Ecology of the Cincinnati Region 
139 
succession, and with the continued dissection of uplands, and the head- 
ward working of ravines, will spread back farther and farther into the 
uplands. The hydrophytic forests will give place to mesophytic ones, 
which mark the temporary climax of many upland successions. But this 
temporary climax forest will in time give way to the xerophytic associa¬ 
tion, which initiates the xerarch succession characteristic of slopes. 
A forest of oaks (Quercus Muhlenhergii, Q. rubra), sugar maple 
(Acer saccharum), red elm (Ulmus fulva), basswood (Tilia americana), 
hop hornbeam (Ostrya virginiana), and thorns (Crataegus), replaces the 
mesophytic beech forest of the upland. The undergrowth is usually of 
saplings of the same kinds of trees, although the proportions vary con¬ 
siderably, depending on the stage in the succession. In the more meso¬ 
phytic places, sugar maple is dominant. Near the margins of steep 
bluffs, it may be entirely absent. Even where it is an important constitu¬ 
ent of the forest, it may be almost lacking from the undergrowth, if the 
trend of the succession is toward a less mesophytic forest. 
B. CLEARING ASSOCIATIONS 
The forest cover has been removed from a large area of the uplands, 
and in many parts of this area, a clearing succession is in progress. 
1. Meadows. 
It will be remembered that natural openings in the upland forests 
contained a characteristic herbaceous vegetation. Wherever a few trees 
are removed, this herbaceous vegetation appears, so that in a short time 
such a clearing has much the appearance of a natural opening. More 
extensive clearing is attended by similar results. If the cleared upland 
is wet, a meadow association resembling that of wet prairies appears; 
if dry, it is soon occupied by a number of xerophytic annuals and per¬ 
ennials. 
The clearing successions are probably similar to, but more rapid than 
the original upland successions. Upon the wetter uplands, the earlier 
stages of a hydrarch succession are shown. 
Wet meadows. —Depressions are filled with water for at least a part 
of the year. Larger ones exhibit a typical pond-swamp succession (dg, 
13 ). The number of aquatics is determined by the permanency of the 
pond. Submerged aquatics, other than algae, have not been found, and 
pondweed (Potamogeton dimorphus) was observed in only one instance. 
The rush (Juncus effusiis) frequently forms a distinct marginal zone (dg. 
