Lynchburg Virginian. [volume] (Lynchburg [Va.]) 1829-185?, 1829-07-02

It's remarkable, that notsihsi anding this great
Inhibition. the branches furnished with leaves
weighed less AZ evening than they did in the
morning. SO much had they lost by transpira-
ilon but II was not 50 with the branches de-
prived of their leaves. They mb.brd but one
ounce of water, Notwithstanding which, they
weighed more at evening than they did in the
morning This DIR Hales thinks an incon,esti.
BILE proofs OF the certain connexion between tho
perspirat,oo and elevation of the sap.
But when we recollect that early in the
spring, before the leaves are put out NJ all, the
sap lows more abundantly than nj any other
time, las 10 the maple and grape vne) aud par
iIeuiaIly so after cold nights are succeeded by
warm days, IL seems that other causes must DO
looked for TO solve this great phenomenon. II
Is known that In proportion NJ the leaves ex.
pand and INCREASE on these and other plants,
he wound made by tapping OF cutting off a
branch, ceases 10 bleed, as II IL termed and
that when the tree in full leaf II will not bleed
nj all. Tue cause, therefore, OF The fow ol the
zap is not Transportation, although lis circula-
tons are mainly dependent on the leaves For
II a branch which is vigorously growing ~ sam
mer, be deprived of n portion Of its leaves. IL
will DIMINISH its yigor aud il we strip IL alto.
gether, II will cease 10 grow. We also know
that those branches that ara most abundantly
FURNISHED with leaves grow the best---it would
seem therefore that the leaves are organs Of
| suction, or pumps, To elevate or Keep the sap
In circulation during the summer, or temper
ME season OF he year. How then are we to
account for this prodigous flow Of the sap in
the spring, before The leaves are deveIoprdi
Mr., Duhamel says that in the spring, before
the leaves are oui, the flow of sap comes nv
much n, least, IL not more, from the upper par,
of the wound or cut in a tree than il does rom
| ha In, ul frn fha "a
by him aud others. II seems 10 be proved. He
took young tree, which he sawed off about
ls inches above the ground. The upper part
of this tree he suspended in the same position
IN which II grew. This was done very early in
the season, Il think February before there was
any appearance of vegetation For several
days sucoessvelyshe examined both the stump
and the suspended top ot the tree. When the
weather was cold, the cuts Of both remaine d
dry, rs they did during the nights, bur when
warm, sunny days succeeded frosty, or cold
aiehts. both the siumps aud The top became
mos, nj the wound, aud The juices in some in.
stances were active enough TO GALL from the cut
of the upper portion OF thn tree; but in all en-.
ses when there was sufficient heat to affect the
stump, the sap in the detached part was eqnal-
~ put in motion. This was. think, n syca-
more nee. In this case, as in making a Trans
flow from the wosd. between the prh and the
bark, and not from the bark itself. But nj u
later period, as before stated, when the tree
Is in leaf the sap will appear, after II has been
elaborated, ~ the inner part OF The bark. II is
Tor this reason that IN tapping maple trees they
Away cut into the wood, for IL you cui ihIou h
the bark only, the sap will no. flow.
From this and other experiments that have
been made, il appears that the sap is retained
IN the cellular tissue, or the vascular organs
during the winter, in n soluble state, and M
soon as the hca, Of the sun is sufficiently great
10 liquiiy IL, il flows from all parts of the ire,
where these vessels exist, and more or less a
bundantly. according 10 the nature OF ih,
plant: thes" vessels being larger and more a
hundant in some trees than IN others, and pro
baby better filed with sap in some than in o.
theirs. This may be the cause why nipple
,refs furnish sap 50 abundanlIy when cold frns
~ nights are succeeded by warm sunny das s
and why The sap will flow from the south sid,
of this tree, when il will not from the noril
| side.
| May not this answer one, if not two Of Mr.
| Collins questions, viz the fourth and eighth
Perhaps il is not conclusive as TO the last Bu
do not understand that il is necessary that il
should freeze in the night 10 induce the sap {,
flow IN tho day--only thai when frost is sue
ceeded by warm sun, the sap will flow NOR,
) abnndantly than il does ord narily when Their,
has been succession Of warm days, aud The
sap has been constantly flowing by which
means, per haps, the organs tina, contain the
fluid may be exhausted and may require lime
to replenish themselves. All this, however, is
hut con lecture Tor have never found an,
| satisfactory reason offered " hch will explain
this phenomennn, as II ~ most certainly, il il
be true, that frosty nights hre accessory TO the
flow q. the SAP, as above stated. In tropical
climates where there is no frost trees are tap
ped, and the sap flows regularly and con
stantly-more in The day than in the night
because there IS more heat 20 aid its circu
laiion. But this seems 10 show that frost Al
night is not necessary To its flowing in he day
time.
Is the circulation Of tho sap permanent du.
ring the warm season Although trees, gene
rally, cease TO put ont new, or extend their old
shoots during midsummer, Chat is The latter
part of June, July and the early part of August
aud the terminating buds of The shoots of III.
year, are, in many trees formed when IN,
heat or dryness has passed off, these ierminn
ling buds will Frequently hurst out, aud make a
new growth. This is called the growth of IN.
second crop. II The sap does not cease, alto
gether, 10 circulate it certainly becomes Sc
sluggish that &c find the bark will Hdhere "a
The wood, which IN the spring could be easily
separated. Aud alter midsummer, the san hay.
ing resumed its course, the bark can again be
detnc hed with ease hence it is, that ia both
spring and fall you eau bud trees, while in
winter and midsummer II cannot nsually be
done Whether this arises from the exiremo
dryness of The soi, Which furnishes litlr or no
nonrishment To the roots during lis coninu
ance or whether most Of the sap that il drawn
into them, and thence into the tree is carri.d
off by excessive perspiration during the hot
and dry season; or whether il be owing partly
to both, are questions We shall not undertake "a
decide. But to us there appears no doubt that
TO these causes, jointly or seyerally, are to be
attributed that apparent inactivity in the sap
that IS so manifest during midsummer and
which lead many people TO believe that its cir.
culstions are stopped altogether
But the principal question is still unanswer
ed and have no doubt will remain So We
may, however. examine il n lille, aud see whe
AL a H.. r