Daily Kennebec journal., 1902-04-30
pisputins Some Popular Theories.

Disputins Some Popular Theories.
Al this season, with Arbor day at
hand, it is of interest to note the
opinion of Professor Gannett Of the
United States geological survey as TO
| the relation between forest area and
rainfall. Professor Gannett is the
mates We recently quoted rs to the
| forest area Of the several states, ana
he one of the highest authorities on
these matters. IN a recent bulletin
issued by the American Geographical
| Society he takes occasion to dispute in
vigorous terms some popular theories
which other eminent authorities in
their turn have advanced and support
cd. He is at variance with most Of the
writers on this matter, and even if he
is right and the others wrong it does
not make the observance Of Arbor day
less desirable or the scientific study Of
forestry less a national necessity. Let
Us nave his own words on the subject
of forests ana rainfall.
Some ken observer says Professor
IGannett. long ago detected the fact
that forested regions enjoyed a heavier
rainfall than these not forested, and
jumpcL to the conclusion that rainfall
was produced by forests, and that the
removal OF forests diminished the rain
fan Looking over the earth. he found
lmaly tre+less desert regions and
forthwith instanced them as frightful
examples of mems wastefulness.
Syria, Northern Africa, parts Of Italy,
are often quoted as illustrations of
mans destruction Of climate. In re-
ply. man can certainly plead not
guilty The geography Of this Medi-
terraueln region, the configuration Of
land ana water ana the direction of
the prevailing winds. are such as To
give it a light raiufall-forests or no
forests. The situation is really this
Want Of rain vents the growth OF
trc, S; want Of trees does not prevent
rain"
On the Kindred subject Of increase IN
the number ana violence of floods by
reason Of forest destruction Professor
Gannctt is equally contrary ana posi-
tive. He calls this a persistent error
ana proceeds to dispose Of it with ID
few tersc statements Of fact. 1T is
probable" he says, that the clearing
of land by cutting away forests ana IN
dcrgroWth does change the regiment
Of streams, iucro asing their flood
!, height ana diminishing the flow at low
stages. IN other words, water prob
ably runs off or cvaporates more rapid
. IL from bare ground than from ground
covered with forests. But where the
, forests are cut away the ground is
seldom left bare; it is cultivated or
quickly becomes covered with bushes
which hold the water quite as effective
lly as forests. The main fact is. how
ever. that the floods in our rivers are
no greater or more frequent now than
in tho past"
IN similar manner The professor
throws aside the theory in regard to
the effects Of the Gulf stream and
Japan current ON climate. He con-
siders this theory as one Of the popular
delusions which should have heen dis
posed Of long ago, ana which has no
excuse, for longer remaining in good
, society The well known mild climate of
the northwest coast of America and the
western coast Of Europe, he declares,
, cannot be intelligently attributed Ia
these ocean currents. ''Can il be sup
posed that the Japan current, however
warm ii may be when it leaves the
tropics, retains any appreciable -ex-
cess Of heat after a journey of G0OQ
miles in northern attitudes? As a mat
ter of fact. no trace of this current
reaches the shores Of North America.
IN the North Atlantic The condition is
much the same. The Gulf stream dis
Iappears as current long before the
British isles are reached"