Vermont farmer. [volume] (Newport, Orleans County, Vt.) 1870-1877, 1874-10-30
THE FALL OF THE LEAF.

The phenomenon of the "fail of the leaf"
common as it is. is very difficult to explain
satisfactorily. The following are the facts,
so far as we understand them, which are
exceedingly interesting and instructive. 1t
seems that nature begins lie provision for
separation almost rs soon rs the leaf Is born
in spring. When first put forth into the at
mosphere the stalk of the leaf, supposing
one to be present, is continuous with the
stem. As the leaf and its stem grow, how
ever, an interruption between their tissues
(fibrous and cellular) occurs between the
base and leaf.stalk, by means of which
more or less complete articulation or joint
is gradually and ultimately formed. This
articulation it produced by the continuation
of the growth of the stem after the leaf has
attained its full growth, which it generally
docs in few weeks. The growth Of the
leaf being completed, the base of its petiole,
or foot-stalk, is no longer able to adapt itself
to the increasing diameter of the stem, and
n fracture between that base and the stem
necessarily ensues; the excelsior advances
from without inwards, until it finally reach
es the bundles of woody fibre, which form
the main support of the leaf While, how
ever, nature is forming wound, she is at
the same time making provisions to heal it,
for the cuticle or epidermis of the stem is
seen to grow over the surface of the scar, so
that when the leaf is detached the tree does
not suffer from the effects of an open wound.
The provision for the separation being thus
completed, the leaf is parted from the stem
by the growth of the bud mt its base, the
force of the wind or even its own weight.
Therefore, as soon rs the glorious colors OF
the autumn leaves begin to fade, this pro-
vision for separation is completed, and the
winds sing their death-dirge rs they carry
them away from their summers home on
the branches of the trees, and scatter them
in countless numbers upon the ground. The
fall of the leaf is, therefore, the result of a
regular vital process, which commences
with the first formation of the leaf, and it is
only completed when it is no longer useful
10 the trees. There is no denying, however,
that the frosts of the autumn, by suddenly
contracting the tissues at the base of the leaf
stalk, accelerate the fall of the leaves. All
must have noticed, on n frosty morning in
autumn, lnaI inc sllSnlcst DIeilh Vi hlI HloN-
ing among the decayed and dying leaves
will bring them in complete showers from
the trees to the ground. The leaves of the
beech, hornbcam and oak die in autumn,
but frequently remain attached to these
trees throughout the winter months, provld-
ed that the trees are not so situated as to be
exposed to violent winds Such leaves
when examined, will be found to be contin'
uous with the stem, ard therefore without
that articulation or joint which so naturally
assists in the separation of tho leaf from tbs
tree. Those dead leaves fall of when the
new leaves are put on in spring; they are
in fact, pushed off by tho expansion of the
stem when the growth of the season com
mences. The leaves of the evergreen tree!
and shrubs, and of coniferous trees, as tb,
pine and fir, do not fall in autumn, but II
spring, when the growth of the season !
proceeding; and, as this annual leaf-fall i
only partial, consisting of one-half or on,
third at a time, there is always n suflicien
number of leaves left on such trees to kee
them clothed with perpetual verdure
Hence it is that their foliage consists O
leaves which have been attached to the stem
from one to three or five successive years.
The London Garden.