134 



PLANT BIOLOGY 



ingly indispensable are forests. When the early settlers 

 reached this country, they found a virgin forest covering the 

 whole land. Their first work was to clear 1 and in order to get 

 open spaces for cultivation and as a means of protection 

 from attacks of the Indians. They cut down the trees ruth- 

 lessly and the timber and wood which was not needed was left 

 to decay or become the prey of forest fires. This forest de- 



FIG. 66. Rock containing a fossil fern which grew in the swamps of the 

 Coal Period. (Tarr and McMurry.) 



struction has continued even to our own day. But at last 

 men are beginning to see that unless this slaughter of our 

 trees is stopped, our timber supply will soon be gone. In fact, 

 government experts tell us that if the tree areas that yet re- 

 main are not managed according to a different system, twenty 

 years hence we shall reach the end of the timber supply in the 

 United States. 



142. Further study of forest products. Study No. 61. (Op- 

 tional.) Select one or more of the following forest products for fur- 



