Outdoors_lol_09-34

Jeff Green | Aug 27, 2009

Oaks are a relatively common tree in our area. Tall, graceful, and valuable in so many ways, they are pleasure to have in the forest or neighborhood. Worldwide, there are some 500 – 600 different species of oaks, with 11 species native to Canada, and 10 to Ontario. Only four oaks are considered native to this part of Eastern Ontario.

There are two broad families of native species of oaks in Ontario – white oaks and red oaks. White oaks have leaves with rounded lobes or large irregular teeth. Their acorns mature at the end of the first growing season and are considered edible, said to be even sweet tasting, although I can’t confirm this from personal experience. Members of the red oak group have pointy-tipped lobes and acorns that mature at the end of the second season and are very bitter – a fact that I can confirm from personal experience.

Of the three white oak species in our area, two are widely-distributed. First is the Bur Oak (Quercus marcocarpa), known by some as Mossycup Oak. Although this slow growing tree is considered medium-sized, it can also grow quite large. On good sites, mature trees can reach 30 meters (100 ft) in height and 100 cm (40 inches) in diameter at chest height, and live 200 to 300 years. It is reported to be tolerant to air pollution and drought. In our area I have noticed a good number of large, wide-spreading Bur Oaks at the edges of fields at various places on either side of Highway 7 between Carleton Place and Perth. It is found in a variety of habitats, including deep rich bottomland soils as well as upland limestone soils and even over granite bedrock. The best distinguishing feature of this oak is the large acorn – it has a distinct fringe on the cup which covers about one quarter of the acorn.

The other tree-sized member of the white oak group is the White Oak (Quercus alba). This is a beautiful, long-lived tree, characteristic of the broadleaf forests of southern Ontario and extreme southern Quebec. They are medium to large trees, growing up to 35 metres (115 feet) high and up to 120 cm (48 inches) in diameter at chest height. White Oaks are reported to grow better in forests or rural areas than in urban settings.

While more common in the southern part of our area, White Oaks can also be found further north. For example, we have a few dozen medium-sized White Oaks growing on our property east of Sharbot Lake. Ontario’s oldest known living White Oak is growing in a nature preserve near Peterborough and is estimated to be about 450 years old, and trees several centuries old are not uncommon.

White Oak leaves have long narrow lobes with the characteristic rounded tip, and can turn a spectacular deep crimson in the fall. I took some photographs of red White Oak leaves one fall and eagerly anticipated their return the following year. However, I was disappointed as the leaves went from green to brown that year without ever passing through the red phase, and I still can’t predict when White Oak leaves will provide their crimson show. In a good year, acorn production for forest-grown White Oaks may average 10,000 acorns per tree, but this is likely on the low side. A 70-year-old White Oak in Virginia produced 29,000 acorns in one particularly good year!

The third member of the white oak group is the Chinquapin Oak (Quercus muehlenbergii). It is more common in Southern Ontario and the US; however it can be found near Kingston and the Thousand Islands as a shrub or small tree. Its leaves resemble beech leaves with pronounced teeth, which is unusual for an oak native to Canada.

The only member of the red oak group found in forests in our area is the Northern Red Oak (Quercus rubra). Northern Red Oak is widespread in eastern North American and is our most common oak. Moderate to fast growing, this tree grows on a variety of soils and topography, often forming relatively pure stands. It is an important lumber species and popular shade tree with good form and dense foliage. Trees up to 90 cm (36 inches) in diameter and 150 yrs old are not uncommon. Good acorn crops are produced at irregular intervals, but even in good years, only about 1 out of every hundred acorns is available to regenerate Red Oak – the rest are eaten by squirrels, insects, deer, Wild Turkeys, Blue Jays and other wildlife.

Oaks are important to the wildlife and people of the Land O’Lakes area. Long live the oaks!

Please feel free to report any observations to Lorraine Julien at This email address is being protected from spambots. You need JavaScript enabled to view it.  or Steve Blight at This email address is being protected from spambots. You need JavaScript enabled to view it.