Tree Study 



727 



divides into roots, and the roots into rootlets, which are covered with root- 

 hairs. It is important to understand what each of the parts of a tree's 

 anatomy does to help carry on the hfe of the tree. 



or \ 



Crown 



A tree with parts named. 



The roots, which extend out in every direction beneath the surface of 

 the ground, have two quite different offices to perform : First, they absorb 

 the water which contains the tree food dissolved from the soil; second, they 

 hold the tree in place against the onslaught of the winds. If we could see a 

 tree standing on its head with its roots spread in the air in the same manner 

 as they are in the ground, we could then better understand that there is as 

 much of the tree hidden below ground as there is in sight above ground, 

 although of quite different shape, being flatter and in a more dense mass. 

 The roots seem to know in which direction to grow to reach water ; thus, the 

 larger number of the roots of a tree are often found to extend out toward a 

 stream flowing perhaps some distance from the tree ; when they find plenty 

 of food and water the rootlets interlace forming a solid mat. On the 

 Cornell Campus are certain elms which, every six or seven years, completely 

 fill and clog the nearby sewers ; these trees send most of their roots in the 

 direction of the sewer pipe. The fine rootlets upon the tree-roots are 

 covered with root-hairs, which really form the mouths by which the liquid 

 food is taken into the tree. 



