THE FOREST AS A CONDITION. 73 



says, "can retain 1,000,000 to 1,500,000 cubic 

 meters of water (i English square mile will hold 

 14,000,000 to 20,000,000 cubic feet). It will, in 

 many cases, depend on a difference of 20 to 30 

 cubic meters (700 to 1000 cubic feet) per second 

 of waterflow from the surface of a square mile, 

 whether a flood will be dangerous or not. The 

 bare slope would give up these 20 to 30 cubic 

 meters per second, and deliver the 1,000,000 

 to 1,500,000 cubic meters in 15 hours. If it is 

 remembered that damaging flood-waters are of 

 short duration, it becomes evident how even mod- 

 erate assumptions regarding the amount of water 

 retained in the moss-cover (or in the forest litter 

 and soil of a forest) produce favorable results." 



It stands to reason that in this direction the con- 

 dition of the forest cover must have much to do 

 with the degree of its effectiveness, and that in 

 this connection the condition of the forest floor is 

 of more moment than that of the leaf canopy. 

 Hence we may find that while the tree growth 

 may be left intact, yet, if the loose litter and under- 

 brush has been burned off and the soil been com- 

 pacted by the tramping of sheep and cattle, the 

 effectiveness in regulating waterflow is much im- 

 paired. 



It is also apparent that with heavy rainfalls 

 and on steep declivities on compact and sparsely 

 fissured limestone rock, even the best-kept forest 

 growth may not be capable of retarding the surface 



