

<I inch (~2.5 ern) size class fraction (fig. 1). Gvosssectional disks were taken along the main stem(s) at stump 

height, at 4-ft intervals, and at points where the d.0.b. 

measured 6 inches (15 cm), 3 inches (7.6 cm), and 1 inch 

(2.5 cm). Disks (2.5 cm and 7.6 em) were also taken from 

randomly selected branches greater than 3 inches (7.6 cm) 

d.o.b. beyond the butt swell, usually about 5 em from the 

cut end, These disks, along with samples of twigs, foliage, 

and deadwood, were weighed in the field using spring 

scales of varying capacities and sealed in plastic bags for 

laboratory analysis. 

Tree Mesasuremenb 

The growth form of p-j trees is such that some tree 

measurements, especially stem diameters, were quite 

difficult to abtain before the destructive sampling process 

began. Thus, the tree measurements listed below are in the 

order obtained during the sampling process and do not 

imply any relative rank of importance. 

Measurements before any limbing or felling: 

(4) Crown class (dominant, codominant, intermediate, 

or suppressed) 

(2) Foliage class (dense, medium, or sparse) 

(3) Crown form (rounded, oblong, triangular, tapered, 

or irregular) 

(4) Crown projection (on ground) 

Before felling: 

(5) Number of stems (greater than 3 inches [7.6 cm] 

d.a.b.1 

-at root collar 

-at stump height 

-at breast height 

(6) Number of forks (greater than 3 inches i7.6 cm] 

d.0. b.) 

(7) Stem diameters (d.o.b.1 

-diameter at root collar (d.r.c.1 

-diameter at stump height (d.s.h.) (12 inches I30 cm]) 

-diameter at breast height (d.b.h.) 

After felling: 

(8) Total tree height (includes stump) 

(9) Maximum crown diameter (across the stump) 

(10) Minimum crown diameter (across the stump) 

(1 1) Tree age (at stump height). 

The individual tree measurements are tabulated by 

species in appendix 5. 
Figure 1.--The various size classes used for 

biomass determinations (Brown 1978). 

Laboratory Analysis 

The tree disks, along with the samples of twigs, foliage, 

and deadwood, were used to determine the moisture 

contents of the various size fractions. The disks were also 

used to determine the specific gravity of the wood. On all 

disks greater than 1 inch (2.5 cm), the bark was removed in 

the laboratory, dried, and weighed separately. The 

samples were ovendried to a constant weight at 35" C, and 

moisture contents were computed on a green-weight basis. 

Percentage of bark was determined by a dry-weight basis 

from the disks greater than 1 inch (2.5 cm). The moisture 

content values were utilized to convert the green weights 

of the sine fractions determined in the field to ovendry 

weights. 

The specific gravity of the wood was determined from the 

green volume and the ovendry weights of the disks. 

RESULTS 

f otal Tree Biomass 

The results include aboveground biomass measurements for 109 trees, 76 pinyon and 33 juniper. The 

individual tree weights are given in appendix 6. The means 

of the tree variables and the average biomass are shown 

in table 1 by diameter classes. For a given diameter class, 

the pinyon were taller, had a greater crown spread, had less 

taper in the main s%em(s), and weighed more than the 

juniper. The largest pinyon sampled had a green weight 

of 11,146 Ib (5 068 kg) and the largest juniper, 3,421 Ib 

(1 555 kg). 

The proportions of the total biomass in the various size 

fractions are shown in table 2. The component proportions 

were also computed on a green-weight basis, but the percentages in each size fraction differed only slightly (1 to 2 

percent) from the dry-weigh? basic calculations, and thus 

are not reported here. The proportion of total biomass in 

wood and bark greater than 3 inches (7.6 cm) is greater in 

pinyon than in juniper. In both species, the proportion of 

foliage decreases as tree size increases; also, juniper has 

greater proportion of foliage than pinyon (table 3). 

Although the proportion of deadwood increases as tree 

size increases, the proportion of wood and bark greater 

than 7.6 crn also increases. Phis indicates that these 

species, or at least the trees sampled in this study, do not 

reach an overmature or decadent stage as commonly 

reported far the two species. The largest and oldest 

pinyon sampled had over 90 percent of its total biomass in 

wood and bark greater than 7.6 cm. The diameter growth of 

this pinyon has been essentially constant for more than 

three centuries (Meeuwig and Budy 1979). The tendency of 

these species %a increase in the proportion of tree weight 

in wood and bark greater than 7.6 cm may be a ckaracteristic of woodland trees because studies an ~~uthf?rn 

conifers indicate that the proportions of tree weight in 

wood or foliage remain relatively constant as tree size 

increases (Taras and Clark 1997; Clark and Paras 3976). 

The most important aspect regarding the distribution of 

biomass is the amount of slash, that is, all the biomass less 

(0 to 

.O in) 

in > 

0.25 in) 
than 7.6 cm. Conventional cordwood harvesting of these or the various size fractions can be estimated using the 

species leaves approximately 50 percent of the biomass moisture contents given in table 4. Moisture content was 

of even the larger trees. If the resources are to be calculated an a green-weight basis; thus, to obtain a green 

utilized to their fullest and not create greater management weight simply divide the ovendry weight by 1 minus the 

problems, the application of total tree harvesting appears moisture content expressed as a decimal. 

advantageous 

The equations and weight tables presented in this report 

are on an ovendry basis. The green weight of the total tree 

Green weight = ---- Ovendry wgight 

1 - moisture content 

Table 1 .--The tree variable means and the average biomass for each diameter class 

-- T~~~.y-yiallales (XI . . . . . . . . . . . . . . - Diameter Sample Crown Average biomass 

Species class trees Height d.s.c. d.s.h. d.b.h. Max Min Average Forks Ag?. Green Dry 

cm No. m . - - - - - -cm- - - - - - -- - - - - - - - -m- - - - - - - - No. Yr - - - - - - -k g------- 

Pinyon <lo 4 2.0 6.0 4.9 2.1 1.4 1.0 1.2 0 56 4.3 2.3 

10-20 19 4.2 15.9 14.6 9.8 2.7 2.2 2.5 0 79 66.8 35.1 

20-30 17 6.1 24.7 23.5 19.0 4.4 3.6 4.0 2 97 247.1 135.5 

30-40 17 7.1 36.3 34.5 28.7 5.6 4.4 5.0 12 126 583.0 333.4 

> 40 'I 9 9.0 55.2 53.1 47.5 8.0 6.3 7.2 35 164 1627.2 966.0 

Juniper 10-20 7 4.2 17.2 15.3 8.3 2.9 2.1 2.5 0 91 52.9 28.4 

2Q-30 8 5.1 25.9 22.3 14.3 3.7 3.1 3.4 1 98 135.1 73.4 

30-40 7 5.0 34.0 28.8 16.9 4.5 3.6 4.1 4 124 226.9 121.3 

> 40 11 6.7 58.2 48.3 32.2 6.7 5.4 6.1 13 147 666.3 368.7 

Table 2.--The distribution of aboveground biomass (dry weight) In size fractions 

Diameter 

Species class 

crn 

Pinyon <1Q 

10-20 

20-30 

30-43 

> 40 

sampse 

trees 

No. 

4 

19 

17 

17 

19 

Average 

biomass 

kg 

2.3 

35.1 

435.5 

333.4 

966.0 

Juniper 10-20 7 28.4 24 15 14 8 40 2 

20-30 8 73.4 28 18 10 8 33 3 

30-40 7 121.3 23 23 12 6 30 6 

> 40 11 368.7 36 19 9 5 24 7 

Table 3.--The distribution of wbcawegectaund biomass (dry weight) in tree components 

... 

Diameter Sample Arerage .... Tree comgone~~ proportions 

Species class trees biomass Wdd Bark Deadwood1 Foliage 

crn No. kg - - - - - - - - - - - - - - - - -Percent- - - - - - - - - -- - - - - - - - - - 

Pinyon 410 4 2.3 47 18 5 29 

10-20 19 35.1 5 1 16 6 27 

20-30 17 135.5 57 17 7 19 

30-40 17 333.4 58 17 11 14 

40 19 966.0 62 15 12 11 

Juniper 10-20 7 28.4 48 1 0 2 40 

20-30 8 73.4 53 11 3 33 

30-40 7 121.3 53 11 6 30 

> 40 1 I 368.7 59 10 7 24 

'Deadwood component not separated into wood and bark tract~ons. 
Table 4.--The average malsture canteast of the total tree and sf the various size fractims 

Diameter Sample Total Size fractions (cm 

Species cBese trees tree 7.6 2.5 to 7L0.64 to 2.5 K0.d Foliage ~eaduwd 

CUP No, - - - - - - - - - - - -. - - - - - - - - - - - - - - - - -Percent green weight- - - - - - - - - - - - - - - - - - - - - - - - - - - - 

Pinyon < 10 

10-20 

20-30 

30-40 

> 40 

Juniper 10-20 

20-30 

30-40 

> 40 

Regression Analysis 

The relationships between tree variables and ovendry 

weights were evaluated by screening all possible combinations of variables and weights using forward and reverse 

stepwise multiple regression techniques. Since all the 

relationships were nonlinear, logarithmic transformations 

(base e) were used throughout the analysis. The improvement in the standard error of the estimate and the 

sequential and partial F-test critera were used to select 

the number of tree variables to be included in the final 

prediction equations (Draper and Smith 19663). For most 

weight categories, the final equations have two tree 

variables. The addition of more variables did not significantly improve the prediction equations and also would not 

lend itself to the construction of weight tables. 

Although the use of logarithmic equations for predicting 

weights is acceptable, the bias encountered when the 

logarithmic estimates are converted back to original units 

has been questioned. Baskerville (1972) suggested the use 

of a correction factor for this downward bias. However, 

Magwick and Satoo (1975) pointed out that the bias using 

logarithmic equations is of minor importance compared 

with the variation among samples. Although Brown 

(1978) applied correction factors for the logarithmic transformation bias to most of his crown weight equations, he 

omitted the correction factor in some cases because it contributed more bias than it eliminated. In this sturdy, the bias 

encountered was low and the use of a correction factor 

introduced greater bias. Thus, a correction factor was not 

applied to the logarithmic estimates. 

In order to express the precision of the predictive 

equations, coefficient of determination (R2), standard 

error of the estimate, percent mean error, and the percent 

bias are reported for each equation. For predictive 

purposes, most investigators presently use some measure 

of the actual deviation between the predicted and observed 

weights (Brown 1978; Faurot 1977; Whittaker and 

Woodwell 1968). The percent mean error is an indication 

of the average variation af the sample. Faurot (1977) 

states that expressing the deviation in percentage overcomes the inherent problem of heterogeneous variance. 

The percent mean error is analogous to the standard 

deviation of the regression and is also similar to the 

estimate of the relative. error reported by Whittaker 

and Woodwell (1968). Percent mean error is obtained as 

follows (Faurot 1977): 

Percent bias is obtained as follows (Faurot 1977): 

where 

Vi = observed value 

7 = arithmetic estimated value 

~7 = number of observations 

k = number of independent variables. 

Equations 

The prediction equations for the various size fractions 

are presented in table 5 for pinyon and in table6forjuniper. 

All equations are logarithmic (base e) and follow the model: 

where 

W = weight, kilograms 

H = height, meters 

DSH = diameter at stump height (30 cm), centimeters 

BBH = diameter at breast height, centimeters 

C = average crown diameter, meters 

S = number of stems at breast height. 
An interaction variable, LwDmLwC, was introduced in the 

regression analysis and proved to be beneficial to some of 

the prediction equations. For the pinyon equations, D is 

the DSH and for the juniper equations, 161) is the DBH. The 

advantage of using the interaction variable is that it increases the precision of the equations while still lending 

itself to the construction of weight tables using two 

independent variables. The equations listed in tables 5 and 

6 have the deadwood component included in the various 

size fractions. The deadwood component was weighed 

separately in the field because of its lower moisture 

content, and then its ovendry weight added to the 

appropriate size fraction. Although 76 pinyons were 

weighed, the four trees in the < 10 cm diameter class were 

eventually deleted from the regression analysis. The prediction equations were much improved by deleting the four 

small saplings. Equations are being developed for seedlings and saplings in the <10 cm diameter class, and will 

be reported elsewhere. 

Of the various tree measurements, the average crown 

diameter was the most significant variable for both 

species. Although the stem diameter measurements were 

also significant, the stump height diameter was more useful in the pinyon equations and the breast height diameter 

was more useful in the juniper equations. Height had no 

predictive value in the juniper equations, but it was 

significant in the pinyon equations for the total biomass 

and the biomass greater than 7.6 cm. 

Thus, in order to use the equations presented in this 

paper, three variables are required for pinyon: crown 

diameter, stump diameter, and tree height. Only two 

variables are required far juniper: crown diameter and 

d.b.h. However, for multiple stem junipers, it is advised to 

correct the g(eater than 7.6 cm biomass for the number of 

stems. For single stem junipers, no correction is needed. 

Weight Tables 

Equations from tables 5 and 6 were used to construct 

weight tables. Predicted ovendry weights of the greater 

than 7.6 crn (3 inch) and the less than 7.6 cm biomass are 

presented in tables 7-10 by stem diameter and average 

crown diameter or height classes. The predicted total 

aboveground weight for pinyon can be obtained by adding 

the weights in tables 7 and 8. For juniper, the total 

weight is presented in table 11. 

Note that the prediction equation for the juniper weight 

of the greater than 7.6 crn biomass contains a correction 

factor for the number of stemS at d.b.h. This correction 

factor ranges from only 1-2 kg for most junipers with up to 

20 multiple stems, and thus is important mainly for the 

smaller trees. 

The tables and equations presented in this report were 

developed from trees sampled within Nevada and thus 

should be validated in new areas before using. Extrapolation beyond the data range or to species other than 

singleleaf pinyon and Utah juniper is not recornrnended 

without rescaling the variables to fit the population. Trees 

with similar bole and crown diameters may vary considerably in weight because sf differences in crown size, crown 

form, and density of foliage. 

Table 5.--Prediction equations for estimating orendry weigh? of the abswegsound biomass of singleleaf pinyon trees greater then 

16) cm at the root caPlllsr (basis: 72 trees) 

Tree 

component E$uatianP ... . 

Total LnW= -2.025 + 1.399 (LnDSH) + 0.674 (LnH) -f 0.922 (LnC) 

>2.5 cm = -4.280 + 1.762 (LnDSM) + 1.146 (LnH) + 0.653 (LnC) 

>7.6 cm = -6.024 + 2.159 (LnQSH) + 1.663 (LnH) 

g7.6 crn = -3.203 -c 1.761 (LnDSH) + 3.280 (LnC) -0.554 (LnDSMeLnC) 

2.5 to 7.6 crn - -6.843 + 2.460 (LnDSH) + 4.013 (LnC) - 0.742 (LnDSHdnC) 

0.64 to 2.5 cm = -6.128 + 2.211 (LnDSH) + 3.685 (LnC) - 0.727 (LnDSHgLnC) 

< 8.64 cn = -4.078 + 1.556 (LnDSH) 9 3.293 (LnC) - 0.571 (LnDSHdnC) 

Foliage = -2.434 + 1.082 (LnDSH) + 2.814 (LnC) - 0.378 (LnDSHeLnC) 

Standard error Percent mean Percent 

__e2 _- ofestimate error bias 

0.987 9.156 15.9 4.0 

,988 ,173 17.0 5.3 

.988 .I84 18.6 2.4 

,973 ,194 19.5 -1.0 

.959 .293 30.3 -2.4 

,935 ,312 34.5 -3.5 

,918 .304 34.2 -2.5 

,912 ,395 33.2 -2.4 

'Where 

W= weight, kilograms 

DSH= diameter at stump height (30 cm), centimeters 

H= height, meters 

C= average crown diameter, meters 

hn= natural logarithm, base e 
Table 6.--$rediction equations for estimating ovenday weight of the ebesveground biomass 0% Utah juniper trees greater than 10 

cm a% the root collar (basis: 33 trees) 

Free 

component Equation1 

Total LnW= 0.2% + 0.845 (LnDBW) + 1.444 (LnG) 

>2.5 crn = -1.232 + 1.113 (LnDBH) + 4.466 (LnC) 

97.6 crn = -1.423 r 1.241 (LnDBH) + 0.347 (LnDBHaLnC) - 0.274 (LnS) 

c7.6 crn = -0.951 + 1.118 (LnDBH) + 2.703 (LnC) -0.394 (LnDBH-bnC) 

2.5 to 7.6 crn = -3.467 + 1.293 (LnBBH) + 3.693 (LnC) - 0.552 (LnDBH-LnC) 

0.64 to 2.5 crn = -3.182 + 1.185 (LnDSH) + 3.072 (LnC) -0.61 (LnDBH-LnC) 

4 0.64 cm = -3.388 + 1.251 (LnDBM) + 3.071 (LnC) - 0.553 (LnDBHdnC) 

Foliage = 0.047 + 0.616 (LnDBH) + 1.219 (LnC) 

Standard error Percent rnearnPercent 

Rz of estimate error -. - . . -. . . . . . . . . .. . . . . . . . . . . . . . . . . . . .. . . . . -. . . . . . . . . . . . . bias 

0.963 0.210 20.0 -0.6 

,966 .232 23.8 -0.5 

,968 ,243 24.4 -0.2 

,950 ,232 22.3 -1.6 

,937 ,344 34.7 -1.8 

,908 ,348 42.5 -4.2 

,921 ,271 26.0 -3.4 

,915 ,261 26.9 1 .O 

'Where 

W= weight, kilograms 

DBH= diameter at breast height. centimeters 

C= average crown diameter, meters 

S- number of sterns at d.b.h. 

Ln= natural logarithm, base e. 

Table 7.--Predicted ovendry weights (kg) for the greater than 3 inch (7.6 cm) $lomas$ of singleaf pinyon 

Tree Mpht (m) 

D.r.h. 1 2 3 4 5 6 7 8 14 12 13 14D.s.h. -. -. -. -. . . . . . . . . . . . . . . ... . . .- . . . . . . . . . . . - . . . . . . . . . . . . 9 10 ___-_..-- 

cm -----------------------------------------------kg----------------------------------------------- Inches 

10 4 

15 6 

20 8 

25 10 

30 12 

35 14 

40 70 104 137 177 221 16 

45 18 

50 20 

55 7 747 863 986 1115 22 

60 1041 1189 24 

65 1238 1414 26 

70 1452 1659 1877 28 

75 1686 1926 2178 30 

80 612 791 987 1200 1431 1677 1938 2213 2504 32 

. . Tree height (ft) . . . . . . . . . . . . . . . .- 

LnW = -6.024 + 2.459 (LnDSH) + 4.663 (LnH) 

Standard error (SE) = 0.184 

Mean error (E) = 18.6 percent 

Average bias (83) = 2.4 percent 

R2 = 0.998 
Table $.--Predicted orendry weights (kg) for the less than 3 inch (7.6 cm) biomass for singleaf pinyon 

- Average crown diameter (ft) 

bnW = -3.203 + 1.161 (LnDSH) + 3.280 (LnC) - 0.554 (LnDSHdnG) 

Standard error (SE) = 0.194 

Mean error (E) = 19.5 percent 

Average b~as (B) - -1.0 percent 

R2 = 0.973 

Table 9.--Predicted owendry weights (kg) for the greater than 3 Inch (9.6 cm) biomass for Utah juniper 

Average ... crown diameter (m) 

D.b.h. 1 2 3 4 5 6 7 8 9 10 11D.b.h. 

cm lrrches 

5 Is 3 1 3 

25 28 10 

30 12 

35 340 383 14 

40 447 505 16 

45 645 18 

50 -. . . . . . . . . . . . . . . . . . . . . . . . . . 802 20 

3 7 10 13 16 20 23 26 30 33 36 

. . . . . . . . . . -. . . . . . . . . . . . . . . Average crown diameter (ft) -- -- .- -. 

LnW = -1.423 + 1.241 (LnDBM) + 0.347 (LnDBM 8 LnC) - 0.274 (LnS)' 

Standard error (SE) = 0.243 

Mean error (E) = 24.4 percent 

Average bias (5) = -0.2 percent 

R2 -7 0.968 

'For trees w~th multiple sterns, multiply the weight by §-0.274 
Table 10.--Predicted owendry weights (kg) far the less (than 3 inch (7.6 cm) Momass lor Utah juniper 

- Awerage crown diarnetearn) 

D.b.h. 1 2 3 4 5 6 7 8 9 10 dl B.b.h. 

cm ----..-------------------------------kg--------------------..-------------/nches . . - . . . . ..A. . . . . -. . - . . . -. . . . . . . - -. 

15 6 

20 

25 

30 

35 413 467 14 

40 

45 

50 . -. --- . -. - .- -- 

3 7 10 13 I6 20 23 26 30 33 36 

Average crown diameter (ft) 

LnW = -0.951 + 1.118 (LnBBH) + 2.703 (LnC) - 0.394 (LnDBH LnC) 

Standard error (SE) - 0.232 

Mean error (E) = 22.3 percent 

Average bias = -1.6 percent 

R2 = 0.950 

Table 1 I .--Predicted ovendry weights (kg) of (total abaweground biomass for Utah Blsniper 

-- 

Awerage crown diameter (m) 

~.b.h. a 2 3- 4 5 6 7 8 - 9 18 41 ~.$.h. 

3 7 10 43 16 20 23 26 30 33 36 

Averaoe crown diameter (ft) 

Ln W = 0.296 + 0.845 (LnDBH) + 1.444 (LnC) 

Standard error (SE) = 0.240 

Mean Error (E) = 20.0 percent 

Average bias (B) = -0.6 percent 

RZ = 0.963 
The results of this study indicate that the aboveground 

biomass of pinyon and juniper is c1osely correIated with 

average crown diameter for both species, and stem 

diameter at stump height for pinyon and diameter at breast 

height for juniper. These tindings agree in part with those 

reported by Storey (1969). Although his study evaluated 

each tree variable separately, our analysis indicated that 

the precision of the estimates was improved by using 

multiple regression techniques. 

Aldon, E. F., and H. 

1973. The sout n-juniper ecosystems: 

a bibliography. USDA For. Serv. Tech. Rep. WM-4, 20 

p. Rocky Mt. For. and Range Exp. Stn., Fort Collins, 

Colo. 

Aldon, E. F., and '6. J. Loring, tech. coard. 

1977. Ecology, uses, and management of pinyon-juniper 

woodlands: proceedings of the workshop. USDA For. 

Serv. Gen. Tech. Rep. RM-39, 48 p. Rocky Mt. For. 

and Range Exp. Stn., Fort Collins, Colo. 

Barger, 8. L., and P. F. Ffolliott. 

1932. The physical characteristics and utilization of 

major woodland tree species in Arizona. USDA For. 

Sew. Wes. Pap. RM-83, 80 p. Rocky Mt. For. and 

Range Exp. Stn., Fort Collins, Golo. 

Baskerville, G. L. 

1972. Use of logarithmic regression in the evaluation of 

plant biomass. Can. J. For. Res. 2(49):49-53. 

Beeson, @. D. 

1974. The distribution and synecology of Great Basin 

pinyon-juniper. Thesis. Univ. Nevada, Reno. 95 p. 

Blackburn, W. H. 

1967. Plant succession on selected habitat-types in 

Nevada. Thesis. Univ. Nevada, Reno. 662 p. 

Box, T. W, G. M. Van Dyne, and I\]. E. West. 

6. Syllabus on range resources of North America. 

Part iv, pinyon-juniper ranges. Utah State Univ., 

Logan. Mirneo. 

Bradshaw, K. E., and J. L. Reveal. 

1943. Tree classification for Pinus moncaphylla and 

Juniperus antahensis. J. For. 41 :100-104. 

Brown, J. K. 

1978. Weight and density of crowns of Rocky Mountain 

conifers. USDA For. Sew. Res. Pap. INT-197, 56 p. 

Intermt. For. and Range Exp. Stn., Bgden, Utah. 

Clark, A., Ill, and M. A. Taras. 

1976. Biomass sf shortleaf pine in a natural sawtimber 

stand in northern Mississippi. USDA For. Serv. Res. 

Pap. SE-146, 32 p. Southeast For. Exp. Stn., Asheville, 

N. C. 

Clendenen, G. W. 

1979. Gross cubic-volume equations and tables, outside 

bark for pinyon and juniper trees in northern New 

Mexico. CBSDA For. Serv. Res. Pap. INT-228, 21 p. 

Intermt. For. and Range Exp. Stn., Qgden, Utah. 

Draper, N. R., and H. Smith. 

1966. Applied regression analysis. 407 p. John Wiley 

and Sons, Inc., New Vork. 

Faurot, J. L. 

1977. Estimating merchantable volume and stem residue 

volume in four timber species: ponderosa pine, lodgepole pine, western larch, Douglas-fir. USDA For. 

Sew. Res. Pap. INT-19 ,55 p. Intermt. For. and Range 

Exp. Stn., Qgden, Utah. 

Fogg, @. G. 

1966. The pinyon pines and man. Econ. Bat. 28:103-185. 

Gary, H. h. 

1976. Grown structure and distribution of biomass in 

a lodgepole pine stand. USDA For. Serv. Res. Pap. 

WM-165, 20 p. Rocky Mt. For. and Range Exp. Stn., 

Fort Collins, Cob. 

Gilfsrd, G. E., and F. E. Busby, eds. 

1975. The pinyon-juniper ecosystem: a symposium. 

194 p. Utah State Univ., Coil. Nat. Resour., Utah Agric. 

Exp. Stn., Logan. 

Herman, 6. R. 

1953. A growth record of Utah juniper in Arizona. J. For. 

54 :2QO-201. 

Howell, J., Jr. 

1937. The relation of crown diameter to cubic volume of 

one-seeded juniper. J. For. 35:829-831. 

Howell, J., Jr. 

1941. Pinyon and juniper woodlands of the southwest. 

J. For. 39542-545. 

Howell, J., Jr., and 83. W. Bexen. 

1939. Volume tables for Juniperus monosperma and 

Juniperus scopulorurn. USDA Soil Conserv. Serv. 

Reg. Bull. 59, 4 p. 

Magwick, W. A. I., and T. Satoo. 

1975. On estimating the aboveground weights of tree 

stands. Ecology 56:1446-1450. 

Mason, L. R., and S. S. Wutchings. 

1963. Estimating foliage yields on Utah juniper from 

measurements of crown diameter. J. Range Manage. 

20:161-166. 

Meeuwig, 8. O., E. L. Miller, and J. D. Budy. 

1978. Estimating pinyon-juniper cordwoad with the lineintersect method. USDA For. Serv. Res. Note INT-242, 

8 p. Intermt. For. and Range Exp. Stn., Ogden, Utah. 

Meeuwig, R. Q., and J. B. Budy. 

1979. Pinyon growth characteristics in the Sweetwater 

Mountains. USDA For. Serv. Res. Pap. lN7-227, 26 p. 

Intermt. For. and Range Exp. Stn., Bgden, Utah. 

Moessner. I<. E. 

1962. Preliminary aerial volume tables for pinyon-juniper 

stands. USDA For. Serv. Res. Pap. INT-69, 12 p. 

Intermt. For. and Range Exp. Stn., Ogden, Utah. 

Myers, 6. A. 

1962. Pwenty-year growth of Utah Juniper in Arizona. 

USDA For. Serv. Res. Note RM-71,2 p. Rocky Mt. For. 

and Range Exp. Stn., Fort Collins, Golo. 

Reveal, J. L. 

1944. Single-leaf pinyon and Utah juniper woodlands 

of western Nevada. J. For. 42:276-278. 

Springfield, H. W. 

1976. Characteristics and management of southwestern 

pinyon-junipsr ranges: the status of our knowledge. 

USBA For. Serv. Res. Pap RM-160, 32 p. Rocky Mt. 

For. and Range Exp. Stn., Fort Collins, Cola. 
Storey, T. G. 

1969. Tree weights and fuel size distribution of pinyon 

pine and Utah juniper. In Project Flambeau, final 

rep., vol. Ill. Pacific Southwest For. and Range Exp. 

Stn., Berkeley, Calif. 90 p. 

Taras, M. A., and A. Clark, Ill. 

1975. Aboveground biomass of loblolly pine in a natural, 

uneven-aged sawtimber stand in central Alabama. 

Tappi 58(2):103-1615. 

Taras, M. A., and A. Clark, Ill. 

1977. Aboveground biomass of longleaf pine in a natural 

sawtimber stand in southern Alabama. USDA For. 

Serv. Res. Pap. SE-162, 32 p. Southeast For. Exp. 

Stn., Asheville, N.6. 

West, N. E., D. R. Cain, and G. F. Gifford. 

1973. Biology, ecology and renewable resource 

management of the pigmy conifer woodlands sf 

western north America: a bibliography. 36 p. Utah 

Agric. Exp. Stn., Utah State Univ., Logan. 

Whittaker, R. H., and G. M. Woodwell. 

1968. Dimension and production relations of trees and 

shrubs in the Brookhaven Forest, New York. Ecology 

56(1):1-25. 

Young, H. E., ed. 

1971. Forest biomass studies. 240 p. Coll. Life Sci. and 

Agric., Univ. Maine, Qrono. 

Young, H. E., ed. 

1973. IUFRQ biomass studies. 531 p. GOBI. Life Sci. 

and Agric. Univ. Maine, Qrona. 

Young, H. E. 

1976a. A summary and analysis of weight table studies. 

30 p. Complete Tree Institute, Univ. Maine, Orono. 

Young, H. E., ed. 

4976b. OSLO biomass studies. 302 p. Goll. Life Sci. and 

Agric., Univ. Maine, Orono. 
Figure 2.--Geographic distribution of study plots. This map shows the pinyon-juniper 

woodlands in the Great Basin and pinpoints the location of 19 study sites. (Derived 

from ERTS-I photography, Beeson 1974.) 
Table 12.--Plot location and physiographic features 

Plot 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

4 3 

14 

15 

16 

17 

18 

19 

Trees 

1-4 

5-8 

9-1 8 

17-20 

21-24 

25-28 

29-36 

37-42 

43-49 

50-56 

57-63 

64-70 

71-78 

84-92 

93-99 

100-1 05 

106-1 07 

108-111 

112-114 

Mountain 

range 

Pine Nut 

Pine Nut 

Pine Nut 

Bald Mountain 

Wellington Hills 

Wellington Hills 

Toiyabe 

Toquirna 

Shoshone 

Paradise 

Monitor 

White Pine 

Ruby 

Sweetwater 

Sweetwater 

Sweetwater 

Pine Nut 

Pine Nut 

Pine Nut 

Location 

T W See. 

15N 22E 11 

15N 22E 2 

13N 22E 34 

8N 25E 34 

8M 24E 15 

9N 23E 21 

19N 44E 22 

16N 46E 20 

13N 39E 23 

12N 37E 13 

15N 49E 8 

12N 59E 23 

25N 56E 14 

7N 25E 31 

7N 25E 29 

9N 25E 29 

14N 22E 12 

15N 22E 2 

15N 22E 20 

Elevation 

(ft) 

7250 

7200 

8800 

7000 

7200 

5900 

6850 

7200 

7400 

7000 

7700 

6900 

6800 

7550 

7200 

6900 

6300 

7100 

61 00 

Plot T~pographlc 

aspect Slope position 

Percent 

S 9 Middle 1/3 of slope 

SW 12 Lower 1/3 of slope 

E 12 Lower 1/3 of slope 

SW 8 Lower 1/3 of slope 

E 2 Plateau 

N 18 Stream bottom 

E 45 Upper 1/3 of slope 

N E 7 Middle 1/3 of slope 

SE 5 Ridgetop 

N 15 Lower 1/3 of slope 

N 22 Lower 1/3 of slope 

NW 10 Lower 1/3 of slope 

SW 5 Ridgetop 

SE 15 Plateau 

E 5 Middle 1/3 of slope 

NE 20 bower 1/3 of slope 

S E 5 Lower 1/3 of slope 

S 5 Lower 1/3 of slope 

E 3 Plateau 
Table 13.--Pinyon tree measurements 

Diameter Tree Tree Diameter ..- Crown diamet~c 

class no. ht. RC SH BH Max Min Awe. 

Forks .....____ Class Crown Stems 

no. Age Crown Foliage form RC-SH-BH 

Table 14.--Juniper tree measurements 

Diemetw Tree free Diameter Crown biamctea_ Forks Class -_ Crown Sterns 

class no. ht. RC SH BH Max Miw Awe. no. Age Crown Foliaqe form RC-SH-BH 
Table 15.--Pinyen tree weights 

Dlameter Tree -- Green Weight -- Dry Weight - 

- >3 1-3 %-I <*/I F D Total > 3 I- 1- < % F 19 Total 
Table 15.-- con 

Table 16.--Juniper tree weights 

Diameter Tree -. .. ..... Green Weiqht p-y Weiqht 

class no. > 3 4-3 l,he-l <% F B ~ollal -- >3 1-3 %-I .-< */d .... D Total 
Miller, E. L., R. 0. Meeuwig, and J. D. Budy. 

1981. Biomass of singleleaf pinyon and Utah juniper. USDA For. Serv. Res. Pap. 

INT-273, 18 p. Intermt. For. and Range Exp. Stn., Ogden, Utah 84401. 

Biomass determinations in singleleaf pinyon (Pinus monophylla) - Utah juniper 

(Juniperus osteosperma)stands in Nevada indicate that stem diameter and average 

crown diameter are the tree measurements most highly correlated with ovendry 

weights. The equations and tables developed provide a means for estimating the 

total aboveground biomass as well as the weights for the various size fractions by 

species. The tables can also be used to estimate the cordwood and slash resulting from 

fuelwood harvesting operations. 

KEYWORDS: biomass, weight, Utah juniper (Juniperus osteosperma) singleleaf 

pinyon (Pinus monophylla), prediction equations, weight tables 

* U. S. GOVERNMENT PRINTING OFFICE: 1981-777-028191 REGION NO. 8 
The Intermountain Station, headquartered in Ogden, 

Utah, is one of eight regional experiment stations charged 

with providing scientific knowledge to help resource 

managers meet human needs and protect forest and range 

ecosystems. 

The Intermountain Station includes the States of 

Montana, Idaho, Utah, Nevada, and western Wyoming. 

About 23 1 million acres, or 85 percent, of the land area in the 

Station territory are classified as forest and rangeland. These 

lands include grasslands, deserts, shrublands, alpine areas, 

and well-stocked forests. They supply fiber for forest industries; minerals for energy and industrial development; and 

water for domestic and industrial consumption. They also 

provide recreation opportunities for millions of visitors each 

year. 

Field programs and research work units of the Station 

are maintained in: 

Boise, Idaho 

Bozeman, Montana (in cooperation with Montana 

State University) 

Logan, Utah (in cooperation with Utah State 

University) 

Missoula, Montana (in cooperation with the 

University of Montana) 

Moscow, Idaho (in cooperation with the University of Idaho) 

Provo, Utah (in cooperation with Brigham Young 

University) 

Reno, Nevada (in cooperation with the University 

of Nevada)