Illinois Natural History Survey Circular 56 



2. What is the color of the soil? Soil color often indicates 

 organic matter content (dark or black soils usually have 

 al)iMidant organic matter) and the degree of weathering that 

 the soil has undergone. 



3. What is the texture of the soil? Texture reflects the relative 

 proportions of sand, silt, and clay in the soil. A loam soil 

 contains all three soil-grain sizes, has optimum water- 

 percolation rate and water-holding ability, and is highly 

 resistant to soil compaction. 





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F"ic;lrf. 2. The increment borer (left) and the increment hammer (right) are tools 

 used by the arborist or forester to obtain cores from the wood of standing trees. 

 The cores obtained with each have been marked with ink to make the widths of 

 the annual rings more evident. In each instance, the upper core's most recent 

 annual rings are closely spaced, indicating a slow growth rate; the rings of the 

 lower cores are widely spaced, indicating the rapid growth of healthy trees. 



