PRUNING PRINCIPLES 95 



but later attention should prevent their becoming a menace 

 to the plant. 



89. Renewal pruning of apple and pear.— E. S. Goff* points out that 

 as apple trees increase in age the size of the fruit tends to become 

 smaller. This he believes to be due to the increased difficulty of 

 sap circulation in the fruit-bearing twigs. An instance is pointed 

 out in which water sprouts on part of an apple tree were allowed 

 to develop in place of a large limb that had been broken off. The 

 fruit in this part of the tree was much larger than on the remaining 

 older parts. The question is therefore raised whether the size of 

 fruit on old apple and pear trees cannot be maintained by a careful 

 system of renewal pruning. 



90. p. Since each plant part is iiidk'idiia! (so), competi- 

 tion among tlic parts may make one part tJirive at the ex- 

 pense of another. 



A,s elal)orated plant food i,s formed it passes to growing 

 and storage tissues (20). Toward the close of the season 

 much of it is stored in or near the buds which are to start 

 growth the following spring, when, with crude sap, it pushes 

 out into shoots, leaves or flowers. There is thus competition 

 among these various parts for a share of botli kinds of food ; 

 but only those favoral)ly placed or, througli some unex- 

 pected circumstance, such as a constrictiijn, similarly 

 favored, secure an adequate supply of each. Then other 

 things may give certain twigs the lead and the inferior ones 

 a check. Hence each shoot draws ujion its parent l^ranch 

 both for elaborated food and crude sap. Nay, more, 

 each mav steal from its fellows, as when yqxx lush shoots, 

 such as water sprouts and suckers, are produced. These 

 shoots are seldom furnished with sufficient leaves to supply 

 their own needs, so, being watery, the}- draw elaborated 

 plant food from nearby twigs and limbs. For this reason 

 careful fruit growers remove these shoots while small be- 

 tween mid-spring and early summer, so as to direct the 

 plant food where it will do the most good. The sprouts, 

 being green, are easil)' broken oft" at the time mentioned. 

 The slight wounds formed, being small, readily heal in a 

 few weeks. 



♦Am. Card. 23, No. 285, Pag; 302. 



