operations Under the Weeks Lazv. 35 



rapidly during such downpours, that only a small proportion of 

 the falling water can sink into even the loosest of soils. The 

 water, therefore, unless held by the sponge-like leaf mould, rushes 

 down the steep slope carrying its maximum load of soil and sand. 

 The truth of these statements is evident to anyone who has ever 

 been in these mountains during one of these heavy rains. 



It is also worth nothing that the season of heaviest rainfall in 

 these mountains is usually the season of lightest rainfall in the 

 low countr}^ To conserve this summer water and give it to the 

 streams evenly and regularly means an even and regular supply 

 of water to the rivers during their season of low water. 



Erosion as Affected by Man. 



Among the ways in which man's work accelerates erosion may 

 be mentioned lumbering, clearing and cultivating the soil, burn- 

 ing the forests, and pasturing. The effects of all these agencies 

 are presented to even the casual observer in the area under dis- 

 cussion. They all tend materially to increase erosion regardless 

 of the type of soil or the geological formation of the region. The 

 greatest amount of damage is done to the soil, and consequently 

 the greatest amount of danger comes to the streams if the slopes 

 are steep and the soil loose and sandy. In this area the most 

 extensive formation is the Carolina gneiss, which makes high 

 mountains and ridges with very steep slopes, and produces a very 

 loose, micaceous and sandy soil. This is therefore a region which 

 should be protected from agencies which tend to accelerate 

 erosion. 



Man's activities have less effect upon overcreep than upon any 

 other type of erosion prominent in the mountains, but it appears 

 tliat by killing out the roots, and by tilling the steep slopes, he 

 greatly accelerates even this type. As to his effect upon the other 

 types, hundreds of bare and fallow and cultivated washed and 

 gullied mountain slopes, and many sediment-laden streams 

 throughout the region give unmistakable evidence of the dis- 

 astrous results of his activities. 



Of all man's activities, lumbering the mountain slopes has the 

 least eft'ect in accelerating erosion, and, indeed, if the work be 

 done with reasonable care and without burning, every stick of 

 marketable timber may be removed from a mountain slope with- 

 out any danger of excessive erosion. In this region it is the 

 undergrowth that holds the soil, and any agency that does not 

 destroy this will have little or no tendency to bring about in- 

 creased erosion. 



Fire is a notable agent of waste in this region, since it not only 

 increases erosion but wantonly destroys the marketable timber, the 

 young trees and the undergrowth. As far as could be determined 

 from observations in the field there is a marked increase in the 



