PURE SPRUCE. 37 
light in the forest, a certain amount of which is necessary for the 
germination and subsequent development of the young trees. 
The reproduction of Spruce is often hindered by Witch Hobble. 
This shrub frequently comes up in considerable quantities on lumbered 
land, and also in the uncut forest where the density is not great, and 
sometimes prevents the development of small Spruces by the dense 
shade of its large leaves. It is found most abundantly on hardwood 
land. 
PURE SPRUCE. 
The question is often asked why, in spite of the excellent reproduc- 
tion of Spruce, the lands on the western slope of the Adirondacks do 
not yield as heavily as those in the White Mountains of New Hampshire. 
(Pl. XI, figs. land 2.) The average yield of Spruce in certain sections 
of the latter region is 10,000 board feet per acre, while in the Adiron- 
dacks a yield of 4,000 feet is considered large. The reason is not 
that the Adirondack land is less productive, but that there is a greater 
amount of hardwood timber in mixture. When the two regions are 
compared, however, it will be found that the laws governing the distri- 
bution of the trees are identical, and that the reasons for a larger 
amount of hardwoods in the Adirondacks lie in the difference in topog- 
raphy. The western slope of the Adirondacks may be described as a 
high plateau broken into hills, ridges, and knolls, interspersed with 
lakes, swamps, and flats. Those sections of the White Mountains where 
the yield of the Spruce is So great are characterized by high mountains. 
Much of the timber land is, in consequence, on the long steep slopes 
of the high ridges where the soil is thin and unsuited to the growth 
of the hardwoods. There are, however, many high flats covered with 
Spruce, on which the soil is deep enough to admit hardwood trees. 
Here the Spruce predominates chiefly because it has succeeded in 
occupying the ground first and the hardwoods have been excluded. 
Such conditions are exactly duplicated in the western Adirondacks 
on limited tracts, and in such places the Spruce is dense and the yield 
large. Spruce occurs pure, therefore, either in sections where hard- 
wood trees have difficulty in growing, or where, through some acci- 
dental circumstances, it has succeeded in establishing itself before any 
other species. For the first reason it is found chiefly on steep slopes 
and in rough situations, and for the second reason on Spruce flats and 
swamps where the old timber has been destroyed by fire or wind, and 
Spruce happened to spring up more abundantly than other trees. 
In the Adirondacks the patches of pure Spruce are usually composed 
of comparatively young trees. The reason for this is that the situ- 
ations where pure stands are found are exposed to windfall. Thus, on 
the slopes which face the dangerous wind, on the thin soil of Spruce 
flats, and in the moist swamps, windfall is common, and the timber is 
usually blown down before it reaches maturity. . After a tract of land 
