16 



side of the leaves. The heavy loss of water from the leaves 

 following this injury causes them to deteriorate and fall off 

 in large quantities. 



Treating Cavities. 



ISTo tree is so often found with cavities as the apple, and 

 perhaps none will thrive with so much decay of the heart- 

 wood, etc., as this species. The principal cause of the decay 

 is poor pruning and lack of antiseptic treatment of wounds. 

 When long stubs are left after pruning, the decay works into 

 the heartwood and a cavity results. These long stubs never 

 heal over, since the healing surface is not in direct communi- 

 cation with the How of plastic substances. Large wounds, if 

 not painted, will decay even if the branches are cut close. 



Apple trees will live and thrive for many years, even when 

 the heartwood of the trunk is completely destroyed, since the 

 sapwood appears to be immune to most of the organisms 

 causing decay. Modern tree surgery methods, however, can 

 be used to good advantage on^ apple trees. A cavity should 

 first have a thorough cleaning, followed by treatment with 

 creosote, and should then either be filled with cement, or the 

 orifice of the cavity tinned over or covered with some other 

 suitable material. 



Effects of Drought. 

 It often happens that in a wet spring trees will produce 

 more foliage than they can support throughout the summer, 

 especially if a severe drought occurs, resulting in a prema- 

 ture loss of foliage. The ideal moisture conditions for fruit 

 trees consist in having a plentiful supply of moisture during 

 the growth and early ripening of the fruit, with a bright and 

 relatively dry period, characteristic of Indian summer, for 

 the maturity. If there is too little moisture in summer the 

 fruit is likely to be small ; on the other hand, a dry summer 

 followed by heavy fall rains affects the quality of the fruit 

 and the ripening of the tissue, and is conducive to winterkill- 

 ing. As already noted, it may also have some effect on the 

 occurrence of the Baldwin spot. 



