ILLINOIS NATURAL HISTORY SURVEY 



CIRCULAR 52 



Fig. 1. — The upper two twigs are from a vigorous white ash. The 

 current season's growth — the part between the tips of the twigs and the bud 

 scale scars (indicated by arrows) nearest the tips — is long and thick and 

 has plump buds. The previous season's growth (partially shown to the right 

 of the arrows) is also long and thick. The lower two twigs are from a less 

 vigorous tree. The current and previous seasons' growths are shorter and 

 more spindly and have small buds. 



A second method of determining growth rate in many tree 

 species is measuring the width of annual wood rings produced in 

 the trunk. This is accomplished with most ease and least damage 

 to the tree with an increment borer or increment hammer 

 (Fig. 2). These tools are available through special purchase at 

 most garden supply stores. Both are commonly used by the 

 trained arborist and forester, w r ho can compare cores of wood 

 from trees to determine their growth-rate characteristics. 



Determine the soil conditions 



In addition to the condition of the plants it is desirable to 

 know the condition of the soil. In most instances, the best tool 

 for such use is a soil profile tube (Fig. 3), but a spade or trowel 

 can also be used for taking samples of the soil. 



Several factors affecting the condition of the soil should 

 be considered. 



1) Topsoil depth is important. The greater the depth, the 

 greater the volume of soil with physical, chemical, and biological 

 characteristics favorable for root growth. 



