286 The Principles of Fruit-growing. 



eventually becomes plant -food by being washed off 

 onto the soil, though the chief value of the wash is 

 no doubt the softening and loosening effect which it 

 has on the bark. 



Another means of releasing the pressure upon 

 hide -bound trees is to slit the bark the entire length 

 of the trunk or hide -bound portion. This is done 

 by simply thrusting the point of a knife through the 

 bark until it strikes the wood, and then drawing the 

 blade down the entire length of the portion to be 

 treated. When the knife is withdrawn, the slit is 

 scarcely visible ; but after a time the slit widens, 

 as the tree begins to expand. This method is to be 

 advised only as an extreme resort, for it is better to 

 keep the bark fresh and elastic by good tillage and 

 by the use of washes ; but the slitting is of no 

 damage to the tree, as a rule. The washing also has 

 the additional advantage of killing Carious insects 

 and their eggs which may be in or about the bark. 

 Spraying with Bordeaux mixture will kill the lichen 

 or "moss" on the trunks. 



Scraping trees. The outer layers of bark of any 

 tree gradually die and peel off, as the tissue grows 

 upon the inside. This old, rough bark is of no 

 direct use to the plant, but it probably affords some 

 protection to the tender tissues within. It also af- 

 fords a lodgment for insects and fungi. Trees which 

 are kept in a good condition of growth and which 

 are watched carefully, will need very little attention 

 in the removing of the bark, but if the shaggy bark 

 accumulates to any great extent, it is well to scrape 



