Herbaceous Understory

The herbaceous understory of interior, old-growth forest is a source of rich diversity, beauty, and often, extreme fragility. Numerous herbs are restricted to mature forests and cannot survive clearcuts (Duffy and Meier, 1992) or even natural openings due to forest fires or tornadoes. In general, ferns are typically restricted to forests, and these interior forests provide habitat for a number of species including the bristle fern, dwarf filmy-fern, glade fern, mountain spleenwort, hay-scented fern, shield ferns, and silvery spleenwort (Horn, 1995).

Among the many flowering plants found along the forest floors, two of the most conspicuous plant groups in mature forests are the lilly and orchid families. In most cases, these species require a mature deciduous forest canopy over them in order to do well. Within the lilly family are the wake robin, painted trillium, large-flowered trillium, blue-bead-lily, mandarin, false lilly of the valley, lilly of the valley, twisted stalk, turk's cap lilly, and wild yellow lilly. The better-known orchids include ladies' slipper, showy orchis, Habaneria spp., Appalachian twayblade, and spotted coral root. Other species of interest include wild ginger, baneberry, five-leaved windflower, papooseroot, ginseng, spikenard, waterleaf, and bee-balm (Horn, 1995).

Horn (1995) argues that "even though the forests are defined by the canopy trees present, the real biodiversity of an interior forest is in the shrubs and herbs, which commonly go unnoticed. We quickly note the loss of trees with urbanization and the logging process; at times even emphasize their loss when talking about the loss of forest habitats. Yet I do not know of even a single species of tree in the eastern United States which has become extinct. On the other hand, the small herbs live within such a small area (a microhabitat) that they have specialized to specific soil, sun, and moisture conditions. The herbs do fine as long as the canopy trees remain intact. But, with humans has come fragmentation of the forests such that all we commonly see are small areas of forest subjected to the 'edge effect': where greater wind and sun influence microhabitats, the forests are dryer and warmer during the summer. To the trees this is commonly not much of a problem, but to the herbs with shallow roots and exacting micro-habitat needs, this is just the change that may be detrimental to their survival."

An increase in mature forest interior habitat will better the prospect for the survival and continued evolution of many plant species of the herbaceous understory--some of which are already listed as threatened or endangered.

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