236 WEST VIRGINIA EXPERIMENT STATION. 



well as in the central section of the spruce area would have 

 served to attract the beetles away from the living trees. The 

 only objection to this theory that presents itself is my observa- 

 tion in 1890, that the 1887 cuttings showed, in stumps and tops, 

 less evidence of the abundant occurrence of the beetle during 

 that year, than was found in the cuttings of 1884 and 1885. This 

 may have been due, however, to the time of year the timber 

 was cut, a fact that was not taken into consideration at the 

 time. 



It would therefore appear from our present knowledge of the 

 subject that the destructive spruce bark beetle, more than any 

 other insect common to the spruce, may have caused the first 

 trouble, and that the chain of circumstances which lead to its 

 invasion of the healthy timber was as follows : 



The disturbing influences of the first white settlers in the 

 region, followed by the opening of roads through the spruce 

 wilderness, notably the Parkersburg & Staunton turnpike, 

 through the middle of the section, and the Northwestern turn- 

 pike through the northern section of the region; the hunters' 

 burnings; the clearing around the Dobbins mansion in 1856 ; 

 the influence of the opposing armies in 1861 ; the great fire in 

 the "Canaan" in 1863 ; the windfalls of 1877 ; the hacking be- 

 tween 1860 and 1880; the opening of the W. Va. Central Kail- 

 road in 1881 to 1885 ; together with intervening severe drouths 

 and storms, all contributed to favorable conditions for the mul- 

 tiplication of the species and its numerous allies, and the conse- 

 quent destructive invasion. 



It would also appear that the continued cutting of timber 

 since 1885, together with the increase of the natural enemies of 

 the species, with possibly sudden changes in climatic condi- 

 tions, was the cause of the trouble ending when it did, and that 

 the first mentioned condition served, more than any other, to 

 prevent the re-occurrence of similar trouble from the attack of 

 this insect. 



This conclusion will apply as well to any other of the same 

 class of bark beetles which may have been the cause of the 



