﻿24 BULLETIN" 9, TJ. S. DEPARTMENT OF AGRICULTURE. 



expect to rent land in America at the Australian price of 4 cents an 

 acre a year, there is nevertheless cheap and suitable land in Cali- 

 fornia and the Southwest. 



TANNIN CONTENT OF CALIFORNIA BARKS. 



The first acacia barks analyzed by the University of California 

 were those of Acacia decurrens mollis, A. decurrens dealbata, and A. 

 pycnantha. In the report upon these barks 1 it was shown that the 

 California-grown bark of mollis was twice as thick as that of dealbata 

 of the same age and that it yielded about twice as high a percentage 

 of tannin. This agrees very nearly with comparisons' made upon 

 barks grown in Australia and in Algeria. The actual tannin contents 

 of these three barks grown at Berkeley were as follows: 



Per cent. 



Acacia decurrens mollis „ . . 48. 6 



Acacia decurrens dealbata 24. 8 



Acacia pycnantha 46. 8 



Dr. Hilgard states that these tannin determinations were made 

 by the permanganate method, repeatedly checked by the gelatin or 

 hide-strapped method, with but trifling differences in the results, so 

 that the figures fairly represent what hides will take up. 



One of the trees, 13 years old when cut for these experiments, was 

 12 inches in diameter at 3 feet above the ground, and 40 feet high. 



It will be observed of these analyses that California-grown A. pyc- 

 nantha bark, contrary to Australian experience, did not exceed mollis 

 in richness of tannin content. Later analyses seem to confirm this 

 general fact : That A . decurrens normalis and mollis are proportionately 

 richer in tannin when grown in California than when grown in 

 Australia. As yet, however, the quantity of bark which has been 

 produced is not sufficient to settle this interesting and important 

 point, though everything points to the desirability of both of these 

 forms of Acacia decurrens for planting in California, particularly in 

 the Coast Range, where the bark so far tested has been grown. 



Another report 2 gives some interesting statistics about the planta- 

 tion at Santa Monica, which has been under charge of the University 

 of California since 1894. This report states that Acacia decurrens 

 and A. pycnantha, 25 months from seed (20 months planted in the 

 field), have grown twice as rapidly as the same species mentioned in 

 Australian reports. Many trees of this age had attained a height of 

 16 feet and the very poorest were 2 inches in diameter and 9 feet 

 high. Mr. Lyon estimated that at 4 years of age such a plantation 

 would yield a crop of bark equal to that of 7 or 8 year old Australian 

 groves; that is, from 80 to 90 pounds of bark to a tree. 



''Report of Dr. Hilgard, Jan. 23, 1884. 



2 Third Annual Report of the First Board of Forestry of California; Chapter on Acacias, by W. G. 

 Lyon, State Forester, 1890. 



