CANADIAN FORESTRY ASSOCIATION. 



103 



creasing home consumption than in North America. Were it possible to limit the 

 annual cut in North America to a volume equivalent to the annual growth, as now 



35,100,000,000 



CONSUMPTION OF TIMBER, 

 (N THE UNITED STATES OF AMERICA 

 IB5O - I90O 



a?,ooo,axy>oo 



PER CAPITA 

 CONSUMPTION 



12,800 



DIAGRAM No. 3. Showing on the right the increase in the total 

 consumption of wood in the United States by decades from 1850 to 1900. 

 On the left per capita consumption is given for the same period. 



obtains quite generally in Europe, there would be such a shortage of supplies that 

 not only would exportation become impossible but prices would advance to previously 

 unheard of figures. The gradual exhaustion of the remaining forests, together with 

 their devastation by fire, will soon force this result, and the most of us will live to see 

 the day when North America will import at great cost a poor substitute for the car- 

 goes of the finest timber in the world which she has been sending to foreign lands at 

 practically the cost of cutting and transportation. 



The conservation of water for useful industrial purposes and for the prevention 

 of calamities by flooding of the streams, is a function of the forest which is second 

 only in importance to that of wood production. The keynote of worth in stream flow, 

 whether for irrigation, power, navigation or domestic use, is sustained flow. Likewise 

 the keynote of safety from floods, erosion or silting is sustained flow, and the forest is 

 the great and almost only regulator of stream flow. 



The rainfall of any country returns to the air and the ocean in four ways: by 

 evaporation and transpiration, called the ' fly-off/ and by surface run-off and seepage 

 .run-off, which together form the stream flow. 



The evaporation and transpiration of moisture on forested areas is well known 

 to be much less in temperate climates than from non-forested areas. The less that 

 is returned to the air, the greater the amount left for the stream flow. The greatest 

 value of the forest, however, is in decreasing the surface run-off, and thereby increas- 



