16 BULLETIN 9, U. S. DEPARTMENT OF AGRICULTURE, 
ACACIAS FOR TANBARK. 
At the present time the chief commercial value of acacias seems to 
be for tanbark, although even with the tanbark species there are 
important by-products. The tanbark industry is bound to increase 
in importance; tanners are searching farther and farther for the 
materials they need, especially since, for the treatment of heavy, 
high-grade leathers, no real substitutes for the best vegetable tans 
have yet been discovered. 
IMPORTANT TANBARK SPECIES. 
All of the leading tanbark acacias are from Australia and are gen- 
erally known as wattles. This term is of local origin. THarly settlers 
in the Australian bush made huts by weaving or wattling green 
branches together, and since acacias were most often used the name 
wattle has since been applied to the strong-growing species. In his 
time Von Mueller designated only five acacias as wattles, though he 
names many others as yielding tanbark. Dr. Maiden applies the 
term to more than 30 species whose bark he has tested. It is evident, 
however, that while many will yield bark worth using, when the tree is 
cut for timber (this is true of all the more valuable timber species) only 
A. pycnantha and the best varieties of A. decurrens justify planting for 
tanbark alone. Acacia decurrens mollis and decurrens normalis are 
the largest and best of the decurrens forms, and are stronger growing 
trees than A. pycnantha, but the latter yields the richer bark. These 
trees, then, are all that are worth serious attention for tannic acid. 
Acacia melanoxylon, decurrens, dealbata, longifolia, and others whose 
timber is of first importance yield tanbark only as a by-product. 
The two decurrens varieties (Acacia decurrens mollis and A. decur- 
rens normalis) may be taken as the typical tanbark acacias. Von 
Mueller’s statement in 1882 of the value of.their bark can scarcely 
be improved upon: 
It varies in its content of tannin from 30 to 40 per cent in bark artificially dried. 
One and one-half pounds of the bark give 1 pound of the leather, while 5 pounds of 
English oak bark are requisite for the same result. Melbourne tanners consider a ton 
of black wattle bark sufficient to tan 25 or 30 hides; it is best adapted for sole leather 
and so-called ‘“‘heavy” goods. 
AcaAciIA PYCNANTHA. 
Acacia pycnantha is now strongly recommended by all who have 
studied tanbark production from this genus. The Kew Bulletin of 
1893 especially urges the planting of A. pycnantha. Naudin says that 
the bark of this species has been known to contain 46 per cent of 
tannic acid, and that ordinarily it yields from 85 to 40 per cent. 
According to Von Mueller it is ‘“‘second perhaps only to Acacia 
