WHAT IS FORESTRY? 3 
fall is too slight to raise field crops successfully, the 
forester claims that such areas should not be allowed 
to le idle, but should be made to yield repeated crops 
of timber, and aside from supplying the locality with 
this useful material, the owners will receive an income 
from their property, otherwise unproductive. 
The civilization of North America is practically 
founded on wood and at present we are using our 
timber three times as fast as it grows. Over half our 
population live in wooden houses and two-thirds of our 
citizens use wood for fuel. Every boy realizes that our 
household furniture is almost entirely made of wood; 
that our newspapers and magazines are composed largely 
of wood pulp, and that the railroads upon which our 
foodstuffs and clothing are transported have not yet 
found a satisfactory substitute for the wooden railroad 
tie. Indeed wood is indispensable; but unfortunately 
through reckless cuttings and forest fires over half the 
original forest has been destroyed. When the present 
virgin forests have disappeared we shall be compelled to 
use small knotty second growth timber of vastly inferior 
quality and a timber famime manifesting itself in high 
prices and inferior forest products will be felt. 
Even could substitutes be found for wood products 
a certain amount of the country would have to remain 
under forest cover, for it is generally believed that if 
less than twenty per cent of the land area of a continent 
is covered with forest growth in time the country be- 
comes arid. The effects of forest cover in impreving the 
climate by checking the foree of harmful winds and in 
controlling the run-off of spring rains have been men- 
tioned and a theory has been recently advanced that 
rains in the interior of a continent are largely dependent 
upon the presence of forests lying across the track of the 
