10 



BULLETIN 8 6 3, U. S. DEPARTMENT OF AGEICULTUEE 



The difference felt in temperature of the air in midsummer out in 

 the open road or field and in the shade of a single tree or of woods. 

 The same as experienced on a cold windy day in winter. 



Field study. — In an excursion with the teacher to the hills and 

 fields the class can learn, by actual observation, the bond between 

 the forest and the river. 



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 





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Figure 4. — The forest floor. Leaves and twig litter on the ground beneath the trees, 

 spongy layer of decomposed vegetable matter or humus, this and the lower layer of 

 soil interlaced with tree roots and rootlets, and the clay subsoil. Dense growth of 

 seedling and sapling trees covering and protecting the soil 



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 

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

 steady supply of water for the pasture, the farm, 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 



