458 BOARD OF AGRICULTURE. [Pub. Doc. 



wounds. The hornbeams and birches " bleed " very freely, 

 and if pruned at all it may be done in summer. Trees of 

 these species pruned in February bled so badly later that the 

 sap forced off portions of the tar dressing which had already 

 become quite dry. ~ 



Length of Time required to heal Wounds. 

 No accurate statement can be made as to the length of 

 time trees require to heal wounds of given sizes. Never- 

 theless, some interesting data can be given and some average 

 growths indicated. The length of time required to heal a 

 properly made and adequately protected branch wound de- 

 pends mainly on : — 



1. The species operated upon. 



2. The age and vigor of the tree. 



3. The position of the wound on the tree. 



4. The size of the wounds and the number on the tree. 

 In our experience, wounds on forest or ornamental trees 



heal much more readily than those on fruit trees. Those 

 healing most rapidly were the common willows and the 

 white ash, both of which made the first year an average 

 growth of callus of over one-half inch from the circumfer- 

 ence of the wound toward the centre. At this rate a wound 

 one inch in diameter would heal in one season, but the rate 

 of healing of larger wounds is likely to grow less in the 

 succeeding years. 



While 3"0ung and vigorous trees of most species healed 

 wounds well, healing on old and decayed trees proceeded very 

 slowly, if at all. Mr. Mosher states that the young trees he 

 examined from 1895 to 1899 healed branch wounds, on an 

 average, at the rate of three-quarters of an inch per 3'ear ; 

 still, the largest wounds that ho had seen healed perfectly in 

 that time were not over two inches in diameter. It was 

 found. that in seven years certain wounds two to four inches 

 in diameter had healed very well, others on similar trees had 

 healed only a little, while others on trees of the same species 

 had not healed at all. It was often the case that, while cer- 

 tain wounds on a tree were healing well, others on the 

 same tree were not healino: at all. Some trees failed to heal 



