THE RED OAK
Peter Duinker, Halifax Tree Project
2020-06-15
There are more than 500 species of oaks in the world; 11 of them are native to Canada but only one to Nova Scotia – the red oak. This species (Quercus rubra L.) has the largest range of all the oaks in Canada, growing naturally all the way from Cape Breton to Lake of the Woods in northwestern ON. It has sharp points on the leaf lobes, similar to those of pin oak (Quercus palustris Muench.) but with a much broader leaf blade. We will feature pin oak in a later post. The other oaks we might have in the city streets all have leaves with rounded lobes (e.g., white oak (Quercus alba L.), swamp white oak (Quercus bicolor Willd.), English oak (Quercus robur L.), and bur oak (Quercus macrocarpa Michx.)).
I am a fan of planting more red oaks in our streets. In the older neighbourhoods of the urban core, red oak currently accounts for less than 5% of the number of street trees. My observations are that it seems to be relatively robust in the early years after planting, signifying high survival rates. It is long-lived (trees over a hundred years of age are common), the wood is hard and strong, and the canopy tends to be quite wide, a street-tree feature we usually cherish because we want the crown to reach over the street surface. I saw a live oak (Quercus virginiana Mill.) in New Orleans that had a crown 20 m tall but about 40 m wide! Red oak is relatively deep-rooted, so it is among our most wind-firm street-tree species.
Oak trees (not only red oaks) have many features to talk about. The fruits are called acorns and pretty much everybody knows what an acorn looks like. Squirrels sure know – acorns are really important for them to eat! Acorns can be consumed by humans, and have been for millennia, but careful preparation is needed to reduce the tannin content. Oak wood is very strong, hard, and heavy and has many uses. Oak wood was used to build ships when they were essentially entirely of wood. Several rooms in my home have oak floors, and we also have several pieces of oak furniture.
When I get deliveries of firewood from a commercial firewood supplier, I relish seeing oak in the mix. Barrels used for storing and aging wine and whisky are made of oak (but not red oak). The original stoppers in wine bottles are called corks because they were made of the bark of the cork oak tree (Quercus suber L.) which grows naturally in Portugal, Spain, and Italy. Red oak is a wonderful climbing tree because the strong branches are often abundant and grow close to horizontal out of the stem.
Each province of Canada has designated a tree species as its official arboreal emblem. You can look up the full set of official tree species on the Tree Canada website. Ours, established under the NS Official Tree Act of 1989, is the red spruce (Picea rubens Sarg., which we will not feature in this series because conifers are not planted in the streets of Halifax). Prince Edward Island chose the red oak at some time during the 20th century - some websites say 1905, another says 1987. I found the PEI Provincial Emblems and Honours Act of 1998, and it says this: “The tree known botanically as Quercus rubra L. and popularly known as the red oak is adopted as and shall be the silvan emblem of the province. 1997,c.36,s.3.”. That Act replaced the Provincial Emblems Act of 1988, which I can’t find online! Don’t you just love that word “silvan”?
We have some interesting red oaks in various places around Halifax. Apologies for profiling mostly trees on the Halifax peninsula, but that’s where I live, work, and play, so I notice the street trees here more often than elsewhere. My favourite big red oak used to be the one, on private property, on the west side of Chestnut St. just north of Watt St. It actually has a form more akin to an elm (see photo, right). However, I recently discovered the mighty red oak on the east side of Bellevue St. just north of Inglis St. (below, left). Oak St. has some nice mature specimens, especially on its north side, just west of Oxford. Finally, each year I monitor the development of the elms and red oaks along the active-transportation corridor on the east side of Barrington St. south of the Macdonald Bridge. I photographed them this week. The oaks are always behind the elms in leafing out, and the elms there seem to be doing better than the oaks. One photo shows an elm on the left and a red oak on the right – both are doing well (below, right). The other photo shows a struggling red oak between two really properous elms (bottom photo. All these trees were planted at the same time (about ten years ago) and roughly the same size. I really hope that the oaks will hang on and soon show signs of better health!
