Evening star. [volume] (Washington, D.C.) 1854-1972, 1882-12-04
Forests and Climate.
From the Architect.

the Arcnltect.
A paper has been prepared by DR.. Schom-
burgk, the director Of the Botanical Gardens at
Adelaide, ON the influence of forests Oh climate.
The object of the author is to prove that the
destruction of forests usually has the effect of
reducing the rainfall, while, on the contrary
the planting of trees broadcast over a country
is one of the best methods which can be adopted
for ameliOrating its climate and increasing the
annual fall of rain. 1t cannot indeed; be proved
that the climate of South Australia is altering
for the worse in this respect. In fact, a COM
parisOn Of the meteorological records will show
that the annual average rainfall for the colony
during the past ten years has been II 4 inches
as compared with POI inches for the previous
ten years. The fact is, that in the agricultural
districts of the colony, and especially in those
which were not originally timbered the bring
ing of the land into cultivation has had the
effect of slightly fayOring the TALL of rain. PlOwed
land attracts moisture to much greater degree
than the unbroken SOIL In considering the
effect which the removal of the forests per Sc has
in altering the climate in South Australia the
only direct test that could, be taken from the
records issued by the government astronomer
is the experience Of the neighbOrhOod of AIDE
laide. If the time is divided which has elapsed
since 1889, the year in which observations were
commenced. into two periods, there is found for
the first an average rainfall of 22.S inches, and
for the second one of 21.7 inches. 1t will thus
be seen that. on the whole, the rainfall at Ade-
laide is diminishing. though very slightly. and
perhaps the diminution in the amount of tim
Der may have something to do with the change.
DIR. SchOmburgk, in searching for illustrations
of the effect of trees on climate, goes further
af1eld, and brings forward some striking in
stances in which it is evident that loss of forests
means loss of rainfall, and rice uersa He re-
calls how the Russians by burning down some
of the TransCaucasian forests at the time of the
struggle with the Crcassans, converted the
country from fertile land into desert simply
through the cutting off of the supply of rain
Similar instances of rain having deserted
country denuded of forests have occurred in
the Nautilus in Jamaica, the Azores and it
may also be added to still more remarkable
extent in several of the smaller West India
islands. No sooner had the forests of these
places been destroyed than the springs and riv-
uets ceased to flow, the rainfall became irregu-
lar, and even the deposition of dew was almost
entirely checked. On the other hand. it is gen.
orally accepted as fact that Mehemet Ali in
creased the fertility of Egypt enormously by
planting trees. He alone planted some 20, coo 900
on the Delta; his successors followed up the
work, and it is noteworthy circumstance that
the rainfall rose from six inches to forty inches
Planting has also, it would seem. produced re-
markable effects in France and Algiers. Extern
sive regions have been planted with gums and
other trees. which. for the most part, grew to
about thirty or forty feet in height, and it is
noticed that the quantities of rain and dew
which now fall on the adjacent land are double
what they formerly were.