Our Carolinian Zone

by John Brouwer

At Beaver Creek we are privileged to live close to natural areas: the Laurel Creek conservation area and the environmental reserve. But what we often fail to recognize is that these natural areas lie within a unique natural system – the transitional area between the deciduous forests to the south and the mixed woods of mainly conifers, birches and related short season hardwood species to the north.

We live on the northern edge of the deciduous forest which is generally known as the Carolinian forest region – a region extending south to northern Florida which experiences killing winter temperatures but a good summer growing season. Many of our trees are also native species as far south as the Carolinas and northern Florida. And in southern Ontario we have a few trees of native species tulip tree, cucumber tree, kentucky coffee tree, sassafras, pawpaw, flowering dogwood, and black gum which become prolific further south.

To our north the longer and colder winters no longer favour many deciduous trees and the pines and faster growing hardwoods start to become more dominant, as these don't require long growing seasons. The boundary between the deciduous forest and the northern mixed forest generally follows a line from Toronto to Grand Bend.

A major characteristic of deciduous forests is that they lose their leaves in the autumn after a colour display. The other equally spectacular feature is the flower show in the spring while the trees are still leafless. There is a brief, intense period of growth after the spring thaw when large numbers of woodland wildflowers sprint through their seasonal cycle before the forest floor plunges into shade. The trillium is the best known of this woodland flower which blooms only while the forest floor is in sunlight.

The trees that become dominant in our native forests are sugar maple and beech, so when we see sugar maple and beech growing together we can often conclude that this is an old growth forest. Because sugar maple and beech require shade to germinate and grow they usually only grow within an existing forest of other trees. As the maples and beeches mature, they shade their surroundings, preventing sun-loving trees from growing and seeding themselves.

Most of the conservation area and the environmental reserve is naturalizing farmland. However there are a few places where we have a mature woodlot. Just north of the green houses at Columbia Lake on the west side of Laurel Creek is an old woodlot which has now been fenced off.

The trail along Fischer Hallman Road goes through a mature woodlot past the entrance to the conservation area. Just before the trail reaches Laurel Drive, one can turn right onto trails that go through the trees to the demonstration sugar bush. Here you can see the sugar maple/beech forest – trees which reach 80 to 90+ feet providing an impressive cathedral ceiling. And here you can experience that unique spring carpet of wildflowers, including trilliums, which put on their spectacular display in April before the trees shade the forest floor. Make sure you take the time to walk or bike down to this area in April to see this unique show.

You can also see a smaller version of this by going through the hole in the fence just past Westmount Road but the Conservation Authority would consider you to be a trespasser!?!

Although southern Ontario's Carolinian Zone occupies only ¼ of 1% of Canada's land, it is home to over 1,600 native plant species – about half the number for all of Canada. With about 75 different trees, the area has more than half of 134 native Canadian tree species. This biodiversity heritage needs to be preserved.

Together the conservation area and the environment reserve have about 900 acres of interconnected natural areas which in turn connect to the rural areas northwest of the city. By restoring these to Carolinian habitats, Waterloo will leave a special urban legacy to the future and we would preserve a unique part of our Canadian heritage.

March 2007