PHYSICAL, ECONOMIC, AND SOCIAL 381 



degree colder, than the surrounding air, and sometimes are the means of condensing 

 enormous quantities of aqueous vapor, which they introduce to the soil in a liquid 

 state. Moreover, it is not uncommon, especially in winter time, to see the soil which is 

 immediately shaded by a tree, receive more water than a neighboring point in the forest 

 where there is a gap in the shade. For the rest it would seem that the loss of water aris- 

 ing from its retention by the crowns is inferior to the increase of water obtained by the 

 presence of the forest itself. This fact has assuredly been established in the case of the 

 broadleaved plantations in the neighborhood of Nancy; it would seem also certain in 

 the case of the plantations of Scotch pines and larches, and it is probable even for those 

 of spruce pine. One can therefore affirm that, in spite of the screen afforded by the 

 treetops, generally speaking, the forest soil receives more water than does the neigh- 

 boring soil under cultivation. 



(3) The forest causes an enormous diminution in physical evaporation, and prevents 

 surface flow almost entirely. Moreover in numerous cases where one of these phe- 

 nomena and a fortiori when both simultaneously play a preponderating part, as 

 often happens in hot countries and on sloping ground, it is unreservedly admitted that 

 the forest is favorable to the feeding of the subterranean sheet, and in consequence to 

 that of springs. 



(4) So far as our researches have actually progressed, we cannot be sure that the forest 

 is favorable or unfavorable to the feeding of subterranean waters in level ground or 

 in cold or temperate climates. 



As a matter of fact we are ignorant as to whether its vegetation does not abstract more 

 water from the soil than do agricultural vegetables, as the lowering in the level of the 

 phreatic waters observed under the woodlands would seem to indicate. It may be that 

 such an increase in the communication is compensated by the increase in the watering 

 of the soil, and the reduction in physical evaporation when these two last factors are 

 unimportant (as for example at low altitudes and in cold climates). For the rest, the 

 facts noted are contradictory; cases of springs are quoted which have dried up in conse- 

 quence of clearings as, on the other hand, superficial dryings up of the soil have been 

 observed, where replanting has taken place. Doubt is therefore forced upon us in this 

 special case; the action of the forest on the feeding of the springs remains uncertain, and 

 it is probably variable according to circumstances which, as yet, remain unelucidated. 



(5) Nevertheless it must be observed that springs are only numerous and important 

 in mountain regions, and there certainly the forests are favorable to them. 



In the plains the springs are infrequent, and have a feeble output. We are therefore 

 justified in repeating, as our fathers declared, that the forest is the mother of the rivers; 

 the labors of modern science have served only to establish the parentage, universally 

 and at all times recognized, which connects the spring with the tree which shades it. 



To-day there is strong sentiment in favor of forests. Newspapers defend, Congress 

 discusses and prepares laws for them, associations organize for the protection of existing 



1 La Foret, A. Jacquot, pp. 287-305. Digest and part translation made with a view to 

 preserving Jacquot's picturesque language. According to scientific research Jacquot 

 exaggerates, but it must be borne in mind that he is presenting the subject of forest 

 influences from a popular viewpoint. 



