CAUSES INFLUENCING FLOW OF RIVER. 



17 



west of the city of Nancy, France, which are summarized in the fol- 

 lowing extract taken from a table in the publication referred to on 

 page 16: 



inference in precipitation under forest cover and in a clearing within the forest. <*> 





May to October. 



November to April. 



Entire year. 



Period, 1867 to 1898. 



Within 



the 

 clearing. 



Within 



the 

 forest. 



Within 



the 

 clearing. 



Within 



the 

 forest. 



Within 



the 

 clearing. 



Within 

 the 



forest. 



Average seasonal and annual precipita- 



474. 8 



421.7 



372.1 



360.4 



949.9 | 782.1 







Percentage of precipitation within the 

 forest as compared to that within the 



88.8 



96.9 



92.4 

















« The observations were conducted in a deciduous forest, situated on a slight uplift or plateau to 

 the west of the city of Nancy, France. 



The other element of loss, namely, the amount of water consumed 

 and transpired by the trees, has been repeatedly investigated, but the 

 subject is extremely complicated. The consumption varies with the 

 kind of soil and its physical condition, with the amount of the rain- 

 fall, with the condition of the atmosphere, and, in still greater meas- 

 ure, with the species of tree and character of forest. The figures 

 resulting from these investigations consequently show very wide 

 limits, and it still remains somewhat doubtful whether forests, as com- 

 pared with field crops, require more water for their g-rowth, or less. b 



influence of the forest on water distribution. 



It i.s well known that forests also economize the distribution of rain 

 water. The constantly decaying mold and the litter of freshly fallen 



h A table by Risler, which has been frequently quoted, is here reproduced from 

 Vol. Ill of the Final Report of the State Geologist of New Jersey for 1894 (p. 36) : 



Daily consumption of water for different crops. 



Lucern 



Meadow grass * 122 to 



Oats 



Indian corn 



Clover 



Vineyard 



Wheat 



Rye 



Potatoes 



Oak trees 



Fir trees 



In the Chronique Agricole du Canton de Vaud for June 10, 1901, the general 

 statement is made that forests require only half as much water as cultivated lands of 

 equal area. 



Inch. 





0. 134 to 



267 



. 122 to 



287 



. 140 to 



193 



. 110 to 



157 



. 140 to . 





. 035 to 



031 



. 106 to 



110 



. 091 to . 





. 038 to 



.055 



. 038 to 



030 



. 020 to 



043 



687— No. 4:4—03- 



9, 



