274 AGRICULTURE. 



ence as near as possible to the supporting 

 stem. This is done by making the cut surface 

 parallel to it (Fig. 90) ; for in this case the cut 

 edge of the cambium still receives its food 

 supply from the supporting stem. 



2. Effect of Improper Pruning. But if the 

 limb is cut off so as to leave a projecting stub, 

 healing cannot take place, since the prepared 

 food for the support of this branch was elab- 

 orated by its leaves and sent toward the trunk; 

 the supply having been removed, the cambium 

 layer of this stub cannot grow. As a result, not 

 only will the healing be prevented, but the cam- 

 bium and bark will die back, leaving an unsightly 

 stub of wood to rot down to the supporting 

 limb or trunk ; and when the stub drops out, 

 dust, water, and fungi, or other vegetation, will 

 collect in the cavity left (Fig. 91), and thus in- 

 troduce disease and decay into the heart of the 

 tree, weakening its structure and possibly de- 

 stroying it. 



II. Removal of Large Limbs. 



Should it become necessary to remove a large 

 limb, it would be advisable to saw it off about a 

 foot from the trunk of the tree, so there would 

 be less danger of splitting down the trunk by 

 the weight of the limb. This danger would be 

 further lessened by making two cuts the first 

 below the limb to about the center, the second 

 cut above the limb and just beyond the first cut, 



