LIFE HISTORY OF SHORTLEAF PINE. 
31 
Table 11. — Relation of tree density and diameter growth in 30-year-old pure stands of 
shortleaf of varying densities, Arkansas National Forest. 1 
Prevailing diameter class 
(inches). 2 
Tree den- 
sity (trees 
per acre). 
Decrease 
(trees per 
acre). 
Prevailing diameter class 
(inches). 2 
Tree den- 
sity (trees 
per acre). 
Decrease 
(trees per 
acre). 
4 
800 
720 
640 
560 
8 
475 
390 
300 
210 
85 
5 
80 
80 
80 
9 
85 
6 
10 
90 
7 
11 
90 
i Based on seven plots in the same stand of varying density, hut having uniform soil conditions. 
2 The diameter class having the largest number of trees in the individual stand. 
VOLUME GROWTH. 
The merchantable contents of a tree obviously depends upon total 
height and diameter taken at successive points along the stem. The 
rise in percentage of the rate of increase in the volume of shortleaf 
pine in common with most trees culminates at a comparatively early 
age, considerably prior to the year of maximum production of w r ood 
for the individual tree. Furthermore, the highest annual production 
of wood is reached somewhat earlier than the production of saw 
timber. In stands of relatively equal density those on the poorer 
sites and near the margin of natural distribution reach the maximum 
rate of volume production at a later age than similar stands on 
more favorable sites and more centrally situated within the region of 
distribution. For example, the individual trees in stands in Missouri, 
West Virginia, and New Jersey apparently show the greatest annual 
wood increment at about 70 years, but in North Carolina the culmi- 
nation is reached at about 50 years, and in Arkansas at about 35 
to 4CF years. 1 The contents in board feet and cubic feet of trees of 
different ages, up to 80 years, for two qualities of site, are shown in 
Table 12. 
Table 12. — Volume of shortleaf pine in North Carolina, based on age for two site classes. 
[Based on diameter growth of 332 trees, and volume table. Stump height, 1 foot for trees 6 to 16 inches; 
1.5 feet for trees 17 inches and over.] 
Saw timber. 
Age (years). 
Scribner rule. 
Doyle rule. 
Solid contents. z 
Quality 
Quality 
II. 
Quality 
Quality 
II. 
Quality 
Quality 
II. 
15 
Boardfeet. 
51 
100 
147 
186 
221 
251 
275 
296 
315 
331 
345 
357 
369 
381 
Boardfeet. 
Boardfeet. 
17 
50 
87 
125 
160 
191 
216 
237 
255 
271 
284 
295 
306 
316 
Boardfeet. 
Cubic feet. 
13.5 
24 
34 
43 
50 
56 
61 
65 
69 
72 
75 
78 
80 
82 
Cubic feet. 
20 
6 
23 
38 
51 
63 
75 
86 
96 
105 
113 
121 
129 
135 
3 
7 
11 
17 
24 
32 
39 
46 
53 
60 
66 
73 
79 
"*2." 6 
6.7 
10.3 
13.8 
16.7 
19.3 
22.0 
24.0 
26.0 
28.0 
29.0 
31.0 
32.0 
25 
30 
35 :... 
40 
45 
50 
55... 
60 
65 
70 
80 
1 For volume tables of shortleaf pine based upon height and logs per tree, seo a forthcoming bulletin on 
the Importance and management of shortleaf pine. 
2 Total volume of stem, including bark, between stump and top diameter, outside bark, of 5.5 inches. 
