Rmearch Nobsog27’

1981

Growth and Yields of &Year-Old Planted Hardwoods

On Sharkey Clay Sol1

R. M. Krinard and H. E. Kennedy, Jr.

SUMMARY

Yields of five hardwood species at age 5, planted

at 1 O- by 1 O-foot spacing on Sharkey clay soil, were

ranked cottonwood>sycamore>green ash>sweetgum-Nuttall oak. By species, per acre volume of

stemwood ranged from 29 to 446 cubic feet and total

above-ground dry tree weight ranged from 1.08 to

7.68 tons.

Additlonrl koywordr: Cottonwood (Populus

deltoides), sycamore (Platanus occidentalis), green

ash (Fraxinus pennsylvanica), sweetgum (Liguidambar styraciflua), Nuttall oak (Quercus nuttallii).

INTRODUCTION

Growth and yield information pertaining to planted

hardwoods on slackwater sites in the Midsouth have

been generally confined to cottonwood (Populus

deltoides Barb. ex Marsh.). Such sites are less

productive than medium-textured soils and offer

poorer economic returns. Most forested areas remaining on clay soils are cut-over and depleted.

Clearing and planting should provide the quickest

economic returns, although demanding the highest

initial investment. The actual production values

possible from several hardwood species are needed

by the forest manager. Volume and weight data of

5-year-old trees of five hardwood species planted

on Sharkey clay soil are provided in this note.

SPECIES AND METHODS

The study area was planted in a split-plot design

with six replications. Mowing or disking for weed

control were major plot effects, and species were

minor plot effects. Species measured were cottonwood, sycamore (P/atanus occidentalis L.), green

ash (Fraxinus pennsylvanica Marsh.), sweetgum

(Liquidambar styraciflua L.), and Nuttall oak (Quercus nuttallii Palmer).. Species subplots consisted of

4 rows by 6 rows of planting spots on 10x10 feet

spacing. Plots were cross-disked or mowed three to

five times a year for the five growing seasons.

Mowed plots of sweetgum and Nuttall oak were not

considered because of survival 550 percent.

In March 1976, before the sixth growing season,

height and diameter of all trees were measured. Two

trees from each species on each of the six disked

plots were felled and weighed with and without

branches in the fielcl. For five of the weighed trees

of each species, samlples of bole and branches were

obtained for later determination of moisture content

and dry weight. Weighed trees were also measured

for bole volume by taking diameters at 2-foot intervals along the main stem to the tip. An additional 18 to 25 felled trees per species were

measured for volume in both the disked and mowed

plots. Stem cubic volume was obtained by Newton’s

prismoidal formula.

Regression equations were developed for total

stem volume, using C)*H as the independent variable

Southern Forest Experiment Station/T-10210 U.S. Postal Services Bldg., 701 Loyola Avenue, New Orleans, La. 70113

Forest Service, U.S. Department of Agriculture.

Serving Alabama, Arkansas, Louisiana, Mississippi, Eastern Oklahoma, Tennessee, Eastern Texas.

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Table 1 .-Survival, diameters, heights, stem volumes per acre and total tree weights per acre py spe+?s.and +’

weed control treatments at age 5 -.

, , ”

,I_ .

Species Treatment I Stemvolume

,-,,

Survival ‘Dbh Tii Total treewt: 1 i, a*.,

i ST w ,!g !*

Cottonwood

Cottonwood

Sycamore

Sycamore

Green ash

Green ash

Sweetgum

Nuttall oak

Disk

Mow

Disk

Mow

Disk

Mow

Disk

Disk

percent

91 4.0 25.8 446 52 7.68 0.92

81 2.5 18.0 151 32 2.67 0.56

9 9 2.8 19.9 238 19 5.45 0.41

95 1.2 11.8 4 0 6 2.10 0.11

9 6 2.2 16.3 131 7 4.33 0.22

9 5 1.5 13.4 6 5 11 2.38 0.32

8 5 1.1 9.8 36 6 1.08 0.14

8 6 1 .o 8.6 2 9 6 1.27 0.24

in ft _ ___ ff3/A __ _ _ __ __ tonsfA _ _ _ _

where D=dbh and H=total height, and for total tree

green weight, using powers and cross products of

D and H as independent variables. For each plot,

volume and green weight per tree were predicted

using these regressions and tree values summed

to give a total plot value. Plot values for dry weight

were obtained by applying average moisture content

values to plot values for green weight.

Table P.-Totalstem volume(V) outside bark, where V=b,+b, D*H

Species bo b, r* S,, V

fP

RESULTi AND DISCUSSION

Disked plots

Cottonwood 0.110600 0.002266 0.99 0.08 1.16

Sycamore 0.138971 0.002486 0.96 0.05 0.59

Green ash 0.073700 0.002742 0.68 0.06 0.36

Sweetgum 0.052089 0.003924 0.85 0.01 0.10

Nuttall oak 0.038432 0.003916 0.90 0.02 0.09

Survival, at 5 years, ranged from 81 percent for

mowed cottonwood to 99 percent for disked sycamore (table 1). Whether mowed or disked, sycamore

and green ash had 95 percent or better survival.

Mowed plots

Cottonwood 0.080677 0.002237 0.99 0.03 0.54

Sycamore 0.029682 0.003241 0.98 0.01 0.12

Green ash 0.047868 0.003060 0.93 0.03 0.16

Average dbh ranged from 1 .O inch for Nuttall oak

to 4.0 inches for disked cottonwood. Disking increased average dbh over mowing from 47 percent

for green ash to 133 percent for sycamore. Average

height ranged from 9 feet for Nuttall oaks to 26 feet

for disked cottonwood. Disking increased average

height over mowing from 22 percent (green ash) to

69 percent (sycamore).

D*H, t-2 values ranged from 0.80 for Nuttall oak to

0.99 for cottonwood with ratios,of standard error of

estimate to mean weight ranging from 10 percent for

cottonwood to 24 percent for Nuttall oak (table 3).

Regression equations for predicting total stem

volume outside bark in cubic feet from D*H had

r2 values ranging from 0.85 for sweetgum to 0.99 for

mowed cottonwood (table 2). Standard errors of

estimate, expressed as a percentage of mean volume,

ranged from 6 percent for mowed cottonwood to 21

percent for mowed green ash and Nuttall oak.

Average tree stem volume, according to regression

equations and average tree values for dbh and

height, ranged from 0.07 cubic feet for Nuttall oak

to 1.05 cubic feet for disked cottonwood. Average

tree total dry weight ranged from 5.8 pounds for

sweetgum to 35.9 pounds for disked cottonwood.

Average moisture content of cut trees was 52

percent for green ash, 67 percent for Nuttall oak,

104 percent for both sweetgum and sycamore, and

123 percent for cottonwood.

For total tree green weight D*H, compared to D*, In dry weight, the average ratio of stem weight to

provided equivalent fit for cottonwood and syca- total weight ranged from 54 to 57 percent for sweetmore, slightly poorer fit with green ash and sweet- gum, green ash, and Nuttall oak, and was 67 percent

gum, and slightly better fit with Nuttall oak. Using for cottonwood and 69 percent for sycamore.

R. M. Krinard is Mensurationist and H. E. Kennedy, Jr., is Principal Silviculturist at the Southern Hardwoods Laboratory, maintained at

Stoneville. Mississippi, by the Southern Forest Experiment Station, Forest Service-USDA, in cooperation with the Mississippi

Agricultural and Forestry Experiment Station and the Southern Hardwood Forest Research Group.

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Table 3.-Total tree weight (W)green basis, where W=ba+br D*H

Species bo b, r* a., w

Ibs

Cottonwood 5.944333 0.178922 0.99 7.7 78.8

Sycamore 18.314908 0.211899 0.90 8.0 52.1

Green ash 7.903848 0.289740 0.88 7.1 33.9

Sweetgum 7.771218 0.355748 0.82 2.2 13.1

Nuttall oak 8.237939 0.495070 0.80 3.5 14.6

The regression equations and ZD*H per plot allow

per acre estimates with standard errors of estimate

(table 1). Maximum total stem volume outside bark

was 446 cubic feet per acre for disked cottonwood,

nearly 90 percent more than disked sycamore,

the next best growing species. Disked cottonwood

yielded 1.535 tons dry weight per acre per year,

40 percent more than disked sycamore (1.091 tons

per acre per year). The other three species yielded

only 14 (sweetgum) to 56 (disked green ash) percent

as much dry weight as disked cottonwood.

Statistically, at the 5 percent level, all disked cottonwood values (average dbh and height, stem volume

per acre and total tree dry weight per acre) were

greater than other species. Disked sycamore dbh,

height, and stem volume per acre was greater than

disked green ash, but no difference showed in total

tree dry weight between the two species. No differences occurred between sweetgum and Nuttall oak.

Within a species, disked values were greater than

mowed values except for green ash stem volumes

per acre.

The value of disking over mowing for weed control

with hardwood plantings on clay sites is well illustrated. Besides controlling vegetative competition,

disking enhances nutrient availability, particularly

N, because of periodic incorporation of green herbaceous matter (accompanied by its release of N

during decomposition) and its effect on mineralization in the soil. Additionally, disking improves

water infiltration, gas exchange between the soil

and atmosphere, and root proliferation by causing

branching when roots near the surface are cut.’

‘Kennedy, Harvey E., Jr. Foliar nutrient concentrations and

hardwood growth influenced by cultural treatments. (Manuscript

in preparation by U.S. Dep. Agric. For. Sew., South. For. Exp. Stn.,

New Orleans, La.)

Cottonwood growth on fine textured soils compares poorly to growth on medium textured soils57 feet vs. 32 feet in height in 5 years when averaged

over 14 select clones.* Yet, no species in this study

approached cottonwood growth and yield, although

all five are rated as species to favor in management on Sharkey and as suitable for planting on

those sites.3

The four species other than cottonwood were

planted on a Coastal Plain minor stream bottom

at the same spacing and with cross disking.4 Soils

were Arkabutla silt loam in the bottoms and Dulac

silt loam on adjoining lower slopes. Estimated site

indices at age 50 are 10 feet taller for ash and

sweetgum, 15 feet taller for sycamore, and 20 feet

taller for Nuttall oak on Arkabutla soil as compared

to Sharkey soil.3 Site comparison at age 5 can be

made by using the average of the tallest tree per plot

for each species on Sharkey and the tallest six trees

measured per species on the Coastal Plain site. On

Sharkey, sycamore was 2 feet shorter, green ash

had the same height, sweetgum was 8 feet shorter,

and Nuttall oak was 3 feet shorter.

A yield comparison at age 5 may be made by

assuming that the weight sample trees are representative of tree development on the two sites (on

Sharkey clay, the average weight sampled trees by

species were within 0.2 inches dbh and 1 foot in

height of overall stand averages). Based on the

average tree per site, total tree dry weight on the

Coastal Plain site was 56 percent greater for sycamore, 3 percent greater for green ash, 314 percent

greater for sweetgum, and 86 percent greater for

Nuttall oak. Total stem volume on the Coastal Plain

site was greater by 9 percent for sycamore, equal for

green ash, 255 percent greater for sweetgum, and

91 percent greater for Nuttall oak. The stem dry

weight to stem cubic volume (green basis) ratio

(pounds per cubic foot) varied between Arkabutla

silt loam and Sharkey clay soils, and was 39 and 31

for sycamore, 41 and 35 for green ash, 40 and 32 for

sweetgum, and 43 and 44 for Nuttall oak.

2Mohn, C. A., W. K. Randall, and J. S. McKnight. 1970. Fourteen

cottonwood clones selected for Midsouth timber production.

U.S. Dep. Agric. For. Res. Pap. SO-62 17 p. South. For. Exp. Stn.,

New Orleans, La.

3Broadfoot, Walter M. 1978. Hardwood suitability for and propertiesof important Midsouth soils. U.S. Dep. Agric. For. Res. Pap.

SO-127,84 p. South. For. Exp. Stn., New Orleans, La.

‘Krinard, R. M., H. E. Kennedy, Jr., and R. L. Johnson. 1979.

Volume, weight, and pulping propertiesof 5-year-old hardwoods.

For. Prod. J. 29(8):52-55.

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