Plant species associated with these communities are adapted to the stress of drought, excessive moisture, and shade in a variety of ways. Rich, mesic forests support a variety of spring ephemerals that avoid the stress of deep shade by emerging, flowering, and fruiting before the forest canopy leafs out. Other herbaceous plants tolerate the shady environment, beginning their growth flush upon closure of the leaf canopy, and fruiting during the summer months. In the extremes of the floodplain forest, tree species tolerate inundation as well as abrasion by debris ice, fallen trees, or manmade objects in floodwater currents. Frequent treefall in these conditions create canopy openings that optimize individual tree growth, resulting in individual trees that are large in diameter and height.
Trees often develop multiple stems.
Xeric Forest Communities Sandy, porous, nutrient-poor soils on southern and western slopes or on hilltops and ridges support xeric forest communities typically of oak and aspen. Oak leaves are low in nutrients, high in acid, and can take from three to five years to decay, further affecting soil development. The irregular oak-aspen canopy of southern forests creates openings for sunlight to penetrate to the forest floor, where a variety of saplings develop, opening the way for succession. Shrub diversity is highly variable throughout this extensive landscape area, providing varied food and habitat for animal species. Mesic Forest Communities Msic forest communities have developed on cool north slopes whose rich soils formed from glacial till and loess, with the fertile leaf litter of the maple-basswood forest.