NoTE ._For Plates I, II, and III, referred to in the foregoing article, see 

 after p. 20. 



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 pycnantha 

 and A. decurrens) have a peculiar value as affording one of the richest 

 tanning barks known. Many analyses of A. pycnantha, the broad-leafed, 

 or golden, wattle, show a range of from 28.5 to 40.47 per cent tannic 

 acid, and the range in A. decurrens, the black wattle, is from 15.08 to 

 30.3 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 30.3 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. All 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 ^1. pycnantha and A. decurrens much 

 exceed A. dealhata 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 should 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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