PRUNING 63 



These values show that, from every point of view, growth has 

 been favoured by a reduction of the pruning : when this is reduced 

 to a minimum, the increase in weight of the shoot as a whole 

 has been 5j times greater than with the maximum amount of 

 pruning, and the advantage has been gained, not only by an 

 increased thickening of old wood left, but by an increase in the 

 number, length and weight of new shoots formed. 



The formation of so much extra new wood from the original 

 two-year shoot, results, however, in a reduction in the amount 

 of new wood formed from the still older portions of the tree. 

 Taking the six inches of the three-year-old branches below the 

 line o, the values were 



New Shoots Formed on Older Wood 



Cut back, leaving 

 6" 12" 24" 36" 



Number . . . 100 91 80 82 



Length . . . TOO 100 81 87 

 Weight . . . 100 108 72 82 



thus illustrating an effect which is well known, namely, that 

 hard cutting back tends to force into growth buds on the lower 

 portions of the branches. 



The response given by different varieties of apple trees to 

 variations in the extent of the pruning appears to vary con- 

 siderably : thus, taking the relative weights of the branches 

 which were cut back to the greatest and least extent in the case 

 of the three varieties selected, the values were 



Early Peach .... 100 : 240 

 Wealthy .... 100 : 192 

 Yellow Ingestre . . . 100 : 122 



but the effect did not appear to be influenced much by the root 

 stock, at any rate in the two cases where data for such a com- 

 parison were available, the relative effect of the lighter pruning 

 being 2 per cent, more favourable on the paradise stock in the 

 case of Early Peach, and 4 per cent, less favourable in the case 

 of Wealthy. 



An increase of several hundreds per cent, in the weight of a 

 very lightly pruned branch over a hard- pruned one, may appear 

 inconsistent at first sight with the difference of only 36 per cent, 

 between the weights of the hard-pruned and unpruned trees as 

 given on p. 59; but there is a difference between a case in 

 which a single shoot has been left unpruned for one season, 

 and one in which a tree has never been pruned at all. The single 



