Evening star., 1940-12-22
Fight to Control
Desert Described
BIZ Frederic J. Hnskin.

North America and on the seacoasts Of
Denmark, Holland and England. and in
many other countries, this war of man
versus sand is being carried on. In
some places man gradually is becoming
victor, but in others sand is gaining
q foot, yard, mile each year.
The greatest sand war in the world
is being fought in the Sahara Desert in
North Africa. In the southern Sahara,
the desert has advanced more than $50
miles in the past two or three centuries.
Every fresh season finds the native
tribes of Nigeria and French Equatoria
driven from more and yet more villages.
Ancient records show that once the
Sahara Desert supported large popu-
lation. Even down to Roman times, the
coast of North Africa from Alexandria
to Tunis was vast grain growing area
Much the same area today is devoid
of vegetation, except in early spring
when flowers grow for a few weeks.
There is no other part of the world
that has a similar story.
Unwise methods of cultivation are
largely responsible for the advancement
Of deserts. In Africa. for example, the
onward march of the Sahara is due
chiefly to the native habit of burning
the scrub and cutting the young tWies
of the savannah dwarf trees to feed
their goats. The scanty rainfall on the
edge of the desert is insufficient TO
enable the trees and plants to replace
the lost shoots. They wither, the
desert sand soon swallows them, and
the rain belt retreats another mile, for
the same process to happen again the
following year.
Mans great battle with sand comes
in trying to coax the water back to
this barren land. The problem is not
great where there are rivers. and 1t Is
only in such areas that man is winning
MS war with sand. For example. with
the aid of the Nile River in Eevpt man
in so years has been able to double
the area of cultivation. Much of this.
OF course, has come from the marsh
lands, but for hundreds of miles along
the Nile the low-lying parts of the
desert have been driven back due to
construction Of dams.
4 X y
Not all rivers, however, can be de-
pended upon, for often they change
their course, while man cannot move
his dams. A notable example is the
Tarim River that feeds Lop Nor Lake
in the far interior of China where
deserts r1,i1lin,,c &c
river, in places, in the past 500 years
has shifted several hundred miles
from its original bed. But in the shift
ing it has brought life TO many sand
ridden areas, leaving other regions to
become deserts
When it is possible to establish per-
manent vegetation over wide enough
area, half the battle against the desert
Is won Permanent vegeta ton, particu-
larly trees, seems to attract rain clouds.
The partial desiccation that has fol-
lowed the destruction of forests in parts
of the United States is an example of
what has happened on every continent
when this fact is disregarded
In this connection, conservationists
point out that there is evidence that
parts of what are now the Sahara and
Libyan Deserts were once well wooded.
Thus it seems evident that if earlier
generations had understood the rain
making role played by trees, Northern
Africa and Arabia, too would be sup
porting large agricultural population
today. Such instances as these are
cited in support of the tree belts re-
Gently established in the Plains States
of this country.
Even where there is ample rain, how.
ever, it is not always easy to keep the
drifting sand from engulfng seeded
fields. On the shores of the Baltic, for
instance, there are sand dunes which
the wind is moving eastward at the rate
OF about yards year. and nothing so
far has been found that will stop them.
Closely woven wire fences have tenn
porary effect, but sooner or later the
sands climb them, and most other
things.
There is convincing illustration in a
little town at the mouth of the Nile
of how sand continues to climb. Here
is case of an inhabited town in which
one now must descend several steps
to enter houses, the doorways of which
not many years ago were on the road
level.
Experiments are being carried on IN
England, Holland and elsewhere to stop
the movement of sand by planting va
rieties of coarse grass. Clumps of grass
soon spread and give shelter to other
plants. In a few years the sand Is well
on the way to becoming moorland, After
the areas are sufficiently covered with
grass, trees are planted Denmark has
reclaimed thousands of acres of land
in this manner during the past few
years.
The classic example of mans Sue
cess in curbing the oncoming sand is
in the Landes district of Southwest
France, where for 5,400 square miles Is
found layer of sand covering i'm
permeable clay. Here, in days gone by
the district was swamp part of the
year, while at other times the sand,
driven by the prevalent west wind, was
burying the cultivated lands and even
the houses. First, the swamps we're
drained by means of bitches, some 1,600
miles of them. Then pine and oak
trees were planted. palisade 20 to-
80 feet high was erected to arrest the