8 



growth at the beghming of the season of 1918 was less than 

 that in our orchard, have not shown anything Hke such good 

 recovery. In all cases these orchards were not plowed during 

 the summer of 1918 or the plowing was delayed until June. 

 The only orchards, except very young ones, that have shown 

 marked recovery were either plowed in the fall of 1917 or in 

 the very early spring of 1918. Severe pruning of such trees 

 by reducing the initial summer leaf surface should tend to 

 hasten the recovery of the trees, but whether it actually haa 

 such an effect or not we cannot say with reference to any fruit 

 except the peach. In case of that fruit, in some years rather 

 severe pruning has seemed to favor better recovery, but in 

 other years it has resulted in the death of the tree. So far as 

 I have observed no harm has ever come from light pruning, 

 such as would be given the trees in an average year, but very 

 severe pruning (dehorning) in spite of its apparent benefits 

 in some years is to be avoided. 



The bark is generally more resistant to low temperature than 

 the sap wood; however, bark killing was often found following 

 this severe winter. It is found most commonly at the base of 

 the trunk or at the base of the branches on the inner side. It 

 seems that the bark ripens more slowly in early winter at these 

 points. The injury on the trunk is serious only when it is large 

 enough to go, let us say, one-third of the way around the tree. 

 That at the base of the branches is the more serious because it 

 heals so slowly. Young Northern Spy trees are particularly 

 susceptible to this branch injury, though any trees that grow 

 so upright that the secondary growth is largely on the other 

 side of the branches are susceptible. It seems probable that 

 the reason for the killing is the same as for the slow healing, 

 that is, the slow movement of the material from the leaves, 

 there being fewer leaves on that side of the branch. In fact, 

 I have had a chance to observe Ben Davis and Northwestern 

 trees where the branches had been so caused to droop by the 

 crops borne that the secondary branches were only on the upper 

 side. In that case the bark injury was on the under side of 

 the branch at the base, thus the injury always seems to be 

 greatest on the opposite side of the branch from that containing 

 the most foliage. It is often recommended that this dead bark 



