110 PRINCIPLES AND PRACTICE OF PRUNING 



102. Pruning, ringing and stripping vs. fruit bud formation. In 

 summarizing his findings in a series of experiments, A. W. Drink- 

 ard, Jr., says :* 



The experiments, which extended over tw$ years, were made to 

 study the effects of pruning, root pruning, ringing and stripping at 

 various seasons on the formation of fruit buds on dwarf apple 

 trees. Spring pruning of the branches at the time of growth re- 

 sumption had a tendency to discourage the formation of fruit buds, 

 but there was apparent stimulation of wood growth in the trees. 

 Summer pruning of the branches the latter part of June, when fruit 

 buds normally begin to show differentiation, checked wood growth 

 the year in which the work was done, and greatly stimulated the 

 formation of fruit buds, as was shown by the bloom and the crop 

 of fruit the following year. Fall pruning of the branches in No- 

 vember did not materially influence the crop of fruit buds, but 

 caused vigorous wood growth the following year. 



Severe root pruning at the time of growth resumption in the 

 spring (April 23), at the time the leaves were well developed 

 (May 31), and at the beginning of fruit bud differentiation (June 

 23), when accompanied or preceded by spring pruning of the 

 branches, produced some stimulation in fruit bud formation. An- 

 other series of experiments showed that the spring pruning did 

 much to offset the effects of root pruning, which treatment retarded 

 wood growth in the current and the succeeding years ; the leaf area 

 of the trees was reduced and the trees showed injury from the 

 treatment. 



Root pruning on April 23, at the resumption of growth in the 

 absence of spring pruning, did not give as much stimulation to fruit 

 bud formation as the same treatment applied at later dates. Ap- 

 parently this was too early for the full effects to be felt by the trees. 

 Root pruning when the foliage was fully developed, and when the 

 fruit buds began to become differentiated, in the absence of spring 

 pruning of the tops, produced very marked stimulation in fruit bud 

 formation. At these three times the treatment retarded wood 

 growth and foliage development in the current and the succeeding 

 year, and the trees suffered from the treatment. 



Ringing at various seasons, when accompanied or succeeded by 

 spring pruning of the branches, produced no noticeable stimulation 

 of fruit bud formation. At the time when growth was resumed in 

 the absence of spring pruning, it did not stimulate fruit bud forma- 

 tion. The treatment was given too early. At the time the foliage 

 was fully developed, in the absence of spring pruning, it gave the 

 best results; however, when the treatment was given at the time 

 the fruit buds began to become differentiated, there was some stimu- 

 lation of fruit bud development. 



Stripping at various seasons when accompanied or preceded by 

 spring pruning, had no stimulating effect on fruit bud formation. 



* Ibid. 



