INSECTS WHICH KILL. FOREST TREES. 5 



owner that his personal interests demand that he take the proper 

 action and that, when necessary, his neighbors will render assistance, 

 as is done in the case of a forest fire. 



Inaccessible areas. — There are yet large inaccessible areas in the 

 East and West where it is not practicable or possible at present to 

 control the depredations by these beetles and which must therefore 

 be left to the same natural adjustment that has been going on in 

 all forests from their beginning. While under such natural control 

 much of the older matured timber will be lost it will usually be re- 

 placed by young growth, either of the same species of trees or of a 

 different species, so that under normal conditions the forest will be 

 perpetuated; but under exceptional conditions and combinations of 

 detrimental influences, such as secondary insect enemies, fire, and 

 drought, extensive areas may be completely denuded, never to be 

 reforested under natural conditions. Therefore it will evidently not 

 be very long before it will pay to adopt insect-control policies even in 

 the areas that are inaccessible for profitable lumbering. 



Examples of Successful Control of Babkbeetles. 



The practicability of the advice based on the results of recent ento- 

 mological investigations is demonstrated by a number of examples of 

 successful control of depredations by destructive barkbeetles. 



CONTROL OF THE EASTERN SPRUCE BEETLE. 



The control of an alarming outbreak of the eastern spruce beetle 

 in northeastern Maine in 1900 and 1901 was effected by the concentra- 

 tion of regular logging operations into the areas of infested timber 

 and placing the logs in lakes and streams and driving them to the 

 mills on the Androscoggin River. Thus, with little or no additional 

 expense, there was a saving to one firm, according to its estimates, 

 of more than $100,000. 



CONTROL OF THE HICKORY BARKBtETLE. 



The complete control of the hickory barkbeetle, which threatened 

 the total destruction of the hickory trees on Belle Isle Park, at Detroit, 

 Mich., in 1903, was effected by felling and removing the infested trees 

 and converting them into merchantable products, all without cost to 

 the park commission. 



CONTROL OF THE BLACK HILLS BEETLE. 



An extensive outbreak of the Black Hills beetle in the vicinity of 

 Colorado Springs, Colo., in 1905-6, which was threatening the living 

 pine timber of the entire section, was brought under control through 

 the efforts of the private owners of forests and those of forest offi- 

 cials in the adjoining National Forests. It was accomplished by 



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