142 



THE PRINCIPLES OF PRUNING 



tissue is laid on over the old, and the old, there- 

 by, quickly becomes sealed in, so 

 to speak, and removed from the 

 agencies of decay. Every obser- 

 vant fruit-grower knows that if 

 a tree which is severely winter- 

 injured in limb and trunk were to 

 bear even a partial crop of fruit 

 in the coming season, it would very 

 likely die outright. If, however, 

 all its energies were directed to 

 the development of new tissue, 

 the injury might soon be over- 

 grown. The injured wood, like 

 the heartwood of the tree, is soon 

 removed from active participation 

 in the vital processes. It there- 

 fore follows that the danger re- 

 sulting from the browning or 

 blackening of the wood by winter- 

 injury depends very 

 much upon the sub- 

 sequent treatment of 

 the plant. Fig. 112 

 shows the body of a 

 young plum tree (in 

 longitudinal and cross- 

 wise sections) which 



112. Showing the new tissue 111- 



formed around winter-injured WaS fr Zei1 black m 



wood. the severe winter of 



