FOREST TREES. 15 
higher and the winds hotter than in wooded regions. 
The sirocco and simoon, of the Asiatic and African 
deserts, are possible only in a country destitute of 
trees. I have been informed by persons who have 
crossed the plains of our Southwestern territories, 
that they have been glad to seek shelter from 
the scorching wind on the lee-side of a wagon, even 
when that side was most exposed to the rays of the 
sun. 
An important application of forest planting in 
Europe is the covering with trees, and rescuing from 
otherwise hopeless sterility, tracts of loose, shifting 
sand. One of the most extensive of these wastes isin 
the southwest part of France, on the shores of the 
Gulf of Gascony. The following description of this 
tract is from Loudon: “The downs there are com- 
posed of drifting sands covering 300 square miles. 
Bremontier compares the surface of this immense 
tract to a sea, which, when agitated to fury by a 
tempest, had been suddenly fixed and changed to 
sand, It offered nothing to the eye but a monoto- 
nous repetition of white wavy mountains perfectly 
destitute of vegetation. In times of violent storms 
of wind, the surface of these downs was entirely 
changed ; what were hills of sand often becoming val- 
leys, and the contrary. The sand on these occasions 
was often carried up into the interior of the country, 
covering cultivated fields, villages, and even entire 
forests. This takes place so gradually by the sand 
sweeping along the surface and thus raising it, or fall- 
ing from the air in a shower of particles so fine as to 
