EVILS FOLLOWING DESTRUCTION 6 FORESTS. 6& 



anives^at the bottom of the valley with a rapidity of flow 

 which is greatly reduced. 



' Can it be doubted that, as a matter of fact, the trunks 

 of the trees and shrubs, the clumps of bushes and briars, 

 the tufts of heaths and brooms, the banks of rocks, and the 

 incalculable mass of vegetable detritus which covers the 

 soil of a forest, are so many barriers, against which the 

 flow comes to break its impetuosity, to lose its force 

 through sub-division, and to arrest its speed ? And ought 

 not the result of the combined action of this multiplicity 

 of obstacles be the reduction in the speed of the floods, 

 which we are desirous to secure.' 



The author quotes in support of his views several state- 

 made by M. Cezanne, and he alleges that in whatever way 

 it may be effected, there is no doubt as to the result. But 

 beyond this mechanical action there is another which may 

 also be called mechanical, but the operation of which is 

 different, though contributing to the same result. In 

 regard to this M. Gorsse says : ' To this action of the 

 covering of the ground succeeds that of the soil. 



' The soil of a forest absorbs and retains a quantity of 

 water much more considerable than other soils. To satisfy 

 ourselves in regard to this, it is only necessary to consider 

 what are its constituents, and what is the action of the 

 different elements of which it is composed. 



' First of all, its surface is covered with a thick layer 

 of dead leaves, and with a carpet of moss, of lichens, and 

 of herbage of all kinds, which uevelope rapidly under the 

 vault of the trees. This covering, so eminently spongy, 

 gorges itself with moisture, imbibes the water, and per- 

 forms the function of immense natural reservoirs, from 

 which subsequently the vegetables pump up the aliment 

 of their transpiration, and springs draw their supply, a 

 double guarantee for a more regular delivery. This is the 

 principal cause of the coolness and humidity under the 

 shade of trees, which is so persistent for a long time after 

 the cessation of the rain. There is not a peasant, a hunts- 

 man, or a tourist, who has not had experience of the fact, 



