Time, Novelty, and Narrative and the Value of Heritage Trees
The 2008 book Heritage Tree of Alberta lists 28 trees in Edmonton that are said to have “heritage value,” but what does that mean? How can we define “heritage tree”? This article attempts to synthesize a definition of a heritage tree by comparing the twenty-eight trees listed in Heritage Trees of Alberta.
The first thing to realize is that Heritage Trees of Alberta was published in 2008 by the disbanded Heritage Tree Foundation of Canada (HTFC) from a list of thousands of trees nominated by everyday citizens. Then, the trees in the book are a curated list of favourite trees selected by the HTFC board and the book’s editor. Generally, three things stand out to me: time, novelty, and narrative.
Heritage Trees and Time
While occupied for thousands of years, the City of Edmonton started as a trading post in 1795. As a bustling frontier town emerged, trees of considerable size and value were likely cut down for the fuel and lumber needed to support the city’s growth.
While Edmonton’s native spruce (Picea glauca) can live for hundreds of years, I am unaware of a single individual that predates the founding of Fort Edmonton. Aspen poplar (Populus tremuloides), a clonal species which lends its name to the Aspen Parkland on which Edmonton is situated, grows relatively short-lived trunks but can live for tens of thousands of years as a regenerating mass of roots and younger shoots. I was unaware of any local examples until I was tipped off to an aspen stand at the south end of Magrath Heights Park – hopefully, more on this in the future.
I have compiled a list of some of Alberta’s longest-lived tree species.
The oldest tree in the City of Edmonton’s tree inventory – a list of all publically maintained trees – was a Manitoba Maple (Acer negundo) known as the Garneau Tree, which was planted around 1874 by Metis settlers Laurent and Eleanor Garneau. The Garneau tree was the only tree in the City’s Inventory that predated 1900. Sadly, the tree met its demise in 2017 over safety concerns.
Edmonton’s Garneau Tree
Remembering the History of the Garneau Tree, The Gateway, September 26, 2017
“[The Garneau’s Tree, a Manitoba Maple] was planted by early homesteaders Laurent and Eleanor Garneau at the rear of their home. Laurent was Métis, and well known in the area as an excellent fiddler, as well as for his role in the Red River Rebellion of 1869, where he served as one of Louis Riel’s soldiers. The Garneaus moved to the south side of the North Saskatchewan River in 1874, where Laurent worked for the Hudson’s Bay Company as a charcoal burner and later as a freighter, before moving to St. Paul in 1901.” – Edmonton.ca
Heritage Trees Are Cultural Artifacts
You can’t plant old trees, but you can grow and nurture young for long enough to become old. Mature urban trees result from continuous care at best and benign neglect at worst. Development, overzealous homeowners, changes to drainage patterns, pests, extreme weather, climate change, diseases, or disruption to the root zone can all result in the premature death of an urban tree; it’s a wonder that we have many mature trees.
Old Age Is Relative (To Ourselves)
How long does a tree need to live before we call it old? The expected lifespan of trees varies from decades to millennia, so it’s a bit of an odd question. While fifty years is ancient for an Amur Cherry (Prunus maackii), a Rockey Mountain Bristlecone Pine tree (Pinus aristata) can live for thousands of years. What matters is how old a tree is relative to a human lifespan. Lacking perspective and a sense of time, we measure their age against our own. Our biology, not theirs, determines heritage due to age.
Edmonton’s oldest elm trees (Ulmus americana) were planted at the turn of the twentieth century. While we view them as old, they are roughly one-third of the way through their life expectancy. If Edmonton’s elms were people, they’d be pushing their early thirties.
It seems that we start thinking of trees as old around the time they reach the average life expectancy of a human – about eighty years. The Stark Oak (1933), Holowash Horsechectnut (1920), and Margaret Martin Willow (1907) are as old as Edmonton’s most senior residents. At 90, the Stark Oak is old – never mind that a burr oak (Quercus macrocarpa) can live for 400 years.
The lens of human life expectancy means short-lived species never achieve heritage status through age alone. While short-lived species are more likely to die from old age, long-lived trees are more likely to die from diseases, climate, and development.
What if we set out to grow as old a tree as possible? Can we consciously grow heritage trees? These questions inspired a local project to grow 1000-year-old trees throughout the city.
Age and Size are the Products of Time and Biology
We think of large trees as old, but a tree’s growth rate varies between species, and size is a crude stand-in for age. The size bias means larger and faster-growing species are more likely to achieve heritage status than their slower, smaller counterparts. One Colorado study found that the diameter at breast height (BDH) of local Cottonwood trees (Populus deltoides) grew at roughly twice the rate as Red Maples (Acer rubrum). Forgive anyone who mistakes the Cottonwood for twice its age. Many long-lived species are known for their slow rates of growth. Their slower speeds of growth may even be a contributing factor to their longevity. The opposite of “play hard, die young” may be “grow slow, live long.”
Might the slower growth rate of some species cause us to underestimate their age and thus undervalue them? If so, we might expect faster-growing trees like Manitoba Maple (Acer negundo) to show up on heritage tree inventories sooner than similar-aged but slower-growing trees like Oak (Quercus sp.).
Tree Age and Urban Development
Since some tree species can live longer than buildings, the development of a site has an enormous impact on the life expectancy of a city’s trees. While mature trees increase property value, they’re susceptible to damage from nearby excavation, soil compaction, and regrading. Developers prefer blank canvases, so clearing the site of trees is standard practice. I have dedicated a separate post to the tree life expectancy and development.
Unfortunately, the benefits of urban trees aren’t fully realized until they reach maturity. A perpetually young urban forest is not as functional or resilient.
How To Grow An Old Tree Takeaways
- Choose tree species with long life expectancies.
- Choose tree species that are not prone to pests or diseases.
- Consider development setback requirements when choosing planting locations.
- Maintain tree health with proper care and pruning done to ISA standards.
- Support landscaping standards for new developments. Ex. Edmonton Landscaping Standards.
- Develop a private tree protection bylaw to preserve trees during development.
- Support protections for plants identified as having heritage value.
Not All Heritage Trees Are Old
While time seems to be one of the more critical identifiers of heritage, it is unnecessary. Two additional but interconnected categories also play a role: novelty and narrative. In my next few posts, I will explore the impact of novelty and narrative on the makeup and survivability of heritage trees in the City of Edmonton.
Add a Tree to the Alberta Tree Register
Do you know of an old, uncommon, unique, or historically relevant tree? Consider adding it to the Alberta Tree Register map and database.