290 MANUAL OF AMERICAN GRAPE-GROWING 



and with neither fruit is ringing widely practiced. Experiments 

 carried on at the New York Agricultural Experiment Station 

 by Paddock, as reported in Bulletin 151 from this Station, show 

 that ringing may well be practiced by grape-growers under 

 some conditions. Since Paddock's experiments, and possibly 

 to some extent before, the grape has been ringed to produce 

 exhibition fruits or a fancy product for the market. 



Ringing consists in taking from the vine a layer of bark 

 around the vine through the cortex and bast of the plant. The 

 width of the wound varies from that of a simple cut made with 

 a knife to a band of bark an inch in diameter. The operation 

 is performed during that period of growth in which the bark 

 peels most readily from the vine, the period of greatest cam- 

 bial activity. The term "ringing" is preferred to "girdling," 

 a word sometimes used, since the latter properly designates a 

 wound which extends into and usually kills the plant. 



The theory of ringing is simple. Unassimilated sap passes 

 from the roots of the plant to the leaves through the outer 

 layer of the woody cylinder. In the leaves this raw material 

 is acted on by various agents, after which it is distributed to 

 the several organs of the plant through vessels in the inner bark. 

 When plants are ringed, the upward flow of sap is continued as 

 before the operation, but the newly made food compounds can- 

 not pass beyond the injury, and therefore the top of the plant is 

 supplied with an extra amount of food at the expense of the 

 parts below the ring. The extra food produces the results 

 noted. 



It turns out in practice that ringing is usually harmful to the 

 plant, as one might expect from so unnatural an operation. 

 Injury to the plant arises from the fact that parts of the vine 

 are starved at the expense of other parts ; and because, when 

 the bark is removed, the outer layers of the woody cylinder 

 dry out very quickly and thus check to some extent the up- 

 ward flow of sap through evaporation from the exposed wood. 



