WHY TO PLANT. 15 



tigation also that from one fourth to one third 

 of the earth's surface needs to be appropriated 

 to tree or plant life, in order to maintain the 

 best conditions of human existence. Such an 

 amount of wooded surface, while it would pre- 

 serve the atmosphere in the best state for man's 

 use as a living creature, would also secure to 

 him the amplest returns from the cultivation of 

 the soil, and the largest rewards of his varied 

 industries. In proportion as this balance of 

 natural forces is preserved, agriculture, com- 

 merce, and manufactures all flourish best. A 

 due measure of forest not only^maintains the at- 

 mosphere in the best condition to be breathed 

 by manj but by its continual growth, if that 

 growth is wisely husbanded and protected, is 

 able to supply him perpetually with fuel and 

 the material upon which the larger part of the 

 arts and industries of life depend. 



But throughout his history man has been 

 found a disturber rather than a maintainer of 

 the beneficial arrangements of Nature in his be- 

 half. In almost all parts of the world which he 

 has inhabited, man has swept away the trees 

 to such an extent as to destroy the balance of 



