8 FARMERS’ BULLETIN 2068 
years, about 90 percent of the bark 
has fallen off. Decay of sapwood 
accompanies the loosening of the 
bark, and as the sapwood sloughs off 
the heartwood begins to crack, or 
check. The heartwood of the Amer- 
ican chestnut is so durable that 
Ficure 7.—Blight canker encircling a 
smooth-barked chestnut limb. The in- 
fection started on the opposite side and 
the canker advanced around the limb 
in both directions. 
blight-killed trees have frequently 
remained standing for 20 years or 
more. 
Utilization of blight-killed chest- 
nut was studied by the United 
States Forest Service and by for- 
estry departments of States within 
the blight area. It was found that 
after the first few years the dead 
chestnut timber deteriorated at a 
rate averaging about 4 percent per 
year. Tests made by the United 
States Forest Products Laboratory 
showed, however, that the heart- 
wood of chestnut trees dead for 1 to 
8 years was almost as sound as that 
of healthy trees. Loss of bark and 
sapwood and the presence of checks 
and wormholes in the heartwood do 
not prevent utilization of chestnut 
that has been dead for as long as 20 
or 30 years. 
Even today some companies offer 
chestnut lumber for sale, and ex- 
tract plants continue to use long- 
dead chestnut wood as a source of 
tannin. In fact, this wood is still 
the source of most of our domestic 
production of vegetable tannin, a 
material needed in tanning leather. 
By 1961, however, practically all the 
operable chestnut will be gone from 
Georgia, Kentucky, and Tennessee 
and the volume remaining in North 
Carolina, Virginia, and West Vir- 
ginia will be extremely scattered 
and inaccessible. 
SEARCH FOR BLIGHT-RESISTANT AMERICAN CHESTNUTS 
In 1918, when it became apparent 
that direct control of chestnut 
blight in the Eastern States was 
impracticable, a search began for 
American chestnut trees and sprouts 
resistant to the blight. Individual 
native chestnuts have been found to 
differ little in susceptibility to the 
blight. Very few large chestnut 
trees still survive in regions where 
blight has been present for a long 
time. Seedlings from these trees 
have been tested but have proved to 
be susceptible to the blight. 
The American chestnut produces 
many sprouts from the roots, es- 
pecially after blight killing. Its 
roots are more blight resistant than 
the parts above ground. Therefore, 
chestnut sprouts are now found 
throughout the natural range of the 
American chestnut. Both sprouts 
