ioo FOREST UTILIZATION 



III. Remarks. 



(a) i The minimum diameter of trees and branches 



peeled depends on the price of bark and the 

 price of stumpage. At the present time, far 

 from the tannery, it does not pay to peel pieces 

 of less than 10 inches diameter. 



(b) The expense of the harvest of oak bark is per 



cord : 



Roads, 450; felling, 27c; peeling, 570^ piling, 



72C. 



On the average a man will peel per hour from 

 0.3 to 0.38 cord. 



(c) Tannin percentages of dressed bark are, after 



Sargent : 



Mangrove 30 % Burr and red oak... 4.6% 



Sumac 18 % Chestnut 6.7% 



Sassafras root 58 % Douglas fir 13.8% 



German oak 14 % Eastern hemlock 13.1% 



Cal. Chest, oak 16.5% Western hemlock 15.1% 



Live oak 10.5% Eastern spruce 7.2% 



Chestnut ,oak 6.2% Ge-rman spruce 8 % 



Spanish oak 8.6% German fir 6 % 



Black oak .-5-9% Larch 7 % 



White oak 6 % Birch 4 % 



C. Wood extracts in particular. 



I. Tannin extracts are manufactured from bark, chestnut 

 wood, quebracho, mangrove and oak. Quebracho wood 

 contains 24% of tannin; chestnut wood 14% (?) of tan- 

 nin. 



II. The wood is shredded in a chipper and the tannin ex- 

 tracted (not entirely) by steam or hot water under 

 pressure. The liquid obtained is condensed. 



III. While in France the sappy branches and young shoots 



of chestnut are preferred, in America the heart wood 

 and especially the butt is preferred. 



IV. The wood is cut 4 feet to 5 feet long. The leather trust 



uses- a cord of 160 cubic feet = i l /4 cords of 128 cubic 

 feet. 

 V. Clear water, cheap transportation and cheap fuel are 



required for successful manufacture. 

 Only sound wood is used ; wormholes in chestnut, 



however, do not interfere with its value. 



VI. Extracts exposed to air or exposed to heat spoil rap- 

 idly. 

 VII. Extracts are shipped in barrels of 56 gallons capacity 



or in tank cars. 

 VIII. The price of chestnut extract is ij^c to 2c per pound. At 



