The Daily bulletin. [volume] (Honolulu [Hawaii]) 1882-1895, 1889-03-14
DO FORESTS INCREASE RAINFALL.

Do FORESTS INCREASE RAINFALL.
The questions arising from the re-
lations of forests to rainfall have
been subjects of dispute among
scientific authorities ever since the
serious discussion of the matter be-
gan. Probably the first considera-
ton given to these questions was
due to an observation of the fact
that countries once well wooded and
fertile are now treeless, arid and
desolate, and the natural conclusion
was that in the different conditions
were to be found cause and effect
that the countries had become de-
sert owing to the destruction of
trees and consequent diminution of
the rainfall. This view was long al
most universally accepted among
scientists rs the correct one. Fin
ally, doubts arose. The progress
of knowledge concerning natural
conditions brought facts to light
that appeared to conflict with the
original hypothesis. AS with most
theories in their early stages, it had
been made to apply too extensively,
and to account for everything within
its scope, ignoring the existing of
modifying factors. For instance, it
was argued that all arid conditions
must be due to the loss OF q previ-
ously existing forest growth, as on
the table lands OF Mexico and the
dry plains Of the far West. Re-
search, however, showed that re-
gions like those could never have
supported forests since their geo.
logical character has been rs it is
now, and results like this caused 4
disposition to deny the influence of
forests on the rainfall at all.
The opinion, however, most OBJ
tanning amsng scientists has been
that, while it was likely that the total
rainfall OF year was not increased
by forests or diminished by their alb
sencc, nevertheless it was probable
that they might exert an important
office in equaIizing it, and, there
fore, making it of more value; and
even should this not be the case, the
forests we're still of enormous ser
vice in storing up the rain, prevent
ing its rapid flowing away or evapor-
alton, holding it in the spongy leaf
mould and causing it to descend
gradually into the springs. On the
great bare plains the rain usually
descends in terrific downpours, flow
ing rapidly away and working al
most as much destruction rs benefit.
Against the theory of an increas-
ed rainfall caused by the forests is
brought the argument that the pre-
cipitation upon given regionis due
to its geological circumstances, its
altitude, the contiguration of the
land, the neighborhood of noun
tains, its situation in relation to the
ocean or to large lakes, the direction
of prevailing air currents, etc. On
the other hand, it is urged in favor
of the forests that they must in
crease precipitation through holding
back the water that falls and per-
mitting its constant evaporation into
the air above; that forests are ac-
companied by cooler climatic condi-
tions than are the bare plains, and
the moisture they produce in the air
is more subject TO the action of fire.
quent cool currents, thus causing 0
more equally distributed rainfall,
and, by squeezing the atmospheric
sponge more thoroughly, also an in
creased rainfall.
1t is interesting to notice the
changes of popular sentiment upon
the subject. The needless action Of
man at first wrought widespread
forest destruction. The public
however, has been susceptible to tn,
influence of the discussions of the
subject, and in this country particu
| larly, where reading is universal, i
} has become matter of popular be
lief that the forests bring the rain
J Some foolish measures and doctrines
have resulted, in the shape OF th'
| growth Of various wild theories o,
E sudden climatic changes, and asser
e tions!as to percepliblo effects from
| the planting Of few thousand acres
! OF consumptiye and willing cotton
e woods on the high plains OF th'
West. However, the influence oil
=, the whole has been healthy in lead
- ing the people to think on the sub
ject, aud recent studies indicat
that the popular instinct is right
after all. and that the forests a.