THE INFLUENCE OF FORESTS ON CLIMATE AND FLOODS 237 



phis or New Orleans. It is hardly fair, comparatively easy ; and it should fur- 

 therefore, as Professor Moore does, to ther be noted that the erosion from flat, 

 compare the mountain watershed of the cultivated lands can be largely pre- 

 Ohio River with the entire drainage vented by proper methods of cultivation 

 area of that stream. The mountain and plowing, which will not allow the 

 watershed is more fairly to be compared water to flow with great velocity 

 with the drainage area above Pittsburg, through the furrows. Plowing should 

 of which it would form a considerable be done not up and down the slopes, 

 proportion. b ut a i on g the contours. Land suitable 

 The sediment brought down by the f or cultivation should be used for culti- 

 mountam stream is, in the course of vation if necessary, but there is noth- 

 years, washed farther and farther i ng i n a n t hi s discussion of Professor 

 down the river, and that carried in sus- Moore's which casts a shadow of doubt 

 pension is gradually deposited, as the O n the efficacy of the mountain forests 

 slope becomes less and the velocity of as conservators of the navigability of 

 the flowing water correspondingly less, streams. 



in the bed of the stream. Subsequent Before leaving this subject, it may be 

 floods find therefore a smaller chan- as we il to say that probably the best 

 nel m which to flow, the bed of the authorities upon it are neither meteorol- 

 river having been raised by sediment O gi sts n or engineers in general practice, 

 brought down by previous floods. The but foresters and forest engineers, and 

 floods, therefore, in the lower reaches, that these are practically, if not quite, 

 finding the channel contracted, are unanimous as to the value of forests, 

 obliged to rise higher and to overflow An engineer whose duty it is to main- 

 bottom lands, and in doing so they wash ta i n harbors and the navigable por- 

 away the banks where these are al- tions of streams, like the officers of our 

 luvial, causing still more material to Corps of Engineers, does not, in the 

 be swept into the channel of the river, course of his daily experience, have 

 At the same time, some of the sedi- mllc h opportunity to observe or study 

 ment from above is deposited over the f ore st questions/ He sees banks cave 

 bottom lands. and the ma t e rial form a bar below ; he 

 Now, the point is and it may as does not see the constantly-moving mass 

 well be once more emphasized that of sediment in the bottom of the 

 even if the banks in these lower por- stream ; he does not see the erosion on 

 tions were protected against washing the mountain slopes ; out of sight is out 

 away, the gradual filling up of the chan- of mind, and he may easily faid to rec- 

 nel of the stream by sediment brought ognize the importance of what he does 

 down from above would in itself cause not observe. Professor Moore ad- 

 the floods to rise higher and higher as mitted that he had never studied ero- 

 the years go by, and to overflow larger sion in the mountains, and yet he pre- 

 and larger areas. Once more to quote sents a paper which dismisses this most 

 Major Suter and Colonel Chittenden, important element in less than one page 

 "the influx of sand from above must and which is offered as a presumably 

 first be stopped." weighty contribution to a great sub- 

 To estimate, therefore, the value of ject! 



the forests in preventing erosion, it is A volume could be filled with quota- 



grossly incorrect to compare the moun- tions from the writings of those who 



tainous area with the total area of a have observed this matter, but as an 



large drainage basin. If we could pro- illustration only one will be given from 



tect the mountain sides, and limit the a review of a work published in 1901 



erosion to what would naturally come on "Forestry in British India," by 



from flat, cultivated land, and from Berthold Ribbentrop, who has spent 



caving banks, the problem would be thirty-four years in the forest service. 



