110 AS CALIFORNIA FLOWERS GROW 



and is carried into the tree. Some of it dodges in 

 between the loose soil and trickles around until it 

 finds some stream, either over or under ground; but 

 it never tears away, tumultuously carrying off soil, 

 as does that enthusiastic raindrop that has just fallen 

 direct from the clouds. 



If there are no trees to hold the earth together, 

 and to keep the water in check, a heavy rainfall is 

 likely to do damage in two ways. First, as already 

 mentioned, by washing away the soil before it 

 reaches the streams; and, second, by raising the 

 creeks and rivers so that they overflow their banks 

 and injure the lower valleys. In the countries 

 around the Mediterranean, they have been cutting 

 the trees off their mountains for many generations. 

 In the middle of the last century, they discovered 

 that the destructive floods in Southern France, Spain 

 and Italy were due to there being no trees left at 

 the sources of the rivers. In France, they began to 

 plant new forests, and in fifteen years there was a 

 marked difference in the frequency and the de- 

 structiveness of the floods. 



Trees prevent floods by keeping the water from 

 flowing off on the surface, and by turning its course 

 so that it seeks subterranean channels. These under- 

 ground streams usually find the surface later in the 

 form of springs. The reason the scientists of Europe 

 turned their attention to the forest problem was not 



