E big trees of California are never attacked 

 by insects. This immunity is extraordin- 

 ary and may be the chief characteristic that 

 enables these noble trees to live so long. Un- 

 fortunately it is not shared by other species. 

 The American forests are infested with thou- 

 sands of species of injurious and destructive in- 

 sects. These insects, like the forest fires, annu- 

 ally kill numerous forest areas, and in addition 

 leave millions of deformed and sickly trees scat- 

 tered through the living forest to impair and 

 imperil it. After some general tree studies 

 which have occupied odd times for years and 

 extended through the groves and forests of 

 every State and Territory in the Union, the con- 

 clusion has been forced upon me that the forests 

 are more widely wasted by insects than by fire. 

 Some of Nature's strange ways are exhibited 

 in the interrelation of insects and fires in tree- 

 killing. It is common for the attack of one of 



