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Nature Link
The Oaks
Tuesday, April 29, 2003
In Canada, there are two general classifications – the red oak group and the white oak group. The reds have leaves with sharp-tipped lobes and include red, black, pin and Shumard. The whites have rounded lobes and include white, bur, swamp white, chinquapin, dwarf chinquapin, and chestnut. Many of these species can be found in the Bickford Oak Woods (hence the name!), described in a previous column.
The leaves of the red group are sometimes hard to differentiate because they can vary. Some hybridization can occur also. The white group, however, is a little easier by their distinctive leaves and twigs.
One of the most common species is red. The leaves have 7-9 lobes, and are bristle-tipped. The bark is smooth and gray when young, and becomes grooved with shallow furrows and flat ridges. This species is what most of our oak furniture and trim is made from. The attached photo shows some very large and straight specimens of Red Oak located in a woodlot north of Wallaceburg (winter 2003). These trees are probably 130-150 years old. (This area was extensively logged in the 1850's-1860's).
Black oak is less common, and the leaves have 5-7 lobes. Bark is similar to red when young, but later becomes dark and deeply furrowed and divided into square-like segments. It occurs on sandier soils (like Rondeau Provincial Park). Black can be substituted for red in furniture building.
The Pin Oak (Swamp Oak) is a rare tree in southern Ontario, found along the north shore of Lake Erie. The leaves are smaller and narrower than Black, and have deep u-shaped notches. The trees are smaller, up to 20m high. The Pin is more common near Windsor.
Shumard (Swamp Red Oak) is a very rare tree in southwestern Ontario. It is found in a couple of locations north of Wallaceburg. It resembles Black, and the leaves have 7-11 toothed lobes. Acorns are extremely large.
White Oak is a common tree in Ontario. Its leaves have 7-9 rounded lobes and are 10-20 cm long. The mature bark is pale gray, and scaly. The wood is excellent for boatbuilding, unlike the porous red oak. Some outstanding specimens are found in Clear Creek Forest.
Bur Oak (Mossycup Oak) is very common and has large, variable leaves up to 30 cm long. The bark is very rough, and has ridges broken into irregular thick dark gray scales.
Swamp White Oak us a medium sized tree. The leaves are up to 17 cm long, and widest above the middle. The base is a wedge-shape. The bark is more scaly and fissured with flat ridges than white. Grows in moister areas, and is easily transplanted.
The Chinquapin Oak is uncommon and has long narrow leaves. They are coarsely toothed. Bark is pale gray and has thin narrow scales. Occurs more in sandy areas. There is also a dwarf variety that is quite abundant in Pinery Provincial Park.
There are a few other species found elsewhere in Ontario, not discussed here.
An excellent reference for more detail of oaks (and other trees) is the book Trees in Canada by John Laird Farrar, published in 1995 by Fitzhenry and Whiteside. This is also available on CD-Rom.
