198 EFFECTS OF FORESTS ON SPRINGS AND RIVERS. 



earth, is kept by the spougy character of the ground in woods from 

 flowing quickly away, and is in part absorbed, or is left to permeate 

 the mineral strata, which is considerably facilitated by the numerous 

 spreading roots of the trees penetrating cracks, fissures, and canals in 

 the superficial ground, by which means the rain water reaches a 

 greater depth, and this in a much greater quantity in forest ground 

 than in the open field. Further, by numerous experiments it has 

 been established that the evaporation of the humidity in the open 

 country is at the least from four to five times as great as it is in wood- 

 lands ; from all which it appears that the moisture absorbed in forests 

 is not so readily evaporated, but is retained and directed to the feed- 

 ing of drainages, springs, and brooklets. 



" 3. If forests be uprooted, more especially in mountainous regions, 

 or even in somewhat hilly country, the rain drops, falling upon the 

 exposed ground with some force, tear it up, and then flowing down the 

 declivity with considerable rapidity carry with them earth and stones 

 towards the brooks and streams and rivers, by which these water 

 courses are suddenly filled up, and experience much higher and more 

 devastating overflowings, and inundations, than was the case while 

 the woods stood, as is explicitly testified by the aforementioned 

 tabulated observations of river levels. 



" 4, Through the extensive clearing away of forests the heat of the 

 summer months and the desiccation of the ground becomes increased, 

 then, as a consequence of this, the duration of droughts is prolonged, 

 and from this there follows naturally a diminished productiveness of 

 the land. 



" These most disastrous effects of the clearing away of forest show 

 themselves in a very marked degree in these countries, once blessed 

 with a luxuriant vegetation, Palestine, Persia, Greece, Sicily, Spain, 

 and the Canary Islands." 



It is stated also that " a great cause of the diminution of water 

 aupply from springs and subterranean reservoirs in Europe has been 

 the draining of lakelets and ponds, and the draining of bogs and 

 marshes, which has taken place, in various parts, of late years." And 

 " a third cause of the diminution of water in springs and rivers at 

 present going on is to be sought for in the greatly extended, and 

 still from year to year extending, operations to bring under culti- 

 vation, to cultivate, and to improve the land." Of both of which 

 statements illustrations are given, with illustrations of the effect of 

 the latter when carried on on hill sides, to increase the violence and 

 the maguitude of torrents and devastating inundations. 



