United States

Department of

Agriculture

Forest Service

Northeastern

Research Station

Research Paper NE-717

David R. Houston

Effect of Harvesting Regime

on Beech Root Sprouts and

Seedlings in a North-Central

Maine Forest Long Affected

by Beech Bark Disease
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The Author

DAVID R. HOUSTON (retired) was a principal plant pathologist with the

Northeastern Research Station’s Center for Biological Control of Northeastern

Forest Insects and Diseases at Hamden, Connecticut. His research focused

primarily on stress-initiated dieback and decline diseases of deciduous hardwoods,

particularly beech, maple and oak.

Abstract

In Maine, northern hardwood stands long affected by beech bark disease often

contain large numbers of American beech trees severely damaged by the disease.

Methods are needed to improve stand quality by reducing the proportion of

susceptible trees, and increasing the number of resistant trees. A 6-year study was

conducted in north-central Maine to determine the effects of commonly used

harvesting systems on the incidence and growth of beech root sprouts and

seedlings. Stands were clearcut or thinned in 1991 in winter or summer. Seedlings

and root sprouts in 15-ft-radius plots (174) around trees or stumps of resistant or

susceptible trees were counted annually from 1992 to 1994, and the annual growth

of more than 3,100 sprouts or seedlings in these plots was monitored. Initially, the

most sprouts developed in the summer clearcuts, but differences attributable to

harvest treatment disappeared after 4 years. By 1994, there were significantly more

sprouts around resistant trees than around severely diseased trees. Interactions

occurred between the amount of root disturbance (leading to root sprouts) and the

amount of light available for growth. Thus, more sprouts developed after clearcuts

than after thinnings, and sprout growth was best around resistant trees left standing

and poorest around susceptible trees that were cut. Summer clearcuts drastically

reduced the number of existing beech seedlings and prevented new “recruits.”

Seedling growth was related primarily to the amount of light received as a

consequence of the harvests or disease-caused crown thinning. Because of the high

initial proportions of beech in these stands, it is likely that only the clearcuts will

materially affect stand composition. The regeneration changes observed support

other studies that reported that clearcuts (and group-selection cuts) encourage

shade-intolerant and intermediate species. However, the presence of advance

regeneration or significant sprout reproduction of tolerant species will ensure that

those species regain their former importance.

Manuscript received for publication 20 February 2001
1

Introduction

Beech bark disease (BBD) results when the bark of

American beech (Fagus grandifolia Ehrh.), infested and

altered by the beech scale insect, (Cryptococcus fagisuga

Lind.), is invaded and killed by one or more species of

fungi in the genus Nectria (Ehrlich 1934; Spaulding et

al. 1936; Cotter and Blanchard 1981; Houston 1994).

The beech scale and probably the principal fungal

pathogen, N. coccinea var. faginata (Lohm. and Watson),

was accidentally introduced to Nova Scotia around 1890

and discovered in Maine in 1931 (Ehrlich 1934;

Mahoney et al. 1999). Today, all of Maine is part of an

“aftermath” zone forest (Shigo 1972) long affected by

the scale/Nectria complex. Dense, young stands of beech

stems of root sprout and seedling origin in aftermath

forests often become highly defective as they accumulate

cankers (Houston 1975). With time, many of these trees

and older susceptible survivors of the original outbreak

lose vigor (Houston 1975), slow in growth, and die

(Houston 1994; Gove and Houston 1996).

Within the aftermath forests, some beech trees (usually

less than 1 percent) remain scale free and show no signs

of BBD. These trees, which often occur in groups

(Houston 1983), are resistant to C. fagisuga (Houston

1982, 1983). Isozyme studies have shown that such

trees are closely related genetically (half- or full-sib

families) or are identical (derived vegetatively from root

sprouts) (Houston and Houston 1987, 1994).

American beech not only produces root sprouts but also

is highly shade tolerant, affording beech a potent

mechanism with which to conserve genes in times of

disturbance and to perpetuate them as forest

development ensues. Root sprouting in beech is a

response to disturbances that wound roots (Jones and

Raynal 1986), e.g., frost heaving, browsing, and logging.

Sprouts arise from adventitious buds that originate

within callus tissues associated with wounds (Jones and

Raynal 1986); their initiation also seems influenced by

exposure to light and higher temperatures (Maini and

Horton 1966; Kormanik and Brown 1967; Held 1983;

Jones and Raynal 1988). Apical control of sprout

initiation seems weaker in beech than in other species

(Jones 1986).

BBD can influence root sprouting directly by adversely

affecting parent-tree vigor and indirectly by causing

changes in canopy density from crown thinning, tree

death, and harvesting. In uncut stands, fewer sprouts

were produced around isolated, low-vigor beech trees

compared with high-vigor trees, though there were no

differences in vigor of the sprouts themselves (Jones and

Raynal 1987). Sprout initiation, growth, and survival

may decrease when only several scattered parent beech

trees decline in stands where beech density is low (Twery

and Patterson 1984). However, sprout initiation or

growth can be stimulated when many trees decline and

die in beech-rich stands (Houston 1975; Ostrofsky and

McCormack 1986). Root sprouting also was influenced

by season of injury. Jones and Raynal (1988) found that

fewer sprouts were initiated when roots of uncut trees

were wounded in fall than in spring. They attributed this

result to high mortality of fall-wounded roots and to

less vigorous callus formation. It also is possible that

harvests conducted in winter when roots and soil are

frozen or snow covered might result in fewer root

wounds and fewer sprouts compared to summer

harvests.

The availability of harvesting practices that control both

how and to what degree root systems are disturbed and

the level to which roots are exposed to light and higher

temperatures may hold the key to regulating root sprout

initiation and development. Understanding the

comparative consequences of such management

practices for trees resistant or suceptible to BBD could

improve the quality of beech in severely affected stands.

Also, it is important to understand how different

management practices influence the incidence, growth,

and survival of beech seedlings present at the time of

harvest as well as those recruited later.

This paper presents results of a study that investigated

how forest management practices affect the initiation

and development of beech root sprouts and seedlings.

Four hypotheses were tested:

1. Root sprout initiation and development and seedling

development in beech is favored more by summer than

winter harvests.

2. More root sprouts will develop, and growth of sprouts

and seedlings will be greater around resistant (highvigor) trees than around diseased (low-vigor) trees.

3. More root sprouts will develop, and growth of root

sprouts and seedlings will be greater around trees in

partially cut stands than in stands with complete

overstory removal.

4. More root sprouts will develop and growth of sprouts

and seedlings will be greater around cut trees than those

left standing.
2

Materials and Methods

Forest Stands

The study area was located on public lands near Lake

Seboeis in north-central Maine. It consisted of 15

contiguous 10-acre (4-ha) blocks of forest that straddled

a broad, north-south-oriented ridge ranging in elevation

from 560 to 760 ft (168 to 228 m) above sea level (Fig.

1). The forest comprised 40 to 100-year-old second- or

third-growth northern hardwoods dominated by beech.

There were heavy admixtures of sugar maple (Acer

saccharum Marsh.) in some blocks.

Block corners were determined by GPS and plotted on a

U.S. Geological Survey quadrangle map (Fig. 1). Parallel

transects were established at 132-foot (39.6-m) intervals

within each block to facilitate locating, numbering, and

mapping all resistant beech trees > 8 inches (20 cm) in

diameter at breast height (d.b.h.). Resistant trees were

defined as those that were free of beech scale and

evidence of BBD. More than 180 resistant trees were

mapped, many of which were in groups.

Trees

From the pool of mapped trees we selected 180 resistant

trees for study. Selected trees were at least 30 feet (9 m)

apart to allow a discrete, 15-ft-radius (4.5-m) plot to be

established around them. In 12 of the 15 blocks, at least

eight suitable resistant trees were found and mapped. In

three blocks there were only three or four resistant trees;

these blocks were designated as no-cut controls.

Each selected resistant tree was paired with a nearby,

highly susceptible tree of comparable diameter and

crown class that exhibited severe BBD crown symptoms.

In all, there were 216 study trees comprising eight

resistant/susceptible pairs in each of the 12 blocks to be

cut and four pairs in each of the three no-cut control

blocks.

Treatments

Harvest treatments and times were chosen to reflect

management practices commonly used in Maine.

Treatments were not assigned randomly but were

dictated by practical considerations of harvest

equipment capability and winter accessibility. Blocks 1-6

were harvested in winter (January-March 1991) when

snow was present or soil was frozen; the remaining six

blocks (7, 8, 11-14) were cut in summer (June-August

1991) (Fig. 1). Felling and extraction were done by

chain-saw crews and skidders.

Three of the six winter-cut blocks (3, 5, 6) and three

summer-cut blocks (11, 12, 13) were clearcut (all

merchantable stems); the remaining blocks (1, 2, 4 and

7, 8, 14) were partially cut to reduce basal area by

approximately 30 percent. No trees were cut in the

control blocks (9, 10, 15). Thus, there were five blocklevel treatments replicated 3 times: winter clearcuts

(WC), winter partial cuts (WP), summer clearcuts (SC),

summer partial cuts (SP) and no-cut controls (NC) (Fig.

1).

Four of the eight resistant/susceptible tree pairs in each

harvest block were chosen randomly to be cut; the

remaining four pairs, including those in the clearcut

blocks, were left standing.

Measurements

Overstory stand data

Prior to harvesting in 1989 or 1990, data on overstory

composition and structure were obtained in plots

centered around each of the 216 study trees. Species,

d.b.h., crown class, and the distance and azimuth from

the center plot tree were recorded for all trees selected by

a BAF 10 prism. In 1992 or 1993, stand data were

obtained in these “prism” plots around the study trees

(or stumps) in the thinned blocks to determine changes

created by the thinnings. At the time of the preharvest

measurements, the condition of all living beech trees,

including the central plot tree, was noted. An index of

tree condition for each block was calculated by dividing

the sum of weighted condition scores (good = 1, fair =

4, poor = 16) by the number of beech trees.

Regeneration data

Data on tree-species regeneration were obtained in a

series of twelve 1-m-radius (3.28-ft) plots (hereafter

termed 1-m regen plots) placed systematically along a

diagonal transect across each block. The following data

were obtained in 1989 and again in 1994 to determine

changes in regeneration resulting from harvest

treatment: counts, by species, of all seedlings and

sprouts that were < 1.0 inch (2.54 cm) in diameter at 4

inches (10 cm) above ground and < 1.0 m tall. Beech

seedlings were recorded separately from beech sprouts.

Study plot data

In summer 1991, 15-ft-radius plots around each study

tree or stump were carefully cleared of tree limbs and

other debris to facilitate counting and measuring beech

sprouts and seedlings. For various reasons, only 174 of

the original 216 plots could be used; these are referred

to as “selected tree plots.”

Each sprout’s point of origin was noted as being the top,

side, or bottom of its parent root, and the parent root’s

horizontal diameter (mm) was measured at the point of

sprout origin. Sprouts were classified as single or a

member of a sprout cluster. In the clusters, the largest,

most vigorous sprout was measured and tagged. If this

sprout died, the next largest living sprout in the cluster
3

Figure 1.—Location of fifteen 10-acre harvest treatment blocks near

Seboeis, Maine: WP = winter partial cuts (blocks 1, 2, 4); WC = winter

clearcuts (3, 5, 6); SP = summer partial cuts (7, 8, 14); SC = summer

clearcuts (11, 12, 13); NC = no cut controls (9, 10, 15).

was recruited and measured. The cause of death of

sprouts and seedlings was determined when possible.

Available solar radiation was measured in July-August

1995 in four randomly chosen selected tree plots in two

of the three blocks in each harvest treatment.

Measurements were obtained with a LAI-2000 Plant

Canopy Analyzer1

 for correlation with growth rates of

the sprouts and seedlings in these plots. Thirty

measurements were made at 4 feet (1.2 m) above

ground in each plot.

1

The use of trade, firm, or corporation names in this paper is

for the information and convenience of the reader. Such use

does not constitute an official endorsement or approval by the

U.S. Department of Agriculture or the Forest Service of any

product or service to the exclusion of others that may be

suitable.
4

Statistical analysis

Data obtained in the 36 1-m regen plots for each harvest

treatment were pooled to provide means for comparing

numbers of beech sprouts and seedlings before and after

harvests. Data were analzyed by ANOVA within years

and Studentized t-tests were used to compare means

between measurement years. Differences were

considered significant if p=0.05 or less.

Data acquired in the selected tree plots (15-ft radius)

were pooled across reps (blocks) to provide means for

comparing numbers of beech sprouts and seedlings in

each year that were around resistant or susceptible beech

trees that were cut or left standing. A 3-way ANOVA was

used to determine differences among main effects:

harvest regime, cut/leave status of plot tree, and the

resistance/susceptibility status of the plot tree, and their

interactions. A Bonferroni test was used to detect

differences among treatment means.

Data for the monitored sprouts and seedlings in the

selected tree plots were pooled across reps (blocks) to

provide means for comparing the diameter and height

growth in each year and overall. A 2-way ANOVA

examined the effects on growth of the harvest treatments

(including the no-cut treatment), the resistance/

susceptibility (R/S) status of the plot trees, and the

interactions; a Bonferroni test compared differences

among harvest treatment means. A 3-way ANOVA

examined the effects on growth of sprouts and seedlings

of the harvest treatments, the R/S status, and the cut/

leave status of the plot trees and their interactions. A

Bonferroni test was used to detect differences among

harvest treatment means. Spearman correlations were

used to examine the relationship of available light to

overall mean height and diameter growth of sprouts and

seedlings.

Results

Stand Composition and Structure

The fifteen 10-acre blocks of forest in this study differed

considerably in preharvest composition and structure

(Table 1). Mean block basal area ranged from 69 to 108

ft2/acre (15 to 24 m2/ha). Beech was by far the dominant

species, ranging from 48 to 90 ft2/acre (11-20 m2/ha).

There were relatively small amounts of sugar maple,

yellow birch (Betula alleghaniensis Britton), and red

spruce (Picea rubens Sargent) in most blocks. Other

species were found occasionally at low levels. In general,

stands highest in total basal area were those on the

southern portion of the study area that sloped to the

southeast or west (blocks 1, 3-8); blocks on the

northern end of the study area, which sloped to the

north and northwest, had lower basal areas, especially of

beech (2, 11-14).

Table 1.—Preharvest mean basal area (ft2/acre) for species in 12 harvested treatment blocks

 Block

Species 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Beech 90.0 66.2 89.4 88.1 80.6 72.5 74.4 58.8 58.1 65.0 48.1 52.5

Sugar maple 5.0 3.8 6.9 12.5 10.0 10.0 8.1 15.6 2.5 13.1 6.9 10.6

Yellow birch 3.8 3.8 1.9 1.3 1.9 12.5 8.8 9.4 9.4 10.0

Ironwood 1.3 .6 1.9 .6

Stripe maple .6 .6 .6 1.3 .6 .6 1.3

White ash 1.3 2.5 .6 .6 .6

Basswood .6

Red maple 5.0

Pin cherry .6

White birch .6

Red spruce .6 9.4 3.8 4.4 6.9 2.5 .6 2.5 3.8 1.3 1.3 2.5

Balsam fir 2.5 1.9 .6 1.9

Hemlock .6 1.3 .6 .6

White-cedar 2.5

White pine 1.9

Total 95.6 85.1 104.4 107.5 100.6 90.6 87.5 98.1 79.4 90.0 68.8 81.9
5

Partial cutting was designed to reduce the overstory by

about 30 percent, but this objective was not achieved in

most cases (Fig. 2). This treatment reduced overstory

volume from 13.5 to 35 percent.

Beech Tree Condition

There was relatively little difference in the condition of

beech trees among the blocks. Beech trees in block 13

(southwest aspect) had the poorest average crown

condition while those in block 6 (northeast) had the

best. Trees growing in the moister lower slopes of block

6 seemed better able to tolerate the effects of BBD than

their counterparts growing on the drier, more exposed

northwest slopes.

Regeneration

There were marked changes in species composition and

numbers of seedlings present in the 1-m regen plots 5

years after treatments (Table 2). Most noticeable was the

presence or increase in abundance of intolerant species,

either light seeded, e.g., the birches, quaking aspen

(Populus tremuloides Michx.), and white ash (Fraxinus

americana L.) or present in the seed bank, e.g., pin cherry

(Prunus pensylvanica L.f.). This was especially the case in

the stands harvested in summer. Beech seedlings

increased or decreased slightly in all blocks except WP

where increases were significant, while sugar maple,

except in the same WP blocks, generally decreased,

significantly so in the clearcuts. Striped maple (Acer

pensylvanicum L.) increased dramatically in the NC

control blocks and SP blocks but decreased in all others.

Conifers generally were more abundant after the

harvests. Species such as bigtooth aspen (Populus

grandidentata Michx.), black ash (Fraxinus nigra Marsh.),

ironwood (Ostrya virginiana) (Mill.) K. Koch, northern

white-cedar (Thuja occidentalis L.), and white spruce

(Picea glauca) (Moench) Voss were found occasionally in

low numbers.

Effect of Harvest Treatments on Numbers

of Beech Sprouts and Seedlings

Mean counts of beech sprouts and seedlings in selected

tree plots are shown in Figure 3A-E. Mean values for the

3 years, expressed both as counts and as numbers per

square foot of beech basal area are given in Table 3. Data

for 1994, the final year of measurement, are given in

Tables 4-5.

The most sprouts and the fewest seedlings were around

plot trees in the SC blocks the year after harvest (Fig. 3C,

Table 3), but sprouts in the SP blocks (Fig. 3D)

increased each year and equaled or slightly exceeded

those in the clearcuts by 1994 (Table 4). Also by 1994,

there were significant differences in the number of

sprouts in the selected tree plots attributable to harvest

treatments and to the resistance/susceptibility status of

the plot trees (Table 4). These differences seemed to

reflect the relative amount of root disturbance rather

than the amount of beech basal area present. Harvest

treatments that created the most disturbance triggered

the most root sprouts (Table 3); the NC blocks had the

fewest sprouts. The number of beech seedlings around

plot trees, while significantly affected by harvest

treatment, was not affected by the R/S or cut/leave status

of the plot tree. By contrast, the number of beech

seedlings seemed to reflect the amount of beech basal

area in the treatment blocks (Table 3). The most

Figure 2.—Mean basal area in partial

cut blocks before and after harvest

(numbers in parentheses are percent

reductions in basal area).
6

seedlings by far were in the WP blocks (Fig. 3B, Table

5), a consequence of the large numbers present before

harvest (which was a consequence of the high beech

basal area). There also were relatively large numbers

of seedlings in the WC blocks (Fig. 3A, Tables 3, 5),

which, prior to harvest, had high basal areas of beech

and large preharvest numbers of seedlings (see results

for the 1-m regen plots that follow). There were little

differences in seedling numbers between the controls

and the SP blocks (Fig. 3D-E, Tables 3, 5), but the SC

was devastating to the seedlings (Fig. 3C, Tables 3, 5).

By 1994 within all harvested blocks, there were more

sprouts around resistant trees or stumps than around

susceptible ones. While this difference was significant

(p=.036) overall, within treatments it was significant

(p<.05) only for the SP harvest (Table 4). Overall,

sprout numbers were not significantly different around

trees left standing vs. those that were cut, but there were

significantly (p=.059) more sprouts around resistant tree

stumps than around resistant trees left standing (Table 4).

By contrast, there were no significant differences in the

number of seedlings around resistant and susceptible

trees by 1994. However, there were significantly more

seedlings around both resistant and susceptible trees in

the winter-harvested blocks (p=<.05) and, within these,

significantly more in the WP blocks (Table 5). The

winter-cut blocks had the highest beech basal area and

also the healthiest trees. Differences in the number of

seedlings present, related to whether trees were cut or

left standing, were not significant, though within the

WC treatments, the number of seedlings was

significantly greater (p=.07) around standing trees than

around stumps (Table 5). Abundant seed was produced

in 1992.

Table 2.—Seedling regeneration (< 1 m tall, < 2.5 cm in diameter) by species in thirty-six 1-m-radius regen plots in each

harvest treatment before (1989) and 5 years after (1994) harvest; values inflated to number of seedlings per acre

Winter clearcut Winter partial cut Summer clearcut Summer partial cut No cut

Species 1989 1994 1989 1994 1989 1994 1989 1994 1989 1994

Beech 6,118 8,515 14,383 **25,008 6,547 6,082 6,225 5,939 9,731 7,191

Sugar maple 59,335**34,490 29,409 32,021 18,962 **6,046 23,792 14,526 25,152 32,880

Yellow birch 1,717 4,258 1,216 **12,307 894 **7,549 393 **16,493 680 1,610

Striped maple 4,472 2,540 9,696 *6,082 5,868 *2,826 13,352 21,538 7,835 **32,307

Red maple 644 501 1,825 1,753 1,395 1,360 2,361 **10,697 3,435 2,433

White ash 250 **3,229 72 250 179 787 0 322 250 858

Quaking aspen 0 36 0 0 0 8,157 0 72 0 0

Pin cherry 36 394 0 143 0 1,217 0 215 0 0

White birch 0 501 0 0 0 322 0 1,753 0 644

Grey birch 0 36 0 0 0 859 0 0 0 0

Balsam fir 0 0 107 72 179 143 751 1,395 1,252 1,717

Red spruce 0 250 322 823 0 36 0 215 0 37

White pine 0 0 0 36 0 36 0 250 0 212

Note: Asterisks indicate significant changes between years within harvest type using Studentized t-test (* = 0.05; ** = 0.01).

Table 3.—Mean number of beech sprouts and seedlings

per acre in the selected tree plots by harvest treatment

(mean of 3 years for harvested blocks, 2 years for

control blocks). Numbers in parentheses are seedlings

per ft2

 beech basal area

Treatment Sprouts Seedlings

Winter clearcuts (WC) 1,736 5,585 (69)

Winter partial cuts (WP) 1,325 14,891 (183)

Summer clearcuts (SC) 2,253 649 (11)

Summer partial cuts (SP) 1,565 3,013 (49)

Controls (NC) 675 2,967 (49)
7

Figure 3.—Mean number of sprouts and

seedlings within 15-foot radius plots for

each measurement year and each harvest

treatment (N = number of 15-foot radius

study plots within treatment).

The estimated number of sprouts and seedlings per acre

(minus the 1-year-old seedlings) in the 1995 random

tree plots was similar (though slightly higher in most

cases) to that in the selected tree plots in 1994 (Table 6).

As with the selected tree plots, seedling numbers seemed

related to the basal area of beech.

Mean counts of beech sprouts and seedlings in the 1-m

regen plots in summer 1989 and in summer of 1994 are

compared in Table 6 and Figure 4. In general, the trends

for change in relative numbers for sprouts and seedlings

in these plots were similar to those in the larger selected

tree plots. However, the estimated number of seedlings

and sprouts per acre for the two sets of plots differed

markedly. The number of sprouts (1994) estimated

from the 1-m regen plot data was consistently about

twice that estimated from the selected tree plot data

(Table 6). By contrast, seedling numbers estimated from

the 1-m regen plot data were both lower (WC, SP, NC),

and higher (WP, SC) than those estimated from the

selected tree plot data (Table 6).
8

Monitored Sprouts and Seedlings

About 1,100 sprouts and 2,050 seedlings were followed

individually in the selected tree plots for 2 or 3 years. In

only nine blocks were the desired 20 sprouts and/or

seedlings present in all plots. Some blocks, especially 11-

15, had plots with few candidates, which resulted in low

block means. Nevertheless, a sufficient number of plants

was measured to provide a clear picture of where and

when sprouts and seedlings developed, how much they

grew, and how well they survived during the study

period. Central to the objectives of this study is the

information gained regarding the occurrence and

development of root sprouts.

Root Sprouts: Patterns of Development

Size of parent roots

Although the sprouts observed in this study were on

roots whose diameters ranged from < 0.04 to 3.1 inches

(0.1 to 7.9 cm) at the points where sprouts occurred, 75

percent occurred where roots measured 0.2 to 0.8 inch

(0.5 to 2.0 cm) in diameter. The distribution of parent

roots by size class was similar for all harvest treatments.

Origin on parent roots

Harvest treatment had little effect on where sprouts

developed on roots; 69 percent originated from the tops

of roots, (28 percent from the bottoms, and 3 percent

from the sides). This sprouting pattern, which reflected

the patterns of wounding, revealed a relatively large

number of injuries to the undersides of roots when they

were bruised against underlying rocks.

Clusters vs single sprout sprouts

Many root sprouts developed in clusters of 2 to 10 or

more; 65 percent of the sprouts monitored in the study

were in clusters. Clearcut blocks had the greatest

proportion of sprout clusters (71 percent) but there were

significantly more clusters than single sprouts only in

the SC blocks; thinned blocks had less (60 percent), and

the controls had equal proportions of single sprouts and

sprout clusters. Within the five size classes of parent

roots (0.2 to 1.2 inches; 0.5 to 3.0 cm) that bore 92

percent of the sprouts, the proportion of clusters to

single sprouts increased consistently as parent-root

diameter increased. There was significantly more (p <

0.01) sprouting as clusters than as single sprouts in the

four largest classes (0.4 to 1.2 inches; 1.0 to 3.0 cm).

Growth of Sprouts and Seedlings

Effects of harvest treatment

When the effects on sprout and seedling growth of the

five harvest treatments, the resistance/susceptibility

status of the plot trees, and their interactions were

analyzed, only harvest treatment was significant

(p=.0003). The mean height and diameter growth of

sprouts and seedlings from 1992-93, 1993-94, and

overall from 1992 to 1994 are given in Table 7. After 3

years, height growth was greatest in the WC’s and less,

successively, in the SC’s, WP’s, SP’s, and NC’s. Many of

the differences were significant. Sprouts outgrew

seedlings by 50 to 60 percent in clearcuts, 30 to 35

percent in thinned stands, and 80 percent in uncut

stands. Diameter growth of sprouts and seedlings in the

WC’s equaled that in the SC’s, which, in turn, exceeded

Table 4.—Mean number of beech sprouts present in 1994 in different treatment blocks in the selected tree

plots around resistant or susceptible trees and for trees that were cut or left standing (no trees were cut in

the NC treatment)

 Resistant plots Susceptible plots 

Treatment Overall All1 Cut Standing All Cut Standing

WC 33.2 40.5b

 (61)2 35.6 (45) 43.1 (55) 25.8ab (39) 27.5 (53) 23.9 (47)

WP 23.5 24.7ab (53) 31.4 (61) 19.9 (39) 22.2ab (47) 22.6 (51) 21.8 (49)

SC 33.1 35.7b (54) 35.0 (49) 36.4 (51) 30.8b (46) 21.8 (41) 38.9 (59)

SP 36.1 43.5b

A (60) 52.3 (60) 34.7 (40) 28.7abB (40) 31.1 (54) 26.3 (46)

NC 14.5 13.8 a (48) 13.8 (48) 15.1a (52) 15.1 (52)

All 33.1 (57) 39.6A (58) 28.5B (42) 25.4 (43) 25.8 (51) 25.1 (49)

1

Means in columns for All trees (cut and standing) followed by a different lower case letter are significantly different (p = 0.05)

using a Bonferroni test; within rows, means followed by a different upper case letter are significantly different.

2

Numbers in parentheses are proportions of sprouts within each treatment.
9

Table 5.—Mean number of seedlings present in 1994 in different treatment blocks in the selected tree plots around resistant orsusceptible trees and for trees that were cut or left standing (no trees were cut in the NC treatment)

Meanbeechbasal Resistant plots1 Susceptible plots1

Treatment area Overall All Cut Standing All Cut Standing

 ft2

WC 80.8 95.7b 94.9b (1.2; 50)2 84.7 (45) 103.7A (55) 96.5b (1.2; 50) 69.8 (35) 127.0B (65)

WP 81.4 192.9a 182.7a (2.2; 47) 195.9 (53) 173.2 (47) 203.6a (2.5; 53) 216.9 (53) 193.0 (47)

SC 57.1 5.8d 5.5c (0.1; 49) 4.6 (46) 6.4 (58) 6.1d (0.1; 51) 5.4 (45) 6.6 (55)SP 61.9 42.5c 44.5c (0.7; 52) 45.0 (50) 44.1 (49) 40.4c (0.6; 48) 35.8 (44) 44.9 (56)

NC 60.4 34.8c 28.3c (0.5; 41) 28.3 40.8c (0.7; 59) 40.7All 73.0 (49) 75.9 (52) 71.0 (48) 76.0 (51) 75.1 (50) 76.6 (50)

1Column means followed by different letters are significantly (p = 0.05) different from each other using a Bonferroni test; within rows, means followed

by A are significantly (p = 0.07) different from those followed by B.

2Numbers in parentheses are seedlings per ft2 beech basal area, followed by proportion of seedlings within each treatment that were around resistant or

susceptible trees.
10

Table 6.—Mean number of beech seedlings and sprouts per plot and per acre from

pre- and post-harvest measurements in thirty-six 1-m regen plots in each treatment

x basal area Estimate 19891 19941 

Treatment of beech/acre basis Sprouts Seed Sprouts Seed

(ft2)

WC 80.8 x/plot 2.0a 2.75b 3.64a 2.97b

x/acre 2,576 3,542 4,688 3,825

(+2,642)2 (-2,027)

WP 81.4 x/plot 3.08a 8.0a 1.61a 17.77a

x/acre 3,967 10,303 2,074 22,887

(+644) (+11,201)

SC 57.1 x/plot 0.53b 4.56b 4.50a 0.33b

x/acre 683 5,873 5,796 425

(+3,750) (+66)

SP 61.9 x/plot 0.61b 4.22b 3.31a 1.30b

x/acre 786 5,435 4,263 1,674

(+2,039) (-945)

NC 60.4 x/plot 0.69b 6.86b 4.22a 1.36b

x/acre 889 8,836 5,435 1,752

(+4,554) (-368)

1

Within columns, means followed by different letters are significantly (p=0.05) different from each

other using a Bonferroni test.

2

Parentheses include numbers above or below those estimated from the 15-ft selected tree plots.

Figure 4.—Mean number of

sprouts and seedlings per acre

in 1-m-radius regeneration

plots before (1989) and after

(1994) harvest treatments.

Significant differences (p <

0.01) between measurement

years for each category are

indicated by different letters

as determined by Studentized

t-test.
11

that in SP’s and WP’s. Diameter growth of sprouts was

twice that of the seedlings.

Differences in height and diameter growth attributable

to harvest treatments seemed related to differences in

the amount of light reaching the understory. Thus, for

both sprouts and seedlings, height and diameter growth

was consistently greater in the summer and winter

clearcuts than in their corresponding partial cuts (Fig.

5A,B). Also, for all but the sprout height growth for

1993-94 in the WP blocks (Fig. 5A) and for both height

and diameter growth in the SC blocks (Fig. 5A,B),

growth of both sprouts and seedlings seems strongly

and positively related to the amount of light received at

4 feet above ground. The least growth occurred in the

NC blocks.

After 3 years, the relationship of light (as a result of

harvest treatment) on height growth was highly

significant only for seedlings (p=0.0007, R2

 = 0.50). The

overall influence of light level (treatment result) on

diameter growth was significant for both seedlings (p =

0.0002, R2+0.46) and sprouts (0.01, R2= 0.27)..

Resistance/susceptibility and cut/leave status of parent tree

There were significant differences in growth of sprouts

and seedlings when the effects of harvest treatment

(excluding the no-cut treatment), the resistance/

susceptibility and cut/leave status of the plot tree, and

their interactions were compared (Table 8). While the

main effect of harvest treatment was highly significant in

nearly all cases, there were highly significant

interactions, especially between harvest treatments and

cut/leave status, and, for seedling height growth,

between resistance/susceptibility and cut/leave status.

Harvest treatment significantly affected diameter but not

height growth of sprouts around resistant trees, and

both diameter and height growth around susceptible

trees; seedlings growth was significantly affected around

both resistant and susceptible trees (Table 9).

In general, growth of sprouts and seedlings was better

(sometimes significantly) around trees left standing in

clearcut blocks, and around the stumps of cut trees in

partial cut blocks (Table 10). Within all harvested

blocks, height growth of sprouts was best around

resistant parent trees that were left standing, slightly less

around cut resistant trees and standing susceptible trees,

and poorest around the cut susceptible trees (Table 11).

Average height growth of sprouts around resistant trees

in the control blocks was about half that in the

harvested blocks.

Seedling growth was best around resistant cut trees and

poorest around resistant leave trees. Growth of seedlings

around susceptible trees was the same whether or not

the trees were cut. Seedling growth in the no-cut control

blocks was poor compared to that in the harvested

blocks, reflecting the growth response of seedlings to

increased light (Table 11). Thus, in some cases, growth

seemed affected more by whether the sprout or seedling

was growing around a resistant or susceptible tree, or a

cut or leave tree, than by when or how the stand was

harvested.

Demographics of Sprouts and Seedlings

Age

Age distributions of all monitored sprouts and seedlings

as of summer 1993 are shown in Figure 6A-C. Most

sprouts were 2 to 3 years old in 1993, a consequence of

injuries made to root systems during harvest in 1991. In

blocks harvested in winter, 54 percent of the sprouts

were 3 years old and 30 percent were 2 years old in 1993

(or 1 and 2 years old, respectively, when first measured

in 1992) (Fig. 6B). By contrast, 70 percent of the sprouts

in the summer harvest blocks were 2 years old in 1993

(Fig. 6C).

Age distributions of seedlings differed from those of

sprouts in that they reflected the ages of seedlings

already established at harvest time as well as those that

became established thereafter. The presence of 1- and 2-

year-old seedlings in harvested blocks in 1993 reflects

those that were added in years after plots were

established, and a large proportion of 1-year-old

seedlings in the control blocks (included in Figure 6A)

reflects the fact that plots in those blocks were not

established until 1993. There were good seed crops in

1992.

The distribution pattern of seedling ages suggests the

occurrence of alternating heavy seed years (Fig. 6A). This

pattern was more evident in some blocks than in others.

Seed years were heavy primarily in even years except in

blocks, 3, 4, 5, and 6, where relatively high proportions

of seedlings originated from seed produced in 1989.

Although these blocks were harvested in winter and

most were clearcut, the age distributions in them and in

other blocks probably is less a consequence of harvest

treatment than of block locations, the patchiness of

seeding trees (BA) over the 150-acre (60-ha) study area,

and possibly cacheing activities of seed-dispersing

agents, particularly bluejays (Cyanocitta cristata L.).

Sprout and seedling mortality

By summer 1993, 140 sprouts and 71 seedlings had

died, and by the next year, an additional 123 sprouts

and 162 seedlings were dead (Table 11). Although nearly

the same number of sprouts and seedlings had died

(263 vs. 233) by 1994, proportionally about twice as

many sprouts (including “successors”) than seedlings

died (24 vs. 11 percent). Sixteen of the 35 successor

sprouts in clusters died between 1993 and 1994; in

most cases, all other sprouts in those clusters also had

died. There was a tendency, toward higher sprout
12

Table 8. —Significant F valuesa for diameter and height growth of sprouts and seedlings for the 3 years following harvest

treatments in 1991 and overall

 1992-1993 1993-1994 1992-1994 

Sprouts Seedlings Sprouts Seedlings Sprouts Seedlings 

Item Diameter Height Diameter Height Diameter Height Diameter Height Diameter Height Diameter HeightHT .0003 .04 .0001 .001 .004 .0001 .0001 .0002 .005 .0001 .0001R/S .03C/L .004HT x R/SHT x C/L .05 .0003 .01 .03 .0001 .01R/S x C/L .0001 .0001HT x R/Sx C/L

a3-way ANOVA of four harvest treatments (HT), resistance/susceptibility (R/S) status, cut/leave (C/L) status, and their interactions.

Table 7.—Mean height and diameter growth of monitored sprouts and seedlings by treatment, 1992-94

 1992 - 1993 1993 – 1994 1992 - 1994

Treatment Number Height Diameter Number Height Diameter Number Height Diameter

cm mm cm mm cm mm

WC Sprouts 152 23a 4a 143 26a 2a 140 50a 6a

Seedlings 428 15A 3A 427 15A 1A 423 30A 3A

WP Sprouts 165 21ab 3b 156 19b 1ab 156 40b 4b

Seedlings 185 6B 2B 523 8B < 1B 511 15B 2C

SC Sprouts 265 21ab 4a 312 21b 1a 219 46ab 6a

Seedlings 175 10B 2B 174 7BC 1A 151 17B 3B

SP Sprouts 163 16b 2b 201 19b 1ab 152 37b 4b

Seedlings 339 4C 1C 389 5CD < 1B 303 9C 1D

NC Sprouts 59 19ab - 65 13b < 1b 56 31b -

Seedlings 176 3C - 311 3D < 1B 166 6C -

Note: Within columns, values with different letters are significantly different (p = 0.05) using a Bonferroni test.
13

Table 9. —Mean height and diameter growth of sprouts and seedlings around

resistant or susceptible trees in the different treatment blocks, 1992-94

 Resistant trees Susceptible trees 

Treatment Height Diameter Height Diameter

cm mm cm mm

W C Sprouts 45.0A1 5.5A 47.8A 4.8A

Seedlings 29.8a 3.5a 29.5a 3.2a

W P Sprouts 37.7A 4.2BC 31.8B 2.9B

Seedlings 16.2b 2.0b 13.4b 1.8b

S C Sprouts 42.0A 4.8AB 38.5AB 4.5A

Seedlings 18.9b 2.5b 16.1b 2.7a

S P Sprouts 34.5A 3.6C 31.2B 3.6AB

Seedlings 7.2c 1.2c 10.1cd 1.5b

N C Sprouts 31.6A - 33.1B -

Seedlings 7.1c - 5.7d -

Note: Within columns, unlike letters indicate significant differences (p = 0.05) among harvest

treatments for sprouts and seedlings using a Bonferroni test.

Table 10.—Situations where the height or diameter growth of monitored sprouts and seedlings

was significantly greater (p = 0.05 or as indicated) around trees cut (A) or left standing (B) in

harvested blocks, 1992-94

 1992-1993 1993-1994 1992-1994 

Treatment Height Diameter Height Diameter Height Diameter

WC Sprouts (B)1 B (0.07)2 NS NS NS NS

Seedlings NS NS NS (B) (B) NS

WP Seedlings (A) (A) (A) NS (A) (A)

SC Sprouts NS (B) (B) NS (B) (B)

SP Sprouts (A) A (0.06) (A) A (0.06) (A) NS

1

Presence of letter indicates significant difference in column, using Studentized t-test; NS = not significant.
14

mortality in the summer treatments (22 to 28 percent)

than in the winter treatments (14 to 15 percent). Overall

sprout mortality was lowest in the no-cut stand, which

also had the fewest sprouts.

Causes of mortality varied in importance for sprouts and

seedlings and between treatments (Table 12).

Oystershell scale (Lepidosaphes ulmi L.) attack was severe

on seedlings in most treatments (especially in the

thinned blocks) and on sprouts in the WP blocks. L.

ulmi was the most important mortality agent in several

blocks. It was not possible to determine why many of

the sprouts and seedlings died, though it is likely that

many were affected adversely by the increased light,

heat, and desiccation associated with sudden and

massive removal of overstory canopy.

Sprout mortality vs. cut or leave status of parent trees

Significantly more of the monitored sprouts around cut

trees died (26.5 percent) compared to those around

leave trees (15.7 percent), a consequence primarily of

the significant mortality in the clearcut treatments (Fig.

7). There was little difference in sprout mortality related

to cut/leave status of their parent tree in the thinned

blocks, though mortality was highest in the summer-cut

blocks. Mortality was highest in SC’s and lowest in the

NC blocks.

Sprout mortality vs. resistant/susceptible parent tree

There was no consistent relationship between the

mortality of the monitored sprouts and the resistance/

susceptibility status of the study plot tree. Overall, 21

percent of the sprouts around resistant, high-vigor trees

died compared to 19 percent for those around

susceptible, low-vigor trees. However, since 62.5 percent

of the sprouts that were monitored were around

resistant trees, it is probable that in the long run, more

of them will survive to become trees, especially if they

are on roots of trees left standing. For both resistant and

susceptible trees, mortality of sprouts was higher in the

summer-cut blocks (resistant tree plots: 26 percent;

susceptible tree plots: 24 percent) than in the winter-cut

blocks (resistant tree plots: 17 percent; susceptible tree

plots: 9 percent).

Discussion

Regeneration

The changes that occurred in species composition

regeneration following harvesting were expected. The

marked increase in light and the soil scarification

created by tree felling and skidding, especially in the

clearcut blocks, created conditions favorable for

germination and establishment of wind-dispersed

pioneer species and for species such as pin cherry that

were present in the seedbank. These results confirm

those of other studies that showed that, at least for the

next generation, clearcutting encourages shadeintolerant and intermediate species (Leak and Smith

1997; Leak et al. 1987; Marquis 1967; Patton 1997).

Both the numbers and growth of sprouts initiated by

treatment disturbances were affected by vigor (resistant

vs. susceptible) of the parent tree (and its root system)

and the amount of light received as a consequence of

crown density of the parent tree or the effects of harvest.

Seedling numbers reflected the numbers present at the

time of treatment (related to beech BA), while seedling

growth was affected primarily by light availability.

The major influence of light on growth of understory

sprouts and seedlings resulted in interactions among

harvest treatments (overall light availability related to

thinned vs. clearcut vs. no-cut stands), crown removal

(cut vs. leave trees), crown transparency (resistant vs.

susceptible trees), and length of time of increased light

availability (winter vs. summer harvests). These

interactions prevented definitive “tests” of the four main

effects proposed in the initial hypotheses.

Table 11. —Mean diameter and height growth of

sprouts and seedlings around resistant or susceptible

parent trees that were cut or left standing in harvested

blocks, and growth data for control blocks, 1992-94

Item Resistant parents Susceptible parents

Harvested Blocks

Sprouts (n = 212) Sprouts (n = 86)

Cut trees Diameter: 4.5 mm Diameter: 4.1 mm

Height: 43.3 cm Height: 39.6 cm

Seedlings (n = 260) Seedlings (n = 371)

Cut trees Diameter: 2.6 mm Diameter: 2.3 mm

Height: 24.1 cm Height: 18.8 cm

Sprouts (n = 221) Sprouts (n = 139)

Leave trees Diameter: 5.3 mm Diameter: 4.0 mm

Height: 46.0 cm Height: 43.3 cm

Seedlings (n = 337) Seedlings (n = 411)

Leave trees Diameter: 2.18 mm Diameter: 2.4 mm

Height: 16.3 cm Height: 19.2 cm

Control Blocks

Sprouts (n = 31) Sprouts (n = 26)

Height: 28.9 mm Height: 34.3 mm

Seedlings (n = 76) Seedlings (n = 92)

Height: 6.6 cm Height: 5.6 cm
15

Figure 5.—Mean height (A) and

diameter (B) growth of monitored

sprouts and seedlings, 1993 to

1994, in eight study plots per

harvest treatment, and mean

percent of available light recorded

at 4 feet above ground, July 31-

August 3, 1995 (numbers at points

are standard errors of the mean).

Hypothesis 1: Root sprout initiation and development

and seedling development in beech is favored more by

summer than winter harvests.

Although data acquired in the 1-m regen plots revealed

that prior to harvest there were significantly more beech

root sprouts in blocks to be harvested in winter than in

blocks to be harvested in summer, these differences had

disappeared by 1994. Similarly, data from the larger

study plots showed that by the third and fourth years

after treatment, there were no significant differences in

the number of sprouts associated with harvest season

even though there were more sprouts in the summer

clearcuts in the first season after harvest (1992).

Increases in the number of sprouts in the 1-m regen

plots were significant only in blocks harvested in the

summer and in the controls.

The slight but consistently larger number of sprouts

(except for the NC blocks) and seedlings (except for the

WC blocks) in the “once entered” randomly chosen tree

plots compared to the often entered selected tree plots

suggests that activities associated with the initial plot

clearing and the subsequent visits may have adversely

affected both sprout and seedling survival. High

numbers of 1-year old seedlings in the control and

thinned blocks in 1995 and their extremely low

numbers in the clearcut blocks attests to heavy seed

production in 1994 and the absence of a seed source in

the cleared blocks.

The slightly greater growth of sprouts and seedlings in

the winter-cut blocks compared to their summer

counterparts is likely a consequence primarily of the

extended period that these plants were exposed to
16

increased light in 1991. It also is possible that the

growth of beech was favored by the shading afforded by

the herbaceous growth that quickly developed,

particularly in the WC blocks.

Hypothesis 2: More sprouts will develop and growth of

sprouts and seedlings will be greater around resistant

than around diseased trees.

By 1994, more sprouts were present around resistant

trees than susceptible ones—significantly so within

stands thinned in the summer (SP) and overall. As a

consequence, more sprouts (62.5 percent) were

monitored around resistant trees than around

susceptible trees. It is likely that the susceptible trees in

this study (chosen because their crowns were

debilitated) were so low in vigor that they responded

less vigorously to root injuries and produced fewer

sprouts.

The vigor of parent trees seemed to affect sprout growth,

though this growth also was influenced by whether

parent trees were cut or left standing (see Hypothesis 4).

Height growth of sprouts was best around resistant trees

left standing, less so around resistant cut trees and

susceptible standing trees, and poorest beneath

susceptible cut trees. This suggests that the vigor of the

parent tree (and its root system) may influence the

success of the sprouts that develop. By contrast,

seedlings responded primarily to the availability of light

because their growth around fully foliated resistant trees

was enhanced if the tree was cut but not when thincrowned susceptible trees were cut.

Figure 6.—Age distribution as of

1993 of monitored sprouts and

seedlings overall (A) in winter-cut

blocks (B), and in summer-cut

blocks (C); (numbers over bars for

seedlings are the seed/years).
17

Hypothesis 3: More sprouts will develop and their

growth and the growth of seedlings will be greater

around trees (or stumps) in partially cut than in clearcut

stands.

By 1994, there were no significant differences in the

mean number of sprouts attributable to cutting regimes.

However, there were differences. Around resistant trees

cut in the winter there were more sprouts in clearcuts

than in thinned blocks. The reverse was true for stands

harvested in the summer. These differences probably

reflect the interactions between the amount of sprouttriggering root injury (more in the clearcuts) and the

amount of protective shading (more in the WC blocks

than in the SC blocks by herbaceous growth, and in the

SP blocks by residual trees).

For both seedlings and sprouts, overall height and

diameter growth was greatest in the clearcuts, less in the

thinned, and least in the no-cut blocks, suggesting that

light is the primary factor influencing growth. The

relative amount of light available is strongly correlated

with the growth of sprouts and seedlings. Interestingly,

growth seems favored by some degree of shade as both

sprouts and seedlings grew better in clearcut blocks

beneath trees left standing and in thinned blocks

beneath trees that were cut (see Hypothesis 4). This

latter relationship also can be seen in WC blocks, where

growth was best and early growth of understory

vegetation reduced the light available to seedlings and

sprouts by about 20 percent compared to the SC blocks.

Hypothesis 4: More sprouts will develop and growth of

sprouts and seedlings will be greater around cut trees

than around trees left standing.

The number of sprouts in the plots was not related to

whether trees were cut or left standing. However, within

the resistant-tree plots, more sprouts developed in

thinned blocks around trees that were cut and around

uncut trees in the clearcut blocks. Again, this may reflect

the interaction between the amount of root injury and

the increased light made available by cutting the plot

trees in thinned plots (more light, more root

disturbances) and not cutting them in the clearcuts

(more protection from drying out, less disturbance).

These differences were not as obvious for susceptible

trees, perhaps because their thin crowns provided little

shade before and after harvest. In some cases in

clearcuts, light passing through the thin crowns of

Table 12.—Mortality rates and causes for monitored sprouts and seedlings by

treatment, 1994

 Mortality by 1994 

Treatment Sproutsa Seedlingsa

WC 32 of 166 dead (19%) 10 of 437 dead (2%)

Oystershell scale (9%) Mortality due to

Mechanical damage (53%) various causes

Unknown (28%)

WP 30 of 183 dead (16%) 55 of 576 dead (9%)

Oystershell scale (47%) Oystershell scale (84%)

Mechanical damage (33%) Mechanical damage (11%)

Unknown (17%) Unknown (5%)

SC 129 of 429 dead (30%) 37 of 211 dead (17%)

Unknown (73%) Oystershell scale (38%)

Mechanical and browse (23%) Unknown (43%)

Other (7%) Browse or mechanical (16%)

SP 67 of 249 dead (27%) 92 of 481 dead (19%)

Oystershell scale (9%) Oystershell scale (60%)

Unknown (49%) Unknown (30%)

Browse (28%) Browse or mechanical (10%)

NC 5 of 70 dead (7%) 39 of 350 dead (11%)

Mortality due to Oystershell scale (18%)

various causes Unknown (72%)

Browse or mechanical (10%)

a

Sprout and seedling mortality by 1993 was 13% (140 of 1,097) and 3% (71 of 2,055), respectively.
18

susceptible trees had encouraged advance development

of herbaceous plants that could have provided protective

shade to developing sprouts. The relatively high

proportion of sprouts in control blocks, where no large

equipment was used, suggests that even a minor

disturbance such as stepping on roots is sufficient to

injure roots and trigger sprouting.

The growth of both sprouts and seedlings was

significantly affected by harvest treatment and especially

by the interaction of harvest regime and the cut/leave

status of the tree. This relationship also reflects the

availability of light that was created by the different

harvest systems and modified by whether the

overtopping plot trees were removed or left standing,

and, for seedlings, whether the plot trees were healthy

and fully foliated or diseased and thin crowned.

Recommendations for Increasing Sprouts of

Resistant Trees

1. Winter vs. summer harvests: No significant differences

in numbers of sprouts were attributable to season of

harvest. More sprouts developed initially after summer

clearcuts, but differences related to season of cut

disappeared with time. Thus, under the conditions of

this trial, the initial flush of root sprouts in summer

harvests attributable to the greater number of root

injuries (roots not protected by frozen ground or by

snow cover) was offset both by the subsequent greater

sprout mortality in the hot, dry, exposed blocks, and by

a continuous production of sprouts in the more

protected winter-harvested blocks. For growth, light was

more important than season of harvest per se, though

within the length of this study, sprouts developing in the

winter-harvested blocks had the benefit of several

additional months of exposure to increased light

regimes in the first growing season.

Recommendation: Conduct winter harvests to enhance

sprout development, growth, and persistence.

2. Resistant vs. susceptible trees: More sprouts developed

around resistant (high-vigor) than around susceptible

(low-vigor) trees, and their growth was best around

resistant trees, particularly when trees were left standing.

Sprout numbers were slightly higher around resistant

trees that were cut in thinned blocks or left standing in

clearcuts. The slightly higher numbers of sprouts around

the harvested resistant trees would not seem to justify

cutting them for this purpose since resistant trees left in

the stand likely will produce more root sprouts in the

long run. And, although not addressed in this study,

leaving resistant trees and removing susceptible ones,

especially in clearcuts, probably will enhance

opportunities for sexual production of resistant

seedlings.

Recommendation: Retain resistant trees even in

clearcuts.

The susceptible trees used in this study were severely

debilitated by BBD and had thin crowns and chlorotic

foliage. Less susceptible trees, more vigorous than those

Figure 7—.Proportion of

sprouts that died in each

treatment around trees or

stumps (ratios). Asterisks

indicate treatments where

differences were significant

(p=0.05) between plots

with trees cut or not cut.
19

used here, may have responded more comparably to the

resistant trees. Since trees vary in susceptibility to BBD, it

is important to retain for seed or sprout production trees

that are least infested, infected, or damaged by the

disease. Root injuries and consequent root sprouting by

susceptible trees, both harvested or retained, can be

reduced by using predetermined skid trails and/or

equipment designed to minimize root damage.

3. Partial vs. clearcuts: Although there were no

significant differences between thinned and clearcut

blocks, the number of sprouts around resistant trees was

highest in winter clearcuts and summer thinnings;

growth was greatest in the clearcuts.

Recommendation: Harvest clearcuts in winter and

conduct thinnings in summer. Identify and retain

resistant trees in all cases.

4. Cut vs. standing trees: In the thinned blocks, more

sprouts developed around the resistant trees that were

cut than around those left standing. However, these

differences probably are insufficient to warrant

removing these resistant trees from the stand.

Recommendation: Identify and retain resistant trees.

It should be noted that improvements in beech quality

or in species composition resulting from these

recommendations will not occur rapidly and may not be

permanent. The results reported here represent an initial

glimpse of the immediate responses by a number of

forest stands to harvesting practices conducted under

“real world” conditions. Research is needed to confirm

the trends observed here for the occurrence and

development of beech root sprouts and seedlings and

other species.

Harvest treatment had little influence on sprout

numbers except that there were significantly more

sprouts initially in the SC blocks than in the NC

controls. The season of harvest, degree of overstory

removal, and cutting or leaving trees had little effect on

the numbers of sprouts.

Acknowledgments

I thank the many people with the Maine Department of

Conservation who facilitated this study. James Ecker and

Gail Tunstead, Bureau of Parks and Lands, played an

important role in locating study areas and resistant

beech trees, overseeing the harvest operations, and

providing advice and assistance during many phases of

the study. Henry Trial, Everett Cram, and Grayln Smith,

Maine Forest Service, provided technical assistance in

locating and mapping resistant trees and in collecting

regeneration data. Lodging for summer crews and

transport during early phases of the work was provided

by the Department of Conservation. J. C. Fagan, USDA

Forest Service, helped organize and analyse the data. W.

D. Ostrofsky, University of Maine, provided valuable

assistance in plot establishment and, along with W. B.

Leak , S. Horsley, and P. M. Wargo, USDA Forest Service,

critically reviewed earlier drafts of this paper.

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20

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Printed on Recycled Paper

Houston, David R. 2001. Effect of harvesting regime on beech root sprouts and

seedlings in a north-central Maine forest long affected by beech bark

disease. Res. Pap. NE-717. Newtown Square, PA: U.S. Department of

Agriculture, Forest Service, Northeastern Research Station. 20 p.

Forests in Maine often contain many trees severely damaged by the disease.

Methods are needed to reduce numbers of susceptible and increase numbers of

resistant trees. This paper describes how commonly-used harvesting systems affect

the incidence and growth of beech root sprouts and seedlings. Harvest treatments

were clearcutting and thinning in winter and summer, 1991. Interactions occurred

between the amount of root disturbance (leading to root sprouts) and amount of light

available for growth. More sprouts developed after clearcuts than thinnings, and

around resistant than susceptible trees. Sprout growth was best around resistant

trees left standing, poorest around diseased trees that were cut. Summer clearcuts

reduced exisiting seedlings and prevented “recruits”; seedling growth was related to

amount of light received—a consequence of the harvests or disease-caused crown

thinning.

Keywords: beech, root sprouts, seedlings, beech bark disease
Headquarters of the Northeastern Research Station is in Newtown Square,

Pennsylvania. Field laboratories are maintained at:

Amherst, Massachusetts, in cooperation with the University of Massachusetts

Burlington, Vermont, in cooperation with the University of Vermont

Delaware, Ohio

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

Hamden, Connecticut, in cooperation with Yale University

Morgantown, West Virginia, in cooperation with West Virginia University

Parsons, West Virginia

Princeton, West Virginia

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

College of Environmental Sciences and Forestry at Syracuse University

Warren, Pennsylvania

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