The Job of a Heritage Tree
In the era of climate change, what roles do heritage trees have in preserving our planet?
ArboretumRoyal Botanical Gardens (Canada)
Choosing trees
Royal Botanical Garden’s (RBG) heritage trees are generally chosen for their old age and large size, but in some instances by their appearance or cultural significance. The goal of the designation is to highlight trees for education, conservation, or management purposes.
Bitternut HickoryRoyal Botanical Gardens (Canada)
A Heritage Tree has at least one of the following traits:
• Distinct size or form
• Association with historic periods
• Modifications from Aboriginal or non-Aboriginal people, like trail blazes
• Represents ancestral crops at risk of disappearing from cultivation
• Association with folklore or traditions
Defining the traits
The characteristics of a heritage tree were first proposed in 2005 by Professor Paul Aird, a member of the Faculty of Forestry at the University of Toronto.
Label on memorial treeRoyal Botanical Gardens (Canada)
Tree home
The cultivated gardens and nature sanctuaries of Royal Botanical Gardens are home to over 20 individual heritage trees, with many of the wild native ones viewable from public nature trails.
Fagus tree in autumnRoyal Botanical Gardens (Canada)
More than a garden
RBG governs multiple properties — cultivated and wild tree collections can be found across our nature sanctuaries, and in our garden areas, including Hendrie Park, Rock Garden, Laking Garden, the Mediterranean Garden and the Arboretum.
Part of our Living Collections
As with a museum exhibit, Living Collections improve the understanding and knowledge of all plants held within the collection. Heritage trees promote humanity’s understanding of the relationship between the plant world, society and the environment.
Trees have immense value
A designated National Historic Site of Canada, RBG protects many remarkable trees across 1,100 hectares of gardens and nature reserves. Many of these trees have significance in beauty, colour, rarity or local history, but are not classified as heritage trees.
Japanese Cedar, RBG's first accession (1932)Royal Botanical Gardens (Canada)
First accession
This Japanese Cedar (Cryptomeria japonica) holds historical significance for the Gardens as the first addition to RBG's plant collections. Still standing in the Rock Garden, this specimen is an example of a tree of importance that is not classified as a heritage tree.
Importance
The designation of "heritage trees" recognizes their important roles — as living legacies, as witnesses to our ever-changing landscapes, and as agents of sustainability.
Sugar MapleRoyal Botanical Gardens (Canada)
Living legacies
Look at the size of this sugar maple compared to the young trees around it. As humans moved in and out of these lands over decades — or centuries — this tree remains a permanent fixture, telling the story of past forests, habitats, or settlements it once was a part of.
Witnesses of change — the exact age of this red oak (Quercus rubra) is unknown, but it’s estimated to be a centenarian, meaning it's at least one hundred, if not hundreds, of years old. This red oak had seen its surroundings change from oak savannah, to farmland, to botanical garden.
Pin Oak leavesRoyal Botanical Gardens (Canada)
Ecological goods and services
A tree's ecological functions provide immense benefits. Forest services include clean air; carbon sequestration; water filtration; the generation of soil and vegetation; homes for wildlife, pharmaceutical and construction materials; and spiritual and psychological health.
Trees: nature's carbon capture tool
RBG calculates the amount (in kilograms) of carbon stored, by each heritage tree.
For example, this shagbark hickory, with a diameter of 91cm, has stored 21,720kg of CO2 in its lifetime. That's the same amount of CO2 produced by driving 372,343km in the average compact car.
Carolinian forestRoyal Botanical Gardens (Canada)
Worthy of protecting
Trees sustain life. Being able to assign specific worth to their benefits helps us understand the impact of heritage trees — but its their role as a living cultural, historical or environmental monument that makes them priceless.
Not indestructible
A long history of adjacent land use changes, air and water pollution, and introduced diseases are causing a gradual decline in forest health. The biggest threat to our forest ecosystem currently is Eurasian invasive plant species.
Magnificent American ElmRoyal Botanical Gardens (Canada)
Disease
An enormous American Elm once stood at RBG near McMaster University. Over 350 years old, it died in 1973 of Dutch Elm Disease.
Cross section from an over 350 year old American ElmRoyal Botanical Gardens (Canada)
Preserving heritage trees: red oak project
To keep the tree healthy and preserve its story, RBG is reducing soil compaction and protecting its roots by removing turf, adding mulch and fencing off the Root Protection Zone. The red oak resides among collections in our biggest garden area, Hendrie Park.
Hendrie Valley in the fallRoyal Botanical Gardens (Canada)
More than a tree
Saving trees saves our history, biodiversity, and ourselves
Mighty trees along nature trailRoyal Botanical Gardens (Canada)
Their biggest challenge yet
Heritage trees have been witnesses to our industrial progression, living through the decline of their own habitats.
Will they survive in an era of rapid climate change?
Their future is in our hands.
Royal Botanical Gardens, Ontario, CanadaHeritage Trees - Royal Botanical Gardens (rbg.ca)
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