Adirondack Beaver 157 



water of the lakes with the incomplete circulation in summer is 

 without sufficient oxygen to support life, below the level of circula- 

 tion." M. C. Marsh ('10, p. 896) makes this statement: "The 

 water soluble substances in bark and in the wood of some trees 

 are capable of killing fishes, but while such products are undesirable 

 in streams the amounts of bark and wood necessary to affect fish 

 in flowing streams are so large that it is not likely that they do 

 much direct damage to fishes by the substances which dissolve from 

 them." An inference that may be drawn from this last quotation 

 is that in waters with arrested circulation, as for example beaver 

 ponds under certain conditions, the water soluble substances in 

 question may accumulate to a degree sufficient to be fatal to trout and 

 other species of fish. 



In the light of what has been said above it is evident that a 

 scientific investigation of a number of representative beaver- 

 inhabited Adirondack streams in their relation to trout would not 

 only be of important scientific interest but would have much practical 

 fish cultural value also. The conditions obtaining in the streams 

 before as well as after the entrance of beavers should, of course, 

 be ascertained and their history followed over a period of years. 



Advantages of Beaver Dams and Ponds. Despite the possi- 

 bilities for harm enumerated above, beaver dams in the Adirondacks 

 cannot be viewed solely in an unfavorable light. There as in other 

 regions, beaver ponds unquestionably serve in many places, as pre- 

 viously noted, as reservoirs of water which keep creeks running 

 during dry seasons, and in other localities may have important 

 value as fire barriers (figures 24 and 25). In periods of heavy 

 rains or at the break-up of the streams in spring they may become 

 very useful in retarding or absorbing agencies to a degree suffi- 

 cient to prevent minor floods. Furthermore, the formation of 

 bottom land and meadows through the activities of the beaver is a 

 matter of some economic value. It is well known that thousands 

 of acres of agricultural land in the United States have been formed 

 as the direct result of beaver dams. In some localities at the 

 present time the principal grazing lands available are the grassy 

 meadows that originated in beaver ponds. Figure 26 illustrates such 

 a meadow found along the Grampus Lake stream in the Long Lake 

 region. The photograph was taken from an old grass-grown dam 

 which at one time had held back a large pond of water. The mud 

 and silt that had been carried down by the stream and settled in 



