228 INFLTJElSrCE OF THE FOREST ON FLOODS. 



Besides the climatic question, wMcli I have already sufficiently' 

 discussed, and the obvious inconveniences of a scanty supply of 

 charcoal, of fuel, and of timber for architectural and naval con- 

 struction, and for the thousand other uses to which wood is ap- 

 plied in rural and domestic economy and in the various industrial 

 processes of civilized life, the attention of European foresters and 

 pubhc economists has been specially di-awn to three points, namely : 

 the influence of the forests on the permanence and regular flow 

 of springs or natural fountains ; on inundations by the overflow 

 of rivers ; and on the abrasion of soil and the transportation of 

 earth, gravel, pebbles, and even of considerable masses of rock, 

 from higher to lower levels, by torrents. There are, however, 

 connected with this general subject, several other topics of minor 

 or strictly local interest, or of less certain character, which I shall 

 have occasion more fully to speak of hereafter. 



The first of these three principal subjects — the influence of the 

 woods on springs and other living waters — has been already con- 

 sidered ; and if the facts stated in that discussion are well estab- 

 lished, and the conclusions I have drawn from them are logically 

 sound, it would seem to follow, as a necessary corollary, that the 

 action of the forest is as important in diminishing the frequency 

 and violence of river-floods as in securing the permanence and 

 equability of natural fountains ; for any cause which promotes the 

 absorption and accumulation of the water of precipitation by the 

 Buperflcial strata of the soil, to be slowly given out by infiltration 

 and percolation, must, by preventing the rapid flow of surface- 

 water into the natural channels of drainage, tend to check the 

 sudden rise of rivers, and, consequently, the overflow of their 

 banks, which constitutes what is called inundation. 



The surface of a forest, in its natural condition, can never pour 

 forth such deluges of water as flow from cultivated soil. Humus, 

 or vegetable mould, is capable of absorbing almost twice its own 

 weight of water. The soil in a forest of deciduous foliage is com- 

 posed of humus, more or less unmixed, to the depth of several 

 inches, sometimes even of feet, and this stratum is usually able to 

 imbibe all the water possibly resulting from the snow which at 

 any one time covers, or the rain which in any one shower falls 

 upon it. But the vegetable mould does not cease to absorb water 

 when it becomes saturated, for it then gives off a portion of its 



