PART VIII. MAN'S CONTROL OF HIS ENVIRON- 

 MENT IN RELATION TO WEALTH 



CHAPTER XXVI 



OUR FORESTS, THEIR USES AND NEED OF 

 PROTECTION 



Problem : Man's relation to forests. 



(a) What is the value of forests to man f 



(h) What can man do to prevent forest destruction f 



Laboratory Suggestions 



Field exercise. Study of cross sections of tree trunks to determine struc- 

 ture and approximate age. 



Demonstration of some uses of wood. Optional exercise on structure of wood. 

 Home work on study of furniture trim, etc. 



Laboratory study or visit to museum to study some economic uses of wood. 



Visit to museum or field trip to learn to recognize some common trees. 



Project. To make a tree survey of my town. 



Project. To make a survey of the forest resources in my locality. 



The Economic Value of Trees. Protection and Regulation of 

 Water Supply. — No one who has traveled over the great South- 

 west can fail to see the value of forest trees. Great areas of land 

 lie devastated, subject to floods in winter and droughts in summer. 

 Yet these areas, if given water supply, would be capable of pro- 

 ducing crops in abundance. Irrigation has proved this in regard 

 to similar areas. Irrigation projects, which now give homes and 

 employment to thousands of people, besides producing annually 

 great quantities of food supplies, would be impossible were it not 

 for protected forest areas. Moreover, nearly 800 western com- 

 munities, with a population of nearly 3,000,000, depend for their 

 water supplies upon streams coming from areas protected by 

 national forests. When the earth's surface is covered by trees they 

 prevent soil from being washed away and they hold moisture in the 



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