456 BOARD OP^ AGRICULTURE. [Pub. Doc. 



usually most actively employed in building up the wood 

 growth of trunk and branches, and also incidentally healing 

 wounds thereon, in the summer months, although this proc- 

 ess may, in some cases, extend into the autumn. 



Most Avounds do not heal at all in June, and we find 

 records whicb credit the entire healing to August, while 

 occasionally a good growth will be made in September. 

 Wounds well made in June or Jul}^ will normalh^ begin 

 healing very soon on most trees, and some old foresters 

 Avith long experience regard these months as the best time 

 to prune ; but there are objections to pruning at this season. 

 Summer pruning is considered to be weakening. It re- 

 moves new growth and leaf surface Avhich has been made at 

 some expense to the tree, but Avhicli, if alloAved to remain 

 until fall, Avould in the mean time return elaborated sap, and 

 do its part toAvard the upbuilding of tlie organism which 

 has thus far supported it. Winter pruning removes the 

 branches after the leaves have fulfilled their office and fallen, 

 being therefore more desirable as regards its effect on the 

 strength of the tree. 



It is most difficult to prune in early summer Avithout 

 loosening^ the edge of the bark around the Avound, Avhich, 

 as Ave have already seen, delays the process of healing. 

 Again, the wound avIU be moist at this season, and the paint 

 or tar used -as dressing will not so readily penetrate and 

 adhere ; while the moisture of the Avound, the separation of 

 the cambium from the wood, and the Avarmth of the season, 

 all are favorable for the introduction of parasitic forms of 

 life about its edges or upon its surface. It may be avcII 

 doubted if any but the smallest limbs should be removed at 

 this season, and by the most skilful Avorkmen. The AVounds 

 ma}^ then be confidently expected to heal quickly and Avell, 

 and, unless too many branches are removed in one summer, 

 there may be no serious injury to the trees operated on. 

 If we prune in spring, Ave find the dangers already alluded 

 to increased by a troublesome flow of what may be called 

 ' ' crude sap." As foresters say, the Avound ' ' bleeds," Avetting 

 not only its surface but also the trunk of the tree, making 

 it impossible for tar or paint to adhere properly, because of 



