CHAPTER L 



THE ECONOMIC IMPORTANCE OF FORESTS 

 Vocabulary 



Erosion, washing away of soil. 



Retention, holding. 



Girdling a tree, cutting off a ring of bark and cambium to kill it 



while standing. 

 Re-forestation, scientific replacement of trees when cut. 



The great importance of forests is little appreciated. When 

 we are told that they occupy 35 per cent of the area of the United 

 States and that lumbering is our second largest industry, still 

 their most important services are overlooked. 



VALUE OF FORESTS 



Control of Water Supply. The most important service rendered 

 by forests is in regulating water supply. The forest area acts like 

 an enormous sponge absorbing the heavy rainfall, in its layer of 

 humus. This secures the following important results. 



1. Prevents floods and causes steady flow. 



2. Prevents drouth by storing water in the wet season. 



3. Prevents washing of soil into rivers. 



4. Keeps rivers at uniform level for transport. 



The effect of forests in this regard can only be appreciated when 

 compared with an area which has no forest protection and is sub- 

 ject to heavy rainfall, such as the Bad Lands of Dakota. Here 

 the water runs off at once in floods, while between rains, the land 

 is almost a desert, due to drouth, and the rivers are so filled with 

 mud and so changeable in levels as to be useless for commerce 

 or power. 



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