PRIMER OF PRIMERS. 191 



tunnellings through the wood. Many insects, 

 while in the larva state, cause great damage to 

 trees by boring or eating the wood. 



Various caterpillars often cause so great a de- 

 struction to the pine-trees as to completely destroy 

 extensive pine forests. 



The greatest enemy of the forest is man. As 

 lord of the forest he is entitled to its products, and 

 if he exercises judgment he can safely harvest his 

 forest crops. 



The removal of the forests from any considera- 

 ble section of country is almost invariably attended 

 by some or all of the following results, namely : 



1. An increase in the frequency and severity of 

 the inundations of the rivers flowing in or through 

 such districts. 



2. An increase in the number and severity of 

 droughts in such districts. 



3. A rapid loss of the soil of the area from 

 which the trees have been removed. 



4. A marked disturbance in the lower courses 

 of the rivers which rise in, or flow through, such 

 districts. 



5. An increase in the number and severity of 

 hail-storms. 



When the forests are removed from any area, 



