22 



rRINCTPLES AND PRACTICE OF PRUNING 



27. Leaf venation. — As has l)een stated, the xylem 

 parts of the vascular bundles lead from the absorbing 

 areas of the roots to the transpiring areas, and the phloem 

 parts from the transpiring areas to parts where growth 



FIG. 16— CONTRASTING GROWTHS OF MAZZARD CHERRY 

 The specimen at the left shows one year's growth in a thicket where the tree 

 "pulled" for light. The two iowest branches and a little stub are dead. The 

 middle specimen is the upper part of the first, three years old at its base. Note 

 ho^.v it continued to extend until it reached fa\orable light, where it developed 

 branches. The specimen on the right is as old as the middle piece — three years. 

 Note how much shorter and how much more branchy it is. It grew in the open 

 ground, where it had no competitors except grass for light and air. 



