Vermont telegraph. [volume] (Brandon [Vt.]) 1828-1843, 1840-02-19

he power OF absorbing HuIdS by ther
roots during the winter, they can have
put little opportunity of parting with any
portion of it again by evaporation, and as
4 necessary consequence, their tissues
become distended and turgid with the sap
thus accumulated This turgidity of the
tissues is at its maximum just before the
season at which plants put forth their
leaves, and is eminently favorable TO rap
id growth when vegetation resumes its |
activity It is well known fact, that
after very long winters, or when a plant
has been prevented by artificial means
from shooting at its usual season, its
branches and leaves are developed with
extraordinary rapidity-a circumstance to
be ascribed entireI y TO the accumulation of
sap in the tissues.
The diurnal changes from light to
darkness appear to be equally i'm ortant
to the well being of plants with the annu-
al changes from summer to winter. If
plants were kept necessarily growing in
light they would be perpetualIy decom-
posing caIbonic acid, and would in conse-
quence become so stunted that there could
be no such thing as tree, and this is
actually the case in polar regions where
the day and night are each of six months
continuance. If on the contrary they
grow in constant darkness, their tissues
become excessively heightened and weak,
no decomposition of carbonic acid takes
place, none OF the parts acquire solidtv
and vigor, and finally they perish. But
in ordinary circumstances, plants which
in the day become exhausted Dy the de-
composition of car5onic acid, and by the
emptylng of their tissues by evaporation,
repair their forces at night by inhalng
oxygen copiously, and so forming new
supply OF carbonic acid, and by absorb
ing moisture from the earth and air With
out the loss of any portion of it, Such
being the case, we must conclude that
plants grow chiefly by day, and this is
conformable to the few observations which
have been made on this subject. Meyer
found that the STEM of Beladonna lilly,
and plants of wheat and barley, grew
about twice as fast by day as by night;
and Mulder states that he has arrived at
similar conclusions in watching the de-
veIopement of other plants.
When speaking of seeds and under
ground stems, the fact was mentioned that
the nutrilive matter which they contain,
and which constitutes their value as arti.
cles Of food. is, in the economy of veget.
able life, intended for the sustenance OF
the young plants which they give origin,
during the early stages of the growth oil
those plants, and before they have become
sufficiently developed to acquire nourish
ment Tor themselves. The heart-wood OIL
trees appears to stand in a somewhat
similar relation TO the young buds of a
tree. serving during the winter as de.
pository for the turgid sap which the
plant accumulated. and yielding it Up
again so soon as the flow of the sap has
fully commenced III the spring.. The saE
which accumulates in the sugar maple
acer SGcchar1nls) during the winter, con
tains large portion of sugar in its com
position; in the spring, as the watery sap
lmblbet by the roots ascends the stem, il
gradually dissolves this sugar out from
+ the heart-wood, and carries it up for the
nourishment Of the then swelling buds
of course, the higher the sap ascends the
stem, the more of this sugar will it have
dissolved; and this is the reason WHY il
is found necessary, in tapping that tree for
the purpose OF obtaining sugar from its
sap, that the openings should be made
high up the stem, and not near the root:
and further, they that should be made to
enter the heart-wood, and not to PASS
through the bark alone. | know that
these facts respecting the sugar maple
have been adduced in support Of the idea
that there is no such thing as down.
ward flow of the sap, and that its elabora-
ton instead of taking place in the leaves,
takes place gradually during its ascent;
but the downward flow of the sap is estab-
llshed by so many incontrovertbIe facts,
that even if we could not give any ex-
planation of this matter, we could by 10
means admit it as establishing the theory
Just adverted to.
A knowledge of the position of the
sap at different seasons Of the year, is of
great importance to those engaged in cut
ting timber; and as all farmers are oblig-
ed to engage in this business more or less
frequently. they will find this a matter
well worthy of their attention 1t is now
believe, universally admitted that that
disease so fatal to timber, the dry rot,
arises from the presence of the sap, more
especially Of the thick tirgid sap. which
can not be well removed by seasoning
Ii then such sap fills the tissues of the
! heart-wood during the winter whilst thew
are free from it in the summer, we will at
once see the bad policy of cutting timber
IN the winter, as Is the common practice;
and also reason why the timber of the
ancient Romans (who it is believed, usu.
ally cut their timber IN the summer.