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

Origin. an$ Relationship to Water Regime
Microrelief, also referred to as mound-and-pool
bpography, humock-and-hollow microtopgra-
P ~ K and pit-and-rnaurtd microtopography, is a
characteristic feature of nonfloodplain forested
wetlands in the Northeast (Tittle 19550; Thompson
et al. 1968; G~ACO 1972; Vogelmann 1976; Messier
1980; Swift 1980; Ehrenfeld and Gulick 1981;
Huenneke 1982; Malecki et aI, 1983; Lowry 19M;
Paratley and Fahey 1986). Some floodplain
swamps also exhibit pronounced mieroreiief
(Buell md Wistendahl 1955; Hardin and Wiatendahl
1983; Menges and WaXler 1983). The development
of microrelief has been attributed to a
variety of causes, irrcluding frost action (Satkrlund
l%O), windthrown trees (Satterlund 1960;
Lyford and MacI~txxi 1%; Malecki et al. 1983;
Beatty 1984; TJowry 1984; EJaraLley and Fahey
1986), concentration of tree roots above high
water Lablea (Bray 1915; 1,owx-y 1984; Paratley
and Fahey 198G), and ri~izomatous growth in
shbs (Ehrenfeld and Gtilick 1981; Lowry 1984).
Since trees growing in swmps generally me
more shallowly rooted than trees on upland sites,
they are particularly susceptible to windthrow
Fig. 4.4), which appears ts be the most common
cause of mound formation. Red maple has a shallow,
horizontal root system in swamps, but often
produces a long tap root in upland habitats where
water tables are deeper (Toumey 1926). Rooting
depth and the frequency of windthrow have been
shown to vary as a function of water table depth
even among forested wetlands. In mixed coniferhardwood
swamps in northern Michigan, Satterlmd
(1960) found that the depth of maximum root
penetration for red maple ranged from as little as
51 cm in swamps with persistently high water
levels to as much as 147 cm in drier swamps. The
frequency of wind-damaged trees was 28% on sites
where the water table was periodically or permanentiy
high, but only 18% in drier swamps.
Mound heights in red maple swamps range
from about 15 cm for small shrub mounds to as
much as 1 m for large tree mounds (Van Dersal
1933; Thompson et al. 1968; Messier 1980; Lowry
1984). Microrelief is usually most pronounced in
the wettest swamps. In southern New Jersey red
maple swamps that are flooded throughout most
Fjg. 4.4. Red maple tree toppled by wind. Windthrow is common in swamps, where trees are shallowly
-*a, is believed to be primarily responsible for the development ofmound-and-pol ~crorelief.