THE SPRUCE INVESTIGATION. 241 



observed in the Cheat region in 1890, but that the dead trees 

 were scattered through the forest among the healthy ones, and 

 that they showed evidences of having died at different times 

 during a long series of years. 



One typical example of a perfect spruce tree was found 

 which was two feet in diameter, and not less than 100 feet tall 

 that had recently died. Upon examination it was found to be 

 infested by a great number of the round-headed bark and sap- 

 wood borers which had entered the sapwood, one-half to three 

 inches, to form pupa cases in which to change to the adult, and 

 that some of them had already changed to the adult and emerged, 

 leaving holes in the bark and wood. It was also observed that 

 the sapwood had commenced to decay, which was a most un- 

 usual occurrence in a spruce tree that had not been dead one 

 year. It was found, however, that the work of the insect offered 

 the most favorable conditions for the premature decay of the sap- 

 wood, especially in the peculiarly formed pupa cases, and the 

 holes left in the bark by the emerging adult. These openings 

 allow moisture and water to enter the empty pupa cases, thus 

 offering the most favorable conditions for the entrance and 

 rapid -development of the fungus that causes the decay of the 

 wood. This explains at least one of the causes of the rapid 

 decay of the dead trees in this section. The abundance 

 of the insects in certain parts of the tree, and their ab- 

 sence in other parts, resulted in the unequal distribution of the 

 decayed condition. 



It was also evident that many of the living trees in this sec- 

 tion were suffering from the diseased and partly decayed con- 

 dition of the heartwood, as observed in the logs at the mill. 

 Hence, the spores of the fungus must be abundant in the air 

 and readily find their way into the openings, in the wood and 

 bark, made by the insect. As to the cause of the trees dying 

 in this section, it is in my opinion owing to the natural deter- 

 ioration of some of the trees, aided by disease and insects, since 

 they do not die in groups as they do when killed by insects, 

 but as a rule, are promiscuously scattered through the forest. 



