THE RED SPRUCE. 
33 
Table 8. — Diameter and age of spruce in Maine.' 
[(a) Averaged according to age.] 
Class. 
Number 
Per cent 
of total 
of trees. numbeI 
Average 
age. 
Average 
butt di- 
ameter. 
Average 
length. 
Average 
top di- 
ameter. 
lender 125 years 
125-150 years 
150-175 years 
175-200 years 
200-225 years 
225-250 years 
250-275 years 
275-300 years 
Over 300 
Average of all 2 
52 
120 
210 
218 
210 
125 
72 
29 
14 
11.4 
20.0 
20.8 
20.0 
11.9 
6.9 
2.8 
1.3 
114.5 
138.7 
162.6 
182.6 
210.8 
235.5 
260.3 
285.6 
311.6 
Inches. 
11.5 
12.1 
12.9 
13.5 
15.0 
15.9 
16.0 
17.5 
18.5 
Feet. 
26.4 
28.5 
29.9 
30.3 
31.3 
32.2 
32.9 
34.4 
37.1 
Inches. 
8.0 
8.5 
9.9 
10.0 
10.3 
11.5 
12.0 
1,050 
192.0 
30.6 
[(b) Averaged according to butt diameter.] 
Class. 
Number 
of trees. 
Per cent 
of total 
number. 
Average 
age. 
42 
97 
123 
158 
162 
117 
94 
76 
62 
43 
19 
57 
4.0 
9.2 
11.7 
15.1 
15.3 
11.2 
9.0 
7.3 
5.9 
4.1 
1.8 
5.4 
162.0 
170.1 
171.7 
12-13 inches - - 
174.0 
3 189. 1 
3 185. 4 
197.7 
214.0 
217.1 
228.7 
19-20 inches 
230.1 
244.8 
1,050 
1 
i From a special report " On the Growth of Spruce, by Austin Cary, in the Second Annual Report of the 
Forest Commissioner of the State of Maine, 1894. In explanation of the foregoing table Mr. Cary says: 
"In all, 1,050 spruce logs were examined for this purpose, taken on drives and mill yards. The length and 
end diameters of each log were measured, and the rings of the butt counted to ascertain the age. About 
two-thirds of the logs were grown in the western part of the State on the drainage of the Androscoggin. The 
remainder were partly from the Kennebec ? partly from the Aroostock branches of the Penobscot. A small 
proportion of the logs measured were cut lor pulp, which renders the selection all the more representative. 
The tables which embody the results of the work need, it would seem, very little explanation. The trees 
were first divided into age classes, and the dimensions of the logs in each class averaged. Then the same 
logs were divided according to butt diameters and the average age ascertained for trees of each size. The 
most usable result of the work is the grand average of these facts for the whole 1,050 logs. The average 
dimensions of the logs represent a tree containing about 23 cubic feet, or say 120 board feet, and this was 
grown on the average in 192 years. Adding to the log 2 cubic feet for stump and 7 more for the top, adding 
also to the age 20 more years for the height growth of the stump, then dividing contents by age gives the 
figures fifteen-hundredths cubic feet. That is to say, a spruce tree on the average and throughout its life 
until cut, maintains a growth of 1 cubic foot in six and two-thirds years. In adult life the growth per tree 
would be considerably greater. In young seedlings it would for many years be less. The percentage of 
growth to stand can not be immediately derived from these figures." 
[In connection with the information just quoted, it seems evident that the words "log" and "tree" are 
used synonymously in referring to the "used length." — Author.] 
2 A log of these average dimensions contains 23 cubic feet, or about 120 board feet. 
3 A 13Hnch tree, of course, is not as a rule older than a 14jV-inch tree. The irregularity shown in the series 
would doubtless be corrected if the larger number of trees was taken, 
Average of 50 pine logs: Age, 102.8; butt diameter, 16.1; length, 30.3; top diameter, 11. A log of these 
dimensions contains 30 cubic feet, or about 175 board feet. 
It is in most cases of little practical value to the lumberman to 
know the direct relation between the actual age and the diameter of 
trees in a selection forest. A knowledge of the length of time required 
for a tree to grow from 1 inch diameter class to the next is, however, 
important. Tables 9, 10, and 11 show this as well as the corre- 
sponding rate of growth per annum of each diameter class. 1 
1 Besides showing these values based on an average of all trees measured, the West Virginia and Adiron- 
dack tables show absolute maximum and average maximum values as well. These are obtained by using 
only values representing maximum and average minimum growth conditions, eliminating all periods which 
show the effect of suppression. 
84949°— Bull. 544—17 3 
