Evening star. [volume] (Washington, D.C.) 1854-1972, 1901-07-24
FOREST AND DROUTH
Professor Garriott of the Weather
Bureau Talks.
DEFORESTAFION DIMINlSHES RAINFALL
No Change of Climate in Last
Few Thousand Years.
PRES ENT HOT SPEL LII

SENT HOT SPELL
Professor Garriott of the weather bureau
was seen by d Star reporter today and
questioned concerning the effect of the cut
ting of the forests en- climate in this coun-
try, especially in relation to the drouth
now prevailing over a large area in the
west.
The influence Of forests on climate
said Professor Garriott, has been given
considerable attention by popular and sci
entific writer's on forestry and meteorology,
and among those who have Investigated
the subject the deduction has been made
that while forests are conservators of rain
fall and have the effect of modifying, with
in their limits, extremes of temperature,
they do not affect the amount of precipita-
ton in any locality.
Forests can originate, grow and exist
only in regions of plentiful rainfall, and if
districts in which the forest has been cut
out were abandoned by man the unchanged
climatic conditions would, in time, produce
another forest. AS a matter of fact, where
soil conditions are favorable abundant rain
fall causes forests, rather than forests
abundant rainfall. General rains often
cover areas thousand miles or more in
extent; they bring their moisture from dis
tances even greater than 1000 miles, and
their paths are frequently measured by the
width of continents 1t Is obvious, there
fore, that cause so slight as cutting
away a few square miles of forest here
and there could have no effect upon an at
mospheric disturbance of the magnitude of
a general rain storm.
Differentiation Diminishes Rainfall.
The argument that deforestation dimin-
ishes rainfall is a historical one, as the
following quotations show. Tt is a familiar
fact that there are many regions in Asia
and southern Europe, once exceedingly fer
tile and densely populated, that are now
sterile and desolate The country border
ing on the Euphrates, and portions of Tur-
key, Greece, Egypt, Italy and Spain are
now incapable of cultivation from lack
of rain due to deforestation. The most
fertile of all provinces in Bucharia was
that of Sogd. In 1896 this province was
described one delicious garden In
1876 another writer says of this same re-
gicn: Within thirty years this was one
of the most fertile spots of central Asia,
a country which when well wooded and
well watered was terrestrial PARADISE
and within the last twenty-five years a
mania of clearing has seized upon the peo-
pie, and all the great forests have been cut
away and the little that remained was raw
aged by fire during the civil war. The con-
sequences followed quickly, and this coun-
Try HIS DeeH TRANSFORMED INTO a hlnQ OF
arid desert The water courses are dried
up and irrigating canals are empty
1T has also been said that in the older
settled portions of the United States there
are arid hills and worn out fields due to
the falling off of precipitation from the
cutting away of the forest growth.
In referring to quotations and state
ments of this kind, it has been remarked
that without more precise data as to rain
fall il would be hazardous to conclude
that we have here case of cause and eff
feet. 1t is certain that the fertility of
many regions in Asia and southern Eu-
rope in ancient days was due to stupen-
dous irrigating devices and canals and
when these were neglected through wars
and other untoward circumstances the fer
tility necessarily ceased
No Change of Climate.
History fails to show any change Of
climate in any part of the world during the
last few thousand years. Plants found in
mummy cases in Egypt. that were plucked
thousands of years ago, show the same
size those now found in that land The
early and late rains and the floods of
Egypt and Palestine were the same as
they are today, and records of observa-
lions in the United States show that the
rainfalls of 100 years ago measured in
New England were greater and no less
than they are at the present time.
"A most marked effect upon climate of
the forest is shown in it's effects upon tenn
U
est the maximum temperatures of summer
are not so high and in winter the extremes
OF cold are not SO great on the plains
In hilly countries fog and low-lying clouds
are frequently observed over and near a
forest, and not on the open plains. A
light misting rain will sometimes fall in a
forest, while in the open fields no rain
occurs. The amount of rain thus precip-
ltated is, however, almost inappreciabie.
Forests Prevent Drouth.
shown IN connection with floods and
periods of drouth. Forests conserve rain
fall. which prevents drouth within their
confines during rainless periods. The litter
which covers the floor of an undisturbed
forest saves rainfall which would other
wise be lost; the water thus retained finds
it's way by seepage to the sources of
springs and streams and thus maintains
their steady flow. DeforestatiOn and
drainage cause a rapid flow of the water
which falls during the rain, and the imme-
diate result is freshets and floods and the
final result is drouth during long-continued
rainless periods Facts do not prove that
forests increase or that deforestation de-
crease rainfalls.
The observations of the weather bureau
show that periods of prolonged intense
heat, attended by drouth conditions have
prevailed in some part of the United States
east of the Rocky mountains on an aver
age of about once in three years. The
LioSl Important Oh THESE curing Inc last
twenty years occurred in 1881. 1887, 1894
1896 1885, 1900. The 1881 period occurred
in September and produced the highest
temperatures on record up to the present
time in the middle Atlantic states. In each
Of the other years named extraordinary
temperatures were reached within areas of
greater or less magnitude.
Present High Temperature.
"a notable feature of the present period
Of high temperatures and drouth is the ex-
tent Of territory within which unprece-
dented maximum temperatures have OBJ
tanned during period extending over more
than four weeks. The drouth and great
heat in this. as in preceding years. has not
been confined to regions in which the for
ests have been cut away. In fact, the
drouth is most intense and destructive over
the great plains where forests have prob
ably never existed, and less severe in sec
tions like Michigan, where deforestation
has occurred
Drouth is the natural result of an alb
sence Of general rains The conditions
which cause periods of abnormal inactivity
tr, fhn