CHAPTER 4 



THE FORESTS OF LONG AGO 



The true pages of the past are the rocks of the earth's crust. BERRY. 



THE forests of the world are constantly changing although 

 the changes are perceptible only over centuries. Since their far- 

 away beginnings they have been changing in extent, in appear- 

 ance and in the species composing them. Their boundaries 

 have moved back and forth like the tides of great seas. Existing 

 in a world that, itself has never remained the same, this power 

 to change has been necessary to forest life. For every living 

 thing, animal or plant, must adapt itself to changing environ- 

 ment or perish. Nothing is static. Temperatures rise and fall. 

 Rainfall increases or grows less. The soil itself changes. And 

 with all these shifting conditions plants and trees, if they are 

 to survive, must keep pace and adapt themselves by changing 

 too. 



When plant life first began in 'the world, it probably started 

 under much more simple and uniform conditions than now 

 exist. Probably the cradle of life was on the warm shores of 

 some shallow sea, with abundant rainfall, hot sunlight, and an 

 almost constant temperature. Every condition was favorable for 

 life and so the first organisms were simple. There was no need 

 for them to be complex at first not until later. Later as plants 

 spread to less hospitable places, or as conditions of life grew 



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