FOREST ENEMIES 179 



So probably from the earliest times forest trees have paid tri- 

 bute to the invasion of insects. How serious or how frequent 

 these invasions were we can never know. Whole species may 

 have been wiped out of existence. 



But today the forest is even more susceptible to insects than 

 ever before. Unskillful lumbering and the killing of many 

 birds that once fed on these injurious pests have made condi- 

 tions more and more favorable for the multiplication of insects. 

 And today we can not afford to let these invasions arrive and 

 take their destructive course before dying down again. We have 

 not the wood to waste. We are under the necessity of com- 

 batting these forest enemies whenever they attack one of our 

 valuable tree species. So far we have not been able to devote 

 enough funds, or man power to this fight and for that reason 

 we have not been able to claim any great victories. Our defeats, 

 on the other hand, have been numerous. The spruce bud 

 worm, an insect working in the young shoots of spruce and 

 balsam has killed over fifty million dollars worth of timber in 

 the last ten years. The chestnut blight has practically wiped out 

 the chestnut. The white pine blister rust is working its destruc- 

 tive way among the white pine on both our coasts. Govern- 

 ment scientists who have studied the depredations of forest 

 insects over the entire country say that collectively these tiny 

 enemies of the forest destroy each year ten times as much 

 timber as fire. 



The number of different kinds of forest insects is enormous. 

 Many hundreds probably, are still unknown, although the 

 most destructive have been classified and studied. They work 

 in different ways and usually each kind of insect has a certain 

 tree species, or a group of closely-related species that it attacks. 



