PRUNING OF PLANTS. 



273 



FIG. 89. DIAGRAMMATIC CROSS-SECTION OF A BASSWOOD STEM 



TWO YEARS OLD. 

 p Pith, m Medullary rays, c Cambium, vb Vascular bundle. 



of healing is carried on by the throwing out of 

 new tissue at the cut edge of the cambium, which 

 gradually rolls out from 

 the circumference to- 

 ward the center of the 

 wound (Fig. 90), where 

 in time it unites and 

 forms a continuous layer 

 of cambium, which gives 

 rise to both wood and 

 bark cells, as in any other 

 portion of the stem. 



It is of tJie utmost im- 

 portance that in remov- 



f KIG. QO. IMPROPER AND PROPER 



ing the limb the cut PRUNING. 



- - , ., , a Cannot heal, b Healing. 



should be made in such 



a manner as to bring all parts of its circumfer- 



