PRUNING AND THINNING. 



PT. IV. 



tliat part of the stein which is above them, without 

 detracting from the bulk of that part of the stem which 

 is below them. This is the great merit which good 

 pruning lays claim to. 

 Example. Supposc a iiurserj plant with two equal leaders ; 

 both are weak in comparison to the stem below, 

 because each has only half the sap which ascends 

 through the stem, and also each has only its own 

 descending sap, while the descending sap of both 

 deposits on the stem below. If one leader is taken off, 

 new vigour is given to the other. The growth which 

 would have been for ever divided, is for ever united. 

 The two leaders are condensed in one, and the grow^th 

 of the favoured one, in the bulk of its stem, is for ever 

 doubled. But this twofold increase of the stem above 

 the fork is no greater than the increase of the stem 

 below the fork ; and the increase of that stem is in no 

 way altered by the pruning : it only receives from one 

 stem the same quantity of descending sap which it would 

 have received from tw^o. Nor is the whole quantity of 

 timber produced by the tree altered, though it is infi- 

 nitely increased in value, by uniting in one long stem 

 what would have been divided into the branches. 

 Throughout all forest pruning the same principle 

 reigns as has been exemplified in the case of the 

 double-leadered nursery plant. Any argument to 

 prove that the double increase of the single remaining 

 leader deteriorates the quality of its wood, w^ould also 

 prove that the quality of the stem below the original 



