Evening star., 1936-08-16

SO slow and infrequent that it attract
| ed no notice. Only within the last
decade has it begun to attract serious
attention. But it gets worse all the
time until it has come to constitute
about the greatest menace that afflicts
the country. The phenomenon Is 30
new. In fact, that very little scientific
study has been made Of it.
First comes a heavy wind. 1t moves
a dune, or line of dunes, a little way.
There it stops for time. Lesser
winds pile up more sand upon it. Then
come more winds and increasing
pressure. A hill delays the flow for a
time, but finally the pressure becomes
sufficient to carry it over the ridge and
over the face of a mesa. There is q
long delay, for the sheltering red cliff
protects the dune from winds. But
eventually 1t hops along again.
It comes to a low juniper forest
and almost completely burieS it..
There are scores of such hillside
groves in this part Of the Southwest.
only the green tops protruding gro
tesquely out Of the white sand.
Eventually the dune jumps along,
leaving the trees clear. But II the
Jump has been delayed they are dead.
because no moisture could reach their
roots.
When the sand moves it moves fast.
It Is becoming a real problem to keep
the highways clear of it. Now, wher-
ever the sand rests for a week or q
month the vegetation, scanty at best,
Is killed or seriously reduced. AT
least q year is required for it to come
back. Controlled experiments now
proximate length Of this period. as
well as the average rate Of progress
Of the sand.
Like Great White Snake.
Now naturally it cannot come back
If another sand dune Is upon 1t, as
soon as one has hoped away. And
the faster the erosion process In the
watershed area the faster the dunes
keep coming, until great white
snake seems to be wriggling across
the countryside. And the more it
rains the faster and erosion, the
closer the humps of the snake, and
the greater the extent Of the desert.
The only thing to do about 1t, say
the soil conservation experts who are
working on the Navajo Reservation,
Is to prevent the sitting Of the streams
so that they will have q chance Of
regaining their original deep chan
nes and willow-lined banks. This
may be accomplished by engineering
methods accompanied by several
years of very rigidly controlled graz
ing on the watersheds.
1t Is a medical truisn1 that every
human being who lives long enough
will die of arterio-sclerosis-th ulti-
mate "old age" That Is, the arteries
will become encrusted with calcium
and the blood, no longer able to flow
through them, will break through.
This is essentially what is happening
to these great acres Of New Mexico
and Misunderstanding the rivers
as arteries and the silt as the calcium.
But it is premature old age brought
on by high living and enlargement
of the capillaries-the f1ood-washed
aroyas. The soil conservation experts
refer to the Rio Grande and the Rio
Puecos as dead or dying rivers, and
speak of bringing them to life again.
Not so many years ago, they say,
the grass on the hillsides was knee
high. 1t held the thin soil. 1t would
support COW to 80 or 40 acres. Now
it isn't ankle-high and grows in thin
tufts. It will hardly support . COW
to 100 acres. This is the result of
too close grazing made necessary by
the increasing population and the
subdivision of the land which did
away with the natural range.
It isn't alone the range country
which Is threatened by the leaping
sands. The rivers continually are
carrying down more and more silt.