HORTICULTURAL RESEARCH 



II. TREE PRUNING AND MANURING 



By SPENCER PICKERING, F.R.S. 



In the previous article an account was given of the results 

 obtained at Woburn in investigations of various problems 

 connected with the planting of trees ; other experiments in- 

 volving the treatment of the tree after it has been planted will 

 be referred to in the present article. 



Pruning 



In the case of trees used for ornamental purposes, correct 

 pruning is a matter of taste and judgment, little more being 

 required than the removal of branches which interfere either 

 with the symmetry of the head or the shortening of branches 

 which project too far beyond their fellows. A similar attention 

 to symmetry is required in dealing with fruit trees but symmetry 

 is not the only desideratum : fruit-bearing and the production 

 of well-developed and ripened fruits should be the main object 

 in view. This is not the place to enter into all the techni- 

 calities of the art of pruning nor is this art always amenable 

 to investigation at an experiment station ; inquiry has to be 

 confined, at any rate in the first instance, to the main principles 

 governing the practice of pruning. 



Under the head of pruning may be included all operations 

 which involve the use of the knife on branches or roots. It 

 is desirable to separate branch-pruning into four categories : 

 (i) the severe shortening of all the branches when the tree is 

 first planted, known as cutting back ; (2) the annual shortening 

 of the new twigs formed during the season, this being what 

 is generally meant by pruning ; (3) the cutting out of badly 

 placed branches, especially those which cross or rub against 

 others, known as thinning; and (4) operations in summer 

 intended to arrest growth, such as pinching off the growing 

 tips of the twigs or half-breaking or twisting the ends of these 



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