The Pacific commercial advertiser. [volume] (Honolulu, Hawaiian Islands) 1856-1888, 1877-02-24
THE PACIFIC
SATURDAY. FEBRUARY "a.
(Frou Hsrper's Bazar.)
The Use of Forests.

a relief to baroness. But that is not all. They
modify, or rather avert, destructive torrents OF
rain. The evil effects of the wholesale cutting
down of extensive tracts Of timber are. 1t may
be said, only beginning to be felt. Direful results,
have ensued, and now 1t is to be hoped we are
taking warning. While extensive forest clear
ings have been made, reckless of consequences,
in India, in the United States, ndother p~ortionso OF
the globe, France was the first country TO awake
TO the folly Of the system. The old seigneurs
loved woods, the peasant-farmer hates them. In
the south, where the land has been more cut up
into small properties than in other parts, the
trees have been so cleared oil that there are
whole communes without any-mountaln COM
muues, which owing to the now unchecked ac-
ton Of the rains, bid fair to be pretty soon
nothing but bare rock. The peasant grubs up a
tree, and thereby gets a few more square yards
for his rye or lucern but thereby also he helps
to keep off the gentle rains, and to bring about
destructive droughts. alternating with no less
destructive floods. That at any rate, was the
conclusion to which years of study and observa-
ton led 81. Becquerel, who, a quarter OF a CEN
fury ago, published his book on the Effects OF
Forests on Climate. He and bis fellow-workers
cried out SO loudly that people got fairly
frightened. In France, replanting began at a
great rate, though, u~nhappily, not to any extent
in the poorest communes in the south, where 1t
IS most needed. Lat:erly, in this country, laws
have been made against the reckless destruction
Of forests.
The Third Napoleon at first advocated the use
of trees part of the Gascon Landes toward Ar
cachon was planted with frs a good deal OF the
| Sologne-a hungry sort OF Bagshot Heath, in
Central France-was treated In the same way.
But by-and-by, as we all know, playing Proyl-
dence " became very expensive the revenue al
ways showed o deficit, and expedients of all
kinds were resorted to &c to raise the wind P"
without increasing taxation. Why not sell
the crown forests ?'' asked Fould, the imperial
fnancier. I" Because" replied his master, " If
- l. I--a., Ill ak -,auk ~ han An2C q.
and then what are we to do for wood2" 4" Burn
coal, ;" replied the lsraelite [" having a long bill
with EDgland will strengthen the entente cor
dale" And he straightway set one of the many
venal saUants of " the Second Empire " to write
a book. in which it was {" proved" that forests
had no appreciate effect upon climate. The
sdvant had some conscience he was forced to
confess that cutting down the trees did cause that
rGUiRement-sweepiDg away OF earth and seam
ing hill-sides with channels, from which (s We
have already noticed) many commune in the
south of France, and not there only, have SUI
fered but he stoutly denied that forests have
any effect in increasing or regulating the rain
fall. This was in 1865 /; and since then NJ. Ma
thieu, Director of the School of Forestry at
Nancy NJ. Cantegoil, Inspector of Forests at
Carcassonne, and others, have been conducting
a series of conclusive experiments. Fortunately
public opinion was too strong even for NJ. Fould.
and, after the reports published within the last
three years, it is not likely that the attempt will
be made again.
Forests, it seems, have a fourfold effect on eli
mate and rainfall. There is the chemical action
OF their leaves, which decompose the carbonlc
acid of the air, fixing the carbon in their woody
tissue, and liberating the oxygen. There is their
physical action in hindering evaporation and
stopping currents of air, and in covering the
ground with a vegetable mould which holds
water like a sponge. And there is the organic
action of the leaves which, in breathing, restores
to the air a part of the water which the roots
have drained from the soil. Lastly, there is the
mechanical action of the roots, which at once
prevent the earth from being washed away by
rain, and also enable the water to filter down
deep into the ground. Forests, then, ought to
make a country cooler, by withdrawing the car
bon from the air the heat that is set free when
wood is burned is the very heat that was being
absorbed while it was growing. A forest may
be looked on as a vast condenslng apparatus tor
storing up the heat of the atmosphere. That Is
what theory says, and experiment confirms it.
The mean temperature of a wooded country is
always lower than that of a similarly situated
treeless country but (and this is importantly the
cold is less extreme, as well as the heat, and
changes of temperature are gradual. or course,
since rain comes because the air is too cool to
hold its moisture any longer in solution, there
ought to be more rain in a wooded than in q
treeless district and SO there is-from six to
eight per cent, as NJ. Fautrat found by putting
up several rain gauges, some in a forest, seven
oAA koOtO N"S SANSNSBo1 OsASAR NNNNSNO
ground some two hundred yards off. Bare soil
soon gets heated, and heats the surrounding air.
This expands, rises, and absorbs, without con-
densing them, the vapors brought by the sea
winds. Rain only comes in such a district when
q contrary wind meets this hot current, packs
its layers one On another, and, as it were,
squeezes ont the wet from them. Hence such
rain, due to 4" atmospheric perturbation" gen.
orally comes in floods, unlike the gentle natural
rainfall of forest land. Storms are rare in
---l A. A.s.N e H. -. A.-
gradually drawn off instead of accommodating.
Hail especially is rare where there are many
trees. NJ. Cantegoil has tracked many of the
hail-storms so destructive in France, and has
found that they generally make a leap over a
forest. Early in June, 1874, for instance, a
hail-storm which had swept over the department
of Ariege entered that of Aude. AS soon as 1t
got to the forest land, the hail totally ceased
but when it reached thu treeless department of
the Eastern Pyrepees, it began again with great
fury yet there was electricity enough in the air
over the forests, for several ~fr-trees were struck
and shivered to pieces. But hail is caused by
the very rapid evaporation of rain passing
through an exceedingly dry stratum of air.
Evaporation, we know, always causes cold (tbis
is the principle of water-coolers, etc., and in
this case the latent heat Of the rain is withdrawn
so rapidly that the result is frozen rain-drops.
Hence, in wooded countries, where the air is
always moist, the evaporation is slower, and rain
falls instead of hail.
Every one must have felt the soft warmth OF
the air in a wood just after night-fall, so differnt
from the chill that comes on after a hot, dry day
in an open plain. No wonder evaporation and
radiation of heat are FIVE times greater in the
latter than in the former. But, it may be said,
if the trees bring more rain, they use up more
than the treeless ground, for their roots drain
the soil and their leaves drain the atmosphere.
Not SO; though wood is more than half water,
the amount of water contained in all the wood in
a forest is the veriest trifie compared with the
rain that falls on it during the year. Moreover,
a series of experiments seems to show that the
amount of water decomposed by an acre of forest
is very much less than required by an acre of
or wheat, or clover. Again, because
pines and other trees (notably the blue gum,
~QlobuLus. which is being planted bY