6 INSECTS WHICH KILL FOREST TREES. 



cutting and barking about 1,000 beetle-infested and beetle-killed pine 

 trees. The cost of the operations was largely, if not entirely, cov- 

 ered by the utilized felled timber, although there was considerable 

 unnecessarj^ expense involved through the felling and barking of 

 trees from which the beetles had emerged and from the unnecessary 

 burning of the bark and tojDS. 



The successful control of another serious outbreak of this beetle, in 

 1906, on an ^tensive .private estate in southern Colorado, was effected 

 through the efforts of the owners, who had some 500 infested trees 

 felled and barked within the necessary period to destroy the broods. 

 A large percentage, but not all, of the infested timber was thus 

 treated. These operations were so successful that not a single in- 

 fested and dying tree could be found when the area was inspected in 

 1908. In this, as in the other case, considerable unnecessary expense 

 was involved in the burning of the bark and tops, but the value of 

 utilizable timber was probably more than enough to pay all expenses. 

 It is evident that in this case a destructive invasion was prevented. 



The practicability of controlling this most destructive enemy of the 

 pine timber of the central Kocky Mountain region, not only without 

 ultimate cost but at a profit on the operations, was demonstrated on 

 a large private estate and the adjoining Pike National Forest in 

 north-central Colorado. An examination of the timber on this estate 

 in the spring of 1907, b}'^ a ranger detailed from the Forest Service to 

 work under instructions from the Bureau of Entomology, showed 

 that the depredations by the beetle had been going on for the past ten 

 years or more and had resulted in the death of the choicest timber to 

 the extent of more than 800,000 board feet. About 65,000 board feet 

 of timber was found to be infested by the beetle at the time of the ex- 

 amination. The owner was notified by the Bureau of Entomology 

 of the dangerous character of the infestation and the required action 

 for its control was recommended, but no action was taken. Another 

 examination of the property was made in the fall of 1907, when it 

 was found that the new infestation resulting from swarms of beetles 

 that had been allowed to emerge from the old infested trees involved 

 nearly four times as much timber, or 240,000 board feet. This alarm- 

 ing increase led to the prompt adoption of the recommendations 

 by the owner and the Forest Service, and by May of the following 

 spring (1908) the small number of trees on the National Forest was 

 cut and barked, to kill the insects in the inner bark, and the 1,000 

 trees on the private estate were felled, the logs converted into lumber, 

 and the slabs burned, which accomplished the desired purpose of de- 

 stroying the broods of the beetle. The owner realized a sufficient 

 revenue from the timber thus involved to cover all expenses and leave 

 a net profit of over $1,200. Examination of the area in the fall of 

 1908 showed that this prompt and properly conducted effort to con- 



[Cir. 125] 



