Ecology of the Cincinnati Region 
175 
mixed with it in greater or less abundance, but in older associations, the 
red cedar stands almost alone (fig. jpj. In other places it is mixed with 
white and chestnut oaks, in which case it forms a very prominent and 
important part of the young forest. In most of the area under consid¬ 
eration, however, red cedar is not even a secondary species in any of the 
pioneer associations, and never becomes the facies. Its limited distribu¬ 
tion within the region is not understood. 
Fig. 39. Red cedar (Jtinipcrus virginiana) is the facies in this clearing association 
(northeast of Milford). 
The direction and steepness of the slope, together with the nature of 
the soil, influence the rapidity of the clearing succession, as they do the 
original succession. Slopes of from 20 to 30 degrees usually retain their 
xerophytic flora long after gentler slopes have become mesophytic. 
Steeper slopes seldom ever become mesophytic. It is in this tension zone 
of intermediate slopes that some of the most interesting clearing succes¬ 
sions are seen. It is here that the influence of soil and exposure is most 
strongly felt. 
