34 



ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 46 



pruning by the final cut, C, which removes the stub flush with 

 the main stem. Avoid tearing the bark down at the bottom of the 

 final cut. Protect the wound with a wound dressing. Most wound 

 dressings are composed mainly of asphaltum. 



Pruning by topping or dehorning (Fig. 34) is more detri- 

 mental than beneficial to trees. It stimulates abundant sucker or 



Fig. 33. — The method of pruning branches indicated here will avoid tear- 

 ing the bark and making ugly wounds on trees. The first cut is made at A, 

 the second at B. The third cut, at C, is made flush with the trunk of the tree. 



watersprout growth that produces a thick crown of slender, weak 

 branches. It creates large wounds that do not callus over. The 

 wood exposed by these wounds is subject to wood rot. 



Sanifation 



As generally understood, sanitation consists of removal and 

 destruction of dead or diseased trees or tree parts that may serve 

 as breeding material for infectious agents or for insects that 

 carry infectious agents. It is an important part of disease con- 

 trol. 



In the control of some diseases, sanitation includes removal 

 of one of the alternate hosts of the diseases. For example, cur- 

 rants and gooseberries are removed in the control of white pine 

 blister rust since the white pine blister rust fungus must go to 

 currants or gooseberries before it can reinfect white pines. 



