194 ILLINOIS ACADEMY OF SCIENCE 



Approaching the ravines, particularly where there are 

 abrupt slopes, a number of trees appear in rather narrow 

 and local communities. The ironwood (Ostrya vir- 

 giniana) seems to prefer steep north exposures and is of 

 rare occurrence. The hard maple (Acer saccharum) is 

 found covering an area 20 rods long by 10 rods wide on a 

 gentle south slope of the south ravine. Basswood and 

 white elm, butternut and black walnut occur along the 

 lower level of the ravines, particularly the south one. The 

 last named occupies a narrow alluvial strip. It is rather 

 remarkable that this species, everywhere considered a sure 

 sign of rich soil, grows normally in Jo Daviess county in 

 two quite distinct sites, namely, on alluvium and on the 

 slopes formed by the weathered Maquoketa shale. In each 

 case the water content of the subsoil is large in amount. 



This piece of timber contains by count and ocular esti- 

 mate, 12,000 trees of all species, each averaging one-fifth of 

 a cord per tree, or about 250 cords for the "forty." This is 

 an exceedingly conservative estimate, but even this will 

 give a stumpage value of nearly flO per acre. As before 

 mentioned, such land is held in high repute for farm land 

 and practically all of this tract could be placed under culti- 

 vation. Being owned by an outsider, it has so far escaped 

 the fate of most of this sort of land and type of forest, and 

 stands as a fine example of what such land will produce as 

 forest crops. Estimating the average age of this stand as 

 60 years, each acre has, by the interest on the forest cap- 

 ital, increased in value about 60 cents a year. A special 

 use, however, of the white oak as first-class fence-post ma- 

 terial greatly enhances the returns from that portion 

 where white oak grows. While as cord-wood each tree is 

 worth about |1.50, as post timber its value is about |2.50. 



The prevalence of white oak on the upper level is ex- 

 plained by the fact that the soil is drier and more sterile as 

 it approaches the border of an area of yellow-gray silt 

 loam or "hardpan" land that lies just west of this wood- 

 land. Everywhere this oak signifies thin soil, by which the 

 soil expert means that it contains a small per cent of 

 humus which results in scanty vegetation. And here our 

 investigation harks back to the primeval white oak forest 

 before pictured, with a small supply of humus and an 

 absence of underbrush and rank herbaceous plants. 



