PRUNING—THE METHOD 435 



to the tissues of the bark, except for a limited translocation by means of 

 _ diffusion. Consequently those portions of shoots or branches above the 

 point where the flow of elaborated foods has been checked by girdling 

 or ringing depend on their own resources in so far as elaborated foods 

 are concerned. That is, they cannot receive foods manufactured else- 

 where in the plant and foods that they manufacture must be stored 

 within their tissues or utilized by them. If the operation is performed 

 during the dormant season or very early during the growing season, 

 vegetative growth above the ringed or girdled point will be checked 

 because of the early exhaustion of the stored carbohydrates and the 

 reduced leaf area will limit the synthesis of a new supply. On the other 

 hand, this new supply that is synthesized cannot be translocated to 

 the roots or other parts of the tree and must be stored or utilized in 

 close proximity to its point of manufacture. Girdling or ringing after 

 the first flush would permit a greater amount of growth beyond the 

 point of operation because food stored elsewhere would be to some extent 

 available for this new growth and following the ringing there would be 

 opportunity for a correspondingly greater accumulation of foods. The 

 general influence of notching and stripping is in the same direction as 

 that of ringing, but is less pronounced because the operations themselves 

 only partl}^ stop translocation through the phloem. 



It is evident that the effect of any of these special practices on 

 accumulation and concentration of food materials is almost certain to 

 be more pronounced in the summer than it is during the spring months. 

 This explains why they so often fail to encourage the formation of fruit 

 buds and greater fruitfulness for which they have been so frequently 

 recommended, the period of fruit-bud differentiation having passed before 

 their concentrating effects are realized. 



The following quotation from Drinkard's'* summary of his work in Virginia 

 bears on this point: "Ringing at different seasons when accompanied by or 

 preceded by spring pruning, of the branches produced no noticeable stimulation 

 of fruit bud formation. Ringing at the time growth was resumed in the absence 

 of spring pruning did not stimulate fruit bud formation. The treatment was 

 given too early. Ringing at the time the foliage was fully developed in the 

 absence of spring pruning gave the best results ; however, when the treatment was 

 given at the time the fruit buds began to become differentiated there was some 

 stimulation to fruit bud development. Stripping at different seasons when 

 accompanied by or preceded by spring pruning, had no stimulative effect on 

 fruit bud formation. The effects of stripping were offset by those of spring 

 pruning. Stripping at the three seasons ah-eady mentioned, in the absence of 

 spring pruning, stimulated fruit bud formation uniformly." 



The facts relating to food translocation and manufacture may also 

 partly explain why ringing so frequently results in an increase in size or 

 in some modifications of the texture or composition of the fruit that 



