IV 
ASSOCIATED TREES 
BIRCH 
YELLOW BIRCH (Betula lutea, Michx. f.) is the char- 
acteristic hardwood tree of the Park. With an average 
diameter of fifteen inches when mature, in some cases 
it reaches a diameter of four feet and a height of go 
to 100 feet. When growing at its best in dense forest 
it forms a long, clear, full trunk and a narrow crown. 
It inhabits a great variety of soils and situations, but 
attains its best development on hardwood flats. Al- 
though it occurs on low marshy ground, Birch avoids 
wet swamps, where it is short, scrubby, and unsound. 
It has a shallow root system, well adapted to meagre, 
stony soil, and it frequently appears on bare rocks, 
spreading its roots over the edge into the soil below. 
Seedlings often come up on logs and stumps, so that 
when the latter rot away the tree is supported only by 
its prop-like roots. In general the Birch is more abun- 
dant on southerly than on northerly slopes. 
Yellow Birch is decidedly tolerant of shade, but not 
to the same degree as Hard Maple, Beech, and Spruce. 
Under dense hardwoods its seedlings are less abundant 
than those of Beech or Maple. In open woods and in 
blanks in dense forest it springs up abundantly, with 
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