296 



PRINCIPLES AND PRACTICE OF PRUNING 



its vigor. The Hudson system typifies this principle 

 (239). 



g. Other conditions being equal, the sizes of vines or 

 vine parts are inversely as their number. Hence the larger 

 the number of shoots, or clusters, or of berries in a 

 cluster, the smaller they will average ; and the larger the 

 number of vines to the acre the smaller the individual 

 vines. 



214. Pruning units. In California the term "pruning 

 unit" is applied to the treatment of single arms, whether 



the method of training be 

 spur or cane pruning. The 

 term, though less used in 

 other parts of the country, 

 is just as applicable un- 

 der similar circumstances. 

 Vines which have reached 

 maturity are pruned so 

 that certain parts are left 

 for fruit production, others 

 for renewal and others for 

 replacing, extension or 

 shortening the arms. All 

 other wood is cut off. No 

 matter what the system of 

 training or pruning the 

 fundamental principles and 

 the rules which govern the 

 system are applied to each 

 arm of every vine so trained, except that vigor of vine. 

 arm or cane may modify the application somewhat. 

 Biolitti presents two diagrams (Figs. 257, 258),* which 

 illustrate units of short and long pruning. His descrip- 

 tion is slightly condensed as follows : 



The unit in spur pruning illustrated in Fig. 257, represents a Ion.;? 

 arm about seven years old. At the end of the arm is the two-eye 



California Bulletin 241. 



FIG. 255 GRAPEVINE SHOWING 

 METHOD OF PRUNING ROOTS 

 READY FOR PLANTING. 



