20 TREE PRUNING. 



on the trunk, which should not exceed a third of the 

 entire height of the tree. The lower branches should 



Ft*. 12. Cor- 

 rect form of head 

 for a tree under 

 forty years old. 



Fig. 13. Cor- 

 rect form of head 

 for a tree forty to 

 eighty years old. 



be sufficiently shortened to check their excessive 

 growth at the expense of the leader, without, how- 

 ever, being so reduced as to impair the vigor of 

 growth of the tree. 



2. The head of the middle-aged tree should form 

 an oval less elongated than that necessary for trees 

 of the first class. The height of the trunk should 

 equal one-third to two-fifths of the height of the 

 tree (Fig. 13). 



3. The head of the old tree (Fig. 14) should be 

 gradually rounded in outline ; the trunk may, in 

 some cases, be made to reach a height equal to half 

 the height of the tree, which has now probably ceased 

 to grow upwards. 



