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 eld 
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 preseut case, 
though the evil is apparently 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 
iug 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. 
