370 GENERAL BOTANY 



which is apt to be beaten into a hard surface layer or, if soft and 

 porous, to become quickly saturated and give way. The result 

 is almost certain to be a disastrous flood and often immense 

 damage caused by greatly swollen streams. In the Adirondacks 

 and in California great damage has already been done in this 

 way where the forests have been wholly or partially cut off or 

 injured by grazing. It is estimated that " upward of two hundred 

 square miles in the United States is annually laid waste by 

 erosion " and that much of this great waste could be prevented 

 by protecting or replanting the forests in the eroded regions. 

 When swollen mountain streams reach the valleys at the foot 

 of the mountains, they flood them and at the same time deposit 

 sand, gravel, and even large bowlders on once fertile and pro- 

 ductive soil. Not only must the cutting of forests on mountain 

 slopes be carefully regulated, therefore, but denuded areas need 

 to be systematically reforested by governments, either state or 

 national, which possess resources adequate for such great tasks. 



Forest products. A great variety of forest products are derived 

 from the national forests, including turpentine, tar, formalde- 

 hyde, and rosin, in addition to the more important wood pulp, 

 timber, and lumber supplies. The lumber and timber are used 

 for various purposes in the industries and the home. These 

 uses include firewood, lumber for construction and building, 

 cooperage, and veneers, and timber for the making of excelsior 

 and wood pulp, railroad ties, and telephone and telegraph 

 poles. For these various purposes it is estimated that " we take 

 from our forests yearly, including waste in logging and manu- 

 facture, more than 22,000,000,000 cubic feet of wood, valued 

 at $1,375,000,000." It is also estimated that almost half of the 

 original lumber supply of the United States has already been 

 used and that "the present rate of cutting for all purposes 

 exceeds the annual growth of the forests." 



The remedy. The obvious remedy for this condition is the 

 scientific control of timber cutting and the replanting of the 

 forests, already in process of depletion, by the state and national 

 governments. It is therefore of the greatest importance that the 

 United States government has adopted the policy of caring for 



