Physiognomy and Structure: No Data Available

Floristics: Across its range, the dominant canopy species in this community is Populus tremuloides, often associated with Fraxinus pennsylvanica. Betula papyrifera is sometimes present or even codominant (Girard et al. 1989). In the eastern portion of its range, Quercus macrocarpa and Populus grandidentata are also typical canopy associates. Populus tremuloides spreads by root suckering and this can result in high stem density, especially in younger stands. Girard et al. (1989) found 722 stems/ha in southwestern North Dakota. There is a significant shrub layer that is dominated by Prunus virginiana. Other common shrub species include Ribes aureum var. villosum, Amelanchier alnifolia, Symphoricarpos occidentalis, Symphoricarpos oreophilus, Corylus spp., Rhus trilobata, and Rosa spp. The herbaceous layer is not as well-developed as the shrub layer but is still significant. Relatively mesic species, such as Maianthemum stellatum, Galium boreale, Aralia nudicaulis, Leymus cinereus, and Cirsium undulatum, and non-native Poa pratensis, are frequently found in the herbaceous layer.

Stands containing Betula occidentalis (22% cover) in the understory at Theodore Roosevelt National Park (Hansen et al. 1984) appear to be a variant of this type; those stands also contain Prunus virginiana (31% cover). A wet-mesic stand containing Betula papyrifera in an exclosure in southwestern North Dakota was described by Girard et al. (1989), who considered it a probable successional variant of this type.

Dynamics:  Fire is necessary to maintain this community, especially in the more mesic eastern portion of its range (MNNHP 1993). In the western portion of its range, this woodland persists for some time, even in the absence of disturbance. In the more mesic eastern portion of its range, this community is succeeded more quickly by other woodland or forest types. This community is usually found on the ecotone between grasslands and woodlands or forests (Girard et al. 1989, MNNHP 1993). In Minnesota, forests and woodlands dominated by Quercus spp. and forests dominated by Populus spp. replace this community. In southwestern North Dakota, woodlands dominated by Fraxinus pennsylvanica succeed Populus tremuloides / Prunus virginiana woodlands.

The occurrence of these stands on the top of north-facing slopes may result in increased snow catch as the winds blow across the tops of other buttes, while the downslope portions are more sheltered. In the spring, the soils on these tops sometimes remain frozen after the frost has gone out downslope. The cold, wet conditions, which are unfavorable for seed germination, may favor Populus tremuloides, which can reproduce by sprouting. Similarly, in the wetter slope positions, the soil may be so saturated as to be unstable for some species. Populus tremuloides may act to stabilize these positions, and thereby be succeeded by Fraxinus pennsylvanica stands.