United States 

I@ / Department of 

Agriculture 

Thinning Cherry-Maple Stands 

I 

Forest Service in West Virginia: 5-Year Results 

Northeastern Forest 

Experiment Station Neil I. Lamson 

Research Paper NE-615 H. Clay Smith 
Abstract 

In northern West Virginia, 60-year-old cherry-maple stands were thinned to 75,60, 

and 45 percent relative stand density. Analysis of 5-year growth data showed that 

basal-area growth was not reduced by thinning. Cubic-foot and board-foot 

volume growth decreased slightly. Individual-tree growth of all trees, dominant/ 

codominant trees, and the 50 largest diameter trees per acre was significantly 

increased by thinning. Dominant/codominant trees in the 45 percent plots grew 

about 0.42 inch more in 5 years than those in the control plots. Optimum stand 

density probably is less than 60 percent relative stand density. 

The Authors 

NEIL I. LAMSON, research forester, received B.S. and MS. degrees in silviculture 

and forest soils from the State University of New York, College of Environmental 

Science and Forestry, Syracuse. He joined the USDA Forest Service, State and 

Private Forestry, in 1972. Currently he is engaged in timber managelpent research 

at the Northeastern Forest Experiment Station's Timber and Watershed Laboratory at Parsons, West Virginia. 

H. CLAY SMITH is Project Leader of timber management research at the Northeastern Station's Timber and Watershed Laboratory at Parsons. He received 

degrees from West Virginia University and Purdue University, and has been 

engaged in timber rnanagement,research with the USDA Forest Service 

since 1962. 

Manuscript received for publication 23 February 1988 

Northeastern Forest Experiment Stajion 

370 Reed Road, Broomall, PA 19008 

May 1988 
1 Introduction 

Thinnings in even-aged hardwood stands usually are made 

to: a) increase the growth of the most valuable trees in the 

stand; b) increase yield by harvesting trees that would die; 

and c) reduce the rotation length and/or increase the size of 

trees at final harvest. In reference to thinning Allegheny 

hardwoods, Roach (1977) stated: "Ideally, to grow a full 

crop of wood products as quickly as possible, we should 

I always have in our stand the minimum number of trees that 

will just use all of the light, moisture and nutrients that are 

available on the site each growing season. The problems I have always been how to define this ideal and then how to 

achieve it." In this paper we report the 5-year results of a I thinning study in cherry-maple stands in West Virginia. 

These preliminary results will help define the optimum 

stand conditions necessary to increase yields and monetary 

returns from managing similar stands. 

Methods 

I In the fall of 1981, 16 plots, each 0.5 acre in size, were randomly located in a 60-year-old cherry-maple stand in northern West Virginia. Each plot was surrounded by a buffer 

i strip that was 75 feet wide. Four treatments were randomly I assigned to each of four plots. The four treatments were 

control and 75, 60, and 45 percent relative stand density I (RSD) according to guidelines for managing Allegheny 

hardwoods (Marquis et al. 1984). Thinned plots and their 

buffer strips were marked according to guidelines in Marquis et al. (1984). The plot and buffer strips were thinned 

from below with about two-thirds of the basal area removed 

consisting of trees smaller than the average stand diameter. 

All trees at least 1.0 inch d.b.h. that were not marked for cutting were permanently identified using tree wires and numbered brass tags (Lamson and Rosier 1984). 

The plots were thinned in the spring of 1982 by a three-man 

crew using chain saws and a rubber-tired skidder (Fig. 1). 

Each plot together with its buffer was logged as a separate 

unit. Trees were topped to a 4-inch d.i.b. and skidded full 

length. Trees less than 7 inches d.b.h. were not skidded. 

Stand data before and after cut are shown in Table 1. 

A postlogging inventory conducted immediately after logging accounted for all residual trees. Crown class of residual trees was determined and logging damage was 

assessed. The logging damage was slight and concentrated in the sapling stems (Lamson et al. 1984). 

Table 1.-Per-acre stand data by thinning treatment 

In the fall of 1986, five growing seasons after thinning, 

diameters of the residual trees were remeasured. lngrowth 

was tallied using a 1.0-inch threshold d.b.h. The &year 

growth dataiare summarized in this paper. 

Before and 5-years after treatment, living epicormic 

brhches were counted on the first two 16-foot logs (33 

feet)' of all trees at least 7.0 inches d.b.h. 

Stems 1 .O+ Stems 5.0+ Stems 11 .O+ 

inches d.b.h. inches d.b.h. inches d.b.h. 

No. of Basal No. of No. of 

Item trees area trees Volume trees Volume RSDa 

Ftzlacre Ft3/acre Bd. ftlacre Percent 

CONTROL 

864 166 288 3,078 70 9,756 115 

75 PERCENT 

Initial 923 s 61 322 2,893 56 7,204 120 

Cut 354 : 52 143 700 7 626 47 

Residual 569 109 1 79 2,193 49 6,578 73 

60 PERCENT 

Initial 904 64 352 2,874 55 5,194 125 

Cut 476 ) 80 21 6 1,216 14 873 68 

Residual 428 84 136 1,658 41 4,321 57 

45 PERCENT 

Initial 827 ) 60 338 2,840 63 5,834 119 

Cut 525 1 98 253 1,602 22 1,546 79 

Residual 302 62 85 1,238 41 4,288 40 

aRelative stand density of trees 1.0+ inches d.b.h. 
Figure 1. - A 60-year-old cherry-maple stand in northern West Virginia before thinning (top) and after thinning. 

2 
Results 

Stand Growth and Mortality 

Basal-area growth. Periodic net basal-area growth was 

increased by thinning (Table 2). The 75-percent plots 

averaged 19 ftVacre of basal-area growth in the 5-year 

period, while the 60 percent, 45 percent, and control plots 

averaged 16, 15, and 10 ftVacre, respectively. Thinning 

reduced periodic mortality from 9 ftVacre in the control 

plots to about 1.4 ft2facre in the thinned plots. Most of the 

dead trees in the thinned plots were those that had been 

damaged during logging. lngrowth was directly related to 

the intensity of thinning, the heavier thinned plots having 

more ingrowth. Thinning also shifted the stand growth 

onto fewer, more valuable trees. For example, in the control plots, the net basal-area growth of 10 ftYacre occurred 

on 746 stems/ 

acre, while in the 45 percent plots, 15 ftVacre of growth 

occurred on only 335 stems/acre. Individual-tree net 

basal-area growth averaged 0.01,0.03,0.04, and 0.05 ft2 for 

the control and 75, 60, and 45 percent plots, respectively. 

Table 2.-Stand growth and mortality by thinning treatment 

No. of trees 5-year net growtha 

Treatment Residual Final lngrowth Mortality Per acre Per tree 

Control 

75 percent 

60 percent 

45 percent 

Control 

75 percent 

60 percent 

45 percent 

Control 

75 percent 

60 percent 

45 percent 

Control 

75 percent 

60 percent 

BASAL AREA (FtYacre) 

166 176 0.1 (8)b 9.0 (126) 

109 128 0.2 (33) 1.4 (48) 

84 100 0.3 (36) 1.6 (50) 

62 77 0.5 (64) 1.1 (31) 

VOLUME (FtVacre) 

3,078 3,493 50 (17) 98 (19) 

2,193 2,636 0 9 (1) 

1,658 2,062 0 9 (1) 

1,238 1,609 0 9 (1) 

VOLUME (Board feeuacre) 

9.756 12,847 889 (19) 124 (1) 

6,578 9,417 784 (14) 0 

4,321 7,259 1,077 (20) 0 

4,288, 7,098 848 (15) 37 (1) 

RELATIVE STAND DENSITY (Percent) 

115 115 - - 73 83 - 57: 67 - - 

45 percent 401 49 - - 9 (335j 0.027 

aNet growth = survivor drowth + ingrowth - mortality. 

bNumbers in parentheses are numbers of trees per acre. 

Cubic-foot volume growth. Per-acre periodic net cubicfoot volume growth of all trees at least 5.0 inches d.b.h. 

was changed little by thinning (Table 2). Thinning to 75 

percent increased cubic-foot volume net growth per acre 

from 415 to 443. The 45 percent plots aver?ged 371 

ftVacre periodic net growth. Mortality in ttie thinned plots 

averaged 9 ftVacre compared with 98 ftVacre in the control plots. Mortality in the thinned plots wap the result of 

trees being severely damaged during loggi~ng. , 

Thinning redistributed the cubic-foot volu+e growth onto 

fewer stems and resulted in increased indiqidual-tree 

growth. For control and 75,60, and 45 pergent plots, average per-tree cu bic-foot volume growth averaged 1.45, 2.49, 

2.99, and 4.42, respectively. There was no ingrowth of 

trees into the 5.0+ inches d.b.h. class in the thinned plots 

because all trees 3.6 to 4.9 inches d.b.h. were cut in 1981 

to reduce the sapling basal area to the recommended 

level. 

Board-foot volume growth. For all treatments, 5-year net 

board-foot volume growth averaged 2,92O/acre of which 

about 900 board feeUacre was ingrowth (trees crossing 

the 11.0-inch threshold d.b.h. for board foot calculations). 

There was no mortality of sawlog-size trees in any of the 

thinned plots except for one tree per acre in 45 percent 
plots. This was a tree that had suffered severe logging 

damage. The number of sawlog-size trees in the control I and 75,60, and 45 percent plots was 88,63,61, and 55 per 

, acre, respectively, while individual-tree growth averaged 

35.1, 45.1, 48.2, and 51.1 board feet, respectively. 

Relative stand density. The RSD for thinned plots 

increased by about 10 percent during the 5-year period. 

The control plots did not change, remaining overstocked 

at 115 percent. 

Individual-Tree Growth 

The data in Table 2 suggest that thinning increased 

individual-tree growth as per-acre volume growth decreased 

only slightly even though there were fewer trees in the 

thinned plots. Statistical comparisons of individual-tree 

growth are shown in Table 3. 

For all trees at least 1.0 inch d.b.h., thinning significantly 

increased the average 5-year diameter growth of individual 

trees. All treatment means were significantly different from 

each other. Average 5-year diameter growth was 0.24,0.48, 

0.62, and 0.76 inch for control and 75, 60, and 45 percent 

plots, respectively. Trees in the 45 percent plots averaged 

3 times as much diameter growth as those in the control 

plots. Five years after thinning, the average d.b.h. in the 75, 

60, and 45 percent plots was 0.23,0.36, and 0.52 inch larger, 

respectively, than in the control plots. 

Thinning also significantly increased the growth of the 

dominanVcodominant trees in 1981 (Table 3). All treatments 

were significantly different from each other. Average 5-year 

diameter growth was 0.69,0.91, 1.03, and 1 .ll inches for the 

control and 75, 60, and 45 percent plots, respectively. 

Table 3.-Average individual-tree diameter growth by thinning treatment 

Dominant/ 

All codominant 50 largest 

Item trees trees (1981) t reedacre 

CONTROL 

Nolacre (1 986) 742 138 50 

1981 D.b.h. (inches) 4.90 11.38 14.15 

1981-86 growth (inches) 0.24 a 0.69 a 0.82 a 

75 PERCENT 

No./acre (1 986) 52 1 123 50 

1981 D.b.h. (inches) 4.61 10.84 13.07 

1981-86 growth (inches) 0.48 b 0.91 b 1 .06 b 

60 PERCENT 

Nolacre (1 986) 379 109 50 

1981 D.b.h. (inches) 4.84 10.60 12.15 

1981-86 growth (inches) 0.62 c 1 .03 c 1.17 c 

45 PERCENT 

Nolacre (1 986) 271 79 50 

1981 D.b.h. (inches) 4.82 11.14 12.12 

1981-86 growth (inches) 0.76 d 1.11 d 1.18 d 

Note: Values in the same column followed by the same letter are not 

significantly different (P < 0.01). 

Serious distortions can result in comparisons of individualtree growth means if the number of trees in each treatment 

are not equal. In this study, the number of trees per acre 

ranged from 742 to 271 for all trees and from 138 to 79 for 

dominanVcodominant trees. The sample size was equalized 

by selecting the 50 largest trees per acre in each plot. The 

25 trees with the largest diameter in 1981 were selected 

from each %-acre plot. 

The 50 largest diameter trees per acre generally showed the 

same response to thinning as all trees and codominant trees 

(Table 3). Average 5-year diameter growth for control and 

75, 60, and 45 percent plots was 0.82, 1.06, 1.17, and 1.18 

inches, respectively. In the 60 and 45 percent thinning 

treatments, the 50 largest diameter trees per acre increased 

in diameter about 0.35 inch more than those in the controls 

in 5 years. 
Tree Quality 

Heavy thinning has been shown to increase the size and 

number of surface defects, particularly on white oak (Sonderman 1984). In this study, the number of live epicormic 

branches at least 1 foot long in the first two 16-foot logs (1 

to 33 feet) were tallied on all trees at least 7.0 inches d.b.h. 

A total of 954 trees was examined. About two-thirds of the 

trees sampled were black cherry and about one-quarter 

were red maple. Other species sampled were sugar maple, 

cucumbertree and white ash (Table 4). Data were summarized by number of trees with fewer than three epicormic 

branches in each 16-foot log. It was assumed that only two 

epicorrnic branches in a 16-foot log would not reduce the 

grade of that log. 

In general, thinning caused few epicormic branches to 

develop. For black cherry, the most numerous and highest 

value species in these plots, 97 percent of the trees in the 

plots thinned to 45 percent had fewer than three epicormic 

branches in the butt log (Table 4). In the second log, the 

percentage of trees with fewer than three epicormic 

branches in the second log was 98,95, and 93 percent for 

the plots thinned to 75, 60, and 45 percent, respectively. 

Epicormic branching on red maple was slightly higher than 

on black cherry, especially at 45 percent RSD. Sugar maple, 

a very tolerant species, produced the most epicormic 

branches. However, since this species is a minor component 

of these stands, it is doubtful that stand value would be significantly decreased by the increase in epicormic branches 

on sugar maple. 

Discussion 

The basic concept of thinning even-aged stands is to leave 

just enough trees to fully occupy the site so that total production is not reduced. In this experiment, 5-year growth of 

total basal area, cubic-foot volume, and board-foot volume 

was not significantly reduced by any of the thinning treatments. It appears that thinning to as low as 40 percent RSD 

still leaves enough trees to fully occupy the site. 

Table 4.-Percent of trees over 7.0 inches d.b.h. with fewer than three epicormic branches 

in the butt and second logs 5 years after thinninga 

Black Red Sugar Cucumber- White 

Treatment cherry maple maple tree ash All species 

.................................................................... Percent 

BUTT LOG 

75 percent 100 (307) 98 (96) 62 (8) 82 (1 1) 89 (8) 98 (403) 

60 percent 97 (212) 99 (103) 86 (14) 100 (10) 100 (1) 97 (340) 

45 percent 97 (147) 85 (33) 100 (2) 50 (2) - 95 (184) 

SECOND LOG 

75 percent 98 (307) 88 (96) 50 (8) 27 (1 1 ) 1 00 (1 5) 97 (423) 

60 percent 95 (212) 88 (103) 64 (1 4) 50 (10) 100 (1) 92 (340) 

45 percent 93 (147) 76 (33) 50 (2) - - 87 (182) 

aNumbers in parentheses ark numbers of trees observed. 

The RSD increased by about 2 percent annually in all 

thinned plots. This is another indication that the sites were 

fully occupied, even at 40 percent RSD. If the stands continue to grow at this rate, the 75 percent plots will reach 

about 93 percent RSD in 5 years. At that time, one could 

expect to see some mortality, which would mean the stands 

would be ready for another thinning. For the 60 percent 

plots, RSD probably will reach about 96 pixcent in 15 years. 

This would mean about a 20-year thinnind cycle for stands 

thinned to 60 percent RSD. For the 45 perhent plots, RSD 

will reach about 95 percent in 23 years. ~de stands will be 

about 90 years old at that time and probably will be ready 

for the harvest cut. However, the reader is Jcautioned that 

these estimates are based on 5-year growth data. The actual 

long-term growth of these stands may differ considerably 

f rom these estimates. 

Thinning did not stimulate the production of epicormic 

branches on black cherry, the most valuable and most 

numerous codominant trees in these stands. It appears that 

individual-tree value of black cherry will not be reduced by 

reducing the RSD to as low as 40 percent. However, at 45 

percent RSD, red maple tended to produce significant 

numbers of epicormic branches. 

Another objective of thinning is to harvest trees before they 

die. Mortality was reduced by all thinning treatments. Mortality of trees 5.0+ inches d.b.h. in the thinned plots was 
only one tree per acre. In all cases, the mortality in the 

thinned plots was due to severe logging wounds, not stand 

competition. Thinning also increased yields because no 

trees were harvested from the control areas. 

Individual-tree growth was increased by thinning. For the 50 

largest diameter trees per acre, thinning to 60 and 45 percent increased the 5-year diameter growth by 0.35 inch per 

tree. For dominant/codominant trees, the 45 percent treatment increased individual-tree growth by 0.42 inch in 5 

years. If these growth rates remain unchanged for the next 

20 years, d.b.h. growth of dominant/codominant trees in the 

45 percent plots will be about 2.1 inches more than that of 

codominant trees in the control plots. For the 50 largest 

diameter trees per acre, d.b.h. of trees in the 45 percent 

plots will be about 1.7 inches larger than those in the control plots. This could mean substantial gains in stand value 

because the codominant control trees will average about 15 

inches d.b.h., while those in the 45 percent plots will average about 17 inches d.b.h. Trees must be at least 16 inches 

d.b.h. to produce a grade 1 butt log. 

One cannot accurately predict long-term stand growth from 

these 5-year growth data. As the thinned stands continue to 

grow, competition will increase and diameter growth of individual trees will slow. However, it is clear that these previously unmanaged, 60-year-old cherry maple stands will 

respond to thinning. These data also show that the optimum 

thinning level may be less than 60 percent RSD as per-acre 

growth was not substantially reduced by thinning to 40 percent RSD. 
I 

I Literature Cited 

I 

i Lamson, Neil I.; Rosier, Robert L. 1984. Wires for long-term 

identiification. Journal of Forestry, 82(2): 11 0-1 11. 

Lamson, Neil I.; Smith, H. Clay; Miller, Gary W. 1984. Residual stocking not seriously reduced by logging damage I 1 from thinning of West Virginia cherry-maple stands. Res. 

Pap. NE-541. Broomall, PA: U.S. Department of Agriculture, Forest Service. Northeastern Forest Experiment Station. 7 p. 

Marquis, David A.; Ernst, Richard L.; Stout, Susan L. 1984. 

Prescribing silvicultural treatments in hardwood stands 

of the Alleghenies. Gen. Tech. Rep. NE-96. Broomall, PA: 

US. Department of Agriculture, Forest Service, Northeastern Forest Experiment Station. 90 p. 

Roach, Benjamin A. 1977. A stocking guide for Allegheny 

hardwoods and its use in controlling intermediate cuttings. Res. Pap. NE-373. Upper Darby, PA: U.S. Department of Agriculture, Forest Service, Northeastern Forest 

Experiment Station. 30 p. 

Sonderman, David L. 1984. Quality response of even-aged 

80-year-old white oak trees after thinning. Res. Pap. NE543. Broornall, PA: U.S. Department of Agriculture, 

Forest Service, Northeastern Forest Experiment Station. 

6 P. 
Lamson, Neil I.; Smith, H. Clay. 1988. Thinning cherry-maple stands in West 

Virginia: 5-year results. Res. Pap. NE-615. Broomall, PA: U.S. Department of Agriculture, Forest Service, Northeastern Forest Experiment Station. 7 p. 

In northern West Virginia, 60-year-old cherry-maple stands were thinned to 

75,60, and 45 percent relative stand density. Analysis of 5-year growth data 

showed that basal-area growth was not reduced by thinning. Cubic-foot and 

board-foot volume growth decreased slightly. Individual-tree growth of all 

trees, dominant/codominant trees, and the 50 largest diameter trees per acre 

was significantly increased by thinning. Dominantkodominant trees in the 

45 percent plots grew about 0.42 inch more in 5 years than those in the control plots. Optimum stand density probably is less than 60 percent relative 

stand density. 

ODC 242: 561 : 562: S 76.1 

Keywords: Thinning, diameter increment, volume increment, Allegheny 

hardwoods. 
Headquarters of the Northeastern Forest Experiment Station are in Broomall, Pa. 

Field laboratories are maintained at: 

a Amherst, Massachusetts, in cooperation with the University of Massachusetts. 

a Berea, Kentucky, in cooperation with Berea College. 

Burlington, Vermont, in cooperation with the University of Vermont. 

a Delaware, Ohio. 

Durham, New Hampshire, in cooperation with the University of New Hampshire. 

Hamden, Connecticut, in cooperation with Yale University. 

a Morgantown, West Virginia, in cooperation with West Virginia University, 

Morgantown. 

a Orono, Maine, in cooperation with the University of Maine, Orono. 

a Parsons, West Virginia. 

a Princeton, West Virginia. 

Syracuse, New York, in cooperation with the State University of New York 

College of Environmental Sciences and Forestry at Syracuse University, 

Syracuse. 

University Park, Pennsylvania, in cooperation with the Pennsylvania State 

University. 

a Warren, Pennsylvania. 

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should be reported to the Secretary of Agriculture, Washington, DC 20250.