PRUNING 79 



produced on the character of the trees, making them more 

 compact than when they were pruned to outside buds, but the 

 effect was less than might have been anticipated, and was not 

 always apparent. In some cases an increase in compactness 

 would be a disadvantage (e. g. King of the Pippins, which was 

 one of the varieties examined), whereas in others, where the tree 

 is naturally of a spreading habit (Lane's Prince Albert, for 

 instance), it would be an advantage. It was only in the case 

 where the twig was cut one inch above a bud, that a definite 

 effect on the vigour of the tree was apparently produced, the 

 values indicating that this vigour had been reduced by about 

 one-third; a similar result had been obtained in a previous 

 series of experiments extending over three years. The explana- 

 tion of such a reduction is probably as follows : when the twig is 

 cut, a callus forms, sealing up the ruptured cells ; wherever the 

 cut is made, this callus forms just above the bud next below 

 the cut : if the cut be made much above the bud, the formation of 

 the callus will probably be a much slower operation than where 

 it is made at the bud itself, and, consequently, before it forms, 

 there will have been a much greater loss of water from the neigh- 

 bouring cells ; the adjacent bud may thereby have been enfeebled, 

 and the ultimate growth from it affected. 



ROOT-PRUNING 



An investigation on root-pruning should, perhaps, be confined 

 to cases where such root-pruning appears to be called for by some 

 excessive vigour of growth : but to produce a sufficient number 

 of such instances suitable for definite experiments would, if 

 practicable at all, have required the lapse of many years. A 

 measurement of the extent to which root-pruning checks the 

 growth was, therefore, made on trees which showed no such 

 excessive growth. The results have already been described in a 

 former chapter (p. 45), and it will only be necessary to recall 

 that root-pruning every fourth year reduced the size of the trees 

 to 43 per cent, of that of trees not so pruned, without any com- 

 pensating advantage of increased crops, except after the first 

 and second performance of the operation; whilst root-pruning 

 every year, or every second year, either actually, or nearly, 

 killed the trees. 



Root-pruning is not an operation which is applicable to com- 

 mercial fruit growing, and it is only in small gardens that it is 

 practised : that it should ever be necessary to injure a tree to 

 such a serious extent in order to make it function properly, 



