Background Report - Town of Georgina

Sutton Secondary Plan Review Study May 2008
Existing Environmental Conditions and Opportunities/Constraints Analysis
Project No. TA4468
Cultural communities within the study area support a typical assemblage of pioneering tree/shrub species
(e.g. white elm, red ash, trembling aspen, white birch, white cedar red-osier/grey dogwood,
hawthorn/buckthorn, brambles) as well as common herbaceous species (e.g. goldenrods, asters) and
forage grass species (e.g. brome grass, orchard grass, bluegrass) that establish on former agricultural land.
Non-native, invasive species are often associated with these communities and typically comprise a fairly
large percentage of the total species composition.
Intact, native plant communities within the study area are associated with upland and wetland habitats
associated with the Black River corridor and the large woodland blocks.
The deciduous forest communities within the study area are comprised of immature to mature
associations of sugar maple, red maple, white ash, American beech, red oak, large-tooth aspen, black
cherry, with eastern hemlock, white pine and eastern white cedar as occasional/frequent associates.
Immature, mixed forest stands of trembling aspen, white birch and eastern white cedar are also associated
with upland habitats. Coniferous forest associations are dominated by eastern white cedar interspersed
with trembling/large-tooth aspen and white birch. The upland forest blocks support an intact and fairly
rich/diverse understorey and groundcover layer. Forest blocks with a fresh to moist drainage regime
(wet-mesic) support a very rich and diverse groundcover layer comprised of herbaceous plants, ferns and
sedges/grasses.
Wetlands within the study area comprise deciduous, mixed and coniferous swamp associations, as well as
thicket swamps, marshes (cattail, graminoid, herbaceous) and open water aquatic communities. These
wetland communities are associated with the large forest blocks within the study area as well as the Black
River corridor and tributaries. Wetlands within the study area are associated with seasonally high water
table conditions and spring flooding along the Black River and its tributaries.
Deciduous swamp communities are comprised of silver/red maple, trembling aspen, black ash, green ash
and balsam poplar with occasional yellow birch, willow and white elm. Understorey vegetation consists
of red-osier dogwood, speckled alder, mountain maple and seedlings/saplings of the hardwood overstorey
trees, including eastern white cedar. The groundcover vegetation is comprised of a diversity of grasses,
sedges (Carex spp.) and ferns. Typical species present include fowl manna grass, reed canary grass, wool
grass, spotted jewelweed, sensitive fern, wood nettle, tall white aster, ostrich fern, false nettle, bulblet fern
and dwarf red raspberry.
Mixed and coniferous swamp communities are dominated by eastern white cedar in association with
swamp maple, trembling aspen, black ash, green ash, yellow birch, white birch and white elm.
LGL Limited environmental research associates Page 4