United States &# Department of 

t Agriculture Revegetation After Strip 

Forest Service Cutting and Block 

Northeastern Forest 

Experiment Station Clearcutting in 

Research Paper NE-625 Northern Hardwoods: 

@ A 1 0-Year History 

C. Wayne Martin 

James W. Hornbeck 
Abstract 

Revegetation was studied during the first 10 years after clearcutting two sites in 

the northern hardwood forest of New Hampshire. One site was a 12-ha block 

clearcut; the other was a 36-ha progressive strip cut harvested in three phases. 

Permanent plots on each site were measured at 140 4-year intervals. Changes in 

the density and biomass of trees, shrubs, and herbs are presented with emphasis 

on the major commercial species and their primary noncommercial competitors. 

The Authors 

C. WAYNE MARTIN is a research forester with the Northeastern Forest 

Experiment Station at the Hubbard Brook Experimental Forest, Campton, New 

Hampshire. 

JAMES W. HORNBECK is a research forester with the Northeastern Forest 

Experiment Station, Durham, New Hampshire. 

Manuscript received for publication 9 February 1989. 

Acknowledgment 

Vincent Levasseur, forest technician at the Hubbard Brook Experimental Forest, 

maintained the permanent inventory plots and played a vital role in collecting the 

data. Susan Karsten assisted with data collection, and Pat Downer and Robert 

Smith assisted with data analysis. 

COVER PHOTO. - Southwest-to-northeast view, showing block clearcut 

in the foreground. The strip cut and an earlier deforestation cutting are in the 

upper right. 

Northeastern Forest Experiment Station 

370 Reed Road, Broomall, PA 19008 

August 1989 
Introduction 

This is a report on the dynamics of the revegetation of a 

block clearcut and a progressive stripcut in the northern 

hardwood type at the Hubbard Brook Experimental Forest 

within the White Mountain National Forest of central New 

Hampshire. We present the rate of revegetation in terms of 

density and biomass accumulation, proportion of density 

and biomass in the floristic groups of herbs, shrubs, and 

trees, and the dynamics of individual tree species for 10 

years after cutting. 

Northern hardwoods are one of the major forest cover 

types in the northeastern United States, covering more than 

6 million ha (Filip and Leak 1973, Kingsley 1985, Leak and 

others 1969). The important timber species and principal 

components of this forest type are sugar maple (Acer 

saccharum Marsh.), beech ( Fagus grandifolia Ehrh.), and 

yellow birch (Betula alleghaniensis Britton). Other important 

but less common timber species include red maple (Acer 

rubrum L.), paper birch (Betula papyrifera Marsh.), white 

ash (Fraxinus americana L.), hemlock (Tsuga canadensis 

(L.) Carr.), balsam fir (Abies balsamea (L.) Mill.), and red 

spruce (Picea rubens Sa7g.) (Bormann and Likens 1979, 

Leak and others 1969). Associated noncomrqercial and 

early successional tree species include pin cherry (Prunus 

pensylvanica L.), striped maple (Acer pensyl~?anicum L.), 

and mountain maple (Acer spicatum Lam.) (Bormann and 

Likens 1979, Marks 1974). 

Forest management and harvesting practices of the first 

half of the 20th century favored the shade-tolerant sugar 

maple and beech to the exclusion of the currently valuable 

yellow birch. By 1969, a shortage of yellow birch for lumber 

and veneer and a shortage of young birch stands for future 

supplies were predicted (Cliff 1969, Marquis 1969). 

Research by the Northeastern Forest Experiment Station at 

the Bartlett Experimental Forest, within the White Mountain 

National Forest in northern New Hampshire, indicated that 

on small patch cuts 3 years after cutting, regeneration of 

merchantable species, especially yellow birch, was best on 

disturbed sites, such as skid roads, and poorest on 

undisturbed humus (Marquis 1965). 

Further work at Bartlett indicated that the temperature and 

moisture conditions of the surface soil greatly affected seed 

germination and seedling establishment of yellow birch 

(Marquis 1969). Marquis (1969) found that surface soil 

moisture remained substantially higher and surface soil 

temperatures substantially lower on exposed mineral soil 

than on humus or litter. Both of these condrtions favored 

yellow birch germination and establishment. However, he 

also found that once established, yellow birch grew much 

better on humus than on mineral soil because of nutrient 

deficiencres of mineral soils. Marquis (1969) also found that 

birches were more productive when grown in full sunlight 

rather than in shade because of better root growth. 

Adequate seed supply is also essential to regeneration, and 

Marquis (1 969) reported that only 15 percent as many 

yellow birch seeds were found two tree heights from the 

source as directly under it. 

On the basis of these results, progressive strip cutting 

evolved from block clearcutting in an attempt to further 

favor regeneration of birches by more closely controlling 

variables such as distance to seed sources, light, moisture, 

and scarification of the seed bed. The strip cutting involved 

cutting strips oriented east to west approximately 25 m 

wide with 50-m-wide uncut strips between each of them. 

After a 2-year period for establishment of regeneration, a 

second series of 25-m-wide strips was cut to the south of 

each of the original cuts. The final series of 25-m-wide 

strips was then cut after a second establishment period of 

2 years. As in block clearcutting, all merchantable stems 

were removed and scarification encouraged by confining 

skidding to cut strips, with appropriate measures to avoid 

erosion (Filip 1969, Marquis 1969, Safford 1983). 

After the first strip cutting, the strip received shade from the 

trees on its southerly border, providing favorable conditions 

for germinaton and early survival. When the second strip 

was cut, it received shade for initial establishment, but also 

allowed the first strip to receive direct sunlight. Both the 

first and second strips thus received shade for seedling 

establishment and then direct sunlight for best growth. 

During these harvests, seed sources were nearby in the 

uncut strips. When the third strip was cut, it received only 

minimal shade, and seed sources were more distant except 

for buried seeds. However, birch and maple seedlings that 

survived the 1st year or two of direct sunlight then had 

optimal growing conditions in terms of light and moisture. 

The strip cutting obviously required more effort and 

expense than clearcutting of a single block. A major reason 

for our study was to determine whether strip cutting results 

in more desirable species composition and stand 

development than does block clearcutting. 

Study Area 

The study was conducted at the Hubbard Brook 

Experimental Forest within the White Mountain National 

Forest in central New Hampshire. Two small watersheds 

were used for this study. The block clearcut (cover photo, 

foreground) is 12 ha and ranges in elevation from 470 m to 

595 m. The strip cut (background) is 36 ha ranges from 

440 m to 730 m in elevation. Both watersheds have 

southerly aspects and slopes of 20 to 30 percent. Red 

spruce is thought to have been first cut on the experimental 

forest in 1909. Heavier logging for additional species 

occurred in 1917 (Bormann and Likens 1979). The forest, 

at the beginning of our study in 1970, contained trees rising 
from natural regeneration after the initial harvests, plus a 

few older trees not taken during the early cuttings. This 55- 

to 60-year-old forest was described in detail by Bormann 

and others (1970), Siccama and others (1970), and 

Whittaker and others (1 974). 

Soils on the study watersheds were derived from coarsetextured, glacial till that has been subjected to frost action, 

erosion, and deposition since glacial retreat about 14,000 

years ago. Till depths range from 0 m to 5 m. The surficial 

layers have weathered to form fine sandy loams classed as 

Lithic and Typic Haplorthods. Soil profiles are often mixed 

due to tree blowdown, but usual development includes 0, 

E, Bhs, Bs, and C horizons (Soil Survey Staff 1988) that 

differ markedly in physical and chemical properties. The 

more common soil series include Marlow, Lyman, Peru, 

Hermon, and Monadnock. Much of the soil is underlain by 

dense basal till nearly impermeable to roots and water. 

Methods 

In preparation for harvest, the strip cut was surveyed into 

49 strips, each 25 m wide. The strips were oriented from 

east to west roughly parallel to the watershed contour. The 

first series of strips (first strips) was harvested from 

September 28 to October 29, 1970, the second series 

(second strips) from September 7 to October 1, 1972, and 

the third series (third strips) from October 1 to November 1, 

1974 (Fig. 1). The third series contained one additional 

strip to complete the cutting of the entire watershed. The 

block clearcut was harvested from October 30 to November 

28, 1970. In Figures 2 and 3, the 1st year before cutting 

refers to the growing season immediately prior to cutting; 

the 1st year after cutting refers to the growing season 

immediately after cutting. 

On both the strip cut and block clearcut, all trees and 

snags >2.5 cm d.b.h. were felled. Commercial portions of 

Figure 1. - East-to-west views across the strip cut watershed showing, rear foreground: (A) first strip cut, (B) first and 

second strips cut, (C) all strips cut, (D) regeneration at 10 years after initial harvest. The cleared area in near foreground 

is an earlier deforestation cutting. - - 
YEARS BEFORE CUT~ING YEARS AFTER CUTTING I 

Figure 2. - Density of stems of all species <I0 cm d.b.h. The data before cutting exclude trees >I0 cm d.b.h. There 

were no stems >I0 cm d.b.h. during the 1~ years after cutting. 

5432 11 2345678910 

YEARS BEFORE CUTTIHG YEARS AFTER CUTTING I 

Figure 3. - Oven-dry weight of above-ground living biomass of all stems <I0 cm d.b.h. of all species of trees, shrubs, 

and herbs. Data before cutting do not include trees >I0 cm d.b.h. There were no trees >I0 cm d.b.h. during the 10 

years after cutting. Each megagram per hectare represents one half ton per acre. 
the trees were transported by rubber-tired skidders to 

landing areas adjacent to the base of the harvested 

watersheds. Skidder operators were encouraged to vary 

their routes to provide scarified conditions necessary for 

successful regeneration of birch. 

Regeneration on the block clearcut and strip cut has been 

surveyed on permanent plots at 1- to 4-year intervals since 

harvest. On the strip cut, fifty-seven 25-m X 25-m plots 

were selected. Nineteen plots were chosen randomly for 

each year. of cut. These plots were later classified by 

elevation with 19 plots at low elevation (440 m to 550 m), 

18 at mid-elevation (550 m to 650 m), and 20 at high 

elevation (650 m to 730). On the block clearcut, forty-eight 

25-m X 25-m plots were chosen at random with no 

stratification since the harvest was completed in a single 

operation and the elevation range of the entire harvest area 

was about the same as for the mid-elevation plots on the 

strip cut. Surveys were conducted before cutting on each of 

the strips, but not on the block clearcut (Figs. 2 and 3). 

Nested subplots were used. The entire 25-m X 25-m plot 

was used to sample trees >I0 cm d.b.h. Trees between 2 

cm and 10 cm d.b.h. were tallied on a I-m X 25-m strip 

running the length of either the east or west side (decision 

by coin toss) of each plot. Saplings measured on these 

I-m X 25-m subplots before cutting were considered to be 

advance regeneration (Figs. 2 and 3). Lesser vegetation 

was surveyed on four 1 m2 subplots spaced evenly along 

the I-m X 25-m strip plot. Within each of these subplots, 

stem counts were made by species for trees, shrubs, and 

herbs in two height classes, <0.5 m tall and >0.5 m tall. 

Data from the subplots were averaged to give stems per 

m2 for each I-m X 25-m strip. Visual estimates of percent 

of plot covered were used in place of stem counts for 

grasses, sedges, rushes, and mosses. 

Estimates of aboveground biomass of regeneration were 

obtained by establishing 46 additional 1-m X I-m plots on 

the strip cut, classified by elevation and year cut. From 

these plots, individual stems by species for trees, shrubs, 

and herbs classified as either ~0.5 m tall or >0.5 m tall or 

by percentage of cover were clipped in July and August, 

dried at 105OC, and weighed. An average weight per stem 

was calculated by species, height class, or percentage of 

cover, by year. These factors were then multiplied by the 

corresponding stem counts from both watersheds to obtain 

biomass estimates in kg ha-'. Trees exceeding 2 cm d.b.h. 

were not clipped. The'ii biomass was estimated using 

appropriate equations selected from Tritton and Hornbeck 

(1 982) (Appendix). 

Results 

Total Stem Counts 

The maximum number of stems (trees, shrubs, and herbs) 

occurred before the 5th year after cutting on both the block 

clearcut and strip cut watersheds (Fig. 2). Maximum density 

on the block clearcut occurred during the 2nd year after 

cutting at 1,061,000 stems ha". This number dropped to 

447,000 by 10 years after cutting. The inventory of 1970, 

before any cutting, indicated that the density of vegetation 

<10 cm d.b.h. on each of the three sets of strips was 

similar at about 300,000 stems ha-'. The density on the 

first strips, after cutting, peaked at 1,183,000 stems ha" 

the 3rd year, and dropped to 606,000 stems haF' 7 years 

later. The peak density in the second strips, also, occurred 

at 3 years after cutting, at 865,000 stems ha-', and 

dropped to 232,000 stems ha" by the 10th year after 

cutting. These lower numbers may have been due partly to 

damage that occurred 2 years after cutting, while the third 

set of strips was being harvested. The density and biomass 

of the advance regeneration at the time of cutting of the 

third strips was twice as great as at the cutting of the other 

strips, probably because of added light after the first and 

second harvests. Density on the third strips after cutting 

peaked at about 1,344,000 stems ha-' 2 years after cutting, 

but dropped to 368,000 stems ha'' by 10 years after 

cutting. 

Total Biomass 

In 1970, before any cutting had occurred, total biomass 

averaged 133 Mg ha-' on the strip cut. The biomass of all 

stems <I0 cm d.b.h., before cutting, averaged 8.9 Mg ha-', 

with a range from 6.9 Mg ha-' to 11.2 Mg ha-' (Fig. 3). 

Harvesting stimulated biomass production on both cut and 

uncut strips. By 1972, just before cutting, biomass of stems 

<I0 cm d.b.h. in the second strips had increased from 6.9 

Mg ha-' to 8.2 Mg ha-'. By 1974, just before cutting, 

biomass of stems <I0 cm d.b.h. in the third strips had 

increased from 8.7 Mg ha-' in 1970 to 16.9 Mg ha'' (Fig. 

3). This increase in biomass on the third strips before 

cutting may have been caused by greater light penetration 

after the adjacent strips were cut in 1970 and 1972 and by 

an increased supply of moisture and nutrients moving from 

cut to uncut strips (Hornbeck and others 19879. However, 

any advantage seems to have been lost during harvest, 

apparently because of breakage, crushing, and burial under 

the logging slash. All strips and the block clearcut had <3 

Mg ha-' the 1st year after cutting. Biomass production on 

the block clearcut accelerated much more rapidly than on 

the strip cut during the early years after cutting (Fig. 3). 

Biomass production was similar on all three sets of strips 

through year 8, and was much slower than on the block 

clearcut. Production on the strip cut seemed to accelerate 

after year 8 with biomass on the second set of strips nearly 
doubling from about 28 Mg ha-' to 54 Mg ha.' between 

years 8 and 10. 

Differences With Elevation 

For the first set of strips, the greatest density occurred at 

low elevation the 1st and 2nd years after cutting, at middle 

elevation during the 2nd through 4th years after cutting, 

and at high elevation from the 3rd through 5th years after 

cutting. For the second set of strips, the greatest density 

occurred at low and middle elevations during the first 4 

years after cutting and at high elevation during the 3rd 

through the 8th year. On the third set, the highest density 

occurred at the middle elevation during the first 2 years. By 

the 4th year after cutting, the high elevation strips had the 

greatest number of stems (Table 1). 

On the strip cut, biomass tended to accumulate most 

rapidly at low elevations and least rapidly at the higher 

elevations for all 3 cutting years (Table 2). Biomass 

accumulated more rapidly on the block clearcut than on the 

strip cut through the 8th year after cutting. 

Table 1. - Number of stems per ha of all species by elevation and year of cutting on both the strip cut and block 

clearcut watersheds. 

Years since cutting 

Year 

cut Elevation 1 2 3 4 5 6 7 8 10 

Thousands 

1970 High 475 861 1300 941 1490 894 - - 930 

Mid 786 1399 1274 1051 797 782 - - 422 

Low 992 1076 976 81 4 789 609 - - 466 

Block 891 1061 81 5 - 542 - 467 - 447 

1972 High 61 2 579 77 1 71 6 - - - 755 33 1 

Mid 637 874 91 0 873 - - - 35 1 167 

Low 866 865 91 5 99 1 - - - 397 198 

1974 High 802 1072 - 909 - 1339 - - 620 

Mid 1064 1497 - 696 - 592 - - 185 

Low 91 9 1464 - 762 - 570 - - 299 

Table 2. - Biomass of all stems of all species by elevation and year of cutting on both strip cut and block 

clearcut watersheds. Each Mg ha-' represents one-half ton per acre. 

Years since cutting 

Year 

cut Elevation 1 2 3 4 5 6 7 8 10 

1970 High 

Mid 

Low 

Block 

1972 High 

Mid 

Low 

1974 High 

Mid 

Low 

Mg ha'' 

5.5 9.6 10.5 

6.4 8.0 8.0 

12.7 17.5 21.9 

23.6 - 35.4 

4.5 7.6 - 7.4 11.5 - 

6.7 10.0 - 

- 6.8 - - 8.1 - - 11.4 
Proportion of Trees, Shrubs, and Herbs 

Throughout the study, tree density generally declined, shrub 

density remained relatively constant, and herbaceous 

density increased. Generally, the highest elevations had the 

fewest trees and the most herbs, while the lowest 

elevations had the most trees and the fewest herbs. The 

1st year after cutting, herbs accounted for less than 11 

percent of the stems on the low and mid-elevations of the 

first strips and on the block clearcut (Fig. 4). At the high 

elevation strips, herbs accounted for approximately 33 

percent of the vegetation. Density of shrubs ranged from 3 

to 8 percent of all stems. Trees accounted for 85 percent 

of stems on middle and low elevation strips and on the 

block clearcut, but only 64 percent at high elevation. 

Ten years after cutting, herbs accounted for 54 to 66 

percent of stems on the first strips, depending upon 

elevation, and 41 percent on the block clearcut. Trees 

dwindled to 10 to 28 percent on the strip cut and to 52 

percent on the block clearcut. On the second set of strips, 

depending on elevation, trees ranged from 40 to 54 percent 

of the total the 1st year after cutting, shrubs ranged from 7 

to 12 percent, and herbs ranged from 34 to 53 percent. By 

10 years after cutting, herbs comprised 54 to 71 percent of 

the stems, shrubs 8 to 17 percent, and trees only 12 to 30 

percent. 

On the third strips, trees comprised 56 percent of the 

stems at low elevation to only 22 percent at high elevation 

during the 1st year after cutting. Shrubs accounted for 6 to 

14 percent and herbs 30 to 72 percent. By 10 years after 

cutting, trees accounted for 10 to 28 percent, shrubs 4 to 

11 percent, and herbs 61 to 80 percent. 

Although herbaceous density increased during regrowth, 

herbaceous biomass was relatively minor and decreased 

rapidly over time. On the block clearcut, herbs contributed 

5 percent of the biomass during the 1st year after cutting 

(Fig. 5). Herbaceous biomass ranged from 3 to 28 percent 

of the total biomass during the 1st year after cutting on the 

three series of strip cuts. By the 5th year after cutting, 

herbaceous biomass dropped to less than 5 percent at all 

elevations on both watersheds. By the 10th year after 

cutting, herbaceous biomass was down to less than 0.1 

percent. 

Shrubs played a more major role in terms of biomass on 

both watersheds, especially during the first 5 years after 

cutting (Fig. 5). The 1st year after cutting, shrubs averaged 

19 to 50 percent of the biomass with no clear trends by 

elevation. At the end of the 4th year after cutting, the range 

had dropped to 4 to 35 percent of the total. But by 10 

years after cutting, shrubs accounted for less than 10 

percent of the biomass on the first strips, less than 3 

TREES SHRUBS 

100 1974 Cut 

80 

60 

40 

20 

n 

- HMLB 

L 

HML B HMLB 

1 st 4th 5th 10th 

YEARS SINCE CUTTING 

Figure 4. - Density of revegetation with herbs, shrubs, and 

trees expressed as a percent of the total by elevation and 

year of cut. H, M, L, and B represent high, mid, low 

elevation strips, and block clearcut, respectively. Herbs are 

represented by hatched bars, shrubs by dark bars, and 

trees by white bars. 

percent on the third strips, and less than 2 percent on the 

block clearcut and on the second strips. 

Trees accounted for 40 to 60 percent of the biomass the 

1st year after cutting with a couple of exceptions. By 10 

years after cutting, trees accounted for more than 90 

percent of the biomass on the first strips, for more than 97 

percent on the third strips, and for more than 98 percent on 

the second strips and on the block clearcut. 
TREES SHRUBS 8 HERBS 

1974 Cut 

20 \>\ 

>:.., ,>, $ 

O HMLB 

1972 Cut 

1970 Cut 

1 H M L 

1 st 4th 5th 10th 

YEARS SINCE CUTTING 

Density of Trees 

Density of commercial and noncommercial trees was 

generally greater on the block clearcut watershed than on 

the strip cut. On the strip cut, density was higher at low 

elevations than at high elevations, and the first strips were 

more dense than the others (Table 3). Furthermore, density 

of trees dropped dramatically during the 10 years after 

clearcutting. 

Yellow birch was the most numerous tree on the block 

clearcut after cutting, with pin cherry second. At low 

elevation, yellow birch was the most numerous tree on the 

first strips, until the 10th year when sugar maple became 

more numerous (Table 4). In the second strips, yellow birch 

and sugar maple had similar densities and were more 

numerous than the other trees. In the third strips, sugar 

maple was clearly most numerous after the 1st year. 

At the middle elevation, yellow birch was the most 

numerous tree, on the first strips, until the 5th growing 

season, when sugar maple assumed that role. In the 

second strips, yellow birch was most abundant the 1st 

year, beech the 2nd and 3rd years, and then sugar maple 

became most numerous. In the third strips at mid-elevation, 

sugar maple was clearly most numerous (Table 5). 

Figure 5. - Aboveground living biomass with herbs, 

shrubs, and trees expressed as a percent of( the total by 

elevation and year of cut. H, M, L, and B represent high, 

mid, low elevation strips, and block clearcut,~respectively. 

Herbs are represented by hatched bars, shrqbs by dark 

bars, and trees by white bars. 

At the high elevation, yellow birch was clearly the most 

abundant tree species in the first strips, but shared that 

role with sugar maple by the 10th year on the other two 

sets of strips (Table 6). 
Table 3. - Number of stems of trees only, 40 cm d.b.h., per ha. There were no trees 310 cm d.b.h. measured 

during the 10 years after cutting (see appendix for a list of species included as tree species). 

Years since cutting 

Year 

cut Elevation 1 2 3 4 5 6 7 8 10 /' 

1 970 High 

Mid 

Low 

Block 

1972 High 

Mid 

Low 

1974 High 

Mid 

Low 

Thousands 

326 181 

369 224 

440 277 

402 - 

133 106 

192 162 

257 234 

- 1 20 

- 1 73 - 21 6 

Table 4. - Trees: block clearcut and low elevation strips, stems per ha (thousands). 

Years since cutting 

Type Year of 

cut cut 1 2 3 4 5 6 7 8 10 

Block 

Strip 

Strip 

Strip 

Block 

Strip 

Strip 

Strip 

Block 

Strip 

Strip 

Strip 

Block 

Strip 

Strip 

Strip 

'\Block 

btrip 

Qtrip 

Strip 

Block 

Strip 

Strip 

Yellow Birch 

21 4 - 90 

242 125 95 

112 88 - 

- 48 - 

Sugar Maple 

31 - 26 

50 47 60 

85 88 

- 122 - 

Beech 

32 - 25 

37 25 15 

16 18 - - 17 - 

Pin Cherry 

75 - 50 

22 15 26 

3 1 - - 4 - 

Striped Maple 

18 - 13 

16 8 7 

12 9 - - 3 - 

Mountain Maple 

1 - I 

3 3 3 

3 2 - 

Strip 1974 - 1 - 0 

8 
Table 5. - Trees: strip cutting, mid elevation, stems per ha (thousands). 

Years since cutting Year 

cut 1 2 3 4 5 6 7 8 10 

Yellow Birch 

102 58 

2 1 - 

18 - 

Sugar Maple 

86 94 

66 - 

117 - 

Beech 

20 7 

52 - 

16 - 

Pin Cherry 

3 9 

7 - 

2 - 

Striped Maple 

6 9 

14 - 

8 - 

Mountain Maple 

2 0 

1 - 

7 - 

Table 6. - Trees: strip cut, high elevation, stems per ha (thousands). 

Years since cutting Year 

cut 1 2 3, 4 5 6 7 8 10 

Yellow Birch 

75 356 

43 - 

28 - 

Sugar Maple 

3 1 25 

24 - 

18 - 

Beech 

22 19 

6 - 

14 - 

Pin Cherry 

6 3 

4 - 

3 - 

Striped Maple 

4 8 

11 - 

9 - 

Mountain Maple 

13 11 

8 - 
Biomass of Trees clearcut (Tables 8 and 9). This was the highest percentage 

since cutting; the lowest of 14 percent occurred the second 

year after cutting. At the high elevation of the first strips, 

commercial tree biomass went from 68 percent the 1st year 

after cutting to 72 percent by the 10th year. The low and 

mid-elevations went from 77 to 80 percent the 1st year 

down to only 36 percent of the total tree biomass. In the 10 

years after cutting of the second and third strips, biomass 

of commercial trees stayed relatively constant or increased 

as a percent of the total tree biomass. The exception was 

a big drop between the 1st and 2nd years of the 

mid-elevation of the second strips from 92 percent to 37 

percent. 

Biomass of commercial and noncommercial trees was 

greater on the block clearcut than on the strip cut. By the 

10th year after cutting, the biomass of trees on the second 

strips was much greater than on the third strips which, in 

turn, was greater than on the first strips (Table 7). In nearly 

all instances, biomass accumulated faster at lower 

elevations than at higher elevations. 

At 10 years after cutting, commercial trees (sugar maple, 

yellow birch, beech, paper birch, and white ash) accounted 

for only 37 percent of the tree biomass on the block 

Table 7. - Biomass of trees 40 cm d.b.h. per ha. There were no trees 210 cm d.b.h. measured during the 10 

years after cutting. Each Mg ha -' represents one-half ton per acre. 

Years since cutting 

Year 

cut Elevation 1 2 3 4 5 6 7 8 10 

1970 High 

Mid 

Low 

Block 

1972 High 

Mid 

Low 

1974 High 

Mid I Low , 

Table 8. - Percentage of tree biomass accounted for by commercial tree species: sugar maple, yellow birch, beech, 

paper birch, white ash. 

Years since cutting 

Year 

cut Elevation 1 2 3 4 5 6 7 8 10 

1970 High 

Mid 

Low 

Block 

1972 High 

Mid 

Low 

1974 High 

Mid 

Low 
Table 9. - Biomass of commercial trees: sugar maple, yellow birch, beech, paper birch, white ash. Each Mg ham' 

represents one-half ton per acre. 

Years since cutting 

Year 

cut Elevation 1 2 3 4 5 -6, 7 8 10 

1970 High 

Mid 

Low 

Block 

1972 High 

Mid 

Low 

1974 High 

Mid 

Low 

On the block clearcut, pin cherry had the most biomass 

throughout the 10 years after clearcutting, w,ith a maximum 

of over 31 Mg ha-' occurring at about 7 years after cutting. 

The biomass of yellow birch steadily increased after cutting 

to 10.8 Mg ha-' by the 10th year (Fig. 6). 

In the first strips at low elevation, pin cherry had the most 

biomass throughout the 10 years, with 14 Mg ha-' at the 

10th year. After the 3rd year after cutting, yellow birch had 

the second highest biomass (Fig. 7). At the middle 

elevation, no single species was clearly dominant in terms 

of biomass until the 5th year after cutting, when pin cherry 

accumulated the most biomass, with sugar maple second. 

At the high elevation, yellow birch accumulated biomass 

faster than other species after the 6th year after cutting, 

with pin cherry next. 

In the second strips at the low elevation, sugar maple had 

more biomass than any other species throughout the 10 

years after cutting, reaching 17.5 Mg ha-' by the 10th year. 

Yellow birch was the second commercial species in terms 

of biomass with more than 10 Mg ha.' at 10 years (Fig. 8). 

In the middle elevation of the second strips, the biomass of 

the four major species was similar throughout' the 10 years, 

but beech was always near the top. At 10 yehrs after 

cutting, yellow birch had the most biomass at 12.2 Mg ha-', 

with beech next at 12.1 Mg ha-', then sugar maple at 10.3 

Mg ha-', followed by pin cherry. At the highest elevation of 

the second strips, yellow birch had the most biomass with 

14.5 Mg ha-', with beech second. 

In the third strips, at low elevation, no species expressed 

dominance in terms of biomass for the first 4 years after 

cutting, then pin cherry and yellow birch emerged. By 10 

years after cutting, yellow birch had accumulated 14.3 Mg 

ha-' with pin cherry at 9.2 Mg ha-' (Fig. 9). At midYEARS SINCE CUTTING 

Figure 6. - Aboveground living biomass of yellow birch 

(YB), sugar maple (SM), American beech (AB), and pin 

cherry (PC) during the 10 years after clearcutting the block 

clearcut. Each megagram per hectare represents one half 

ton per acre. 
YEARS SINCE CUTTING 

YEARS SINCE CUTTING 

Figure 7. - Aboveground living biomass of yellow birch Figure 8. - Aboveground living biomass of yellow birch 

(YB), sugar maple (SM), American beech (AB), and pin (YB), sugar maple (SM), American beech (AB), and pin 

cherry (PC) at three elevations of the first set of strips, the cherry (PC) at three elevations of the second set of strips, 

1970 strip cut. Each megagram per hectare represents the 1972 strip cut. Each megagram per hectare represents 

one-half ton per acre. one-half ton per acre. 
Size Classes at Year 10 

High Elevation 

SM . ....... 

YEARS SINCE CUlTING 

Figure 9. - Aboveground living biomass of yellow birch 

(YB), sugar maple (SM), American beech (AB), and pin 

cherry (PC) at three elevations of the third set of strips, the 

1974 strip cut. Each megagram per hectare represents one 

half ton per acre. 

elevation, pin cherry never really became a factor. By 10 

years after cutting, yellow birch had accumulated 17.9 Mg 

ha-', with sugar maple at 11.6 Mg ha-'. At the high 

elevation, 10 years after cutting, yellow birch had 

I accumulated 12.7 Mg haS1, with beech next at 7.9 Mg ha". 

By year 10, many of the trees had grown to sizes with 

measurable d.b.h. (Table 10). The rapid initial growth of pin 

cherry is illustrated by the large number of measurable 

trees on all three sets of strips and the block clearcut. 

Yellow birch had the second largest number of measurable 

stems and is expected to combine with sugar maple and 

beech to dominate the measurable trees when pin cherry 

begins its early die-off. No trees exceeded 10 cm d.b.h. by 

10 years after harvest. 

Discussion 

On the basis of past studies, the site should be occupied 

by a full range of species including advanced regeneration, 

sprouts, seedlings of tolerant trees, seedlings of intolerants, 

shrubs, and herbs immediately after a major disturbance 

such as clearcutting. During the first 2 years, herbs should 

dominate, then shrubs, especially Rubus; and then between 

3 and 5 years intolerant, unmerchantable tree species 

should take over (Bicknell 1979, Bormann and Likens 1979, 

Egler 1954, Marks 1974, Marquis 1967, Oliver 1981). 

On our watersheds, the density of vegetation peaked 

between 2 and 4 years after cutting, but the individuals 

were very small seedlings of trees, shrubs, and herbs as 

indicated by very low biomass (Figs. 2 and 3). Advance 

regeneration was not a major factor, nor were sprouts. On 

the block clearcut and the first set of strips at all elevations, 

tree species were 64 to 86 percent of the stems the first 

year after cutting (Fig. 4). On the second set of strips, tree 

species accounted for 40 to 54 percent of the stems the 

first year (Fig. 4). On the third strips, trees accounted for 

only 22 to 56 percent, with the most trees at low elevation 

and the least at the high elevations. 

Herbs generally increased in numbers throughout the first 

10 years after cutting; but in terms of biomass, herbs were 

never very important. They were more important the 1st 

year after cutting than ever again, and they were more 

important at the high elevation than at the lower elevations. 

Shrubs generally increased in number between the 1st and 

3rd years after cutting, remained constant until at least the 

6th year, and seemed to decline by the 10th year. 

However, these changes were not extreme and shrub 

density remained remarkably constant over the first 10 

years after cutting. Shrub biomass was generally greatest 

during the first 2 years after cutting and declined to minor 

importance by 10 years after cutting (Fig. 5). 

Pin cherry and the other unmerchantable species were 

more abundant on the block clearcut than on the strip cut. 
Table 10. - Trees per ha (standard error), 10 years after cut, by diameter classes and year cut. - 

d.b.h. (cm) d.b.h. (cm) d.b.h. (cm) 

Elev' 2.5-4.9 5.0-7.4 7.5-9.9 2.5-4.9 5.0-7.4 7.5-9.9 2.5-4.9 5.0-7.4 7.5-9.9 

First cut Second cut Third cut 

Yellow Birch 

3143 (1 540) 229 (1 19) 0 

2467 (1 703) 267 (134) 0 

1467 (528) 267 (136) 67 (67) 

Strip High 

Mid 

Low 

Block 

Strip High 

Mid 

Low 

Block 

Strip High 

Mid 

Low 

Block 

Strip High 

Mid 

Low 

Block 

Strip High 

Mid 

Low 

Block 

Strip High 

Mid 

Low 

Block 

Sugar Maple 

0 0 0 

1467 (896) 267 (134) 0 

2533 (557) 333 (123) 67 (67) 

Beech 

1486 (608) 171 (1 18) 57 (57) 

2600 (634) 0 0 

1000 (554) 0 0 

Pin Cherry 

971 (444) 514 (288) 57 (57) 

1533 (810) 1133 (544) 67 (67) 

400 (146) 600 (306) 333 (260) 

Striped Mapie 

229 (1 14) 57 (57) 0 

1667 (317) 133 (84) 0 

867 (303) 0 0 - - - 

Mountain Maple 

343 (158) 0 0 

400 (256) 0 0 

1867 (502) 267 (168) 0 

But even there, the birch, beech, and maple accounted for 

575,000 stems the 1st year, while there were only 124,000 

unmerchantable stems. By the 5th year, there were 

140,000 merchantable stems versus 64,000 

unmerchantable, and by year 10, 177,000 merchantable 

and 36,000 unmerchantable (Table 4). Unmerchantable 

stems were even less important on the strip cut and were 

less abundant with increasing elevation (Tables 5 and 6). 

However, while there were fewer pin cherries than other 

tree species, their biomass was greater, at least on the 

block clearcut and on the first set of strips. 

tree seedlings ha-': 55 percent were yellow birch, 21 

percent were beech, and 10 percent were sugar maple. On 

the block clearcut, over 750,000 seedlings ha-' occurred: 

64 percent were yellow birch, 11 percent beech, and 4 

percent sugar maple. 

By year 5 after harvest, the total number of tree seedlings 

had decreased to around 200,000 ha.' on both the strip cut 

and block clearcut. On the strip cut, 32 percent of all 

seedlings were yellow birch, 12 percent were beech, and 

35 percent were sugar maple. On the block clearcut, 40 

percent were yellow birch, 11 percent were beech, and 11 

The most important consideration for the forest manager is percent were sugar maple. 

emergence and development of commercial species. The 

1st year or two after cutting, a forester visiting the site is 

confronted with a predominance of herbs and shrubs, 

notably asters and Rubus. However, by year 4 herbs are 

no longer competitors, and by year 10, shrubs have been 

relegated to the understory. 

By year 10, the total number of trees decreased to about 

70,000 ha-' on the strip cut, but remained at about 200,000 

ha-' on the block clearcut, largely due to continued 

germination of yellow birch. The composition at year 10 on 

the strip cut included 18 percent yellow birch, 10 percent 

beech, and 38 percent sugar maple. On the block clearcut, 

the composition was 63 percent yellow birch, 6 percent 

beech, and 7 percent sugar maple. 

With regard to commercial tree species, in the 1st year 

after strip cutting, there was an average of over 400,000 
For the block clearcut, the percentages for individual 

commercial species were fairly stable through the first 10 

years. However, on the strip cutting, there was a significant 

shift from domination by yellow birch in year 1 after harvest 

to domination by sugar maple at year 10. We do not know 

why this shift occurred, but do not view it as detrimental 

since sugar maple is commercially valuable. 

Pin cherry was the principal competitor to commercial 

species on both the block clearcut and the strip cut 

throughout the 10 years. Pin cherry, which accumulated 

considerable biomass and was highly visible, accounted for 

<5 percent of the stems on the strip cut throughout the 

study. Pin cherry was much more of a factor on the block 

clearcut since it accounted for 22 percent of the tree 

seedlings during year 5 and 11 percent at year 10. 

Because of the short life of pin cherry, we anticipate that it 

will no longer be a competitor after another 10 years. 

Solomon and Leak (1969) indicated that for a stand to be 

adequately stocked, there should be 956 stems ha.' of 

commercial species having minimum diameters of 12.5 cm. 

They also gave a formula for estimating the number of 12.5 

cm d.b.h. trees that could be expected to survive from 

smaller diameter trees. We suggest that there is ample 

stocking at 10 years. However, projected stocking from 

those merchantable species that have reached 2.5 cm 

d.b.h. in 10 years (Table 10) suggests that it may be 

premature to predict the stocking of the future stand at ten 

years of age. 

Strip cutting in northern hardwoods has not gained 

acceptance or widespread application, partly because of the 

added work in locating the strips, and the need to reenter 

the stands on two added occasions. In our study, strip 

cutting failed to meet the objective of increasing the 

proportion of yellow birch in the regenerating stand. On the 

basis of our results, strip cutting does not appear to be 

worth the added effort silviculturally, and is thus not a 

viable option for managing northern hardwoods. However, 

as pointed out by Hornbeck and others (1987), strip cutting 

is a valuable tool for nutrient conservation. 

Summary and Conclusions 

Maximum density occurred before the 5th year after 

cutting, at about 1,000,000 stems per ha of all species of 

plants. 

By 10 years after cutting, total density had returned 

nearly to precutting levels. 

Cutting of the early strips increased the density and 

biomass of the advance regeneration in the uncut strips, 

but this advance regeneration was destroyed during the 

subsequent logging and was not an overriding factor in 

the regeneration of the watersheds. 

At 10 years after cutting, the rate of biomass 

accumulation on the block clearcut seemed to be leveling 

off at 50 Mg ha-'. On the strip cut, biomass still seemed 

to be accumulating exponentially at 35 to 50 Mg ha-'. 

On the strip cut, maximum density was reached at low 

elevations 2 to 5 years before it was reached at high 

elevations. 

Total aboveground biomass increased much faster on the 

block clearcut than on the strip cut. On the strip cut, 

biomass accumulated faster at low elevation than at high. 

Density and biomass of tree species was greater on the 

block clearcut than on the strip cut and greatest at the 

low elevations of the strip cut. Density of regeneration 

was greatest on the first set of strips cut. 

Generally, on both watersheds the density of herbaceous 

stems increased over the first 10 years, shrub density 

remained constant, and tree density declined. 

Herbaceous biomass, while never very important, 

declined to very low levels by 10 years after cutting. Ten 

years after cutting trees accounted for more than 90 

percent of the biomass. 

Ten years after cutting, yellow birch was the most 

numerous commercial tree on the block clearcut; sugar 

maple was the most numerous commercial tree on the 

strip cut. 

Pin cherry biomass was much higher on the block 

clearcut than on the strip cut and higher at lower 

elevations of the strip cut than at higher elevations. 

Yellow birch biomass was greatest on the block clearcut 

and at higher elevations of the strips. 
Literature Cited 

Bicknell, S.H. 1979. Pattern and process of plant 

succession in a revegetating northern hardwood 

ecosystem. New Haven, CT: Yale University. 218 p. 

Ph.D. dissertation. 

Bormann, F.H.; Likens, G.E. 1979. Pattern and process in 

a forested ecosystem. New York: Springer-Verlag. 

253 p. 

Bormann, F.H.; Siccama, T.G.; Likens, G.E.; Whittaker, R.H 

1970. The Hubbard Brook Ecosystem Study: 

composition and dynamics of the tree stratum. 

Ecological Monographs. 40:373-388. 

Cliff, E.P. 1969. Our birch resources. In: Birch symposium 

proceedings; 1969 August 19-27 ; Durham, NH. Upper 

Darby, PA: U.S. Department of Agriculture, Forest 

Service, Northeastern Forest Experiment Station: 1-5. 

Egler, F.E. 1954. Vegetation science concepts: I. Initial 

floristic composition a factor in old-field vegetation 

development. Vegetatjo. 4:412-417. 

Filip, S.M. 1969. Natural regeneration of birch in New 

England. In: Birch symposium proceedings; 1969 August 

19-21; Durham, NH. Upper Darby, PA: US. Department 

of Agriculture, Forest Service, Northeastern Forest 

Experiment Station: 50-54. 

Filip, S.M.; Leak, W.B. 1973. Northeastern northern 

hardwoods. In: Silvicultural systems for the major forest 

types of the United States. Agric. Handb. 445. 

Washington, DC: US. Department of Agriculture: 75-77. 

Hornbeck, J.W.; Martin, C.W.; Pierce, R.S.; Bormann, F.H.; 

Likens, G.E.; Eaton, J.S. 1987. The northern hardwood 

forest ecosystem: ten years of recovery from 

clearcutting. Res. Pap. NE-596. Broomall, PA: U.S. 

Department of Agriculture, Forest Service, Northeastern 

Forest Experiment Station. 30 p. 

Kingsley, N.P. 1985. A forester's atlas of the Northeast. 

Gen. Tech. Rep. NE-95. Broomall, PA: U.S. Department 

of Agriculture, Forest Service, Northeastern Forest 

Experiment Station. 96 p. 

Leak, W.B.; Solomon, D.S.; Filip, S.M. 1969. A 

silvicultural guide for northern hardwoods in the 

Northeast. Res. Pap. NE-143. Upper Darby, PA: US. 

Department of Agriculture, Forest Service, Northeastern 

Forest Experiment Station. 34 p. 

MacLean, D.A.; Wein, R.W. 1976. Biomass of jack pine 

and mixed hardwood stands in northeastern New 

Brunswick. Canadian Journal of Forest Resear;ch. 

6(4):441-447. 

Marks, P.L. 1974. The role of pin cherry (Prunus 

pensylvanica L.) in the maintenance of stability in 

northern hardwood ecosystems. Ecological 

Monographs. 44:73-88. 

Marquis, D.A. 1965. Regeneration of birch and 

associated hardwoods after patch cutting. Res. Pap. 

NE-32. Upper Darby, PA: US. Department of Agriculture, 

Forest Service, Northeastern Forest Experiment Station. 

13 p. 

Marquis, D.A. 1967. Clearcutting in northern hardwoods: 

results after 30 years. Res. Pap. NE-85. Upper Darby, 

PA: US. Department of Agriculture, Forest Service, 

Northeastern Forest Experiment Station. 13 p. 

Marquis, D.A. 1969. Silvical requirements for natural 

birch regeneration. In: Birch symposium proceedings: 

1969 August 19-21; Durham, NH. Upper Darby, PA: US. 

Department of Agriculture, Forest Service, Northeastern 

Forest Experiment Station: 40-49. 

Monteith, D.B. 1979. Whole-tree weight tables for New 

York. Applied Forestry Research Institute Res. Pap. 40 

67 p. 

Oliver, C.D. 1981. Forest development in North America 

following major disturbances. Forest Ecology and 

Management. 3:153-168. 

Safford, L.O. 1983. Silvicultural guide for paper birch in 

the northeast (revised). Res. Pap. NE-535. Broomall, 

PA: U.S. Department of Agriculture, Forest Service, 

Northeastern Forest Experiment Station. 29 p. 

Siccama, T.G.; Bormann, F.H.; Likens, G.E. 1970. The 

Hubbard Brook Ecosystem Study: productivity, 

nutrients, and phytosociology of the herbaceous 

layer. Ecological Monographs. 40:389-402. 

Soil Survey Staff, Department of Agronomy, Cornell 

University 1988. Keys to soil taxonomy (fourth printing). 

Soil Management Support Services Technical Monograph 

No. 6. Cornell University, Ithaca, NY: US. Department of 

Agriculture, Agency for International Development. 

271 -280. 

Solomon, D.S.; Leak, W.B. 1969. Stocking, growth, and 

yield of birch stands. In: Birch symposium proceedings: 

1969 August 19-21; Durham, NH. Upper Darby, PA: U.S. 

Department of Agriculture, Forest Service, Northeastern 

Forest Experiment Station: 106-1 18. 

Solomon, D.S.; Leak, W.B. 1986. Simulated yields for 

managed northern hardwood stands. Res. Pap. 

NE-578. Broomall, PA: U.S. Department of Agriculture, 

Forest Service, Northeastern Forest Experiment Station. 

24 p. 
Tritton, L.M.; Hornbeck, J.W. 1982. Biomass equations for 

major tree species of the northeast. Gen. Tech. Rep. 

NE-69. Broomall, PA; U.S. Department of Agriculture, 

Forest Service, Northeastern Forest Experiment Station. 

46 p. 

Whittaker, R.H.; Bormann, F.H.; Likens, G.E; Siccama, T.G 

1974. The Hubbard Brook Ecosystem Study: forest 

biomass and production. Ecological Monographs. 

441233-254. 

Young, H.E.; Ribe, J.H.; Wainwright, K. 1980. Weight 

tables for tree and shrub species in Maine. Misc. Rep. 

230. Orono, ME: Univ. of Maine, Life Sci. and Agric. Exp. 

Stn. 84 p. 

Appendix 

Oven dry weight of above-ground biomass regression 

equations (Tritton and Hornbeck 1982); "log" refers to 

the logarithm to the base 10, and "In" is the natural 

logarithm: 

Sugar maple (Young 1980): 

In weight (Ibs) = 1.2451 + 2.3329 In d.b.h. (in) 

Yellow birch (Young 1980): 

In weight (Ibs) = 1.1297 + 2.3376 In d.b.h. (in) 

Beech (Young 1980): 

In weight (Ibs) = 1.3303 + 2.2988 In d.b.h. (in) 

Pin cherry (MacLean and Wein 1976): 

log weight (kg) = -0.6657 + 1.7041 log d.b.h. (cm) 

White ash (Montieth 1979): 

weight (kg) = 3.2031 - (0.2337 mm d.b.h.) + 

(0.006061 mm d.b.h.2) 

Striped maple (Whittaker 1974-A. spicafum): 

log weight (g) = 2.3096 + 2.2524 log d.b.h. (cm) 

Balsam fir (MacLean and Wein 1976): 

log weight (kg) = -0.4081 + 1.6217 log d.b.h. (cm) 

Red spruce (MacLean and Wein 1976): 

log weight (kg) = - 0.21 12 + 1.5639 log d.b.h. (cm) 

Red maple (MacLean and Wein 1976): 

log weight (kg) = -0.5881 + 1.6728 log d.b.h. (cm) 

Paper birch (MacLean and Wein 1976): 

log weight (kg) = - 0.501 2 + 1.7284 log d.b.h. (cm) 

Aspen (MacLean and Wein 1976): 

log weight (kg) = -0.7891 + 2.0673 log d.b.h. (cm) 
Martin, C.W.; Hornbeck, J.W. 1989. Revegetation after strip cutting and 

block clearcutting in northern hardwoods: a 10-year history. Res. 

Pap. NE-625. Broomall, PA: US. Department of Agriculture, Forest 

Service, Northeastern Forest Experiment Station. 17 p. 

Changes in the density and biomass of trees, shrubs, and herbs were 

measured periodically over 10 years following a progressive strip cutting 

and block clearcutting of northern hardwoods. At 10 years after clearcutting, 

yellow birch was the most numerous commercial or uncommercial tree on 

the block clearcut; sugar maple on the strip cut. Pin cherry dominated the 

biomass on the block clearcut and the first set of strips throughout the 10 

years; yellow birch and sugar maple on the second and third sets of strips 

at 10 years. 

Keywords: biomass; Hubbard Brook; pin cherry; regeneration; stocking; 

sugar maple; yellow birch. 
Headquarters of the Northeastern Forest Experiment Station is in Broomall, 

Pennsylvania. Field laboratories are maintained at: 

Amherst, Massachusetts, in cooperation with the University of Massachusetts 

Berea, Kentucky, in cooperation with Berea College 

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 

Orono, Maine, in cooperation with the University of Maine 

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 

University Park, Pennsylvania, in cooperation with The Pennsylvania State University 

Warren, Pennsylvania 

Persons of any race, color, national origin, sex, age, religion, or with any handicapping condition are welcome to use and enjoy all facilities, programs, and services of 

the USDA. Discrimination in any form is strictly against agency policy, and should be 

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