TOP -WORKED TREES 267 



grow too long, and are likely to be broken by 

 snow and wind. 



In trees which have been set only two to four 

 years, the top can be changed in two years ; 



192. The pear tree pruned. 



but apple trees which are fifteen or twenty years 

 old can ordinarily not be changed so rapidly. 

 Four or five years may be required in some cases. 

 Fig. 193 is a Lombard plum tree which was 

 grafted to a Japanese variety. The tree was four 

 years old when grafted, and the second year there- 



