4~~2% ;s United States Department of 

Agriculture 

Forest Service 

Sauthern Farest 

Experiment StatIan 

New Orfeans, 

Louisiana 

General Technicat Report SO-46 

August, 1983 

Biomass of Four Hardwoods from 

Lower Piedmont Pine-Hardwood 

Stands in A 
Biomass data was recorded for 73 trees growing in mixed natural oak-pine stands on 

Lower Piedmont sites near Auburn, Alabama, during a study of the feasibility of harvesting 

southern hardwoods by extraction using a Rome TXH Tree Extractor. Hawested trees 

included sweetgum, hickory (mockernut and pignut), southern red oak, and white oak 

trees measured from 4 to 11 inches dbh. Collected biomass data included the portion of the 

below-ground biomass (stump wood - including central root system) that was extracted 

with the above ground (whole tree) biomass. The extracted below ground biomass averaged 

18 percent (green basis) of the complete harvested tree weight. Whole tree above ground 

biomass, green without foliage, ranged from 78 to 1,135 pounds for sweetgum, 174 to 71 1 

pounds for hickory, 167 to 1,227 pounds for red oak, and 112 to 615 pounds for white oak. 

Sweetgum had the highest moisture content at 110 percent for total tree wood component 

and hickory bad the lowest at 54 percent. The proportion of stem wood to branch wood 

ranged from 59 to 89 percent with the larger trees having more stem wood. Specific gravity, 

density, and moisture content of wood and bark for the four tree species are presented. The 

proportion of trees in wood and bark and in stem wood and branch wood, both in green and 

oven-dley conditions, are presented. Regression equations as a function of tree diameter and 

total height are also presented for complete trees and their components, Tables have been 

developed for complete tree, whole tree, and main stern. biomass. 
Biomass of Four Hardwoods From Lower Piedmont 

Pine-Hardwood Stands in A 

INTRODUCTION 

There is a growing interest world wide in more 

complete utilization of forest resources for products 

and as an energy source (FA0 1976). This interest 

has created a need for predicting the total biomass 

of the complete tree according to characteristics that 

affect its use - what portion is in wood and bark, 

and what portion is in stem wood and branch wood. 

This paper presents statistics, prediction equations, 

and tables for biomass characteristics of four southern United States hardwoods - sweetgum (Liquidam bar sty raciflua L, ), hickory (mockernut, Carya 

tomentosa (Poir.) Nutt. and pignut, C. glabra 

(brill.) Sweet), southern red oak (Quercus falcata 

Michx, var. falcata), and white oak (&. alba L.). 

The tree data was collected in conjunction with a 

field evaluation of the Rome TXH Tree Extractor 

(Sirois 1977), and therefore the range of tree sizes, 

4 to 12 inches dbh, was limited to the capacity of the 

machine for harvesting hardwoods. The evaluation of 

the tree extractor took place near Auburn, Alabama, 

in natural uneven-aged pine-hardwood stands growing on Lower Piedmont sites. 

Definitions of the tree components used in this 

report are: 

Complete Tree - All of the harvested biomass 

including roots and stump wood extracted from the 

soil, main stem, and all crown branches without 

foliage, 

Whole Tree - All of the harvested biomass above 

a 6-inch stump height including main stem and all 

crown branches without faliage, This portion of the 

tree may also be caZled ""total tree'yin other reports, 

Stem - That portion of the tree between a 6-inch 

high stump and a 3-inch diameter top, This portion 

of the tree may also be called ""blew in other reports. 

Crown ------ All of the stem above a 3-inch top plus 

all live branches above and below this point, 

PROCEDURES 

Field Test 

A sample, stratified by dbh for each of the four 

hardwoods, was selected from two sites. Selected 

sample trees were dominant or co-dominant in crown 

form, except that in the small tree size class, 4 to 6 

inches dbh, it was necessary to include some intermediate trees, Because the tree extractor was not 

successful in harvesting all of the selected sample 

trees, all diameter classes are not fully represented. 

When additional extraction data was needed and 

additional trees were available in the area, these 

trees were harvested and measured. For the purposes of the biomass portions of the study, the dbh 

classes of the sample trees were: 

Class Range in dbh 

3.0 < dbh < 5.0 

5.0 < dbh < 7.0 

7.0 < dbh < 9.0 

9.0 < dbh < 11.0 

11.0 < dbh < 13.0 

The mean and ranges of tree measurements are 

shown in table 1: . 

The field test took place in April and early May 

so all trees were harvested and the biomass data was 

taken before leafing of the trees. Because of the time 

of the year and the apparent bud swelling it can be 

safely stated that sap flow had begun and tree moisture contents were more representative of summer 

conditions than vllinter dormancy. After extraction of 

each trcte, green weight by components were weighed 

before the next tree was harvested, Weight data included extracted root and stump weight as harvested 

without soil, weight of the tree stem from a 6-inch 

Donald I;. Sirois is Project Leader for Engineering Research, Southern Forest Experiment Station, Forest Service - USDA, 

Auburn, Alabama. 
Table I.-Means and ranges of tree measurements for each tree species by dbh class. 

Dbh Sample Dbh TotaI height Grow ratio - class trees Average Range Average Range Average Range 

inches number years 

Hickory 

4 7 

6 5 

8 6 

- 

18 

Red Oak 

4 3 

6 9 

8 5 

10 6 

12 2 - 

25 

White Oak 

4 2 

6 4 

8 8 - 

14 

stump height to a 3-inch top without branches, and dry basis. Documentation of additional equations 

crown weight including all branch wood. Measured developed for calculation of other parameters and for 

dimensions were length of extracted root to a 6-inch weighing of moisture, wood, and bark contents of the 

stump height, total height, crown height (butt to whole tree for the computer analysis are presented 

first live limb), and height to 3-inch top. Diameters in Appendix 111. 

outside bark (dob) were taken at a 6-inch stump, 

dbh, base of live crown and mid-height (one half of Analysis 

total height). At the time of measurements, sample 

disks were cut from the tree butt, midpoint, a 3-inch 

top, and two branch samples (1 to 2 inches dob) for 

determining moisture, density, and bark content of 

the trees. The disk samples for subsequent lab tests 

were sealed in plastic bags to prevent moisture loss. 

Weighted least square regression equations were 

developed for predicting the green and dry weights 

of wood and bark for complete and whole trees and 

their components. The independent variables used 

in the final regressions were dbh and total height, 

The predictions of tree biomass characteristics are 

based on the following model. 

Laboratory 

The laboratory procedures for determining specific 

gravity and moisture content were similar to those of 

the Southeastern Forest Experirnent Station at 

Athens, Georgia (Clark and Schroeder 19'77). Specific gravity was calculated using green volume and 

oven-dry weight. For moisture content, samples were 

dried to a constant weight at an oven temperature of 

103°C. Moisture content was calculated on the ovenwhere : 

Y = predicted tree or component weight 

x = D2Th 

D = dbh in inches 

Th = total tree height in feet 

b = coefficient 
By employing a weighing factor of DZTh to the 

model to correct for heterogeneous variance about 

the regression line, it is felt that this simpler model 

retains the statistical advantages of more common 

linear models while overcoming their shortcomings 

(Husch, Miller and Beers 1972 and Cunia 1964). 

RESULTS 

Complete tree data, including harvested roots and 

stump wood, was collected in addition to the normally reported whole tree, above-ground biomass from a 

6-inch stump. The average values for complete trees 

and the percent of stump biomass have been reported 

earlier ( Sirois 1977). Prediction equations and related tables for complete tree green weight are included in Appendix I. Whole tree biomass, both green 

and dry weights basis, are shown in table I1 for the 

four hardwoods by diameter classes. The average 

green weight for whole trees ranged from 78 pounds 

for the smallest (sweetgum in the 4-inch class), to 

1,227 pounds for the largest (red oak in the 12-inch 

class). The proportion of whole tree green weight of 

wood versus bark averaged 95 percent for sweetgum, 

86 percent for hickory, 92 percent for red oak, and 

95 percent for white oak (table 11). On the green 

weight basis the proportion of bark decreased with 

increasing tree size, and the proportion of wood increased. On a dry weight basis the proportions 

changed only slightly from those of the green weight 

values. 

In addition to reporting the wood and bark cornposition of the sample whole trees, the proportion 

of the above ground biomass in stems and branches 

were also determined. These data are presented in 

table I11 on both a green and dry weight basis. On 

a green weight basis, with data from all diameter 

classes pooled, the proportion of the whole tree in the 

stem was 78 percent for sweetgum, 71 percent for 

hickory, 73 percent for red oak, and 72 percent for 

white oak. For all of the four species, the stem proportion of the tree increased with dbh. This trend 

was less definite for red oaks than for the other 

species. This was due to the greater branching of 

the crown with a less definite main or central stem. 

Table 11.-Average whole tree weights with proportions of wood and bark on both green and dry weight basis 

Tree component Tree component Dbh Total Sample Whole tree proportions (green) Whole tree proportions (dry) 

class height trees green weight dry weight Wood Bark Wood Bark 

inches 

Sweetgum 

4 

6 

8 

10 

Hickory 

4 

6 

8 

Red Oak 

4 

6 

8 

. 10 

12 

White Oak 

4 

6 

8 

feet 

36 

44 

57 

72 

43 

48 

57 

36 

42 

49 

54 

5 1 

39 

43 

57 

number 

3 

5 

6 

1 - 

15 

7 

5 

6 - 

18 

3 

9 

5 

6 

2 - 

25 

2 

4 

8 

- 

14 

pounds ..... 
Table 111.-Average whole tree weights with proportions of biomass in sterns and branches on both a green and oven dry weight 

basis 

Tree component Tree component I3bh Total Sample WhoIe tree proportions (green) Whole tme proportions (dry) 

class height trees green weight dry weight Stem Branches Stern Branches 

inches 

Hickory 

4 

6 

8 

Red Oak 

4 

6 

8 

10 

12 

White Oak 

4 

6 

8 

feet number pounds pounds 

41 

116 

269 

674 

1x1 

161 

458 

98 

172 

390 

644 

658 

69 

197 

364 

..................... percent 

Wood and Bark Characteristics 

The specific gravity, moisture content, and green 

weight per cubic foot of both wood and bark for the 

whole trees and their components are reported in 

table IV. The values for moisture and green weight 

per pound were very consistent for the two oak 

species. Both sweetgum and hickory trees had a wide 

difference in moisture content of the components for 

wood and bark with associated high variability for 

measured values. For sweetgum both the stem wood 

and branch bark had high moisture contents, 162 

and 148 percent respectively, while hickory experienced only high moisture content in the branch bark, 

148 percent, as compared to 67 percent for the stem 

bark. Similar differences have been reported for other 

species of both hardwood and pine (Clark and 

Schroeder 1977, Taras 1980) and have been related 

to differences in bark characteristics and sap flow 

incipient to leafing. Our data was taken at probably 

the most unstable time of the year for the moisture 

content measurement, at least for sweetgum and 

hickory, for our two site and stand conditions. The 

more consistent results of the two oak species is 

possibly because they were generally found within 

a narrower range of site conditions within the two 

stands and were less advanced in breaking of dormancy. All four species were randomly harvested 

during the same 2 month period, April and May, and 

the same laboratory procedures were used in all 

cases. Overall, the average whole tree values of 

specific gravity, moisture content, and green weight 

per cubic foot are in good agreement with other published values for the four hardwood species (McMillin and Manwiller 1980). 

PREDICTION EQUATIONS 

Regression equations have been developed for predicting the green and dry weights of complete and 

whole tree biomass and for the components of wood, 

bark, main stem (tree length to 3-inch top), and 

crown (including all live branches). These equations 

are presented by species in tables 1 through 4 in Appendix I. 

In comparing values of whole (total tree) weight 

of southern red oak trees predicted by this equation, 

developed from trees in south central Alabama, to 

those predicted for southern red oaks growing on the 

Highland Rim in Tennessee, using the equation 

Y = 0.06632 (D2Th)1.11245 developed by Clark, Phillips, and Hitchcock (1980), we find that it predicts 

higher weights by 7 to 23 percent depending upon 

dbh. The percent difference decreases with increasing 

dbh. This difference is due to difference in tree form 

rather than differences in form of the equations. The 
Table W.-Average whole tree and component wood and bark specifk gravity, moisture content, and 

green weight per cubic foot for four hardwoods 

Tree component Specific gravity Moisture content Green wt. per cubic foot 

percent pounds 

Sweet 

Wood 

Whole tree 

Stem 

Branches 

Bark 

&%ole tree 

Stem 

Branches 

Hickory 

Wood 

Whole tree 

Stem 

Branches 

Bark 

Whole tree 

Stem 

Braches 

Red Oak 

Wood 

Whole tree 

Stem 

Branches 

Bark 

Whole tree 

Stem 

Branches 

White Oak 

Wood 

Whole tree 

Stem 

Branches 

Bark 

Whole tree 

Stem 

Branches 

Alabama trees were shorter, with a significantly 

higher pereent of wood in the crown, and had less 

stem taper for equivalent dbh classes than the Tennessee trees. Also, it should be noted that the Tennessee trees were hamested during the dormant 

winter months and the Alabama trees during the 

spring, so the Alabama trees had a higher bark moisture content and therefore higher bark green weight 

per cubic foot. 

The differences in predicted values for whale or 

total green tree weights indieate the need for using 

care in applying biomass equations from one region 

to another, especially if the equations are developed 

from trees harvested at different times sf the year. 

BIOMASS TABLES 

Biomass tables for green and dry weights of eomplete tree (including roots and stump), whole tree, 

and tree length (main stem to 3-inch top) have been 

produced from the equations of tables 1 through 4 

for the four species of hardwoods. The biomass tables 

5 through 16 are presented in Appendix 11. As indicated in the discussion under Prediction Equations, care should be used in applying these table 

values to other regions that may have trees of different form or green weights per cubic foot of wood 

andlor bark. 
LITERATURE CITED 

Clark, Alexander 111; Phillips, Douglas R.; Hitchcock, Harry 6. 111. Predicted weights and volumes 

of southern red oak trees on the highland rim in 

Tennessee. Res. Pap. SE-208. Asheville, PJC: 

U.S. Department of Agriculture, Forest Service, 

Southeastern Forest Experiment Station, 1980. 

23 p. 

Clark, Alexander 111; Schroeder, James 6. Biomass 

of yellow-poplar in natural stands in western 

North Carolina. Res. Pap. SE-165. Asheville, NC: 

U.S. Department of Agriculture, Forest Service, 

Southeastern Forest Experiment Station. 1977. 

44 p. 

Cunia, T. Weighted least squares method and construction of volume tables. For. Sci. 10 (2) : 180- 

191. 1964. 

FAO, Wood chips production, handling, transport, 

2d ed. Rome, Italy; 1967. 136 p. 

Huseh, Bertram; Miller, Charles I.; Beers, Thomas 

W. Forest mensuration. New York: The Ronald 

Press Co. 1972. 410 p. 

MeMillim, Charles W.; &lanwiller, Bloyd G. The 

wood and bark of hardwoods growing on southern 

pine sites - a pictorial atlas. Gen. Tech. Rep. 

SO-29, New Orleans, LA; U.S. Department of 

Agriculture, Forest Service, Southern Forest Experiment Station, 1980. 58 p. 

Sirois, Donald L. Feasibility of harvesting southern 

hardwood trees by extraction. Paper No. 7'7-1.567. 

American Society of Agricultural Engineerings. St. 

Joseph, MI: 1977, 15 p. 

Taras, Michael A. Above ground biomass of choctawhatchee sand pine in northwest Florida. Res. Pap. 

SE-210. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southeastern Forest Experiment Station. 1980. 23 p. 
Appendix I-Prediction tables and related equations 

Table 1.-Sweetgum regression equations for estimating green and oven-dry biomass 

for trees 3 to 12 inches dbh 

Weight (Y) coefficient of Standard 

pounds Regression equations1 detemination error 

Y 

Complete tree (excluding leaves) 

Green Y = .I76557 D2 Th 

Dry Y = .lo139 D2 Th 

Complete tree wood 

Green I? = .I6823 Dz Th 

Dry Y = .09664 D2 Th 

Complete tree bark 

Green Y = .00758 D2 Th 

Dry Y = -00433 D2 Th 

Whole tree (excluding leaves) 

Green Y = .I4360 D2 Th 

Dry Y = .08262 D2 Th 

Whole tree wood 

Green Y = -13602 I32 Th 

Dry Y = .a7828 D2 Th 

Whole tree bark 

Green Y = .00758 D2 Th 

Dry Y = .00433 D2 Th 

Stem-stump to $-inch top no branches 

Green Y = .I2536 D2 Th 

Dry Y = .07281 D2 Th 

Stem wood 

Green Y = .I1909 D2 Th 

Dry Y = .06903 D2 Th 

Stem bark 

Green Y = .00627 D2 Th 

Dry Y = .00378 D2 Th 

Crown-above 3-inch top plus branches 

Green Y = .01824 D2 Th 

Dry Y = .00981 D2Th 

Crown wood 

Green Y =I .01Ci02 D2 Th 

Dry Y = .00926 D2 Th 

Crown bark 

Green Y = -00132 I32 Th 

Dry Y = .00055 D2 Th 

1Y = bD2 Th, where Y equals weight in pounds, D equals inches dbh, and Th equals feet 

of total tree height. 
Table 2.-Hickory regression equations for estimating green and oven-dry biomass for 

trees 3 to I2 inches dbh 

FVeight Coefficient of Standard 

pounds Regression equationsf determination error 

Y 

Complete tree (excluding leaves) 

Green Y = .22822 D2 Th 

DKY Y = .I4676 D2 Th 

Complete tree wood 

Green Y = .20824 D* Th 

DW Y = -13494 D2 Th 

Complete tree bark 

Green Y = .01611 D2 Th 

Dry Y = .00937 Dz Th 

Whole tree (excluding leaves) 

Green Y = 0.189G0 D2 Th 

Dry Y = 0.12241 D2 Th 

Whole tree wood 

Green Y = 0.17378 D2 Th 

DKY Y = 0.11304 D2 Th 

Whole tree bark 

Green Y = 0.01611 D2 Th 

Dry Y = 0.00937 D2 Th 

Stem-stump to 3-inch top no branches 

Green Y = 0.14908 D2 Th 

Dry Y = 0.09407 I22 Th 

Stem wood 

Green Y = 0.13285 D2 Th 

Dry Y = 0.08576 D2 Th 

Stem bark 

Green Y = 0.01417 D2 Th 

Dry Y = 0.0083 1 D2 Th 

Crown total-above 3-inch top plus branches 

Green Y = 0.04705 D2 Th 

Dry Y = 0.03099 D2 Th 

Crown wood 

Green Y = 0.04441 D2 Th 

Dry Y = 0.02960 D2 Th 

Crown bark 

Green Y = 0.00257 D2 Th 

Dry Y = 0.00139 D2 Th 

-- - 

lY = bD2 Th, where Y equals weight in pounds, I) equals inches dbh, and Th equals 

feet of total tree height. 
Table 3.-Red Oak-regression equatlolks for estimating green and oven-dry biomass for 

trees 3 to 22 inches dbh 

Weight Coefficient of Standard 

pounds Regression equations1 detemination error 

Y" 

Complete tree (excluding leaves) 

Green Y = 0,23398 I32 Th 

Dry Y = 0.13033 D2 Th 

Complete tree wood 

Green Y = 0.21583 D2 Th 

DTY Y = 0.11901 D2 Th 

Complete tree bark 

Green Y = 0.01547 D2 Th 

Dry Y = 0.00987 D2 Th 

Whole tree (excluding leaves) 

Green I?' = 0.20134 D2 Th 

DTY Y = 0.11308 D2 Th 

mole tree wood 

Green Y = 0.18587 I32 Th 

Dry Y = 0.10321 D2 Th 

Whole tree bark 

Green Y = 0.01547 D2 Th 

Dry Y = 0.00987 D2 Th 

Stem-stump to 3-inch top no branches 

Green Y = 0.14857 D2 Th 

Dry Y = 0.08112 D2 Th 

Stem wood 

Green Y = 0.13534 D2 Th 

Dry Y = 0.07258 D2 Th 

Stem bark 

Green Y = 0.01323 D2 Th 

DW Y = 0.00854 D2 Th 

Total crown-above 3-inch top plus branches 

Green Y = 0.05177 D2 Th 

Dry Y = 0.03197 D2 Th 

Crown wood 

Green Y = 0.05025 D2 Th 

Dry Y = 0.03060 D2 Th 

Crown bark 

Green Y = 0.00232 D2 Th 

Dry Y = 0.00137 D2 Th 

lY = bD2 Th, where Y equals weight in pounds, D equals inches dbh, and Th equals 

feet of total tree height. 
Table 4.-White Oak-regression equations for estimating green and oven-dry biomass 

for trees 3 to 12 inches dbh 

Weight Coefficient of Standard 

pounds Regression equations1 detemination error 

V 

Complete tree (excluding leaves) 

Green Y = 0.22314 D2 Th 

Dry Y = 0.13150 D2 Th 

Complete tree wood 

Green Y = 0.21466 D2 Th 

Dry Y = 0.12645 D2 Th 

Complete tree bark 

Green Y = 0,00698 D2 Th 

Dry Y = 0.00415 D2 Th 

Whole tree (excluding leaves) 

Green Y = 0.17998 D2 Th 

DW Y = 0.10633 D2 Th 

Whole tree wood 

Green Y = 0.17305 D2 Th 

Dry Y = 0.10218 D2 Th 

Whole tree bark 

Green Y = 0.00693 I)2 Th 

Dry Y = 0.00415 D2 Th 

Stem-stump to 3-inch top no branches 

Green Y = 0.14856 D2 Th 

Dry Y = 0.08112 D2 Th 

Sfem wood 

Green Y = 0.14208 D2 Th 

Dry Y = 0.08315 D2 Th 

Stem bark 

Green Y = 0.00579 D2 Th 

Dry Y = 0.00351 D2 Th 

Crown total-above 3-inch top plus branches 

Green Y = 0.03211 D2 Th 

my Y = 0.01966 D2 Th 

Crown wood 

Green Y = 0.03097 D2 Th 

Dry Y = 0.01902 D2 Th 

Crown bark 

Green Y = 0.00114 D2 Th 

Dry Y = 0.00064 D2 Th 

lY = bD2 Th, where Y equals weight in pounds, D equals inches dbh, and Th equals 

feet of total tree height. 

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DOCUMENTATION FOR HARDWOOD 

BIOMASS PROGRAM 

1, The percent of wood (green) and bark (green) 

are calculated for each section of the stem (butt, 

mid, 3-in top) and for each branch, using the 

weights obtained from lab samples. 

total wood weight % wood = total disk weight (wood + bark) X 100 

total bark weight % bark = total disk weight (wood + bark) X 100 

2. The proportional weighting factor (FW), for 

section of the stem, was calculated using the 

equation: 

The numerator is the square of the DIB at the 

section for which the weighing factor is to be 

calculated. 

3. The weighted percents wood (green) and bark 

(green) for the stem are determined by applying 

the weighting factor of the section to the percent 

of wood and bark for the section, as determined 

in #I. The weighted percents for each section 

are summed to get the weighted percent for each 

stem. The weighted percent of wood and bark for 

the branches are averaged, because only two 

branches were sampled and no branch diameters 

were recorded. 

Weighted $& wood = 

XpSt FWsectinn X 41; woodsection (#I) 

Weighted Cr, bark = 

2;zt Fwsection X % barksection ( # 1 ) 

Weighted (ro wood (Branches) = 

% wood (Branch 1) i- % wood (Branch 2) 

Total weight of wood = 

stem weight (lbs) X % wood 

100 + 

branch weight X % wood 

100 

Total weight of bark = 

stem weight X % bark branch weight X % bark 

100 i- 100 

5. The percent moisture (dry wt, basis) in the 

wood, for each section of the stem and each 

branch are calculated: 

% moisture in wood = 

green wt. of sample - dry wt. of sample X 100 dry wt. of sample 

and can be greater than 100 %. 

6. The dry weight of wood in the stem is calculated 

by: 

wwdl = Ws, x was 

-, , %M 

Where; 

Wwdl = calculated dry wt. of wood in stem 

W,, = green wt, of stem 

Wds = weighted % wood for the stem t 100 

% M = weighted Ojo moisture for the stem 

7, The dry weight of the wood in the branches is 

calculated by : 

dry ~t, of wood = green top wt. X 

weighted gfo wood 

loo-) - 

1 -+ weighted % moisture 

100 

2 8. The percent moisture (dry wt. basis) for the 

Weighted % bark (Branches) = 

% bark (Branch I) f % bark (Branch 2) 

bark, at each section of the stem and for each 

branch are calculated by: 

2 (ro moisture in bark = 

4. The total green weight of wood and bark for each green wt. of sample - dry wt, of sample 

dry wt. of sample x 100 tree is determined by using the equation: 
9. The weighted percent moisture (M) for the bark 

on the stem and branches are calculated by: 

weighted % M (in bark) = 

weighted % &.I: in (bark on branches) = 

% M (Branch 1) 4- % M (Branch 2) 

10. The dry weight of bark (Q7db) on the stem is calculated by: 

Wdb = Calculated dry wt. of bark on the stem 

WS~ = green wt. of stem 

Wb, = weighted % bark for the stem t 100 

% M = weighted % moisture in bark on stem. 

11, The dry weight of bark in the branches is calcclated by: 

dry wt. of bark I= green top pit. 

weighted (ro wood 

100 )- 

I -t- weighted % moisture 

100 

12. Total dry weight of each tree is the sum of the 

components : 

Total dry wt, of tree = dry wt. wood (stem) + 

dry wt. bark (stem) + dry wt. wood (branches) 

+ dry wt. bark (branches) 
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Sirois, Donald L, Biomass of four hardwoods from Lower 

Piedmont pine-hardwood stands, Gen, Tech. Rep, SO-46. 

New Orleans, LA: U.S, Department of Agriculture, Forest 

Sewice, Southern Forest Experiment Station; 1983. 18 p. 

Biomass equations for complete tree, whole tree, and stem 

wood, with and without bark, both green. and dry, are presented for four southern hardwoods - sweetgum (Liquidambar styraciflua L.); hickory, both mockernut and pignut 

(Carya tomerztosa (Poir.) Nutt. and C. glnbra (3Iill.) 

Sweet) ; red oak (Quttrcus falca ta hfichx. var. falcn ta) ; and 

white oak (Q, alba L.), Weight tables are also provided for 

the whole tree and stem wood of the four hardwoods. 

Kaywords: Whole tree, complete tree, prediction equations, 

biomass. 

*U S GOVERNMENT PPiNTLNG OFFICE 1933- 675-87hii04