The San Francisco call., 1904-04-10
FORESTS AND CLIMATE.

rORESTERS and clmatologists in this country will
r. be surprised the action of the German Meteor
illogical Society in its report upon the influence of
forests upon climate. Without the full text of the report
it may be easy make mistakes in discussing it. But
Berlin telegram says that its conclusion is that for
ests have appreciabe effect upon climate. Without
knowing just what is included in the climate,
somewhat in the dark the full meaning of the
port 1t stated that observations of temperature and
humidity, taken the forests and clearings Brande-
burg and at remote points therefrom, justify the
cluson that forests do affect climate, and that like
observations in the marshes of Russia confirm this
The diagrams and tables accompanying the report
are be shown exhibit at the St. Louis Exposi-
ton Taking the report be stated in the Berlin
telegram, the examination of the subject is incomplete
1t has been conended that forests humidity
but they conserve it. Against this it formerly
pointed that humidity the prairie States existed
without the influence of forests. This for long
time supposed to negative the claims of the foresters
that affect humidity But the experience of years
has proved that provided storage and
servaon the reees prairies in the form OF soughs
swamps ponds and lakes These reservoirs caught and
held the rainfall and evaporation carried the moisture in
the air. be distributed by the thunder showers com
to all that region.
In the progress of settlement natural reservoirs
have been drained for cultivation and it is discovered
that the climate has become arid The precipitation
of moisture the late fall and winter and early spring
the reservoirs which originally stored being DESTROYED
it into the drainage channels and gravity carries
away, increasing the floods in the Mississippi River and
its tributaries Not being stored. the summer humidity
is decreased, the is distributed to the soil bv
the showers and the of the earth driving
out 1t takes original precipitation to do the work
than formerly There in which the moisture
from the great lakes is unusual in quantity when the
ground is unfrozen and it is saturated sufficiently 10
avoid drought But the main problem remains caused
by draining the natural reservoirs.
No one has contended that the annual rainfall
of California caused by the forests source is the
moisture evaporated from the Japan current the evap
oraton being caused by difference in temperature be-
the air and the surface of that ocean stream IF
the Sierra Nevada range bare granite wall the
State would receive the rainfall as now But the
results would be very different The water wou1d al
off, from roof fast it falls The creels
and rivers would all be torrents. and when the rain
ceased would Immediately dry up the water would
all be back in the
1t is demonstrated that stripping the mountains Of the
forests that cothe hem and destroying the lesser
taton by grazing by fire. produce exactly the same
results if they had always been naked rock The for
ests the moisture. By their agency il nene
trates the soil and slowly finds its way into the creeks
and springs and through them the rivers preserving
steady off and supplying the of irrigation to
make the valley lands fertile If the German experi
deny this function to the forests we must assume