NORTHEASTERN FOREST EXPERIMENT STATION 

Upper Darby , Pennsylvania 

F 

No. 25 

November 1953 

Growth Behavior Of White Pine In An 

Uncut Stand In Southwestern Maine 

Measurements of growth in a white pine stand in the 

Massabesic Experimental Forest over a 15-year period show 

that some trees contribute more than three times as much 

volume as other trees of the same size and species. 

Fourteen *-acre plots were measured in 193'7 and again 

in 1952. These plots were in a rather open, mixed stand of 

white pine, hemlock, and scattered hardwoods. In 1952 the 

trees were 60 to 70 years old. An average of less than two 

trees per acre, usually smaller than 8 inches in diameter, 

died in the 15-year interval. 

During the 15-year period, the volume per acre on the 

14 plots increased from 7,750 board feet to 14,675 board 

feet (table 1). In terms of compound interest, this is an 

increase of 4.3 percent per year. (~hree-fourths of the 

volume is in white pine, one-fifth in hemlock, and the rest 

in hardwoods . ) 

Since trees grow at different rates, even when they 

are the same age, some trees contribute more of the growth 

per acre than others. To show these variations, the trees 

in each species and diameter group were divided into three 

classes (as of 1937). Class 1 is the slowest growing, Class 

3 the fastest. 

The percentage increase in volume is faster for 

smaller trees, while ;boar\d-foot increase is faster for 

larger trees: Therefore, growth was expressed both in board 

feet and as a percentage (tables 2 and 3). 

The average annual growth has been 462 board feet per 

acre during the 15-year period. White pine, with the greatest number of trees per acre, accounted for 360 board feet. 

More than half of the white pine growth (51 percent) was put 

on by the fastest-growing one-third of the trees (table 4). 

The number of years a tree needs to grow one inch in 
398 43 

331 414 

- No. Cu.ft. Cu.ft. - No. Cu.ft. Cu.ft. - No. Cu.ft. Cu.ft. 

5-8 43 239 386 21 80 l40 43 137 204 

9-12 35 548 894 11 134 208 7 104 124 

13-16 15 483 751 4 85 122 -- -- -- 

17+ 2 124 175 2 76 98 -- -- -- 

Total 95 1,394 2,206 38 375 568 50 2W 328 

Table 2.--Average .erowth per tree per year, in board feet 

I 

Diameter White pine, by Hemlock, by Hardwoods, by 

group growth class-- growth class-- growth class-- 

in 1937 

(inches ) 1 2 3 1 2 3 1 2 3 

1?+ 8.56 10.52 12.35 2.64 5.36 7.33 -- -- -- 

Average 3.55 6.60 10.49 2.38 5.15 7.93 0.06 0.29 0.68 

Table 3.--Average grovAh per tree, 1937 t3 1952, in percentage 

P * 

Table 1.--Growth behavior of white pine stand, 1937-52 

l~ed maple, red oak, black oak, and white oak. 

2~oard-foot volume in International &-inch rule. Cubic-foot volume from local volume table. 

r 

Diameter 

group 

in 1937 

(inches) 

F'hite pine, by 

growth class-- 

Hemlock, by 

groxth class-- 

1 2 3 1 2 3 

Hardwoods, by 

growth class-- 

1 2 3 
Table ,!+.--Distribution of annual board-foot increment 

per acre 

I I Growth class-- ( I 

I White pine 62 115 183 360 1 

Species 

I Hemlock 13 29 45 

87 1 

Hardwoods 1 4 10 15 

Total 76 148 238 462 

Table 5.-Number of years to grow 1 inch in diameter 

Total 

12 3 

diameter is a good guide to its thrift and condition (table 

5). Pineandhemlock, instands suchastheonesampled, 

should grow 1 inch in diameter in less than 7 years. More 

than half the trees grew slower than this; they yielded less 

than 3 percent increment. . 

Diameter 

POUP 

in 1937 

(inches) 

There is a marked difference in growth rate between 

trees of the same species as well as between different species. Even unmanaged, well-stocked, thrifty stands can be 

expected to grow more than 450 board feet per acre yearly 

when the trees are about 60 years old. In this particular 

stand, 20 percent of the trees (faster-growing white pines) 

produced 48 percent (225 board feet) of the annual per-acre 

growth. 

4 

White pine, by 

growth class-- 

12 3 

Hemlock, by 

growth class-- 

12 3