DRESSINGS FOR WOUNDS 161 



wounds should not be painted because the trees are short-lived, 

 quick-growing, quick to heal, and because large cuts are uncommon 

 on them. He also agrees that wounds less than 3 inches in diameter 

 on trees younger than thirty years need not be painted. 



But, he writes, the experimenters state that when trees are sprayed 

 yearly with a fungicide, it is doubtful whether any decay will de- 

 velop. If this proves true, it will be fine indeed. In the experiment, 

 however, young, low trees were used, except for a couple of years' 

 observation on older trees with a few 5-inch wounds. With older 

 trees having wounds open from seven to ten years or longer it is 

 not at all certain that decay will be kept out by spraying alone, 

 especially since larger trees are not so minutely covered in spraying. 

 A thirty-year experiment to discover the effect of spraying on the 

 decay of apple trees would eventually be of considerable value. The 

 data in the bulletin are of great value, even though the conclusions 

 drawn are too broad and unnecessary in view of the "way out" 

 which will soon follow. 



Armed with a hammer, a saw, and perhaps a chisel, go into an 

 orchard of some fifty years' standing. Notice a wound not fully 

 healed, but evidently daubed with paint some years ago. Rap this 

 wound sharply with the hammer. A cave-in occurs; or instead the 

 wound seems sound at the surface, but gives evidence of being a 

 sort of bung to a decaying mass half an inch farther in. Pry out 

 the bung and you will see. So much for paint as a preservative I 



Now select a fair-sized perfectly healed wound and saw off the 

 healed part or cap. You are very apt to discover a decayed wound 

 or even a hollow limb. Therefore it is seen that we can have perfect 

 healing over a decaying wound. Let us see how such a condition 

 of affairs can affect the owner of an orchard. From an upward and 

 outward swinging section of a tree are suspended four or five 

 barrelfuls of apples. The limb looks sound — all wounds being 

 nicely healed — and the owner ventures out upon it. Crack, snap, 

 crash! So much for perfect healing! 



These examples show there is just one reason why we mu.;t 

 apply something to pruning wounds — that is, for the preservation of 

 the wood. The most effective of preservatives must be used — either a 

 carbolineum or a grade one creosote oil. The bulletin says we should 

 never use these oils because they are the most injurious of paints in 

 killing back the bark. But usually where there is a must, there is a 

 may, if the problem is sufficiently studied. The solution of the problem 

 I will presently come to. First, however, we must see what happens 

 when our painting kills the bark : Under dead and dying bark borers 

 start, and following them comes a whitish rot of the sap wood 

 which also affects the heart wood or middle of the limb. This 

 destroys the tensile strength of the wood to such an extent that in 

 two or three years the limb is likely to break down under its fruit 

 load (Fig. 82). 



Now we come to a method of applying the liquid to preserve 

 thoroughly both wood and bark in a healthy state. Since ordinary 



