49 



PARAGRAPH XX. 



SPRINGS AND RIVERS. 



The influence exercised by the forest over the discharge of the 

 rivers cannot be established by experimentation. 



Experiments consisting in guage readings within the same river 

 basin, prior to, and after deforestation, are out of the question ; 

 and if they were possible, the results obtained would be in- 

 fluenced, in all probability, more by the periodic change of the 

 rainfall than by the presence or absence of the forests. 



Another possibility in parallel experiments would be the com- 

 parison of the discharges of streams situated together as close 

 as possible, draining one and the same geological formation, 

 having one and the same rapidity of fall, and one and the same 

 aspect: The drainage basin of one of these streams should be 

 deforested, and the other should be kept abundantly stocked with 

 forests. 



Even here, however, absolute parallelism of the factors [other 

 than forests] influencing the discharge of the two rivers cannot 

 be established. A near approach to parallel factors was obtained 

 by the Biltmore Estate with the help of the Hydrographic Branch 

 of the National Geologic Survey, when there was controlled by 

 it, on the one hand, the discharge of Davidson's river, Transyl- 

 vania county, North Carolina; and, on the other, the discharge 

 of the Tuckaseegee river, in Jackson County, North Carolina. 

 These streams are draining the same geologic formation ; their 

 headwaters are found within one and the same range of moun- 

 tains ; the steepness of the slopes is the same on both watersheds. 

 A vital difference, however, is found in the treatment to which 

 the soil of the forest has been subjected : The headwaters of 

 Davidson's river have been protected from fires, from heavy 

 lumbering, from reckless farming, and from erosion on the hill- 

 sides ever since 1895. The headwaters of the Tuckaseegee river, 

 on the other hand, have been burnt, farmed, pastured, and 

 logged ; so much so that, in many cases, the entire litter on the 

 forest floor is destroyed. 



SCHENCK, FOREST POLICY. 4' 



