822 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION. 



are now inclined to believe that the death of the spruces in northern 

 New York and New England is almost wholly due to this cause. It 

 is the belief among some lumbermen that the spruces are dying of old 

 age. There is undoubtedly a natural limit to the life of any tree, but 

 why should this cause have been confined to the spruce only within 

 the last ten or fifteen years? Spruces, like other trees, have died of old 

 age since the world began ! Again, summer droughts and winter storms 

 and severe cold weather should not affect the spruce more than any other 

 tree of our forest, especially the pine and the hemlock. On the con- 

 trary, the spruce is our hardiest tree. It lives farthest up on mountain 

 summits; it is the northernmost of our evergreen trees, living nearer 

 the Arctic circle than even the larch. It can withstand severe drought, 

 flourishing on rocky ground where the soil is thinnest; it grows luxuri- 

 antly in swamps where the ground remains frozen later than elsewhere, 

 and the arrangement of its branches enables it to withstand heavy 

 snows and winter storms as well, if not much better, than any other tree 

 of our northern forests. The adverse forces of nature, winds, gales, 

 frost, snow, sudden heat, and drought have acted for ages upon the 

 spruce, and by the processes of natural selection the weak qualities of 

 other evergreen trees have apparently been eliminated from it ; it has 

 survived and persisted by reason of its unusual powers of endurance, 

 its toughness, and insensibility to the rigors of a northern and subarctic 

 climate. It has, however, of late years, and perhaps periodically, been 

 the special prey of boring insects, species which also attack its allies 

 and the pines, but which seem, in regions from which the pine has been 

 eliminated by the ax of the lumberman, to concentrate their forces on 

 this tree. 



Remedies. — When a growth of these trees is invaded by insects boring 

 in or under the bark, the loosened bark should at once be stripped off 

 and burnt. If the tree is dead it should be cut down and the bark 

 stripped off and at once used for firewood, even if the wood is kept for 

 future use as fuel. Trees infested by caterpillars may leave out again 

 and gradually assume nearly their original health and vigor. But the 

 best remedies are those of a preventive nature. In the present case, 

 though the evil is apparentlj'^ diminishing in Maine, our observations 

 have taught us that the dead firs and spruces wherever examined are 

 teeming with thousands and even millions of small bark-beetles in all 

 stages of growth. It would therefore be wise to prevent any further 

 spread of the evil by cutting down dead spruce and fir timber and sell- 

 ing it off" for fuel. Forests should be thoroughly cleared, and even pine 

 stumps should be barked and the bark burned, for, as already stated 

 (p. 175), we have taken thousands of these spruce beetles from under 

 the bark of white-pine stumps. • In fact, stumps, in the summer succeed- 

 ing the falling of the tree, are a general resort for all sorts of destruc- 

 tive boring insects ; and should it be too expensive a matter to pull up 

 such stumps, if the bark is torn off, the naked stump will be much less 

 frequented by noxious insects. 



