Mixed forests

Georgian Bay Islands National Park

Sugar maple and beech forest at southern tip of Beausoleil Island National Park of Canada
Sugar maple and beech forest at southern tip of Beausoleil Island National Park of Canada
© Parks Canada/ Collection GBINP

Forests have become established along the south shore of Georgian Bay, where glaciers dumped thick till layers thousands of years ago. They also may be found on some of the larger, more protected islands such as Giant's Tomb, southern Beausoleil and those in the mouth of Twelve Mile Bay.

These forests, which once covered all of southern Ontario, are part of the Great Lakes-St. Lawrence Forest Region. As a whole, this region is a transition zone between the great hardwood forests which cover much of eastern United States and the boreal forests of the north. Thus we have both northern and southern species here.

Where the forests border the shore of Georgian Bay, the moderating effect of the Bay is very pronounced. Here it is typical to find a greater predominance of southern affinity plants such as silver maple, hop-hornbeam, red baneberry and black snakeroot.

The most common hardwood trees are the sugar maple and the smooth-barked beech trees. Red maple, striped maple, red oak, white oak, trembling aspen and white birch are also found in great abundance within the forested areas. Coniferous trees such as white pine and hemlock are scattered among the hardwoods and may grow as relatively pure stands between the rock outcrops and where the soils are too thin or acidic for hardwoods.

The canopy of leaves dictates which plants will grow on its rich but light-deprived floors. Flowering plants must bloom early to take advantage of the spring sunshine before it is blocked out by a new growth of leaves. For this reason, late April is a colourful period in the hardwood forest. Carpets of white and red trilliums, Indian cucumber-root, mayflower, hepatica, adder's tongue, clintonia, wood lily, spring beauty, violets, and yellow lady's-slipper, one of the 20 or so species of orchids occurring within the park, can be seen. Although not many flowers bloom later in the summer, brilliant red or yellow mushrooms, brown and white banded bracket fungi and the deep orange of rotting wood lend their colours to the forest. In the wetter troughs are the brilliant greens of sensitive fern and royal fern.

The forest floor is covered with thousands of young sugar maple seedlings which, unlike many plants, require little light to survive. They bide their time until, when a tree falls, one or two of the hardier ones surge upwards in rapid growth, taking advantage of the break in the canopy.

Hidden in the leaf canopy above, red-eyed vireos, common but seldom seen birds, conceal their nests and hunt for insects. Northern orioles, flycatchers, eastern wood peewees and thrushes also take advantage of the hardwood species. Other species of bird you will find here include pileated woodpeckers, scarlet tanagers, rose-breasted grosbeak, yellow-bellied sapsucker, redstart, and broad-winged hawks.

On the forest floor and the lower levels of the forest "apartment" you could see raccoons, beaver, grey squirrels, white-footed mice, hairy-tail mole, southern flying squirrels, spotted salamanders and western chorus frogs.

Because these forests are not pure hardwood stands, but contain white pine, hemlock and spruce, a few northern or boreal forest plants and animals are found here as well. Unlike in the hardwood forest areas, there is no time of year when the thick umbrella of needles allows in much light. Hence, many of the plants such as partridgeberry and wintergreen, conserve energy by keeping their leaves all year. Tamarack or larch is the only coniferous tree which drops all of its needles each autumn.

Northern starflower, squawroot and the ghostly Indian pipe are also common. Indian pipe and squawroot are saprophytes which lack any green colouring or chlorophyll. They are unable to manufacture their own food like most plants, but take nourishment from decaying material in much the same way as fungi. This is a special adaptation to living in almost lightless conditions.

Red squirrels are very common on the island and nest wherever there are a few conifers.

Porcupines, woodland jumping mice, masked shrews, four-toed salamanders, red-bellied snakes and grey tree frogs are other typically northern species which are found here. For the same reasons there are red-breasted nuthatches and many species of warblers. Woodpeckers and black-capped chickadees are common but nest and feed on both coniferous and hardwood species.


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