FAVORABLE TO WHITE MOUNTAINS 



the forest cover of the 

 White Mountains has a distinct 

 and measurable effect upon the 

 navigable streams which head in that 

 region is the unequivocal and emphatic 

 statement of the United States Geologi- 

 cal Survey. The Director of the Sur- 

 vey has filed his preliminary report on 

 the White Mountains with the National 

 Forest Reservation Commission, and, 

 as earlier announced, the findings are 

 favorable to the purchase of lands un- 

 der the Weeks law. 



The report of the Geological Survey 

 is based on the results of exhaustive in- 

 vestigations and specific field tests 

 which have been carried on during the 

 last year. While the Survey has been 

 subjected to frequent criticism and 

 even bitter attacks, owing to its refusal 

 to submit a perfunctory report assum- 

 ing that a known and definite relation 

 exists between forests and stream flow 

 in the White Mountain region, the out- 

 come of its investigations must not only 

 satisfy the most radical forest enthusi- 

 ast, but it precludes the possibility of 

 criticism by those who have opposed 

 the acquisition by the Government of 

 any forest lands, on the theory that 

 forest preservation does not affect 

 stream flow. The investigations are be- 

 lieved, indeed, to solve definitely a 

 problem that has long been a source 

 of strenuous contention among scien- 

 tists, including the friends of forest con- 

 servation, and while these investiga- 

 tions have direct reference to the en- 

 tire White Mountain area, they estab- 

 lish a principle which is of far wider 

 application. 



The Weeks Forest Reservation Law 

 places upon the Geological Survey the 

 responsibility of establishing, before 

 purchase, the fact that forest lands 

 have an effect upon the navigability of 

 navigable streams, and the law pro- 

 vides that the Survey shall make a field 

 examination of every tract offered to 

 the Government for sale thereunder. 

 The Survey has insisted on following 

 the plain mandate of the law and mak- 

 ing such axaminations, not at an office 



desk but actually on the ground, in a 

 thoroughgoing, scientific manner. 



In the southern Appalachian Moun- 

 tains tracts aggregating 1,962,800 acres 

 have been certified to by the Geological 

 Survey as affecting the navigability of 

 streams by reason of the excessive 

 erosion which follows deforestation in 

 these areas. Owing to the geologic con- 

 ditions in the White Mountains, no ex- 

 cessive erosion, according to the Sur- 

 vey geologists, can be shown to follow 

 deforestation. Therefore the Survey 

 carried forward its further investiga- 

 tion in the White Mountains along the 

 lines of trying to show that deforesta- 

 tion and subsequent burning of the for- 

 est mulch results in a more rapid run- 

 off and therefore tends to make un- 

 stable the flow of streams. 



The hydrometric showing presented 

 in the preliminary report covers results 

 on two small, almost exactly similar 

 drainage basins of about 5 square miles 

 each, on the east branch of Pemige- 

 wasset River, one largely clothed with 

 virgin timber and the other deforested 

 and burned. The facts observed are 

 so striking as to render the position of 

 the Survey impregnable. Careful meas- 

 urements of precipitation over the areas 

 and of the run-off of the respective 

 streams show that not only was the 

 snow held better in the forested area, 

 but that during a period of 17 days in 

 April, including three extended storms, 

 the run-off of the stream in the de- 

 forested area was a comparative flood 

 practically double that of the stream 

 flowing through the forested area, as 

 shown graphically below. 



6.48 inches. 



Run-off of Shoal Pond Brook (forested 

 area) during three storms in April, 1912. 

 __^ K ^ KBK _^r~R~ - in. 



Run-off of Burnt Brook (deforested area) 

 during same storms. 



Diagram comparing run-off from forested 

 and deforested basins. 



In the Shoal Pond Brook basin (the 

 forested area) the Survey established 



441 



