﻿18 BULLETIN" 9, U. S." DEPARTMENT OF AGRICULTURE. 



terminals of the former leaf-stalks, and occasionally they may show 

 on the younger growth. 



The tree is less valuable for tannin than for timber; but a tree so 

 large and rapid-growing, the bark of which has a 15 or 20 per cent 

 tannin content, should not be neglected in calculations for tannin 

 production, especially since the development of the manufacture of 

 tannin acid extract. A. melanoxylon properly belongs to moist and 

 not frosty situations, and its roots are surface feeders. When young 

 it is particularly susceptible to drought, and will die on soil the least 

 bit arid ; moreover, it succumbs readily to desiccating winds, such as 

 the drying northers of California. Von Mueller reports it as being 

 hardy (with some forms of A. decurrens) on the Isle of Arran, Scotland. 

 This does not, however, prove the hardiness of the tree so much as 

 it does the variation of local climatic conditions, since A. melanoxylon 

 has been injured by frost (7° F.) at Chico, Cal. It is useless to plant 

 it in arid uplands, but its resistance to trying city conditions and its 

 power of utilizing sewage make it of value as a street tree. 



Tanbark Acacias Abroad, 

 australia and new zealand. 



In Australia acacias have been utilized for tanbark for a long time, 

 the natural supplies being drawn upon exhaustively and the artificial 

 culture of acacias consequently neglected, since there was an abun- 

 dance of tan-yielding species, on hand. 



Some 35 years ago, however, Baron von Mueller called attention to 

 the rapid depletion of the natural supply, and from that time a volu- 

 minous and important official literature upon acacias and acacia cul- 

 ture grew up. Since 1875 these reports have aroused general as well 

 as local interest in the planting of the species for tanbark. 



The three earliest and most careful estimates of planting costs, 

 based upon actual experiments in 1878, 1884, and 1889, give, respec- 

 tively, the following figures : 



(1) Acacia decurrens, 100-acre basis, rented at $1.50 an acre a year, 

 400 trees planted per acre: 



Aggregate sales of bark, first 8 years, 1,215 tons $23, 290 



Aggregate expenses, including interest 7, 270 



Profit , - 16,020 



(2) Acacia pycnantlia, 100-acre basis, bought at $15 per acre; 1,200 

 trees to the acre: 



Aggregate sales of bark, first 7 years, 500 tons $12, 000 



Aggregate expenditure, first 7 years, including interest 8, 700 



Profit - 3,300 



