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

Urbanization
In most areas of the Northeast, urbanization
(including highway construction) is now responsible
for more inland wetland losses than all other
causes combined. In major metropolitan areas, it
has been the principal factor for decades. The
impact of urbanization on wetlands in any geographic
area usually is closely related to the
population density of that area. Once again,
northern New Jersey is a prime example. The
Office of Technology Assessment (1984) reported
that 20-50% of Troy Meadows and three large
swamps (Great Piece, Little Piece, and Hatfield)
in the Passaic River basin have been destroyed as
a result of highway construction and subsequent
commercial, industrial, and residential development.
The effects of urbanization are noticeable
even in the most rural parts of the Northeast.
Construction of interstate highways has spawned
a series of resort communities in areas such as
the Poconos of northeastern Pennsylvania (Tiner
1984), upstate New York, and the White Mountains
of New Hampshire. Significant wetland
losses have occurred in some of those areas as a
result.
Data gathered in southern New England trend
analysis studies (Table 8.2) suggest that residential
and commercial development and the development
of recreational facilities such as golf
courses and athletic fields frequently contribute
heavily to wetland losses in rural and suburban
areas undergoing rapid population increases.
Once again, road construction is an integral part
of such urbanization. In Maine, as in much of the
Northeast, the impacts of urbanization were historically
greatest in coastal wetlands and along
major rivers (Widoff 1988). Current losses are
most common in small (less than 4 ha) inland
wetlands in southern Maine where population
growth has been most dramatic. Widoff ranked
residential and commercial development as the
single most important cause of vegetated wetland
loss in Maine; she estimated that urbanization
has been responsible for nearly 4096 (more than
16,000 ha) of the totaI losses.
Peat Harvesting
One additional agent oi wetland deskruetion in
some areas of the Northeast is the harvesting of
peat, primarily for horticultural use. Peat harvesting
is a major industry in states such as Minnesota
and North Carolina, but it has been practiced to
some degree in several of the northeastern states
as well. It is an important cause of wetland loss in
the Poconos of northeastern Pemylvania ('I'iner
1984). In Maine, this industry peaked during the
1930's and 1940'9, but most operations closed down
for economic reasons (Widoff 1988). Widoff estimated
that 2% (910 ha) of Maine's vegetated wetland
loss may be due to peat harvesting.
Peat harvesting for horticulture generally is
carried out in Sphagnum bogs, which contain
large quantities of poorly decomposed fibric peat.
This type of peat has the highest moisture retention
capacity and so is most valuable as a soil
conditioner. Since red maple swamps have mineral
soils or well-decomposed (sapric) to moderately
well-decomposed (hemic) organic soils, they
are of little value as a source of horticultural peat.
During the 19'70'9, when the United States experienced
a brief, but severe, shortage of fossil fuels,
considerable attention was focused on the possible
use of peat as a supplementary energy source. The
uncertainty of continued fossil fuel availability
suggests that pressures to harvest peat from
northeastern wetlands for energy production may
increase. Sapric and hemic peats generally have
higher energy value per unit of weight than fibric
peat (F'arnharn 1979). For this reason, red maple
swamps and other types of forested wetlands with
organic soils may be seriously considered as potential
sources of energy-producing peat in future
years.
Other Forrns of Wetland Alteration
Although direct losses clearly have the greatest
impact on the wetland resource, other alterations
beside total destruction may also significantly affect
the structure and functions of wetlands and their
value to society. The following paragraphs identify
some of these additional forms of alteration.
Tree Cutting
Cutting of wetland trees for fuel and fence posts
was common in the Northeast prior to the decline
of agriculture in the late nineteenth century. Widoff
(1988) noted that timber harvesting is still
widespread in Maine wetlands during the winter.
In southern Rhode Island (Golet and Parkhurst
1981) and in New Jersey (Tiner 1985), selective
cutting of Atlantic white cedar has converted some
mixed wetland forests to predominantly red maple.
Larson et al. (1980) speculated that much of
the shrub swamp and shallow marsh in their
southeastern Massachusetts study area was formerly
forested wetland that had been cleared for