Pruning and Thinning 865 



manner similar to that following the second season's 

 growth, except that the heading back is less severe. It is 

 after the third year that the second story of scaffold 

 branches is started from the central leader at a distance of 

 about 30 to 40 inches above the first set of branches. 

 Three or four laterals are selected for this upper story and 

 the others are removed. The second story scaffold branches 

 are then treated like the first ones were two years earlier. 

 The upward growth of the leader is now suppressed and 

 the tree is continued with an open center. It is sometimes 

 advisable to add a third story. 



Advantages. 



1. The system results in a strong tree since the lateral 

 branches are smaller than the central leader and therefore do 

 not form weak crotches, as are likely to occur when all of the 

 main branches are of equal size. 



2. The weight of the tree is distributed among six to eight 

 main branches well placed on a central trunk rather than among 

 three or four branches as is the case in open center trees. 



3. The trees have a greater bearing surface than do open 

 center trees, since the space in- the center is more completely 

 occupied. 



4. Sufficient light and air are permitted to all parts of the 

 tree since on the discontinuance of the central leader above the 

 second scaffold the top then assumes some of the characteristics 

 of a strictly open center tree. 



5. A rather low spreading top is secured and at the same time 

 a somewhat larger tree than under the open center system. 



Disadvantages. 



1. In practice there is a tendency for growers to leave too 

 many scaffold branches and thereby create a crowded condition. 



2. There is danger of either the upper or lower set of scaffold 

 branches becoming dominant unless the pruner uses skill and 

 good judgment in maintaining the proper tree balance. 



