6 
also very common in the bark of both dead trees and those other¬ 
wise healthy. 
The elm in its natural habitat grows in a loose and shaded soil 
composed of leaf mold to a considerable depth, and does not root 
deeply. (See Plate VI.) If other trees and the underbrush which 
offer more or less protection to the elm roots are cut away, and 
especially if the land is pastured and the soil thus packed, or if, as 
in the city, the root system is cramped in earth sometimes perme¬ 
ated by escaping gas, too closely packed, unmulched, and unnatu¬ 
rally drained, and exposed for long summer periods to the hot 
glare reflected from the paved streets, the leaves of the tree in 
the meantime being constantly exposed to gas and smoke, and cov¬ 
ered for weeks with dust from the street, we have an environment 
for this tree as unnatural as it would be possible to make it and 
permit the tree to live at all. The feeding roots are thus exposed 
to drouth, and sometimes remain for weeks at a time about as dry 
as the dust of the street. The soil is exhausted of plant food, and 
nothing is done to renovate it. The tree is starved and weakened, 
the uppermost twigs begin to die, and insects, instinctively attracted 
to the weaker trees, come in and finish the work. Their injury, at 
first scarcely perceptible, serves merely to accelerate the decline of 
the tree, but sometimes, unfavorable conditions having reached a 
temporary climax, the work of the borers, stimulated rather than 
retarded by such conditions, quickly overwhelms the tree, girdling 
its trunk and killing it as if by a sudden stroke. 
Professor Garman is sure that in Kentucky insects were not 
the primary cause of the wide-spread loss of elm trees in 1899 an d 
the years preceding. His discussion of conditions and effects is so 
instructive and convincing that I quote from it at length. 
“The white elm,” he says, “has a peculiar way of sending its 
main roots out close to the surface of the ground. Sometimes a 
root upon which a tree chiefly depends is covered in places with 
less than two inches of soil. Roots after leaving the base of the 
trunk actually turn toward the surface, where they extend for 
long distances in the rich surface soil. The trees taken up on the 
:ollege grounds for examination illustrate the point very well. 
[Plate VI.] The living tree had three main laterally directed 
roots of this sort. They were vertically flattened for about eight 
inches and then contracted rather abruptly to two inches in diame¬ 
ter, tapering gradually from this point to their extremities. After 
leaving the trunk they rose toward the surface and lay for a dis¬ 
tance of nineteen feet out from the tree among the roots of clover 
and grasses. Besides their main roots were a few whip-like roots 
of the same sort, lying even nearer the surface than the large ones. 
