resque regions of frost and snow; while
the botanist finds more to exercise his observation in the crowded
variety that marks the region of perpetual summer.

But while vegetation is more generally social in high latitudes, several
families of Northern trees are entirely wanting in this quality. Seldom
is a forest composed chiefly of Elms, Locusts, or Willows. Oaks and
Birches are associated in forests, Elms in groves, and Willows in small
groups following the courses of streams. Those Northern trees which are
most eminently social, including the two just named, are the Beech, the
Maple, the Hickory, the coniferous trees, and some others; and by the
predominance of any one kind the character of the soil may be partially
determined. There is no tree that grows so abundantly in miry land,
both North and South upon this continent, as the Red Maple. It occupies
immense tracts of morass in the Middle States, and is the last tree
which is found in swamps, according to Michaux, as the Birch is the last
we meet in ascending mountains. The Sugar-Maple is confined mostly to
the Northeastern parts of the continent. Poplars are not generally
associated exclusively in forests; but at the point where the Ohio
and the Mississippi mingle their waters are grand forests of Deltoid
Poplars, that stamp upon the features of that region a very peculiar
physiognomy.

The characteristics of different woods, composed chiefly of one family
of trees, would make an interesting study; but it would be tiresome
to enter minutely into their details. Some are distinguished by a
superfluity, others by a deficiency of undergrowth. In general, Pine and
Fir woods are of the latter description, differing in this respect
from deciduous woods. These differences are most apparent in large
assemblages of wood, which have a flora as well as a fauna of their own.
The same shrubs and herbaceous plants, for example, are not common to
Oak and to Pine woods. There is a difference also in the cleanness and
beauty of their stems. The gnarled habit of the Oak is conspicuous
even in the most crowded forest, and coniferous woods are apt to be
disfigured by dead branches projecting from the bole. The Birch, the
Poplar, and the Beech are remarkable for the straightness, evenness, and
beauty of their shafts, when assembled in a dense wood.

Some of the most beautiful forests in high latitudes consist of White
Canoe-Birches. We see them in Massachusetts only in occasional g