GEXEEAL PHYSICAL EFFECTS OF REMOVAL. G15 



amount of water. Water reaching the ground in the form of 

 rain, clew and snow, is chiefly retained by the litter and humus, 

 whence part of it penetrates into the layer of soil occupied 

 by the roots of the trees, and part of it is evaporated into the 

 lower strata of the atmosphere. The soil -covering of litter 

 therefore forms a permanent water-reservoir which is never 

 completely dry, and is constantly supplying springs with water. 

 Forest moss in particular retains large quantities of water ; it 

 absorbs the heaviest falls of rain, so that the casual observer 

 can hardly imagine what has become of the water. 



If mountain-slopes are deprived of litter, the soil being 

 exposed by the sun's rays or merely slightly covered, atmos- 

 pheric precipitations are not retained ; very little water penetrates 

 into the hardened soil, most of it lainning down into the valleys. 

 The numerous mountain-rills of water unite in a few hours 

 time into overflowing mountain-torrents, which carry destruction 

 down to the villages below. The steeper the mountain-slopes, 

 and the more abrupt the descent of the rills, the more rapidly 

 does the water collect and the greater its force ; the loose 

 transportable forest soil is carried down into the valleys, 

 permanent water-courses are formed in the mountain-sides, 

 which, after a few years, become deep ravines and constantly 

 encroach on the surrounding land. The rapidly accumulating 

 water often forms a powerful torrent and carries down sand, 

 gravel, stones, rocks, in fact every thing in its path, to the 

 agricultural lands below. This erosion is most destructive on 

 steep limestone and sandstone formations, and in many countries 

 every storm of rain or rapid melting of the snow causes the 

 greatest anxiety (as in the Eifel, Aarthal, Haardtgebirge, 

 Franconia, Tyrolese and Swiss Alps, Rhone-valley, &c.). 



When once a forest has lost its soil-covering of litter, moss 

 and humus, it has practically lost all its natural utility to the 

 welfare of a country ; for this chiefly consists in a uniform 

 distribution of the yearly atmospheric precipitations. Countries 

 where the mountain-forests have been destroyed are more and 

 more exposed to ruin by floods. Whatever damage may have 

 been caused in certain cases by the clearance of forests, is as 

 certainly effected in forest districts where the pest of excessive 

 removal of litter is permitted. These effects are merely the 



