



CHAPTER VII. 



THE TKEE ITS BOOT-SYSTEM. 



WE may now suppose the young oak-plant to be 

 rapidly developing into a tree. Technically the seedling 

 is said to be a plant after the first year, and when it 

 reaches the height of a few feet the young tree is called 

 a sapling; these ideas are by no means well defined, 

 however, and we may regard them as arbitrary terms of 

 little or no scientific value. 



The principal changes which are noticeable as the 

 little tree grows larger are the gradual increase in the 

 length and thickness of the stem, and in the number 

 and spread of the branches put forth year after year. 

 Corresponding with these increments, each spring sees a 

 greater number of leaves than the one before, and it is 

 easy to prove that the roots also become more numerous 

 and complex each season. 



The above simply expresses certain facts of observa- 

 tion, but it is more accurate to link them together as 

 follows : 



In each successive season of growth the young oak 

 develops more leaves than it did before in other words, 

 the total area of the leaf -surface exposed to the air and 



