22O 



AMERICAN FORESTRY 



to base on such change any important 

 argument for congressional action. The 

 pages devoted by Professor Moore to 

 such discussion are not pertinent to the 

 case at all. 



In discussing the influence of forests 

 on floods in the latter half of his paper 

 Professor Moore fails to distinguish 

 between the characteristics of the many 

 non-navigable head-water tributary 

 streams and those of the main naviga- 

 ble stream. It should be kept clearly in 

 mind that the steep mountain basins of 

 these head-water tributaries are the 

 areas where reforestation is advocate:! 

 because they are the areas of greatest 

 erosion and greatest flood damage. The 

 marked increase in the frequency, 

 height and violence of floods in recent 

 years in the Southern Appalachians has 

 been on these head-water tributaries 

 such as the Doe, the Watauga, the 

 Nolichucky and the French Broad, for 

 instance, of the Tennessee system and 

 not in the lower Tennessee itself. In 

 March, 1907, for instance, the remark- 

 ably destructive flood in the Ohio river 

 system was at and above Pittsburg, not 

 down at Cincinnati, Louisville, or Cairo. 

 On the Savannah, the Broad, the Ca- 

 tawba, and all other large rivers head- 

 ing in the Southern Appalachian moun- 

 tains the locus of maximum flood vio- 

 lence and destruction is near where 

 they, or their head-water components, 

 first leave the mountains, not far out on 

 the plains along their middle and lower 

 reaches. Professor Moore confuses 

 these two portions. Instead of focus- 

 ing his attention on the navigable mid- 

 dle and lower parts of a river system 

 like the Tennessee, he should become 

 acquainted with the upper or head- 

 water part. Colonel Chittenden and 

 other army engineers fall into the same 

 error. The navigable portion of any 

 large river system does not exhibit such, 

 marked change of regimen as a result 

 of deforestation as its constituent head- 

 water tributaries do. Each of these 

 tributary basins is small enough to be 

 affected throughout its entire extent by 

 unusual weather conditions and the 

 tendency in such basins is toward an 



extreme condition while the tendency 

 in the trunk stream formed by the union 

 of many of these tributaries is to a 

 mean of the conditions, either high or 

 low, that characterize the tributaries. 

 Profound changes in the high and low 

 water stages of certain mountain head- 

 water tributaries might occur without 

 producing any strongly marked change 

 of regimen in the middle and lower 

 reaches of the trunk stream. A flood 

 on the Watauga, for instance, five feet 

 higher than any ever previously known 

 and utterly destructive of all property 

 within its reach might not add a couple 

 of inches to the stage of the Tennessee 

 at Chattanooga or be perceptible at Pa- 

 ducah. Professor Moore and others 

 are either ignorant of the locus of maxi- 

 mum flood damage or confuse it in 

 their reasoning with conditions in the 

 middle and lower part of the stream 

 basin where such extremes do not occur. 

 Most of their arguments apply to these 

 lower reaches. It is believed by the 

 present writer that a very general 

 change of regimen on the head-waters 

 will be reflected in a corresponding mean 

 change in the high and low water stages 

 in the main trunk stream in any large 

 river system but this mean change will 

 be far less striking on the trunk stream. 

 It should be remembered, however, that 

 so far as the navigable middle and 

 lower parts of a large river system are 

 concerned the amelioration of flood and 

 drought conditions is not the only, and 

 may not in a given case be the chief, 

 effect, but that the prevention of ero- 

 sion of steep slopes and the consequent 

 serious silting of the navigable portions 

 of the streams will also be a most im- 

 portant effect of reforestation. 



In discussing run-off and absorption 

 on page 16 it is not sufficient for Pro- 

 fessor Moore to say that ''it can be 

 shown that the run-off from a smooth 

 surface and from one covered with 

 sticks, dense grasses, or forests are 

 equal (italics mine) after the rough 

 surface becomes saturated." They may 

 be ultimately equal in total volume of 

 run-off but still be far from equal in 



