rx. TV. 



PRUNING AND THINNING. 



201 



absolute equality will result ; and tins does take place 

 in tlie annual deposit of new layers of wood and bark 

 over the stem and these protuberances. But each of 

 these protuberances creates a piece of dead, disunited 

 wood, which is in general nearly, if not perfectly rotten. 

 This system of pruning, as far as it goes, makes flaws 

 in timber, and disunited knots, similar to the leaving 

 dead branches on trees. These flaw^s are discovered 

 only in the saw-pit, or by the searching augur, and the 

 blame is laid on pruning generally ; whereas pruning 

 living branches close to the stem prevents the very evils 

 , which it is accused of creating. If a dead branch and 

 the stem are cut longitudinally where they join, though 

 the whole branch may have dried in in the form of a 

 cone as far as the central pith of the tree, still there is a 

 perfect unison of the dead wood of the branch with the 

 living wood of the stem, and the junction of each new 

 annual growth of the stem and the branch will be per- 

 fectly visible as long as the branch lived. But from 

 where the branch died each annual growth of the stem 

 will inclose a portion of a mere dead bolt without any 

 junction with it ; and this is one strong reason for not 

 letting trees prune themselves^ as it is called, that is, for 

 cutting off the side-branches before they are killed by 

 their neighbours, and for cutting them as close as pos- 

 sible to the stem ; even then a protuberance of the 

 thickness of the bark will be left, and where the bark 

 is thick and dead, a part of this should be taken away 

 with the branch. 



