Quercus alba – White Oak

Mature tree in Lanark Highlands

The Ottawa area is near the northern range of these iconic, long-lived oak trees.  In the Ottawa Valley the term “white oak” is sometimes used to refer to Bur Oak (Q. macrocarpa), which shares the same Quercus subgenera as White Oak (Q. alba), but they are very different trees.

Pinkish-green buds in spring (O. Clarkin).

White Oak has deeply lobed leaves while Bur Oak leaves, which can be quite variable, are typically violin-shaped, broader at the bottom and not as deeply lobed.  White Oak foliage emerges pinkish-green in the spring and matures as reddish-pink in the fall compared to the light green and dun brown respectively of Bur Oak.  In shade, the leaves of White Oak seedlings often have a blue-green cast.  White Oak bark is quite distinctive being pale and plated compared to the ridged and furrowed brown bark of Bur Oak; however, some particularly tortured young Bur Oak can mimic White Oak with pale, plate-like bark, but look closely at the leaves to distinguish them.

Pale, plated Bark of Q. alba at Britannia CA

White Oak is slow growing.  There is speculation that it was once more prevalent in the Ottawa Valley, but once cut down it was outcompeted by faster growing species like Bur and Red Oak, which are widespread and prolific.  It’s possible that the area along the Ottawa River called Deschênes Rapids was named for the proliferation of White Oak along the banks of the river.  The two remaining populations of White Oak in the Ottawa area are nearby:  near the river in Aylmer and at Britannia Conservation Area.

The largest population in Ottawa is at the Britannia Conservation Area on the west side.  Daniel Brunton documented these in the OFNC’s Trail and Landscape (July-September 1997, Volume 31, Number 3). Farther west of Ottawa, White Oak is found on rocky uplands, often on south-facing slopes, in Pakenham, Calabogie, and on Blueberry Mountain in Lanark County.  On the Quebec side, White Oaks are scattered in Gatineau Park along the Wolf Trail, the Luskville Falls Trail, and as far north as the shores of Lac Mousseau.

Some photographs with location coordinates in iNaturalist:

https://www.inaturalist.org/observations/8197623 – Lobed leaves and plated bark in Aylmer, Quebec.
https://www.inaturalist.org/observations/8337328 – White Oak in Lac Mousseau, Gatineau Park, Quebec.
https://www.inaturalist.org/observations/8197694 – Lobed leaves near Luskville, Quebec.
https://www.inaturalist.org/observations/5264284 – Red fall colour in Aylmer, Quebec.
https://www.inaturalist.org/observations/7684368 – Spring pinkish-coloured buds in Ottawa greenbelt near Kanata.
https://www.inaturalist.org/observations/32419827 – Blue-green leaf colour of seedling in shade at High Lonesome Nature Reserve.
White Oak at Britannia CA
White Oak in Aylmer
White Oak at Blueberry Mountain