299 MINOR USES OF THE FOREST. 
Minor Uses of the Forest. 
Besides the important conservative influences of the forest 
and its value as the source of supply of a material indispensa- 
ble to all the arts and industries of human life, it renders other 
services of a less obvious and less generally recognized char- 
acter. 
Woods often subserve a valuable purpose in preventing the 
fall of rocks, by mere mechanical resistance. Trees, as well as 
herbaceous vegetation, grow in the Alps upon declivities of 
surprising steepness of inclination, and the traveller sees both 
luxuriant grass and flourishing woods on slopes at which the 
soil, in the dry air of lower regions, would crumble and fall by 
the weight of its own particles. When loose rocks lie scattered 
on the face of these declivities, they are held in place by the 
trunks of the trees, and it is very common to observe a stone 
that weighs hundreds of pounds, perhaps even tons, resting 
against a tree which has stopped its progress just as it was be- 
ginning to slide down to a lower level. When a forest in such 
a position is cut, these blocks lose their support, and a single 
wet season is enough not only to bare the face of a considerable 
extent of rock, but to cover with earth and stone many acres of 
fertile soil below.* 
In alluvial plains and on the banks of rivers trees are ex- 
tremely useful as a check to the swift flow of the water in inun- 
dations, and the spread of the mineral material it transports ; 
but this will be more appropriately considered in the chapter 
on the Waters; and another most important use of the woods, 
that of confining the loose sands of dunes and plains, will be 
treated of in the chapter on the Sands. 
* See in Konn, Alpenreisen, i., 120, an account of the ruin of fields and pas- 
tures, and even of the destruction of a broad belt of forest, by the fall of rocks 
in consequence of cutting a few large trees. Cattle are very often killed in 
Switzerland by rock-avalanches, and their owners secure themselves from loss 
by insurance against this risk as against damage by fire or hail. 
