﻿AN ECONOMIC STUDY' OF ACACIAS. 37 



need only to be watered every evening and to be thinned so that the 

 plants will stand an inch or so apart. 



SPROUTING AND LAYERING. 



All the tanbark wattles sprout readily from the stump, and this 

 method of crop reproduction is especially valuable when acacias are 

 grown for firewood. The sand-reclaiming acacias will root even from 

 the recumbent stems. This helps them to spread over the ground. 

 This natural layering process can be aided by slashing the lower 

 branches, bending them down, and covering the gash with earth. 

 A. saligna and A. longifolia thus treated spread almost as well as 

 willows. 



GENERAL CONCLUSIONS. 



The most important fact derived from an economic study of 

 acacias in California is that after some fifty years many species of 

 acacia have proven themselves to be entirely at home over large 

 areas, and have in fact become naturalized. They are worth the 

 careful investigation of tree planters and foresters, for they fill a 

 place which is not occupied by any other group of exotic trees. 

 Since many of them make only slight requirements on moisture and 

 soil, their cultivation need not interfere with that of other exotic 

 trees for special products, such as the Japanese chestnut, cork oak, 

 camphor tree, date palm, eucalypts, algaroba or carob, and maritime 

 pine. 



The unique field occupied by acacia tanbark and by some other 

 products, especially the gums, and the usefulness of the best acacia 

 woods would seem to -justify the general conclusion that plantations 

 properly located and managed are as likely to prosper in America as 

 in other countries. But before extensive commercial operations are 

 decided upon there is need for more complete and painstaking work 

 upon the acacias — their growth and their products — the study to 

 be based upon American-grown trees. As yet the rates of growth 

 and the yields of various species on different soils, especially under 

 plantation conditions, are not definitely determined. Unless such 

 preliminary scientific investigation is undertaken and its evidence 

 accepted, it is likely that industries based upon acacias may be 

 exploited too hastily, and, therefore, present failures will give set- 

 backs such as have resulted where the culture of any particular tree 

 has become a fad. These failures are likely to do much to deter 

 properly qualified persons from entering upon an industry which 

 should ultimately become established on solid foundations. 



So far, acacias have been planted in the United States simply as 

 ornamentals, and the information secured from a study of these 

 specimens has been chiefly cultural. They have proved that the 



