12 PRINCIPLES OF THE GROWTH OF TREES. 



often repeated it perishes. When the leaves of young pear- 

 stocks cease to act, in consequence of leaf-blight, the tree no 

 longer grows; cambium ceases to form, and they cannot be 

 budded. An interesting illustration of the office of leaves oc- 

 curred to the writer a few years since : A yellow gage plum- 

 tree set a heavy crop ; but when the fruit was nearly grown 

 all the leaves dropped. The fruit remained green, flavorless, 

 and stationary, until a new crop of leaves came out. It then 

 finished growing, acquired a golden color, and a rich, excel- 

 lent flavor. 



Perfect fruit requires perfect leaves; and thick, crowded, 

 half-grown leaves give small fruit with poor flavor. The 

 great object of pruning, and of summer pruning especially, is 

 to give plenty of good, healthy, and not crowded foliage, and 

 the crop will also be good. 



The green bark of trees and plants performs an office similar 

 to that of the leaves; and, in connection with the cells adjoin- 

 ing, appears to fulfil sometimes an office which the leaves fail 

 to accomplish. This is, perpetuating the identity of the species or 

 variety. For example, bud a pear-tret on a quince. All the 

 wood above the place of union will be pear-wood ; all below 

 Will be quince. All the supplies which come from the pear- 

 leaves change to quince-wood the moment they pass this point ; 

 and if the budding is performed when the quince-stock is 

 smaller than a quill, yet all the wood below, when it becomes 

 a large tree, will still be perfect quince-wood, as is shown 

 when any chance shoots or suckers spring up from below. 

 Or bud, for example, the Northern Spy, which has dark bark, 

 with the Bellflower, which has yellow; and again, bud the 

 Snow-apple, which has dark-colored bark, on the Bellflower, 

 and the light-colored Sweet Bough on this each being an 

 inch above the last budding. Successive dark and light bark, 

 the peculiarity of each variety, will remain as long as the 

 tree grows : showing conclusively that each part or twig has 

 the power of maintaining its individuality. 



