New Yokk Ageicultukal Expekiment Station. 289 



areas both in the main crotches and around the basal ends of ascend- 

 ing shoots on large branches had died completely, and around the 

 periphery of the region a thin callus ridge had formed under the 

 bark. In cases where the affected areas extended some distance up 

 the branches above the crotch the general appearance was surprisingly 

 like that of ordinary cankers, because the dead area had become 

 sunken and usually a fissure had begun to form around them like 

 that shown in figure C on Plate XVIII and figure B of Plate XL 



The wood underneath the injured bark had become very much 

 stained. Even in cases where the injury was not severe enough to 

 cause the death of the outer bark, the wood was stained to a con- 

 siderable depth. Many of the shoots a centimeter or more in diameter 

 had the entire wood cylinder stained a rusty or dark brown in the 

 affected region in case the bark injury had been severe all around 

 their bases. In instances where the bark was injured chiefly on one 

 side, only that half of the v/ood cylinder had become stained. It 

 appeared as though there had been a diffusion of a stain or of an 

 active discolorizing agent from the disorganizing phloem into the 

 adjoining wood, very much like that observed many times in a num- 

 ber of orchards during early summer of 1911. The crotch injuries 

 found in a Sodus orchard discussed on page 277 were apparently 

 later stages of this type of injury. 



Radial clefts and loosening of hark occurring together. — On a number 

 of thrifty young maple trees from about 5 to 15 years old, along some 

 streets in the western part of Madison, the bark alone and on others 

 both bark and wood were cleft open during the first week of January. 

 The clefts were mostly on the west side, even though some of the 

 trees were along streets going north and south, but since that portion 

 of the city is not closely covered by houses the speed of the west 

 wind is checked but little. The bark on a few of the trees on streets 

 going north and south v^^as cleft either on the north or south side. 

 None of the bark appeared to be loose when examined in January 

 shortly after the occurrence of the clefts, but possibly that was due 

 to the fact that the trees were frozen solid. They were re-examined 

 in early spring and found to have loose bark on both sides, as well as 

 some distance above and below the ends of the clefts. 



The clefts varied in length from about 1 to 6.5 dm. and were most 

 common on Acer platanoides and Acer Negundo. In cases where the 

 clefts in the bark were short the wood underneath was not cleft but 

 in those which were 3 dm. or more in length the wood was usually 

 also cleft more or less. On some vacant land near the western edge 

 of the city was a small clump of Acer Negundo, on the west side of 

 which was one having the bark and wood both cleft. The cleft in 

 the bark was 6.4 dm. long and was entirely closed in early spring 

 while the sap was flowing, but by the latter part of May it stood open 

 about a centimeter in the middle. The tree was sawed off on May 



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