90 MODERN FOREST ECONOMY. 



in mountains \vith great wooded slopes, below these the 

 fields and dwellings enjoy a certain security, thanks to the 

 existence of the forest; but if this forest come to be 

 ravaged, avalanches immediately make their appearance, 

 and carry destruction tp the lower lying properties. It 

 would be easy to give the names of more than one hamlet 

 in the mountains which is thus protected by a forest, the 

 inhabitants of which have no idea that their existence 

 depends on that of the forest/' '* 



The landslip differs from an avalanche; but against 

 this evil also protection is afforded by woods and forests. 

 M. de Grosse having occasion to state that inundations are 

 sometimes attributable to the filling up of the river bed 

 with mud, and sand, and gravel, and stones, brought down 

 by floods, adverts to allegations which had been made 

 that the quantity of matter thus deposited was too incon- 

 siderable to justify the importance attached to it by him 

 and some others, and having in defence adverted to the 

 fact that the quantity was by no means inconsiderable, 

 he goes on to say : ' Now forests exercise a most power- 

 ful influence on the consolidation of the soil and the 

 maintenance of earth and rocks on the slopes of the 

 mountains. They act both by the trunks and the roots 

 of the trees : by the trunks, in arresting the fall of dis- 

 lodged rocks which were rolling over the slopes devoid of 

 woods, towards the bed of the torrents ; by the roots, in 

 opposing an invinsible resistance to the diluent action of 

 water, and insurmountable obstacles to landslips. It is in 

 making a trench in a forest, and observing the inextricable 

 interlacing of roots in which are enclosed clods of earth 

 and fragments of rocks, that one can alone form any idea 

 of the intensity of these resistances. " Vegetables," some- 

 where says M. Cezanne, " always consolidate the soil ; the 

 roots are like the meshes of a net ; they let pass the 



* Philippe Breton, Ingenieur des Fonts et Chaussees, Etude d'un Systeme General 

 de Defense Contre les Torrents des Alpes. Concerte'e entre les Fonctionnaires des 

 Forfts et des fonts et Chaussees (p. 39). 



