CHESTNUT BLIGHT 15 
mately the same tannin content as the heartwood (7 to 12 per cent), 
is not always a serious matter to’ the extract manufacturer, because 
peeled wood is necessary in some of the processes for utilization of 
the chips left after the extraction of tannin. Table 3 gives a brief 
guide for the utilization of chestnut. 
TaBLe 3.—Condition and utilization of products from dead chestnut trees 
Naitber Effect upon products (caused by death of tree) 
of years Aeyereee sonata 
after of trees 
Cordwood or Poles and posts 
tree died Bete Wood Poles (treated) (untreated) Lumber 
1.__...-.| Bark loosening | Slight volume re- | Nearly as good | Nearly as good | Nearly as good 
- and sapwood de- ductions from as green tim- as green tim- as green tim- 
caying onupper | loss of bark in ber. ber except for | ber. 
parts first in- upper parts. greater break- 
fected. age in felling. 
2to3....| Bark loose and | Loss of sapwood | Usually accept- |_____ DO. einai! Do. 
sapwood decay- and bark practi- able if sap- 
ing on most of cally completed. wood remains 
tree. Volume loss 20 sound on the 
per cent on large butt. 
trees and some- 
what more on 
those under 10 
inches. 
ee Bark and sapwood |-___-_ G0 ns2eeceseee Not suitable _ .__|_-.-- Oss ee sues Do. 
all loose. 
Leen Bark off most of |____. (2 Li neem erro [peeetea (3: eeenmepepements Value ieduced, | Loss in value 
upper parts; mainly on ac- and volume 
checking begin- countofcheck-; from checking; 
ning on exposed ing. gradual - in- 
areas. creases in cull 
from decay. 
6 to 10__.| Bark off; check- | Practically no fur- |----- 0s seeseeens|-ees4 O's cazececes! Do. 
ing practically ther volume loss, 
complete. 
BLIGHT-RESISTANT CHESTNUTS 
Since direct control of chestnut blight is impracticable, the dis- 
covery of suitable strains of chestnut resistant to the disease is highly 
desirable. Individual native chestnuts differ in susceptibility to at- 
tack, but search for many years has shown that the number of trees 
actually surviving in regions where blight has been present the long- 
est is very small. Some of these trees are being propagated and 
studied further with the hope of developing a strain of American 
chestnut sufficiently resistant to reach maturity in the presence of 
the disease. The numerous living trees occurring on tracts recently 
killed by blight are generally disease escaping rather than disease 
resistant. For this reason search for resistant specimens is profit- 
able only in areas where all but very exceptionable chestnut trees 
have been dead from the disease for a number of years. Reports of 
unusually resistant trees—those that have not been severely injured 
by the blight—are desired. The Office of Forest Pathology records 
all such trees reported and inspects them as field work permits. . 
For a number of years after the chestnut trees in different locali- 
ties were killed by the blight, the sprouts rarely reached a diameter 
of more than a few inches before they in turn were killed. Some 
sprouts now become much larger and frequently produce viable nuts 
before being killed by the blight. Other sprouts continue to grow 
and produce nuts in spite of the blight cankers on their stems. Just 
what will be the ultimate result of this struggle between host and 
