2A PRACTICAL FORESTRY IN THE ADIRONDACKS. 
inferior soil has led to an impression that they prefer such to rich 
ground. The fact is that they are not found in other situations because 
they are prevented from growing there by the more tolerant species, 
or because the soil does not contain the degree of moisture necessary 
to their existence. The relative demands of the most important species 
ou the quality of soil are shown in the following list, which begins 
with the most exacting: Black Cherry, Hard Maple, Beech, Soft 
Maple, Birch, White Pine, Balsam, Hemlock, Spruce. 
Many kinds of trees are able to hold their position in the forest by 
their great reproductive power, as, for example, the Poplar. This tree 
has an extremely light seed, which is blown for great distances by the 
wind. Itis thus able to seize upon openings made by fire or otherwise, 
and, inasmuch as it thrives on extremely barren soil, it usualiy forms 
an important part in the first forest growth on burned land after a fire. 
The rapid growth in height is an important factor in enabling some 
trees to hold their own against other species. Thus, Pine and Tama- 
rack, both intolerant trees in the Adirondacks, are able to grow above 
the more tolerant kinds, if they can obtain a footing at all, and in this way 
their crowns have the degree of light necessary for their development. 
It frequently happens, however, that the composition of the forest 
in a particular place is not determined so much by the influences dis- 
cussed above as by accidental circumstances. If, for example, an 
opening has been made by the wind, the kind of trees which will come 
up depends in a large measure on the seed which happens to be in 
the ground and on what species happen to be in the neighborhood. 
Other circumstances, as the fact that it is a favorable seed year for 
certain trees, the direction of the wind, etc.. may be the controlling 
influences. Itis through such chances as these that intolerant trees 
are able to obtain a footing in mixture with tolerant kinds. and scat- 
tered individuals, whose regions of best development are elsewhere, 
become a part of the forest. 
FOREST TYPES. 
If nature is left undisturbed, the same type of forest will tend to be 
produced on the same classes of situation and soil in a specified region. 
There will be variations within the type, but the characteristic features 
of the forest will remain constant—that is, the predominant species, 
density, habit of trees, reproduction, character of undergrowth, ete. 
So characteristic and distinct are these forest types that an expert can 
describe the general character of the forest if he knows the region, the 
altitude, the soil, and the situation; and, vice versa, can describe the 
character of the soil, situation, ete., if he knows the type of forest. If 
a portion of the forest is destroyed by fire, wind, or otherwise, the type 
may for the time being be changed; but if left undisturbed it will 
revert to its original form, provided the condition of the soil is not per- 
manently changed. Thus, in the Adirondacks, a gronp of Spruce and 
Pine on an island may be replaced after a fire by White Birch and 
