ILLINOIS TREES: SELECTION, PLANTING. AND CARE 



109 



Fig. 98. — Colorado blue 

 spruce is prized for the 

 bright blue-green color of 

 its needles. Inset shows 

 numerous needles on the 

 tip portion of a branch. 



tible to a fungus disease called Cytospora canker, which may 

 result in the killing of lower branches and occasionally of entire 

 trees. Norway and Colorado blue spruce are more resistant than 

 other spruces to injury by ice and wind. The soft, light, fine- 

 grained wood of spruce is used extensively for lumber and pulp. 

 Wood of red and white spruce is excellent for sounding boards of 

 musical instruments because of its resonant qualities. 



Sweet Gum 



Sweet gum or red gum (Liquidambar styraciflua) , which 

 prefers an acid soil, is a tall-growing tree that reaches a height 

 of 70-100 feet on the bottomlands that are not inundated in 

 southern Illinois. Occasionally it is found growing in moist soil 

 on hillsides. It is an excellent lawn tree (Fig. 99) that is well 

 adapted to the southern and central parts of the state. 



Sweet gum produces conspicuous, five- to seven-pointed, 

 star-shaped, aromatic, alternate leaves (Fig. 99 inset), 4-7 

 inches across, and dark green above and pale green beneath. 

 They become brilliant yellow, orange, red, and purple in autumn. 

 Male and female flowers are borne separately on the same tree. 



