178.S 



Canadian Forcslri) Journal, Jiilij, 191H 



The Function of Watershed Forests 



The effect of the forests upon 

 Canadian streams does not require 

 srienlific datai to prove its reality. 

 Every observer who has compared the 

 flow and uniformity of streams under 

 contrasting conditions of forest 

 growth on the watersheds knows that 

 tree life is a conserver of surplus 

 moisture and a mighty aid in the 

 regulation of the Spring run off. 



In this connection it will be in- 

 teresting to many readers to note the 

 conclusions of Mr. Raphael Zon, 

 Chief of Sylvics, U. S. Forest Service, 

 Washington, after a very thorough 

 examination of available evidence in 

 the United States and foreign lands. 



"The available observations upon 

 the behavior of streams in this 

 country and abroad have established 

 the following facts: 



1. The total discharge of large 

 rivers depends upon climate, pre- 

 cipitation, and evaporation. The 

 observed fluctuation in the total 

 amount of water carried by rivers 

 during a long period of years depends 

 upon climatic cycles of wet and dry 

 vears. 



2. The regularity of flow of rivers 

 and streams throughout the year 

 depends upon the storage capacity of 

 the watershed, which feeds the stored 

 water to the streams during the 

 summer through underground seepage 

 and by springs. In winter the rivers 

 are fed directly by precipitation, 

 which reaches them chiefly as surface 

 run- off. 



3. Among the factors, such as 

 climate and character of the soil, 

 which affect the storage capacity of 

 a watershed, and therefore the regu- 

 larity of streamflow, the forest plays 

 an important part, especially on 

 impermeable soils. The mean low 

 stages as well as the moderately high 

 stages in the rivers depend upon the 

 extent of forest cover on the water- 

 sheds. The forest tends to equalize 

 the flow throughout the year by 

 making the low stages higher and the 

 high stages lower. 



4. Floods which are produced by 

 exceptional meteorological conditions 

 can not be prevented by forests, but 

 without their mitigating influence, 

 the floods are more severe and 

 destructive. 



Delusions Must Give Way to Facts 



{Dominion Advisorij Council on Industrial and Scientijic Research. 



"It should be understood that 

 there is only one way of keeping the 

 forest resource inexhaustible, namely, 

 Dy means of reproduction. 



"We know next to nothing as to 

 whether, and to what extent, the cut- 

 over lands are reproducing the tim- 

 ber that has been removed, still less 

 at what rate such new crop is growing. 



"General principles of silviculture 

 can be imported from Ivurope and, in 

 so far as thie same species occur in 

 Canada that are found in the United 

 States, we can profit to some extent 

 from the work of their foresters: 

 finally, however, climatic and soil 



differences make it necessary to learn 

 how to manage the species under 

 their home conditions. We have in 

 Canada not yet undertaken the first 

 systematic study of the biology of any 

 of our species, a knowledge funda- 

 mental to its sibiculture. This is to 

 be accomplished by observation in the 

 field and by a systematic location of 

 ])ermanent sample plots placed under 

 different treatment and obsen'ed 

 ])eriodically. 



"As regards increment, the rate fo 

 production that may be expected 

 from our species under varying con- 

 ditions, we are also lacking in know- 

 ledge. There are neither volume 



