of 



floods and extreme low water; they check evap- 

 oration and assist drainage; they create soil; 

 they resist sudden changes of temperature ; they 

 break and temper the winds; they do sanitary 

 work by taking impurities from the air; they 

 shelter and furnish homes for millions of birds 

 which destroy enormous numbers of weed-seed 

 and injurious insects. Lastly, and possibly most 

 important, forests make this earth comfortable 

 and beautiful. Next to the soil, they are the 

 most useful and helpful of Nature's agencies. 



Forests are moderators of climate. They heat 

 and cool slowly. Their slow response to change 

 resists sudden changes, and, consequently, they 

 mitigate the rudeness with which sudden changes 

 are always accompanied. Sudden changes of 

 temperature are often annoying and enervat- 

 ing to man, and frequently do severe damage to 

 domestic plants and animals. They sometimes 

 have what may be called an explosive effect 

 upon the life-tissues of many plants and animals 

 which man has domesticated and is producing 

 for his benefit. Many plants have been domesti- 

 cated and largely so specialized that they have 



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