The Brattleboro daily reformer. (Brattleboro, Vt.) 1913-1955, 1917-10-29
REASON WHY LEAVES
CHANGE THEIR COLOR
Not Due, as Many Suppose, to Action
of Frost-Contain Valuable Ele-
ments to Enrich Soil.

mentS to Enrich Soil
Persons who have noted the wonder
full beauty of the foliage of Wantasti-
quet mountain the past few weeks and
varied hues of the tree-covered land
seape around Brattleboro have COM
mented upon the delightful changes
wrought by the frost. 1t requires no
vivid imagination to picture Mother
Nature going about with a liberal sup
ply of paint with which she colors the
leaves of the trees and other plants
and thereby produces the vivid tints
which characterize the foliage of this
season.
In reality the change in coloring is
the result Of certain chemical processes
which take place in the leaves. The
change is not, as many people suppose,
due to the action of frost, but is a
preparation for winter. All during the
spring and summer the leaves have
served as factories, where the foods
necessary for the trees growth have
been manufactured. This food MAX
ing takes place in numberless tiny cells
of the leaf and is carried on by small
green bodies which give the leaf its
color. These chlorophyll bodies, as
they are known, make the food of the
tree by combining carbon taken from
the carbonic acid gas of the air with
hydrogen, oxygen, and various minerals
supplied by the water which the roots
gather. In the fall when the cool
weather causes a slowing down of the
vital processes, the work of the leaves
comes TO an end. The machinery of the
leaf factory is dismantled, so to speak,
the chlorophyll is broken up into the
various substances of which it is com
posed, and whatever food there is on
hand is sent to the BODY of the tree to
be stored up for use in the spring. All
that remains in the cell cavities of the
leaf is a watery substance i'll which
| few oil globues and crystals, and a
small number of yellow, strongly re-
fractive bodies can be seen. These
give the leaves the yellow coloring so
familiar in autumnal foliage.
1t often happens, however, that there
is more sugar in the leaf than can be
readily transferred back to the tree.
When this is the case the chemical com
bination with the other substances pro
duces many-colored tints varying from
the brilliant red of the dogwood to
. lllN lllbLt huSlNlt itu-blbNllS VI the bdh.
In coniferous trees, which do not lose
their foliage in the fall, the green color
| ing matter takes on slightly brownish
tinge, which, however, gives way TO
the lighter color in the spring.
! While the color of the leaf is chang
I ing, other preparations are being made.
At the point where the stem of the leaf
is attached to the tree, a special layer
of cells develops which gradually sever
the tissues which support the leaf.
At the same time Nature heals the cut,
so that when the leaf is finally blown
off by the wind or falls from its own
weight, the place where it grew on
the twig is marked by scar.
; Although the food which has been
prepared in the cell cavities is sent
! back to the tree, the mineral substances
with Which" tire wallis of the cells have
become impregnated during the summer
months are retained. Accordingly, when
the leaves fall they contain relatively
large amounts of valuable elements,
such as nitrogen and phosphorus which
were originally part of the soil. The
decomposition of the leaves results in
enriching the top layers of the soil
by returning these elements and by the
accumulation of humus. That is why
the mellow black earth from the forest
floor is so fertile. But if fires are al
lowed to run through the forest and
the leaves are burned, the most val
liable of the fertilizing elements ar,
changed by the heat into gases and es
cape into the air. As a result, forests
which are burned over regularly soor
lose their soil fertility even if no ap
parent damage is done to the standing
timber.