CHAPTER 6 



FORESTS OF THE UNITED STATES 



The American people have not yet acquired the sense of timber as a 

 crop. WARD SHEPARD. 



THE forests of the United States are unrivaled, among the 

 world's timberlands, for the number of commercially impor- 

 tant tree species they contain. In Russia one finds greater ex- 

 panses of solid, unbroken timber but in our country alone, ex- 

 ist such enormously great areas of forest made up of so many 

 distinct species of tree growth. Over eight hundred and fifty 

 species reach tree size, and in addition to these species are a 

 number of tree varieties and hybrids that bring the total dif- 

 ferent forms of tree life close to twelve hundred. Today over 

 one hundred and eighty have economic importance and as 

 time passes, this number constantly increases, for new uses are 

 being found for species that yesterday were considered value- 

 less. 



This multitude of tree species and of forest types in the 

 United States is partly the result of our great range in climate, 

 elevation, and soil. All these varying factors were bound to 

 result in a great diversity of natural vegetation. But the supreme 

 dictator of the general type of vegetation to be found in a 

 region is rainfall. Very deficient rainfall produces deserts; 

 sparse rainfall, grassland. Only where we have fairly abundant 

 rain is a region able to support trees. 



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