Sacramento daily record-union. [volume] (Sacramento [Calif.]) 1875-1891, 1885-10-31
FORESTS AND CLIMATE.
Some Interesting Information Upon the
Subject Cleaned from Investigation.

SUBJECT Gle6ned from Investigation.
The third number of Petermann's
Mittheilungen" for this year contains an
article by A. Woeikof ON the influence of
forest on climate. The commencement OF
a scientific investigation of this subject was
made when the Bavarian forest meteoro-
logical stations were established, and when
Prussia, Alsace-L Lorraine, France, Switzer-
land and Italy followed the example. As q
general rule 1t may be laid down that in
the warm seasons as between forests and
places close at hand which are treeless ~
the temperature of the earth and air are
lowered in the former, ~ their variations
are less, ~ the relative humidity is greater.
After examining observations as to eyapora-
tons, Herr Woeikof states that the inhu-
ence of forests in diminishing evaporation
from water and the soil is so great that it
cannot be accounted for alone by the lower
temperature of the hot months, the greater
humidity, or even by the shade An i'm
portant influence. which has hitherto been
but little appreciated, is the protection from
the wind afforded by the trees, and
this the writer regards as more important
than all the others together in reducing the
degree OF evaporation. With regard to the
influence OF forests on rain and snow fall,
there is yet only single series of observa-
tons supplying comparative statistics. and
extending over a sufficiently long period.
These were taken in the neigborhood of
Nancy, and they show an important infiu-
ence of forests in increasing the rainfall.
1t might appear that the effects of forest on
rain in the climate of central Europe in
winter would be small, for the difference
between the temperature and humidity of
the forest and the open is very little and
the quantity OF moisture in the atmosphere
is small. But the observations show that
1t is more at this time of the year that for
ests get much more rain. This the writer
attributes to the clouds being lower, the
resistance which the forest offers to the
movement of the air and to the moist west
wind. Forests retain rain by the under
growths OF grass, moss, ETC., much better
than open ground, and let water of super
ficially only after a heavy rainfall :;
the remainder filters upward slowly,
and much of it is used for the evaporation
of trees. Although forests. especially
thick, luxuriant forests, cannot exist with
out certain supplies of moisture, yet it is the
same to them when the supplies come. for
they retain what they get, and use it over
long period. One example of this is the
Lenkoran forest. on the west coast of the
Caspian, where the vegetation is more lux
rant than in any other part of Europe, vet
very little rain falls in summer but the
rainfall in autumn and winter is great.
The water is stored by the forest, and is
used in evaporation during the heat of
summer Humidity of the atmosphere,
however, is not consistent with q high
temperature as the Red Sea shows: but in
the forests the humidity is due to the evap-
Grafton of the leaves-in other words to a
process by which heat is converted into
work, and hence the GOODNESS.
Herr Woeikof then endeavors to ascertain
the influence of forests on the climatic
condition of their neighborhood of the
western parts of the Old World, between
the 3Sth and SD degrees north latitude,
the place selected being in all cases in the
open. Thus for the SD degree eight sta
tons are taken between Valencia, in Ire
land, on the west, and the Kirghiz steppes
on the east for the 50th, Guernsey on the
west, Semipalatinsk on the east, and Is
and so on fer each two degrees of
latitude, to So degrees. The general result
of the observations in so stations in six
different degrees of latitude, is that in
western Europe and Asia large forests have
p great influence on the temperature of the
places near them, and that by their infiu-
enCe the normal increase of temperature
as we travel eastward from the Atlantic
ocean TO the interior of the continent
is not merely interrupted, but they give
places far removed from the coast cooler
summer than those actually on the sea.
A striking example of this is Bosnia. An
examination of the statistics show N that
in Bosnia the summer is 2.5o to 4.5o cooler
than in Herzegovina (2) even on the
island Of LISA, in the full influence of the
Adriatic Sea, the summer temperature is
more than a degree higher than that Of
Bosnia, which is separated by lofty noun
tain ranges from the sea. Bosnia owes this
cool summer 10 its great for
ests, while Herzegovina is almost disaffor-
ested. To sum up: Forests exercise an
influence on climate which does not cease
on their borders, but extends over g larger
or smaller adjacent region according to the
size, kind and position of forest. Hence
man by atterestation and disafforestation
can modify the climate around him; but
It is an extreme position to hold that by
the waste places of the earth
1an be made fertile. There are places in
capable of being afforested, which would
not give the necessary nourishment to
rees.-[ Nature.