Yellow Birch and the Adirondack Forest 13 
TYPE 
The Fundamental Importance of Type: 
Division of a forest area into types is quite as necessary, for 
purposes of management, as it is to obtain facts that can be 
converted into working principles. Operations on any extensive 
Adirondack area, even in logging, bring out the differences in 
forest composition and topography, and these differences have 
been used to define the major types of the region. Any study 
which ignores these differences will cause to be lost, by the law 
of averages, the facts that might be developed into rules of 
management. While this publication recognizes the four major 
types of the region for the sake of common understanding, very 
little intensive work can be accomplished until a more minute 
division is made and the physical factors which create the 
minor differences are recognized and studied. Changes in soil 
depth and composition, drainage, depth of humus, forest com- 
position and even shrub and herbaceous cover all react to cause 
differences in forest reproduction within a type. 
While the four major types are used as the basis of this study, 
other types are mentioned and described, and minor differences 
are pointed out. , 
Swamp: 
This type is of small importance in a study of yellow birch 
in virgin forest, since birch does not enter into the forest as a 
merchantable tree in the true type. Any study which reports 
birch as part of the swamp type in its tables does so because 
the tree appears on the margin of the type and on knolls, or 
well-drained spots where the small size of the area prevents 
elimination from the type. The area of swamp will be reduced 
in the second growth forest on cleared areas by encroachment of 
both birch and red maple from the margins. 
The true swamp type of the Adirondack region is a balsam 
and spruce mixture on flat, poorly drained land. There may 
be areas along streams and lake margins where cedar and hem- 
lock are prominent. Tamarack, as the temporary species of 
such swamps, was once plentiful, but the mature trees are now 
dead, and tamarack occupies only bog margins in the virgin 
