Physiognomy and Structure: Tree canopy varies from hardwood-dominated to conifer-dominated, with open to closed canopy cover. Stands have an irregular structure, though remnants of abandoned forest plantation structure, such as row plantings, may be evident in some cases.

Floristics: The vegetation is a somewhat disparate mix of weedy and native species, and the ecological and floristic organization of the vegetation is not clear. The tree layer is dominated by >80% (>90%?) cover of "weedy" or generalist native tree species, as compared to exotic/invasive tree species. The list of ruderal tree species is as follows: Conifers: Juniperus ashei, Juniperus virginiana, Pinus rigida, Pinus strobus, Pinus virginiana. Hardwoods: Acer negundo, Acer platanoides, Acer rubrum, Ailanthus altissima, Amelanchier spp., Betula populifolia, Crataegus spp., Crataegus crus-galli, Crataegus mollis, Diospyros virginiana, Fraxinus americana, Gleditsia triacanthos, Gymnocladus dioicus, Juglans nigra, Liquidambar styraciflua, Liriodendron tulipifera, Morus spp., Malus fusca, Morus rubra, Populus tremuloides, Prunus pensylvanica, Prunus serotina, Prunus americana, and Robinia pseudoacacia. These species form mono-dominant or mixed dominance stands. Understory shrub and herb species vary from exotic invasives to native generalists. Invasive shrub species include a variety of honeysuckles (Lonicera japonica, Lonicera morrowii, Lonicera tatarica, Lonicera x bella), Rhamnus cathartica, and others.

Dynamics:  Stands most typically represent the tree-dominated stage in the development of vegetation on sites that were heavily disturbed by humans, including plowing, grading, skidding, etc. In these cases, earlier stages of vegetation include annual and perennial weeds, grasslands and shrublands [see ~Eastern North American Ruderal Meadow & Shrubland Group (G059)$$]. Because the extensive soil disturbances typically lead to a mix of weedy native and exotic shrub and herb species, the stands take on a ruderal composition, even if native trees invade or are planted. Canopy cover may be as low as 10%, but eventually stands may have more-or-less continuous canopy, leading to a shift to a more shade-tolerant ground layer.

The successional stages of this type have been described in many studies, particularly the early stages of tree invasion into old fields (e.g., Singleton et al. 2001), as have the limited recovery of these ruderal forests to a composition resembling the historic native forests of the region (Bellemare et al. 2002). See also Wright and Fridley (2010) for the biogeographic variation among stands of this type.

This type may also form in other ways. First, native forest plantation stands (tracked in 7. ~Agricultural & Developed Vegetation Cultural Class (CCL01)$$)) could become ruderal stands if not intensively managed, as the planted trees begin to die out, and the ground layer is invaded by native species. Second, native forest stands that have not been plowed or planted may be stressed to the point where the characteristic native combination of species is altered (Curtis 1959). These stands are probably best tracked as altered variants of native types until the overstory itself is substantially altered.