The record-union., 1898-02-27

elusion is that it will probably never be
possible to conduct an extended series
of rainfall observations within a large
forest area and within large area OF
open land near it. which will show de-
finitely the effect, if any, of forests on
precipitation. We incline to the be-
lief that Mr.. Wilson could find precisely
the improbable" conditions to which he
refers in California.
Mr.. Wilson claims that experiments
in the eastern part of the United States
conducted by Mr.. Roberts. an en-
gineer, show in one group of observa-
est destruction increased rainfall LOS
per cent. per annum over the other
half. He believes that all the evidences
estab lish as truth that while forest de-
struction has gone on steadily, rain
fall has increased with the settlement
of the country.
In India, where the natives would
burn off forest area and cultivate the
soil, and then move on and burn off an
other area, the Government concluded
that denudation of timber was becom-
ing too rapid, and interposed restric-
tive regulations, and for ten years
thereafter forest growth was stimu-
lated and protected over the same areas
and observations were carefully taken.
The result was an increase of rainfall
of 6.S inches, but it is claimed that the
error of rainfall observations in the
central provinces of India is D per cent,
and thus the difference is accounted
for in most part.
Mr.. Wilson, quoting Blanford, the
English Indian observer, claims that
the alleged diminution of evaporation
from the soil under forest cover is
without virtue, as the trees prevent
| neutralizing the supposed beneficial
| influence of non-evaporation. Water
intercepted by foliage from reaching
the soil largely returns to the atmo-
sphere and this interception he shows
by many citations of observations had
is a very large and material percentage.
The essayist also antagonizes, and
cites authorities in support. the popu-
lar belief that the litter of forests,
leaves, moss, etc, forms a conservative
function in increasing the flow of
springs. On the contrary it is held
to diminish spring supply by shedding
water that otherwise would feed into
the soil. What does conserve moisture,
he admits, is the protection by soil
evaporation. Also he admits that soil
cover has an influence ON the physical
conditions of the soil by increasing fill
tration and preserving the granular and
porous structure, thus affording cham
nels for unimpeded drainage.
If the soil cover retards penetration,
the influence of forests upon absorp-
ton is to increase the surface flow and
decrease subterranean drainage So,
he concludes, that soil cover has in
topography, geology and atmospheric
conditions. Also, that trifling changes
in temperature and wind velocity have
far greater effect upon evaporation and
consequent amount of percolation than
has forest shade.
The belief that denudation of forest
slopes augments floods is squarely an
tagonized, and especially the long-en-
tertained doctrine that destruction of
timber on the heads Of American rivers
has dangerously affected and decreased
rainfall
We cannot pursue Mr.. Wilson's es-
say at greater length. His citations
are numerous in support of the doc
trine that forests do not exercise so
large an influence upon precipitation or
the run-off of rivers as has been gener-
ally and popularity accepted. Mr. Will
son wholly ignores the question of
snowfall and cover on mountain slopes
in forest and denuded sections It
needs no word from us to remind any
Californian familiar with the Sierra re-
gion what are the effects of snowfall
upon bare TANKS and submits, and
snowfall upon mountains clothed in
the robes nature dressed them in, upon
rivers and upon lowlands, and gener-
ally upon the surface Of TANKS and of
valleys.
However, conceding all that Mr. Will
does not amount TO a reason in favor
Of forest destruction, nor does it les
sen the Importance of forest preserva-
ton and conservation of forest growth
Outside of mere physical and COM
mercial reasons, there are still others
Of as high Importance; there are like
wise sentimental and esthetic factors
which cut a large figure in forest pres
ervation.
We may here add an extract from the
paper of another essayist, who, in the
Popular Science Monthly" takes an
opposed view to that of Mr. Wilson.
c. d. Walcott says:
As the result of personal inspection
Of a considerable portion Of the forest
reserve of California. l am fully con-
WINGED that the preservation and de-
veiopment of the agricultural interests
Of The great wheat and fruit districts
west Of the range depend largely upon
the preservation and increase Of the
forest covering Of the region whose
drainage is tributary to the agricult-
ural areas. The same is true of the