Spring: A Time for Environmental Awareness and Tree Appreciation

By Tys Theijsmeijer, Sr. Director Ecosystem Stewardship, Royal Botanical Gardens

As spring blooms, let’s celebrate environmental awareness by hugging our favorite trees or planting one for the future. Trees inspire passionate discussions, provide shelter during storms, sequester large amounts of carbon, or simply are a friendly place to rest on a hot summer day. How are the local RBG trees doing? Two new environmental status reports for the RBG forest areas have been posted, for the North Shore of Cootes Paradise and Hendrie Valley. The conditions of the trees vary, and among the most common species are Red Maple and Red Oak. However, forest sustainability is facing numerous challenges.

Throughout every countryside, town, and city, individual majestic old native trees remain – each with a story, and often growing without notice along a roadside or in someone’s front yard. Typically, the most inspiring are recognized through citizen initiatives in honour roles or heritage tree lists.

In Hamilton, a current project called Monument Trees can lead you to some of the more accessible ones. In Burlington, there are equally big trees, and the one I would draw your attention to is the Brant Oak, a now massive white oak that marked the western property boundary edge of Joseph Brant’s property more than 200 years ago. White Oaks were historically a group of species often chosen as property markers due to the great size and age they attain

Most of the largest trees in southern Ontario are in the white oak family. The group includes White Oak, Swamp White Oak, Burr Oak, Chinquapin Oak, and Chestnut Oak. To see all the oaks in one place the best location I know of is the RBG Arboretum. Large White Oaks today have become much reduced in number suffering from air pollution and regular defoliated by the non-native Spongy Moth.  To track down individual large trees for fun, I recommend using 21st technology – iNaturalist smartphone app, and the Big Trees and Vines project, where you can also put in your own favorite large tree.  

We should also take a minute to remind ourselves of the trees species we no longer tend to encounter due to the unintentional introduction of diseases and insects from across the ocean, species our North American trees did not coevolve with.  The list of tree species that have virtually disappeared include some of the most marvelous and culturally important, such as the American Chestnut, American Beech, American Elm and Butternut. Their cultural uses and global trade lead to unintentionally damaging outcomes. This theme of cross ocean introduction of species sending native species out of balance is known as invasive species and is among the top threats to sustaining biodiversity. There is hope for each of these tree species with volunteer groups dedicated to their recovery, and to the keen observer, stately surviving elms now do dot the landscape.

If you plant a tree, the species you choose is a personal decision. With over 60 native species in southern Ontario, each tree offers its own distinct characteristics in terms of color, size, shape, and nuts or fruit. Here are a few of my planting picks of native species that are basic trees to our local ecosystem. The Eastern White Pine (Pinus strobus), also the symbolic tree of peace.  The Northern Red Oak (Quercus rubra), our most common local surviving oak species. The Hackberry (Celtis occidentals), a durable species that exhibits the same beautiful arching vase shape growth form as our lost elm trees.  Honey Locust (Gleditsia triancanthos), perhaps the most cultivated of our native species, and among the most durable for urban environments as its natural habitat is the ragged and dry stony habitat of glacial edges and escarpment. The uncultivated original form of Honey Locust have extraordinary spines to protect the delicious seed pods. And of course, a maple, either Sugar Maple (Acer saccharum) or Black Maple (Acer rubrum), trees that come to life in brilliant fall colour.