ILLINOIS TREES: SELECTION, PLANTING, AND CARE 



35 







Fig. 34 (Above left).— Filling soil 

 over the roots of trees during con- 

 struction may injure or kill roots in 

 the soil beneath and result in the de- 

 cline or death of affected trees. Roots 

 of the elms in this picture are under 

 5-10 feet of soil. 



Fig. 35 (Above right).— This Lon- 

 don plane tree had soil piled to a 

 depth of 4 feet up the trunk for one 

 growing season. The tree produced 

 numerous small roots near the top of 

 the soil fill. However, the bark on the 

 basal portion of the trunk covered by 

 soil was killed and the tree died. 



Fig. 36 (Right). — A wooden frame 

 built around a tree trunk may protect 

 the bark on the trunk from injury by 

 construction equipment but it will not 

 prevent root injury from a fill of soil. 



gravel to prevent the soil from sealing the air spaces in the 

 gravel, then spread good topsoil over the area to the desired 

 depth. The continuous layer of gravel, which extends to the sur- 

 face of the fill around the trunk and separates the original soil 

 and the fill soil, will provide adequate aeration for normal root 

 activity and growth of the tree. 



