28 



ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 51 



stem. Then make the overcut, B, 2-3 inches farther out. These 

 two cuts will cause the branch to break off by its own weight. 

 Complete the pruning with the final cut, C, removing the stub 

 flush with the main stem. Avoid tearing the bark down at the 

 bottom of the final cut. Coat wounds 1 inch or more in diameter 

 with a wound dressing. Most wound dressings are composed 

 mainly of asphaltum. 



Topping (Fig. 24) and dehorning (Fig. 25) are more detri- 

 mental than beneficial to trees. Such pruning treatment stimu- 

 lates abundant sucker or water sprout growth (Fig. 26) which 

 develops into a thick crown of slender, weak branches. The large 

 wounds produced are slow to callus over, and the wood exposed 

 by these wounds is subject to rot. 



Fertilizing 



To maintain the health and promote vigorous growth of 

 shade and ornamental trees, it often becomes necessary to pro- 

 vide nutrient materials that are lacking or present in insufficient 



Fig. 26. — Extensive pruning of large 

 branches or leaders usually results in the 

 production of thick masses or clumps of 

 slender, weak branches. Rot frequently de- 

 velops in the exposed wood. 



Fig. 27. — Lances or needles 

 are useful in supplying water 

 to tree roots. 



