AN ECONOMIC STUDY OF ACACIAS. 27 
ground, 2 feet 8 inches. At Niles, a tree 46 years old, on side valley 
soil, 76 feet above San Francisco Bay, top broken off at height of 
65 io though the tree had been about 80 feet high, diameter 2 feet 
6 inches Near Alvarado, a tree 45 years old, on pen soil, 85 feet 
high, diameter, breast fake 3 feet 9 inches. 
All portions of the Sacramento and San Joaquin Valleys appear 
well adapted to the growth of Acacia melanoxylon. At the Chico 
forestry station and elsewhere it showed no injury, except to the 
_ young tips of the top. branches, during the low temperature of the 
coldest seasons between 1890 and 1913 (16°, 14°, and 12°). Large 
eucalypts were killed to the ground by these frosts. 
The bark of this species yields about 11 per cent of tannic acid, 
which could be utilized profitably when the timber is cut by con- 
centrating it in the form of an extract. ‘The inner bark, as with 
some other acacias, yields a valuable bast or fiber material. 
Acacia decurrens group.—There is little difference in the woods of 
the three leading varieties of the Acacia decurrens group (normalis, 
mollis, and dealbata), but the last two grow more rapidly and attain 
the larger,size. Dealbata trees have been measured and found to be 
°100 feet high and 4 feet in stem diameter. This variety has been 
naturalized in southern India since 1840 and extended over a large 
area. The timber of all three varieties is moderately hard, light 
brown in color, easily worked, and strong; it is used by coopers and 
house builders; it is valuable for posts, for rustic work, for mine 
props under ground, and for fuel. Its weight is about 47 pounds to 
the cubic foot. 
Acacia decurrens normalis and mollis are more generally planted 
than dealbata. Von Mueller gives the weight of their timber at from 
45 to 48 pounds per cubic foot. Maiden reports that three slabs of 
normalis at the Technological Museum, seasoned for more than 
25 years, weighed, respectively, 52, 53, and peanly 63 pounds per cubic 
foot. 
Other tumber species——Many other species of acacia yield valuable 
timber. Of those listed, all have been grown in California. 
Acacia acuminata.—Stem diameter, 12 inches. Wood strong and 
very hard, red-brown in color, and durable. Has a raspberry-like 
scent. 
Acacia aneura.—Stem diameter, 10 to 12 inches. Exceedingly 
hard and strong wood of a dark-brown color. . 
Acacia arabica.—Stem diameter of 2 feet. Wood used for boats, 
water wheels, and many implements, on account of its strength and 
durability. The tanbark is a by-product of this species. (See pl. IT.) 
Acacia armata.—Shrub or small tree. Wood beautifully grained 
and durable. 
& 
