126 FOREST PLANTISTO. 



should be burnt up; all stumps, even those of pines, should 

 be barked, and the bark be removed or burnt ; for 

 stumps, especially those of trees, which have been felled 

 during the preceding two years, are a general resort for 

 all kinds of destructive boring insects, and should be 

 pulled up. But as this, if done on a large scale, is very 

 expensive, we reach the same end by tearing off tlie 

 bark, the naked stump being not frequented by obnox- 

 ious insects. 



The forester, who has made careful observations on the 

 habits of destructive forest insects, is further able to 

 keep his district clean by putting at proper places, so- 

 called " trap-trees." Healthy, living trees, especially 

 conifers, are felled in many spots of the forest at the lime 

 when the obnoxious insects commence flying around, and 

 left on the ground without peeling the bark or removing 

 tlie branches. The insects like to deposit their eggs in 

 these newly cut trees, and if such trees are removed 

 or burnt up ere the eggs are hatched, all danger from 

 attacks of the destroyed generations will be over. But 

 the forester must endeavor to obtain correct knowledge 

 of the habits of injurious insects, because without that it 

 would not be possible for him to determine the most 

 proper time for I'emoving and destroying the "trap- 

 trees." 



The United States Entomological Commission, pub- 

 lished in 1881 in its Bulletin No. VII a very interesting 

 and useful treatise on the insects injurious to forest 

 and shade trees, from which wo can see how numerous 

 and pernicious these insects are in this country. Those 

 who want more information upon this subject, than the 

 limited space of this publication permits to give, are re- 

 ferred to said pamphlet, the author of which is Dr. A.S. 

 Packhard. 



According to the said bulletin oaks are attacked by 

 314 different species of insects ; elms by 43 ; hickories 



