WATTLE TREE. 
By CHARLES A. KEFFER, 
Assistant Chief of Division of Forestry. 
Among the economic trees introduced in the Southern States by the 
Department of Agriculture the Australian wattles (Acacia pyenantha 
and A. decurrens) have a peculiar value as affording one of the richest 
tanning barks known. Many analyses of A. pyenantha, the broad-leafed, 
or golden, wattle, show a range of from 28.5 to 46.47 per cent tannic 
acid, and the range in A. decurrens, the black wattle, is from 15.08 to 
36.3 per cent. These analyses were made in Australia, and the reports 
of the Australian Government on wattle culture contain quite complete 
records of them. Wattle bark grown in California has been analyzed 
by Professor Woodbridge with the following results for the species 
named: A. pycnantha 31.9 per cent tannic acid; A. decurrens 36.3 per 
cent tannic acid. These results are contrary to the average of the 
Australian analyses, which indicate a higher percentage of tannic 
acid in A. pycnantha than in A. decurrens. The average oak bark con- 
tains 12 per cent of tannic acid and the hemlock 13 per cent. 
It will thus be seen that the wattle barks are very rich in tannin, 
and their successful cultivation in this country becomes a matter of 
increasing economic interest aS our own supply of tanning bark 
decreases. 
The acacias belong to the natural order Leguminosae, represented in 
our country by the black locust, the honey locust, the Kentucky coffee 
tree, and the redbud. Ail of the species (312 are natives of Australia) 
contain more or less tannin, but only three are sufficiently rich to be 
worthy of cultivation, and of these A. pycnantha and A. decurrens much 
exceed A. dealbata in the percentage of tannic acid contained. 
The acacias do best on a sandy soil with clay subsoil. On limestone 
formations the bark of trees is greatly inferior in tannin to those grown 
on any other formation, though wattles grow exceedingly well in lime- 
stone soil in South Australia and in California. The seed are hard 
and very small, there being 30,000 to 40,000 to the pound. If planted 
dry, they lie dormant several years, there being well-authenticated 
instances of seed germinating after being over thirty years in the soil. 
To hasten germination boiling water shouid be poured over them and 
left until the seed are soft. Thus prepared they will germinate in 
about three weeks. The soaked seed may be mixed with dry sand, to 
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