FOREST MANAGEMENT OF LOBLOLLY PINE. 
Table 3.-— Average thickness of bark at 4.5 feet from the ground for trees of different diam- 
eters and heights, from 20 to 50 years in age, Somerset and Worcester Counties, Md. 
[Table based on taper curves.] 
Diam- 
eter 
breast- 
high. 
Height of tree (feet). 
Diam- 
eter 
breast- 
high. 
Height of tree (feet). 
30 
40 
50 
60 
70 
80 
30 
40 j 50 
60 
70 
80 
Double width of bark at breastheight. 
Double width of bark at breastheight. 
Inches. 
3 
4 
5 
6 
7 
8 
9 
10 
11 
Ins. 
0.5 
.7 
.9 
1.0 
1.1 
1.3 
Ins. 
0.7 
.8 
.9 
1.0 
1.2 
1.3 
1.5 
1.6 
Ins. 
Ins. 
Ins. 
Ins. 
Inches. 
12 
13 
14 
15 
16 
17 
18 
Ins. 
Ins. 
Ins. 
1.7 
1.8 
Ins. 
1.6 
1.7 
1.9 
1.9 
2.1 
Ins. 
1.4 
1.5 
1.6 
1.7 
1.9 
2.0 
2.1 
Ins. 
1.3 
1.4 
1.5 
1.5 
1.6 
1.7 
1.9 
2.0 
2.1 
0.9 
1.0 
1.1 
1.2 
1.3 
1.4 
1.5 
1.6 
1.1 
1.2 
1.3 
1.3 
1.4 
1.5 
1.2 
1.2 
1.3 
1.3 
"1.1 
1.2 

19 
20 
By far -the most common form of fire in loblolly pine is the surface 
fire. Trie damage to any particular stand varies with the severity 
of the fire and the age and size of the trees. In general, the older 
the stand and the larger the trees the less will the damage be. Even 
a light surface fire in a sapling stand under 6 years of age usually 
kills a large part if not all of the trees outright, whue in an older 
stand such a fire would kill few or none of the trees. Fires in sapling 
stands are especially destructive because they are likely to spread to 
the tops. Crown fires in loblolly pine, however, are limited almost 
entirely to the younger sapling stands, because of the rapidity with 
which older trees prune themselves of lateral branches for a con- 
siderable distance above the ground. The most destructive and 
costly form of fire in loblolly pine is a combination of surface and 
ground or subsurface fire, such as occurs at very dry times in bottoms 
and swamps where there is a deep accumulation of partially decom- 
posed vegetable matter. Such fires kill the largest trees as well as the 
smallest. 
The severity of forest fires and the consequent damage varies with 
a number of factors, among them the amount and relative dryness 
of inflammable material, such as leaf litter, debris, and underbrush, 
the velocity of the wind, and the moisture content of the atmosphere. 
Stands on low, wet sites are less subject to damage by fire than those 
on dry situations. 
It is a common practice of some lumber companies in the South 
to burn over the forest every one to three years to prevent the 
accumulation of inflammable material. Large areas of forest land 
in the South are also burned over annually to improve the grazing, 
which also prevents severe fires. This is a cheap and effective 
method of insuring protection to valuable mature standing timber, 
but is extremely harmful to young stands. Forest fires of any kind 
6242°— 14 2 
