PRUNING. 



23 



Large Branches. — In removing large branches entirely, the cnt shonkl 

 be made just as close to the stem as possible, even cutting through some 

 of the bark of the stem in making it. No limb should ever be cut in sucli 

 a manner as to leave any neck, snag, stump or projection of any kind 

 beyond the trunk of the tree. Large limbs which are only partially re- 

 moved should be pruned back to a sound, vigorous branchlet which 

 springs from it (fig. 3). Descarts has well called the branchlet which is 

 left the sap lifter. It must be sufficiently large to maintain activity in 

 the cambium between M and N, (fig. 3). This insures the early forma- 

 tion of a callus where the cut A-B was made, and the occlusion of the 

 wound. If this sap lifter is not left, the cambium on the stub M-N dies, 



Fig. 1. Fig. 2. 



Fig. 1. — Correct way of removing a small branch A, or a large branch B. No stub 

 should be left. 



Fig. 2. — Wrong way of cutting a small branch A, or large branch B, where a stub is 

 left. Such stubs die and produce hollows. 



either entirely or back a considerable distance from its extremit}', on ac- 

 count of the lack of circulation of sap through it. A callus then begins to 

 form as a collar around or near the base of the projecting stub and grad- 

 ually extends up the stub, sometimes, if the stub decays rapidly, com- 

 pletely healing over at the end but more frequently failing to close on 

 account of the incurving of the callus into the hollow as it deepens 

 (fig. 4). When this occurs, an opening remains at the end of the callus, 

 forming a hollow, as shown in the right hand tree in the frontispiece, in 

 which water collects, accelerating the decay already taking place in the 

 wood of the stub, and gradually extending the decay of the heartwood of 

 the tree below the hollow and to a slight distance above it. There is a 



