INSECT DAMAGE IN THE NATIONAL, PARKS. 3 



nal type of forest growth of that region, is far greater than that rep- 

 resented by the commercial value of the timber; as is also the loss of 

 notable veterans and giants of the different species. These old forests 

 and old trees are at present one of the attractive and instructive fea- 

 tures of the timbered areas of some of the national parks, and if they 

 are protected from their insect and other enemies the}'^ will be even 

 more attractive features in coming centuries. Under present condi- 

 tions, these old trees of the virgin forest are in greater danger of 

 being killed by insects than are the younger trees. Indeed, man}' of 

 them have been killed within recent j^ears. 



The three giant sugar pines on the trail from Wawona to Glacier 

 Point and the Yosemite Valley are examples. Two of them were 

 dead and the other was dying when I saw them in June, 1904, and 

 there was conclusive evidence that their death was caused by the 

 mountain pine beetle. The veteran sugar pine, known as " Uncle 

 Tom," was being attacked at that time by the same species of beetle, 

 and I am informed that it died the following year. The loss of these 

 four giants of the species is irreparable. 



The Sequoias are supposed to be immune to the attack of insects, 

 but they are not. They are more resistant than other species, and 

 that is one reason they have lived so long. However, each species 

 has a barkbeetle enemy which, under favorable conditions, is capable 

 of killing the largest and finest specimens. I saw one of the large 

 redwoods in the vicinity of Eureka, Cal., that had been killed by its 

 barkbeetle enemy, and when in the Mariposa Grove, in 1904, I dis- 

 covered the barkbeetle enemy of the big tree in the living bark of a 

 storm-broken limb. 



THE PRINCIPAL DEPREDATORS. 



The mere mention of the names of the thousands of species of in- 

 sects, each of which causes some peculiar injurj^ during the life of the 

 different tree species, would occupy more space than is allotted for 

 this paper. Therefore we nnist consider the more important of those 

 which are directly responsible for the death of the trees. 



The little genus of Dendroctonus beetles, or tree-killing beetles, is 

 represented in the Rock}' Mountain and Pacific Slope regions by a 

 few species which are more destructive to the conifers of western 

 North America than all other forest insects combined. They are a 

 constant menace to the pine, spruce, and Douglas fir of the national 

 parks. They are certain to be present in every park in which there 

 are forests of their host trees, and have doubtless caused far greater 

 damage than the park officials have realized. 



The species, in the order of their destructiveness, are the mountain 

 pine beetle, the western pine beetle, the Engelmann spruce beetle, the 



