12 FARMERS’ BULLETIN 1641 
based on 78 trees. It is evident that the loss in proportion to original 
volume is heaviest in trees under 8 inches in diameter. No data are 
available for trees above 17 inches, but allowing for a conservative 
increase in bark thickness with diameter, it is estimated that the 
loss will still closely approximate 20 per cent in the 30-inch diameter 
class. 
The percentage of loss in limb wood will be consistently higher 
because of the greater proportion of small diameters. However, as 
the trunk volumes have been calculated to a 4-inch upper limit, the 
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OIAMETER BREAST HIGH (INCHES) 
Ficurp 11.—Reduction in volume of extract wood in trunks resulting from loss of 
bark and sapwood 
amount of wood remaining in the limbs is not great. Table 2 gives 
the amount of limb wood and the percentages of loss in 319 trees at 
one locality in North Carolina. The sapwood averages about one- 
fourth inch in thickness and comprises about one-third to one-fourth 
of the total amount lost. 
TABLE 2.—Limb-wood volumes and percentages of loss through bark falling and 
decay of sapwood 
. : ‘ Average Loss in 
Diameter breast high (inches) Trees volume of | bark and 
' limb wood | sapwood 
Cubic feet Per cent 
1.39 49 
. 3.47 59 
30 to 34 10. o 31 
The heartwood of living chestnut is often attacked by certain 
fungi that cause it to decay. Some of these heart-rotting fungi are 
able to continue to decay the wood in standing dead trees, but how 
fast heart rot progresses in trees infected with rot before death is 
not known. In the case of sound trees there will probably be little 
danger of any material loss in volume from center rot for the first 
10 years after death, and many standing trees have been found to be 
apparently sound 30 years after they have been killed. After 10 
years, however, wind throw must te considered. Trees on the 
