26 



ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 51 



ground freezes in the fall, to carry them through the winter 

 months. 



MAINTAINING YOUR TREE 



Most trees need careful attention at regular intervals to 

 keep them in good health and growing vigorously. Practices em- 

 ployed in maintaining trees include pruning, fertilizing, water- 

 ing, spraying, surgery, cavity treatment, bracing, cabling, and 

 protection against grade changes and lightning. 



Pruning 



Trees are pruned not only to improve their shape and ap- 

 pearance, but to eliminate narrow, weak crotches and poorly 

 located branches, to prevent development of multiple leaders, to 



Fig. 23.— To avoid tear- 

 ing- of bark and wood, 

 three cuts are made, as in- 

 dicated with white lines, 

 in pruning large branches. 



Fig. 24. — Topping or 

 cutting all branches to 

 one level is a shock to 

 the tree and usually 

 causes a dense growth 

 of succulent shoots 

 often called water 

 sprouts. 



''^:|^i^r^teJ 



