128 



PRINCIPLES AND PRACTICE OF PRUNING 



die or break off trees they leave stubs on which dust col- 

 lects and with moisture furnishes congenial conditions 

 for the germs of decay. As the decay extends down the 

 stub it enters the trunk despite the efforts of the cambium 

 to cover over the end of the stub (Fig. 203). In time the 

 whole of the heart wood may rot away, leaving a bee 

 tree ! When properly handled by man that is, when no 

 stubs are left the heart wood will not decay but will 

 continue to perform its function, namely, that of strength- 

 ening the tree so it will bear heavy loads of fruit, ice or 

 snow. 



119. Rational wounds may be defined as those which 

 reduce to a minimum the danger of killing plant tissues 

 in young and growing parts of trees 

 and of decay in mature limbs and 

 trunks. The making of wounds in 

 pruning naturally resolves itself into 

 a threefold question when, where, 

 how? It will simplify matters to con- 

 sider these three phases all together 

 rather than to take them up separately. 

 120. Pruning small twigs and 

 branches may often be done with a 

 knife or a pair of shears (Fig. 88), the 

 former preferred wherever possible, 

 (a) Always such implements should be 

 sharp so as to leave a clean, smooth 

 cut. (b) The surface exposed by cut- 

 ting should be as small as practicable 

 so as to favor most rapid healing, (c) 

 The cut should be made neither too 

 far above, nor too near the upper- 

 most bud left to continue growth, 

 because if made too high, the stub 

 above the bud, being deprived of food, will die back to 

 the bud and thus make a second later cut necessary ; and 

 if too near, the surface will dry out and thus enfeeble or 



FIG. 87 

 HEART DECAYING 



The dark streak 

 shows how the original 

 seedling grew crooked 

 and how the irregu- 

 larity disappeared as 

 the tree increased in 

 girth. A broken branch 

 left a stub which ad- 

 mitted decay to the 

 heart wood, as shown 

 by the dark streak. 



