THE INFLUENCE OF FORESTS ON CLIMATE AND FLOODS 231 



tion of bars, the silting up of channels, 

 do not depend upon extreme conditions. 

 Three or four moderate floods may do 

 as much damage to a navigable river as 

 one extreme flood, and may bring down 

 more sediment to be deposited in the 

 river bed. Professor Moore's authori- 

 ties in this particular discussion are 

 Prof. Cleveland Abbe and two French 

 engineers, M. Belgrand and M. Valles, 

 both of whom wrote their original dis- 

 cussions on this subject over fifty years 

 ago. To his quotation from Profes- 

 sor Abbe we need pay little attention, as 

 it has reference to level ground, 

 whereas we are discussing the effect of 

 forests on steep slopes. Ploughed and 

 cultivated land is very likely quite as 

 porous and quite as able to absorb rain- 

 water as forest ground, as Professor 

 Abbe says. It is quite easy to under- 

 stand, however, how he can make out 

 that "under a forest less rain actually 

 enters the humus," and yet goes on to 

 say "that the amount of water that is 

 eventually given up from the forest 

 humus varies but little from that given 

 up in the course of time by the tin for- 

 ested cultivated soil." Less rain enters 

 the humus but essentially the same is 

 given up from it. 



With reference to the French writers, 

 Belgrand and Valles give exactly the 

 same arguments that are advanced by 

 Professor Moore, and by Colonel Chit- 

 tenden in his recent paper to which the 

 present author published a reply a few 

 months ago. A sample of M. Valles' 

 reasoning may be quoted to show the 

 kind of logic which appeals to his mind. 

 He says that the forest ground is less 

 porous than bare ground because if you 

 should ask a laborer in which he would 

 prefer to dig a hole he will select the 

 latter. He might as well argue that 

 an acre covered to a depth of ten feet 

 with a mattress of barbed wire was less 

 porous than hardpan for the same 

 reason. As a matter of fact, both of 

 these authors entirely agree with the 

 position taken by the present writer and 

 by those who urge the passage of the 

 Weeks bill, that forests should be main- 

 tained on steep slopes which are unsuit- 

 able for cultivation. Belgrand says : 



"The operation of reforestation is 

 thus excellent when practically possible, 

 although it seems demonstrated that the 

 deforestation of the basin of the Seine 

 cannot be considered one of the causes 

 which contributed to increase or to de- 

 crease the height and the number of 

 floods. But the forests diminish very 

 notably the volume of earthy matter 

 transported by the streams, because they 

 prevent the erosion of the eairth, and, it 

 must be recognised that the impoverish- 

 ment of the earth is much more to be 

 deplored than the disasters caused by 

 floods." 



M. Valles says : "If the demand is 

 limited to the reforestation of the sum- 

 mits and uncultivated slopes, we wish 

 well of it, but less from the point of 

 view of diminishing the quantity of 

 water discharged than from that of pre- 

 venting the erosion of the earth, partic- 

 ularly if a study is made of reforestation 

 in itself, which shall indicate to us, first, 

 in what circumstances it can be realized, 

 and in the second place, under what 

 conditions it will be useful at the same 

 time to private interests, and will be for 

 the general good. If it is thus that we 

 are to understand the advocates of this 

 system, we do not hesitate to join with 

 them ; but if their demands are more 

 extended, if they wish us to reestablish 

 on ancient foundations a condition of 

 things which has been usefully modified, 

 if they desire that we should prefer the 

 Druid ical forests to our modern farms, 

 the trees to the corn, the corn to the 

 grain, we say to them for the third time : 

 reforestation will not do." 



Bearing in mind that Professor 

 Moore's argument was written as a 

 contribution to the discussion involved 

 in the Weeks bill, it would be interest- 

 ing to inquire why he did not quote 

 these two passages, if he knew them. 

 If he did not know of them he should 

 not discuss the subject and .give the 

 erroneous impression that these authors 

 denied the necessity of preserving the 

 mountain forests. 



Equally misleading is Professor 

 Moore's quotation from the Austrian 

 engineer, Mr. Ernest Lauda (page 19) 

 and the conclusions of the Tenth Inter- 



