EVILS FOLLOWING DESTEUCTION OB F0EEST8. 57 



tion and drought Mlaw the destruction of forests ; but it 

 is a point upon which many students of forest science 

 have no doubt; and on the assumption of its being 

 a fact established beyond controversy, are based some of 

 the most important operations of forest economy in several 

 of the countries of Continental Europe. Of the floods in 

 question I deem it expedient to give details in greater 

 number, and to a greater extent than to others less con- 

 versant with these may seem to be called for, because I 

 have found in some cases in which a knowledge of the 

 facts was of great importance in view of interests at stake, 

 there was a lack of information both in regard to the 

 magnitude of the evil, and in regard to the connection of 

 this with the absence of forests in the basin upon which 

 the rains fell. 



As introductory to the study of such operations, and to 

 the study of phenomena upon which they are based, it 

 may be mentioned that never do we hear of such inunda- 

 tions originating in densely wooded lands, such as pre- 

 dominate in the north of Europe, but in treeless mountain 

 basins or mountain ridges ; that the formation of torrents 

 has followed the denudation of mountains of forests ; that 

 the extension of extinct torrents has followed the natural 

 reproduction of the forests destroyed ; that torrents have 

 been extinguished, and the formation of torrents has been 

 prevented, by artificial rehoisement, and in some cases a 

 belt of forest stretching acrost a mountain slope, has had a 

 similar effect. 



Sub-Section 1.— Fbanoe. 



In a volume entitled Rehoisement in France, many illus- 

 trations of these several allegations may be found. 



In this volume (pp. 328-334) are given, amongst accounts 

 of other inundations, details of the inundation of the Gar- 

 rone in 1875, by which, in Toulouse alone, 900 persons, it 

 was reported, perished, 600 houses in the town and 2000 in 

 the environs were said to have been swept away ; and the 



