488 
MANAGEMENT OF DUNES. 
the outer tier, and accidental destruction by the exposure of 
the interior, from the burrowing of animals, or the upturning 
of trees with their roots, and all these causes of displacement 
are very much less destructive when a vegetable covering ex¬ 
ists in the immediate neighborhood of the breach. 
Before the occupation of the coasts by civilized and there¬ 
fore destructive man, dunes, at all points where they have been 
observed, seem to have been protected in their rear by forests, 
which served to break the force of the winds in both directions,* 
and to have spontaneously clothed themselves with a dense 
growth of the various plants, grasses, shrubs, and trees, which 
nature has assigned to such soils. It is observed in Europe 
that dunes, though now wdthout the shelter of a forest country 
behind them, begin to protect themselves as soon as human 
trespassers are excluded, and grazing animals denied access to 
them. Herbaceous and arborescent plants spring up almost at 
once, first in the depressions, and then upon the surface of the 
sand hills. Every seed that sprouts, binds together a certain 
amount of sand by its roots, shades a little ground with its 
leaves, and furnishes food and shelter for still younger or 
smaller growths. A succession of a very few favorable seasons 
suffices to bind the whole surface together with a vegetable 
network, and the power of resistance possessed by the dunes 
themselves, and the protection they afford to the fields behind 
them, are just in proportion to the abundance and density of 
the plants they support. 
The growth of the vegetable covering can, of course, be 
much accelerated by judicious planting and watchful care, and 
this species of improvement is now carried on upon a vast 
scale, wherever the value of land is considerable and the popu¬ 
lation dense. In the main, the dunes on the coast of the 
German Sea, notwithstanding the great quantity of often fertile 
• 
* Bergsoe (Reventlovs Virksomhed, ii, 3) states that the dunes on the 
west coast of Jutland were stationary before the destruction of the forests 
to the east of them. The felling of the tall trees removed the resistance 
to the lower currents of the westerly winds, and the sands have since 
buried a great extent of fertile soil. See also same work, ii, p. 124. 
