FOREST-CULTURE IN ALPINE RAVINES. 831 



often wholly dry, it becomes a flood after a storm, and overcomes all 

 the obstacles that oppose its course. There are clear torrents and 

 muddy torrents. The former, which are the torrents of eruptive 

 regions, carry but little matter with them, and are characterized by 

 sudden freshets, which are due to the fact that the waters running over 

 impermeable rocks, are precipitated immediately into the ravines and 

 collect in considerable masses. The torrents of the second class have 

 formed themselves beds in the loose soil, are continually washing away 

 the bases of their banks, provoking slides, carrying with them solid 

 matters derived from the degradation of the hills, and discharging 

 them in the lower valleys and covering the fields with a thick mud. 

 The bed of the torrent is washed out more and more, and the banks 

 increase at the same time ; new ravines are formed, and branches of 

 them, thus eating away the spur of the mountain, which is gradually 

 destroyed, or which, undermined at the base, occasionally slides bodily 

 into the valley, which it closes up. 



Attention has long been given to devising means to limit the 

 ravages of these torrents, which ruin the land, threaten estates, de- 

 stroy roads, and sometimes even compromise the existence of villages. 

 Walls have been built along the banks to protect them, or across 

 the streams to allay the force of the waters. The most efficacious 

 means, however, as yet discovered, has been to maintain the woods on 

 the slopes of the mountain. The effect of cutting away the trees in 

 promoting the formation of torrents has not been doubted by the in- 

 habitants of mountainous regions, and is clearly set forth by M. Sur- 

 rell, who says : " When we examine the tracts in the midst of which 

 torrents of recent origin have been formed, we perceive that they 

 have in all cases been despoiled of their trees and bushes. If, on the 

 other hand, we examine hills whose sides have been recently stripped 

 of wood, we observe that they are cut up by numerous torrents, which 

 have evidently been formed very lately. Here is a remarkable double 

 fact : wherever there are recent torrents there are no longer forests, 

 and wherever the ground is cleared these torrents are formed ; and 

 the same eyes that see the woods fall on the declivity of a mountain, 

 may see appear there immediately a multitude of torrents." 



The disastrous consequences of removing the woods from the Alps 

 began to attract attention in the last century, and have since been dis- 

 cussed in many publications and official reports. In 1853 the prefect 

 of the department of the Lower Alps said in a report to the Minister : 

 *' If prompt and energetic measures are not taken, it will be almost 

 possible to designate the precise m.oment when the French Alps will 

 become a desert. The period from 1851 to 1853 will j)roduce a new 

 diminution in the number of the pojDulation. In 1862 the Minister 

 will remark a continuous and progressive reduction in the number of 

 hectares devoted to agriculture ; each year will aggravate the evil, 

 and in a half-century France will count more ruins and one depart- 



