284 MIJS"OE USES OF THE FOEEST. 



Minor Uses of the Forest. 



Besides the important conservative influences of the forest, and 

 its value as the source of supply of a material indispensable to all 

 the arts and industries of human life, it renders other services of 

 a less obvious and less generally recognized character. 



Woods often subserve a valuable purpose in preventing the fall 

 of rocks, by mere mechanical resistance. Trees, as well as herba- 

 ceous vegetation, grow in the Alps upon dechvities of surprising 

 steepness of inchnation, 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 He scattered on the face 

 of these dechvities, they are held in place by the trunks of the 

 trees, and it is very common to observe a stone that weighs hun- 

 dreds of pounds, perhaps even tons, resting against a tree which 

 has stopped its progress just as it was beginning to shde 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 extremely 

 useful as a check to the swift flow of the water in inundations, 

 and the spread of the mineral material it transports ; but thi& 



leave large spaces between the different quarters of the town for the free pas- 

 sage of the descending masses. Attempts have been recently made to prevent 

 these avalanches by means similar to those employed by the Swiss mountain- 

 eers. They cut terraces three or four yards in width across the mountain 

 slopes and support these terraces by a row of iron piles. Wattled fences, 

 with here and there a wall of stone, shelter the young shoots of trees, which 

 grow up by degrees under the protection of these defences. Until natural 

 trees are ready to arrest the snows, these artificial supports take their place 

 and do their duty very well. The only avalanche which swept down the 

 slope in the year 1860, when these works were completed, did not amount to 

 350 cubic yards, while the masses which fell before this work was undertaken 

 contained from 75,000 to 80,000 cubic yards."— Xa Tetre, vol. i., p. 233. 



* See in Kohi,, 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 rocka 

 in consequence of cutting a few large trees. Cattle are very often killed io 

 Switzerland by rock-avalanches, and their owners secure themselves from los» 

 by insurance against this risk as against damage by fire or hail. 



