rubrum and other mesophytic
species can become so dense that the shade reduces Quercus seedling and forb abundance.
According to TWINSPAN analysis, the data set was split into two major groups: (1) xerophytic to mesophytic
communities of Sesleria caerulea group (128 releves in total); and (2) mesophytic
communities with Molinia caerulea or Carex hostiana as dominant species (53 releves in total).
Charactcristics of old-growth mixed mesophytic
Three principal vegetation types intermingle in the region: mixed mesophytic
forest in the moister riparian and canyon settings and, in drier situations, grasslands and Madrean evergreen woodlands (Amos & Gehlbach 1988).
The forests of Appalachia are called "mixed mesophytic
," because they inhabit a "middle" climate and because the canopy comprises an astonishing number of mature trees, with no one species dominating.
Within the Deciduous Forest Biome of eastern North America, mixed mesophytic
forests are recognized as containing the highest amounts of tree species diversity.
This helophytic and mesophytic
grass is naturally adapted to sandy-soiled aquatic, semiaquatic, and moist environments (reviewed in Duncan and Carrow, 2000).
The presence of this species in a deep mesophytic
ravine harboring other relictual species reinforces data from vascular-plant studies documenting these habitats in the Niobrara River Valley as a postglacial corridor and refugium of considerable phytogeographic significance (Kaul et al.
Plant communities present at the study site are the following: the granite outcrop proper, including Virginia pine scrub "islands" and exposed depression pits, uplant oak-hickory-pine forest, upland mesophytic
forest, and bo ggy woods, including creekside seepage habitats.
In the Chinese deciduous forests there are four different main types: (a) the mixed mesophytic
transitional deciduous forest found principally in the plains between the Chang (Yangtze) and Huai Rivers, on the border between the two biomes; (b) the typical temperate climate deciduous forest that must have been the vegetation of most of the lower Huang He (Yellow River) valley, the Beijing region, and a good part of the center and south of Manchuria; (c) the southern mixed deciduous forest of the warm temperate climate that exists only in the east and north of Manchuria and continues on to the neighboring regions of Korea and the Russian Far East; and (d) the cold temperate climate deciduous forest (basically birch trees), distributed in the form of enclaves within the boreal taiga.
The original vegetation is known to have been deciduous beech and mixed mesophytic
forest (Gordon 1966, 1969), and historical accounts refer to the "dense, dark forests" of the region (Weisenburger 1941).
I sampled old-growth, mesophytic
stands from three regions in eastern North America: the southern Appalachians (in Tennessee and North Carolina), Ohio, and Pennsylvania.