i68 



AMERICAN FORESTRY 



the naked roots of the gum-trees hang 

 sadly from the top of the compact clay 

 banks. 



The Ohio River, which descends 

 from the now denuded slopes of the 

 Alleghany Mountains, "is the cause of 

 the largest and most disastrous floods 

 in the Mississippi.'" The streams swell 

 very rapidly in the southern and west- 

 ern part of the Alleghanies, and it is 

 not unusual for a river to rise twentv 

 meters in a few hours. 



On the banks of the Kansas River, 

 a tributary of the Missouri, one can 

 observe the remarkable effect that for- 

 est vegetation has in protecting the soil 

 against erosion by floods. A stretch 

 of about two hectares, which had been 

 deforested in 1900 was carried away in 

 May, 1903, by a flood. The steep bank 

 of the river, being no longer protected 

 by the trees that had grown along the 

 edge, was swept away and the flood 

 covered twenty-four hectares of arable 

 land with sterile sand. Above this 

 point, where the owners on the river 

 had taken care to preserve the trees 

 along the edge of the bank, the flood 

 caused no erosion.' 



It has been verified in the United 

 States that the flow of the rivers and 

 streams has decreased in all deforested 

 regions. Certain streams near Boston, 

 the power of which was formerly util- 

 ized in manufacturing enterprises, no 

 longer have sufflcient flow and the man- 

 ufacturers have been obliged to use 

 steam. The tributaries of the Connecti- 

 cut have diminished considerably in 

 volume and the beds of some are dry 

 during summer.* 



Mr. T. P. Lukens reports in the 

 magazine Forestry and Irrigation a 

 striking example of the influence of 

 forests in regulating stream-flow in 

 southern CaHfornia. The basin of the 

 San Gabriel River, which includes an 

 area of 222 square miles, having been 

 burned over by fires that destroyed all 

 the forest vegetation, the flow of the 



stream at low water was reduced to 

 ninety inches. During the same pe- 

 riod the minimum flow of th*^ San An- 

 tonio River, the basin of which, 267 

 square miles in extent, was forested 

 over more than one-half the area, did 

 not fall below ninety inches [190 inches 

 according to Mr. Lukens' account]. 



In the same journal Mr. W. B. 

 Greeley gives an account of some in- 

 vestigations made by the United States 

 Forest Service froni 1901 to 1903 of the 

 flow of the Esopus and of the Wallkill, 

 tributaries of the Hudson River. The 

 drainage basin of the latter stream, of 

 clay and marl formation and with mod- 

 erate slopes, contains five and four- 

 tenths per cent of natural reservoirs 

 (lakes, swamps, or ponds) ; eighty-five 

 per cent of the area is cleared. The 

 basin of the Esopus is of permeable 

 soil ; the topography is very irregular 

 and the slope in general twice as steep 

 as in the basin of the Wallkill. Clear- 

 ings have been made over only fifteen 

 per cent of the area. The precipitation 

 and temperature being the same in the 

 two basins, it has been found that the 

 average deviation from the mean 

 weekly flow in the two streams, during 

 the three years, was seventy-eight and 

 one-fifth per cent for the Wallkill and 

 eighty-three and seven-tenths per cent 

 for the Esopus. The presence of for- 

 est growth in the basin of the latter 

 stream counterbalances the unfavorable 

 conditions of topography, and geologic 

 formation of the soil and the absence 

 of lakes and other natural reservoirs. 



A publicist whose economic studies 

 of Germany and the United States have 

 classed him as without an equal, writes 

 in regard to the forests of Canada : 

 "Recent federal laws have just regu- 

 lated the cutting of timber, which was 

 carried on formerly in too destructive 

 a manner. The people have come to 

 the conclusion rightly that forests were 

 not to be considered only as 'a collec- 

 tion of trees to cut down and make into 



•p. Camena d'Almeida, la Terre, I'Amerique, I'Australie, p. 192. 

 ''Forestry and Irrigation, Washington, February, 1904. 



"J. Lcfaivre, attache an Consulat general de France a New York. Rapport au Ministrc. 

 Bull. Min. Agriculture, fasc. B., 1885, imprimerie Nationale. 



