12 DEPARTMENT BULLETIN 863, U. S. DEPT. OF AGRICULTURE. 



As soon as the pupil leaves the open and enters the cool shade of 

 the woods he will note the forest floor the undergrowth of young 

 trees and shrubs, the ferns and moss, and the litter of fallen leaves. 

 With his jackknife, or a trowel, let him dig down beneath this cover 

 into the mold of many years of fallen leaves. The soil will be spongy 

 and moist. What happens when rain falls or snow melts? Under 

 the shadow of the forest it sinks into the spongy earth. (Fig. 4.) 



What becomes of the rain and snow that the forest has soaked up 

 like a sponge? Find a spring. This is where the stored water is 

 seeping out to feed the streams. The rainfall that has been held back 



FIG. 5. Effect of deforestation. Washing of soil and devastation of valuable farm lands 



at tbe heads of streams. 



in the hidden reservoir of the forest is here transformed into a 

 steady supply of water for the pasture, the mill, and the city. 



Let the class now return to the open and dig into the soil on the 

 unwooded slope. It will be found dry and hard. What happens 

 when the rain falls or the snow melts on the open hillside ? It is not 

 held back and absorbed, but rushes down the slope. In a heavy rain 

 the streams rise rapidly. Perhaps the class will find a bridge that 

 has been carried away in a freshet. Someone may tell of the log 

 bridge on the farm that was destroyed. Then what happens when 

 the winter snow melts upon the unprotected mountain slopes and 

 the spring rains swell the rivers? (Figs 5 and 6.) 



