104 FOEEST LANDS FOR THE PROTECTION OF WATERSHEDS. 



certainly not true that only extreme conditions affect the navigability of 

 streams or " determine the character and cost of river control." Extreme con- 

 ditions determine certain elements, such, for- instance, as the height of levees. 

 Colonel Chittenden certainly can not mean to state that ordinary, everyday 

 floods do not carve away banks and cause shoaling of channels, rendering 

 dredging necessary for navigation. A few high but not extreme floods may do 

 much more damage than one extreme flood, and may necessitate more expendi- 

 ture for dredging and other purposes. Extreme conditions are in the nature of 

 freaks. They occur only at intervals of many years. It would seem to be more 

 nearly correct to state that the interests of navigation are governed more by the 

 usual conditions, and that it is possible for extreme conditions at rare intervals 

 to interrupt traffic for a short time without causing much loss. It may as well 

 be argued that it is not wise to attempt improvements on railroads because an 

 earthquake or a tornado or an extreme flood in a river may destroy a portion 

 of the track and interrupt traffic for a while. It matters little in the naviga- 

 bility of a stream if at intervals of twenty, thirty, or fifty years an extreme 

 drought occurs for a few days or weeks, making the depth of the channel 

 insufficient for the largest vessels. 



If it be true, therefore, that extreme conditions do not govern the question, 

 Colonel Chittenden has admited all that the advocates of forests desire. Let us 

 consider, however, the arguments with reference to such extreme conditions : 



The argument with reference to extreme floods appears to be that floods are 

 always the result of combinations from various tributaries; the highest flood 

 from one stream coming at the same time as the highest flood from other 

 streams, occurring after periods of long-continued and widespread precipita- 

 tion. In such cases the forest bed becomes completely saturated, its storage 

 capacity exhausted, and when this point is reached " the forest has no more 

 power to restrain floods than the open country itself." 



It is of course evident that the rainfall may be so great and long continued 

 that the forest bed becomes saturated and that the water flows over the surface, 

 but it does not seeni incorrect to say that in this case the forest has no more 

 power to restrain floods than the open country itself. The discharge will be 

 hindered in the forest by the physical conditions and because the soil will -n6*l 

 be washed away and the water will not be gathered into torrents flowing down 

 through eroded channels. Moreover, it seems a strange argument to maintain 

 that because the retentive power of the forest is not unlimited it is not therefore 

 useful. Even if it be admitted, however, that under a torrential rainfall the 

 water flows away from the forest without hindrance, it is under just such 

 a condition that the forest is most valuable in preventing erosion, for the water 

 is distributed over the forest floor and does not carry away with it the earth 

 beneath. With reference to this point, however, Colonel Chittendeu maintains 

 that there is no more erosion from cut-over lauds than from forested lauds. 

 There are certain reasons for believing that he is not correct. In the first 

 place, the forest cover is always more or less disturbed or injured by the cut- 

 ting, and after cutting is done it is more exposed to the sun and becomes dryer 

 in summer and more liable to take fire. It is believed to be a fact that fire 

 very frequently follows the lumberman and originates on cut-over land. This 

 still further destroys the forest cover, and heavy rain falling on deforested 

 ground is not broken in its fall by the leaves and branches of the trees. In 

 many places, of course, a new growth springs up after the forest is cut, if it 

 is not prevented by fire, and this new growth Will in the course of time become 

 a new forest and the old conditions will be restored, but in the meantime there 

 is a deterioration of the soil covering and a greater liability to erosion, as well 

 as a smaller power of retention and consequent more rapid discharge of the 

 rain waters. In some parts of the White Mountains, tracts once cut clean 

 and burned over do not grow up again. 



Colonel Chittendeu suggests that under extreme flood conditions, such as have 

 been referred to, the presence of a forest may actually produce a worse condi- 

 tion than if the country were cleared, and asserts positively, but without proof, 

 " that the forest does promote tributary combinations * * * and that it 

 may therefore aggravate flood conditions." He continues, " that forests never 

 diminish great floods, and they probably do increase them somewhat." As this 

 statement is not proven, it can only be regarded as Colonel Chittendeu's per- 

 sonal opinion. There is certainly no more reason for believing that forests pro- 

 mote the combination of floods from different tributaries than that they have 



