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.<ck, United States \I DeDaflment of

so-339

June 1987

Growth of 31 -Year-Old Baldcypress Plantation

Roger M. Krinard and Robert L. Johnson

SUMMARY

Survival of baldcypress (Taxodium distichum (L.)

Rich.) planted on clay soil at 6- by lo-foot spacing decreased from 41 percent at age 21 to 26 percent at age

31. In the 1 O-year period, average diameter increased

from 6.1 to 8.6 inches, basal area from 72 to 90 square

- feet per acre, and total volume outside bark, for trees

~3.0 inches d.b.h., from 1,288 to 2,333 cubic feet per

acre. The 30 largest cypress trees per acre averaged

14.2 inches d.b.h. and 72 feet tall at age 31.

Additional keywords: Taxodium distichum, artificial regeneration, diameter increment.

INTRODUCTION

Baldcypress (Taxodium distichum (L.) Rich.) is one of

the better adapted species for flood-prone sites where

many other species cannot survive. While baldcypress is

valuable because of its ecological niche, few mills now

process its lumber and less than 200 million board feet

is produced annually (Williston et al. 1980). However, a

ready market exists for the lumber. Cypress growing

stock volume, mostly second growth, approximates

5.5 billion cubic feet. Planting cypress on sites subject to

flooding is one method of stocking areas where natural

regeneration does not provide sufficient numbers of desirable species to produce a commercial stand of timber.

Little information is available, though, on development of

cypress plantings and growth of individual cypress trees.

This note presents 10 years of additional growth data

and stand changes from age 21 to age 31 in a cypress

plantation (Krinard and Johnson 1976) on Mississippi

River clayey alluvium.

METHODS

The cypress plantation was established in February

1955 on a Sharkey clay soil site on the Delta Experimental Forest in Washington County, Mississippi. The 1.23-

acre area represented five micro-sites of ridge (0.27

acre), slope (0.23 acre), and three flat-sloughs (0.23,

0.23, and 0.27 acre) over a 3-foot elevation change, with

water generally covering the slough 1 to 2 feet in winter.

The site had been cleared, planted to cottonwood (fopu/us deltoides Bartr. ex Marsh.) and lost to flooding three

times, starting in the late 1930’s. The development of

heavy vine competition and annual water problems precluded the establishment of desirable commercial species.

The cypress planting consisted of 64 rows of 14

seedlings per row (896 total seedlings) at 6- by lo-foot

spacing to test regular and deep plantings with and without top clipping. Cultural treatments consisted of three or

four cultivations per year for 4 years and annual mowing

for the next 6 years. Most of the seedlings were vine bent

during that period.

Heights of all cypress were measured at age 4 and

diameters at ages 21 and 31. Where natural regeneration of other species had become established in a cypress planting spot, the d.b.h. of the largest stem was

measured if, at age 21, the stem was 23.0 inches d.b.h.

and not in a suppressed crown position. Heights of 89

cypress, 21 green ash (fraxirwspennsylvanica Marsh.),

and 9 boxelder (Acer negundo L.) were measured to

establish height-diameter relationships for those species.

Outside bark volume information was obtained from

cut trees and from standing trees measured with a denrometer for 25 cypress, 10 ash, and 9 boxelder. Volume

Southern Forest Experiment Stationn-102lO U.S. Postal Services Bldg., 701 Loyola Avenue, New Orleans, La. 70113

Forest Service, U.S. Department of Agriculture.

Serving Alabama, Arkansas, Louisiana, Mississippi, E. Oklahoma, Tennessee, E. Texas, Puerto Rico, U.S. Virgin Islands

1
estimates for those three species and combined other

species, excluding black willow (&/ix nigra Marsh.) and

cottonwood, were obtained from volume equations using

l-inch diameter classes and heights from heightdiameter curves (table 1). Volume is for the main bole

outside bark from a 1 -foot stump to the top.

RESULTS AND DISCUSSION

No statistically significant differences were found between planting treatments in cypress height or survival

by age 4 (Krinard 1959). Average survival was 62 percent (450 trees/acre) and average height was 6.6 feet

(range 2.7 to 11 feet). Average survival decreased to 41

percent (296 trees/acre) at age 21 and to 26 percent

(191 trees/acre) at age 31. Survival on ridge, slope, and

three flat-sloughs, in that order, was 58, 64, 67, 62, and

60 percent at age 4; 48,47,45,33, and 31 percent at age

21; and 29, 32, 27, 21, and 23 percent at age 31.

Average diameter of the cypress increased from 6.1

inches at age 21 to 8.6 inches at age 31. Survivor diameter growth during the last 10 years was 1.3 inches (table

2). From highest to lowest site, average diameter at age

21 was 5.5, 7.2, 6.3, 5.9, and 5.8 inches; at age 31

corresponding diameters were 7.7,9.7, 8.8,8.9, and 8.2

inches. Ninety-five percent of the mortality in the last 10

Table 1 .-Height-diameter equations and volume equations for cypress, ash, and boxelder

Cypress

Log H = 2.073355 - 3.412764(1/A) - 0.847855(1/D)

- 18.889395( l/AD)

FI = 0.92, S, = 3.8, CV = 5.9%

V = 0.000533 D’.5487“4 H’.-*’

FI = 0.99, S, = 1.9, CV = 7.9%

Ash

Log H = 2.150234 -8.328854(1/A) -0.914318(1/D)

FI = 0.92, S, = 3.9, CV = 8.3%

V = 0.000217 D1.159686 H2.0’9012

FI = 0.98, S, = 1.2, CV = 7.8%

Boxelder

Log H = 1.925858 - 4.128692(1/A) - 0.453021 (l/D)

FI = 0.87, S, = 2.3, CV = 4.6%

V = 0.000866 D’.-” H’=‘sss

FI = 0.97, S, = 1.0, CV = 11.5%

H = total height, V = volume (outside bark) from a l-foot stump to

the tip of the stem, A = age, D = d.b.h., FI = fit index, S, = standard

error of estimate in actual units, CV = coefficient of variation.

years occurred in trees c6.0 inches d.b.h. Thus, the

number of cypress trees per acre ~6.0 inches d.b.h. only

increased from 141 to 147 in 10 years, but the number

of trees 110.0 inches d.b.h. more than doubled from 28

to 65. Cypress on the ridge site had lowest average

diameter and least 10 years’ diameter growth both for all

surviving trees and for the seven or eight largest trees

per site.

At age 31 the 37 largest cypress over the whole planting area (30 largest trees per acre) averaged 14.2 inches

d.b.h. with 10 years average growth of 3.3 inches.

Heights averaged 72 feet and ranged from 64 to 78 feet.

Eight of the 37 trees were also measured for height at

age 21, and by age 31 these trees had averaged 15 feet

of height growth in the 10 years.

The two largest trees in the area were a black willow

and a cottonwood. The black willow grew from 15.4

inches and 77 feet to 19.5 inches and 94 feet. The cottonwood grew from 15.3 inches and 70 feet to 20.0

inches and 86 feet. The largest ash tree grew from 10.3

to 16.4 inches and was 82 feet tall; the fastest growing

ash went from 4.6 to 12.4 inches d.b.h.

Considering all measured trees, basal area per acre

increased from 95 square feet at age 21 to 124 square

feet at age 31. By species, basal area in square feet per

acre at ages 21 and 31 were 72 and 90 for cypress, 11

and 11 for boxelder, 7 and 15 for ash, and 5 and 8 for

other species.

At both ages 21 and 31, cypress comprised about 72

percent of the total outside bark volume for all measured

trees (table 3). For trees 13.0 inches d.b.h. cubic volume mean annual increment (m.a.i.) for all species increased from 85 to 106 cubic feet per acre per year,

while cypress increased from 61 to 75. For trees 26.0

inches d.b.h., all species’ m.a.i. increased from 69 to 100

cubic feet per acre per year and cypress increased from

51 to71.

Volume m.a.i. of planted cypress and accompanying

other species other than large cottonwood and black

willow after 31 years on Sharkey clay was similar to

29-year-old natural regeneration which developed following seed tree cutting in two minor bottoms of southeastern Arkansas (manuscript in process): 98 vs. 93

cubic feet per acre per year in trees 25.0 inches d.b.h.

Average dominant heights were 72 feet for both cypress

on Sharkey and the major species, sweetgum, on the

Coastal Plains’ soils.

The cypress trees were still very limby (fig. 1). As a

measure of limbiness, a limb count of the 30 largest

cypress per acre was made to a height of 15.5 feet.

There were an average of 23 limbs per tree, with a range

from 7 to 44 limbs.

Roger M. Krinard is mensurationist and Robert L. Johnson 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.

2
Table 2.-Number of trees per acre at ages 27 and 31. and intervening mortality and average d.b.h.

growth of survivors by l-inch d.b.h. c/asses

D.b.h.

class

Cypress Other species

Trees/acre 10 yrs. Trees/acre 10 yrs.

Age Age d.b.h. Age Age d.b.h.

2 1 Mort. 3 1 growth 2 1 Mot-t. 3 1 growth

Inches

1.011.9 0.8 0.8

2 17.0 15.4

3 42.9 37.3 4.1

4 47.8 29.2 21.9

5 46.2 17.0 18.6

6 38.9 4.1 24.3

7 29.2 0.8 21.9

8 28.4 21.1

9 16.2 14.6

1 0 13.8 18.6

11 10.5 14.6

1 2 0.8 8.9

1 3 1.6 11.3

1 4 1.6 6.5

1 5 0.8

1 6 0.8

1 7 0.8

1 8 1.6

1 9

2 0

2 3 "ii

1.6

0.3

0.1

0.5

0.9

1.1

1.5

2.3

2.5

2.6

2.1

4.4

7.0

. . . ..I

......

......

11.3

19.5

23.5

26.7

6.5

6.5

4.1

1.6

0.8

0.8

"1.6

. .

0.8 0.8

0.8 8.9

4.1 13.8

4.9 13.8

0.8 13.8

1.6 11.3

2.4 4.1

0.8 7.3

0.8

4.1

4.8

Inches

1.4

1.8

1.9

2.3

2.1

3.2

3.0

6.1

4.0

0.8

0.8

4.4

......

......

Total 295.7 104.5 191.2 102.9 17.0 85.9

Avg. 1.3 2.1

Figure 1 .-General view of planted cypress in 31st growing season.
.

Taole 3.-Cubic volume by species and diameter thresholds at ages LITERATURE CITED

21and31 -

Trees ~3.0 inches Trees ~6.0 inches

Species Age 21 Age 31 Age 21 Age 31

_ _ _ _ _ _ _ - _ - _ _ Cubic feet/acre _ _ _ _ _ _ _ _ _ _ _ _

Cypress

Ash

Boxelder

Sugarberry and

persimmon

Black willow and

cottonwood

Total

1,288 2,333 1,079 2,214

149 459 112 439

238 277 156 216

3 3 6 2 1 6 5 4

8 2 163 8 2 163

1,790 3,294 1,445 3,086

Results of the last 10 years-age 22 through age 31-

have shown a slight decline in cypress diameter growth,

with the 30 largest trees per acre decreasing from a

diameter m.a.i. of 0.52 to 0.46 inch per year and a periodic annual increment of 0.33 inch per year. Also, butt

swell tends to. increase as tree size increases, which

tends to inflate diameter growth. But diameter growth of

these plantation trees still exceeds that of natural stand

trees (Putnam et al. 1960).

Krinard, R. M. No advantage to clipping baldcypress

planting stock. Tree Planters’ Notes. 36: 14; 1959.

Krinard, R. M.; Johnson, R. L. 21 -year growth and development of baldcypress planted on a flood-prone site.

Research Note SO-217. New Orelans, LA: U.S. Department of Agriculture, Forest Service, Southern

Forest Experiment Station; 1976. 4 p.

Putnam, John A.; Furnival, George M.; McKnight, J. S.

Management and inventory of southern hardwoods.

Agric. Handb. 181. Washington, DC: U.S. Department

of Agriculture, Forest Service; 1960. 102 p.

Williston, H. L.; Shropshire, F. W.; Balmer, W. E. Cypress management: a forgotten opportunity. Forestry

Report SA-FR 8. Atlanta, GA: U.S. Department of

Agriculture, Forest Service, Southeastern Area, State

and Private Forestry; 1980. 8 p.

dJ.S.COVERNMENTPRlNl'lNGOFFICE:1987 -761-086/ 60038