FRUIT-GROWING AND PRESERVING. 59 



of the tree is due in part to the nature of the root-stock and in 

 part to the influence of various conditions on root-growth will 

 probably have been apparent. That the size of the tree is deter- 

 xnined to a large degree by the root is evident, but it must not 

 be assumed that the growth of the tree is regulated solely by the 

 nature of its root system. Reciprocal action between the parts 

 ■of the tree above and below ground is always in progress, and the 

 root itself is just as dependent for growth on material supplied 

 by the stem and branch system as the latter is on the root for 

 the crude food materials absorbed from the soil. It is thus 

 possible to produce a dwarf form of tree on a strong type of root- 

 stock b}' various methods of control of the stem portion of the 

 tree. As an extreme example, the practice of " ringing," to which 

 reference will be made in due course, may be quoted. A less drastic 

 .method, capable nevertheless of producing quite pronounced 

 results, has come under observation at Long Ashton during the 

 ■course of investigations on the influence of intermediate stocks. 

 As is well-known, the use of the intermediate stock is frequentlv 

 necessary in the case of pears grown on the quince root-stock, and 

 in the case of apples, although normally the required variet3^ is 

 grafted direct on the root-stock, occasions arise — particularly in 

 connection with orchard renovation — when the graft is made on 

 an intermediate stock. The earliest series of experiments, com- 

 menced in 1904, while not showing any clear evidence that the 

 intermediate stock affected the quaUty (flavour, size, keeping 

 powers, etc.) of the fruit, except possibly as regards size, have 

 demonstrated that the stronger intermediate stocks give rise, as a 

 rule, to distinctly more vigorous trees than the weaker. To 

 confirm this result a second investigation w^as commenced in 

 1914. The results suggest that the intermediate stock exercises 

 a dwarfing effect on the growth of a tree if a stronger variety is 

 worked on it, but a stronger intermediate stock does not increase 

 the growth of a weaker variety. So many complicating factors 

 •occur in experiments of this nature, however, that confirmatory 

 evidence from further trials must be forthcoming before these 

 conclusions can be considered established. 



The work on " ringing " has been done at the Long Ashton 

 Institute. It was realised that fruit-growers were under a great 

 disadvantage in having no means of preventing a tree from making 

 excessive v/ood growth, other than by omitting to prune or by 

 withholding manure. Neither method is satisfactory ; the first 

 .results in the flowers developing high up in the tree, and under 

 some conditions the formation of extensive bare branches, while 

 the second starves the tree. It is possible, by careful root 

 ■pruning, to prevent excessive wood growth and throw the tree 



