198 LABORATORY MANUAL OF AGRICULTURE 



moved close to the main branch than if the stub is left 

 longer. The healing of the wound takes place at the cam- 

 bium layer. The hard wood itself at the center of the limb 

 never heals, but is partly covered over by the growth of 

 the cambium layer. When large limbs are removed, the 

 wound is often covered with paint to protect it during the 

 process of healing. 



Equipment. 1. Pruning shears. 



2. Pruning saw. 



3. Pruning knife. 



Directions. Go to a near-by orchard of mature apple 

 trees. Other fruit trees may be chosen, or even forest trees 

 may answer the purpose if orchard trees are not accessible. 

 Select a tree in need of pruning. Remove all broken, injured, 

 or diseased limbs. Remove limbs that are likely to rub or 

 injure other portions of the tree. Remove all water sprouts. 

 Remove a sufficient number of the least desirable limbs so 

 that the light may penetrate to the center of the tree. 



