FOREST LANDS FOE, THE PEOTECTION OF WATERSHEDS. Ill 



springs and the alarming lowering of the mean water level of German rivers, 

 and not less so in a gradual increase in the dryness of the ground, caused by 

 the fall of the level of the underground waters. 



" The unquestioned circumstance, that a large number of rivers now carry 

 down more loose material than formerly, is a consequence of the extensive 

 denudation and careless clearing of the plantations. The slopes of the hills 

 lose a large part of their fruitful soil, and in many cases earth slides and even 

 extensive subsidences of whole slopes take place, while considerable areas of 

 ground in the valleys are smothered up and rendered useless. 



" The loose material which the tributary brooks carry into the main streams 

 ceases to be carried onward as the declivity becomes fess steep, and in conse- 

 quence fills up their beds. The streams are then obliged to seek out new 

 courses, by which the most fruitful ground is devastated and the whole bed of 

 the valley is gradually transformed into a barren layer of loose stones. This 

 drawback affects not only the mountain dwellers, but, in so far as the waters 

 are not able to deposit their loose suspended material in large basins on the 

 way, the population of the lower-lying and well-tilled valleys also. Here the 

 damages further include the circumstance that, by reason of the often elevated 

 position of the riverbed, overflow waters are very difficult to get rid of. 



" Proofs of the foregoing, and especially of the last-mentioned circumstance, 

 are afforded by a large number of river valleys. This Condition of things is 

 of importance in the cases of those river or stream channels which by the 

 formation of weirs are to be made serviceable for purposes of inland naviga- 

 tion, earth slides, damages to river banks, and inundations did not take place, 

 though at a distance from the channel, lie at a lower level than the latter, are 

 swamped to the most damaging extent. 



" The foregoing is not intended to convey the idea that previous to deforesta- 

 tion, earth slides, damages to river banks, and inundations did not take place, 

 but it is intended to show that since the decrease of the forests all these dis- 

 advantages have increased to a serious and disquieting degree." 



Mr. Lauda, of Vienna, compares two similar watersheds of about the same 

 area in Austria, one being much more heavily wooded than the other. He 

 thinks the forests may not exert much influence in high floods, but concludes as 

 follows : 



" If, now, the fliial judgment on the subject of the influence of forests on the 

 regimen of streams be unfavorable to the forests to this extent, that there are 

 denied to it certain of the properties attributed to it generally, it does not follow 

 from this that it is necessary to oppose the rewooding of arid surfaces, the re- 

 planting of the basins of streams, or the maintenance of planations of trees. 

 The general utility of the forest is so well settled, the extraordinary apprecia- 

 tion in which it is held, as a means of protecting the soil against landslides, is 

 so firmly established, its great advantageousness, especially for the spring dis- 

 trict, in holding back earth thrusts and reducing the amount of sediment car- 

 ried by rivers so important, that these reasons alone justify fully the greatest 

 possible promotion of forest culture." 



Mr. Ponti, of Italy, seems to have no doubt that forests on steep slopes are 

 useful in the interests of navigation. He says : 



" In Sicily, the consequence of cutting away the forests on a vast scale in 

 the province of Messina has been also to raise sensibly the bed of the streams, 

 and many of these beds are now above the adjoining fields." 



Mr. Keller, of Austria, thinks that forests affect the regimen and discharge 

 of rivers only to a slight extent except in mountainous regions, regarding 

 which he says : 



" However, there is no doubt that hi many cases deforestation has contrib- 

 uted to the erosion of the mountains and to the deposit of their soil at their 

 foot, as also to an unfavorable change in the conditions of flow and drainage 

 of the waters. This remark applies equally to the regions of high mountain 

 ranges as to the Mediterranean basin. There are also the formation of a 

 cohesive soil takes too long to make good the loss caused by a sudden shower." 



Mr. Lokhtine, of Prussia, does not discuss particularly the effect of moun- 

 tain forests, but among his conclusions is the following: 



"(1) Forests form a beneflcieut factor, acting favorably on the general abun- 

 dance of water in a country, and particularly on the supply of streams and 

 rivers. That is why the destruction of forests should be considered as hurtfu! 

 and dangerous." 



These extracts show that foreign authorities are unanimous as to the benefits 

 of forests on the mountains upon the liow of streams and the interests of 

 navigation. 



