Ecology of Red Maple Swamps in the Glaciated Northeast: A ...

growth form of the dominant shrub species. Species
such as highbush blueberry (Vaccinium coryntbosum),
speckled alder (Alnus rugosa), and
spicebush (Lindera benzoin) commonly grow in
. -
clumps, producing stems that are large in diameter
(often exceeding 4 cm) but few in number,
especially in old stands. Rhizomatous shrubs such
as sweet pepperbush (Clethra alnifoZia), on the
other hand, generally have smaller stems but
occur in very dense stands.
The important contribution of the shrub stratum
to the overall structure of the red maple
swamp community can be seen by comparing the
relative basal areas of shrubs and trees. In six
Rhode Island swamps, shrubs composed from 32
to 68% of the total basal area of woody stems;
values averaged about 7 m2/ha for stems at least
2.5 cm in diameter, and 8 m2/ha for smaller stems
(Lowry 1984).
Fig. 3.8. Young red maple forested wetland with a poorly
developed shrub layer. This swamp was formerly a
wet meadow dominated by tussock sedge (Carex
stricta).
(4-6 m), tall shrubs (1-4 m), and short shrubs
(