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1901 | GENETIC DEVELOPMENT OF FORESTS 301 
affected by the shade of the parent trees. In the midst of the 
deciduous forest isolated white pines are often seen rising above 
their neighbors, and thus stand as relics of a previous pine for- 
est. A pine starting from a seedling condition with young 
deciduous trees as a rule never reaches a height greater than 
that of the trees among which it is growing. At the same time 
the girth of such a tree is much greater, owing to the better soil 
conditions, than it would be were it growing among its kind, 
where it must necessarily grow taller or be crowded out in the 
struggle for light. 
The place of the hemlock in the pine and deciduous forests 
is a peculiar one. It often composes 10 per cent. of the trees 
in a white pine forest, and may reach as high as 50 per cent.” It 
seems to be of about the same age as the trees with which it grows, 
and hence probably started with them. This probably means that 
its seedlings are able to develop like those of the pines, without 
being shaded. Yet it often occupies a prominent place in the 
deciduous forest (fig. g), even when the shade has become so 
dense as to exclude any chance for the development of white 
and red pine seedlings. It apparently occupies this position 
among the maple and beech because its seedlings can endure 
shaded conditions, although they do not thrive in such situations. 
Dwarfed young trees fifteen or more years old are often found 
in the densest shade possible. These develop slowly, until an 
open place is made by the death of the older trees around them, 
when they spring rapidly into prominence and occupy a position 
equal to that of the maple and beech. Like the white pine, the 
hemlock will flourish in the more xerophytic places, but prefers 
the deciduous woods and does best in them. The balsam also 
occupies a position similar to that of the hemlock, although it is 
seldom present in a mature climax forest. The yellow birch 
(Betula lutea) has a constant place with the beech, maple, and 
hemlock. It is more plentiful in the Marquette region than far- 
ther south, but seldom constitutes more than a small percentage 
7SPALDING, V. M., and FERNOW, B. E.: The White Pine Bull. 22. U. S. 
Department of Agric., Div. of Forestry. 1899. 
