The cherry birch is one of the most endangered woody tree species in Canada with an estimated five naturally-occurring plants known to exist in Ontario. That’s a paltry number. But there is actually a lessened chance of this botanical beauty dying out, thanks in large part to an innovative program at the University of Guelph. The Arboretum’s living gene bank, which began operation in the mid 1970s, is helping to spare rare trees like the cherry birch from extinction in Canada.
You’ve heard the term buy local. Well, the Arboretum is coining a new one – “grow local.”
“We’ve gone around to different populations in the last three or four decades and collected seeds from all of the rare plants that grow here (in Ontario),” says Chris Earley, the Arboretum’s interpretive biologist and education co-ordinator. “We propagate these seeds that are the same genetically as what has always grown in the province.
“It’s like a tree zoo of genetic material. That allows us to provide material for restoration with plants that are actually adapted to growing in this area.
“We’re trying to promote using native species instead of invasive species, but also to grow local.”
Earley says Guelph is situated at the northern edge of the Carolinian zone. In the United States, many of these woody species are more common, but they are rare at the northern edge of their range here in Ontario. Say some were to be negatively impacted by development or severe weather events. The Arboretum has the genetic materials stored for any environmental agencies looking to restore woody plants that are adapted to specific local conditions.
“It’s a very cool preservation story,” Earley says. “We are able to keep these trees alive and reintroduce them back into natural areas so that they can continue to be part of the ecology of that area.”
The Arboretum’s gene bank is relatively unique in Canada and it contains genetic material from most of the country’s woody plants that appear on the Committee on the Status of Endangered Wildlife list.
Some of these species, like the cherry birch (for which the Arboretum is also developing a specific stewardship program with the support of the Ministry of Natural Resources), cucumber tree, red mulberry, Kentucky coffee tree, blue ash, bayberry, and Hill’s oak (in addition to soon-to-be-listed plants like bear oak or swamp cottonwood), can be found throughout the Arboretum’s grounds (look out for the Be Aware of the Rare signs), though the bulk of the gene bank’s inventory is kept in isolated orchards.
The gene bank was created in response to the loss of habitat in southern Ontario. As woody plant populations were put at risk, there was growing urgency to collect genetic material so species weren’t lost for good.
“It was originally a part of the Rare Woody Plants of Ontario program that started here in 1978,” the Arboretum’s horticulturalist Sean Fox says of the gene bank. “The majority of the collection work and surveying started in the early 1980s under the direction of then curator, Dr. John Ambrose..”
Fox says there were three phases to the process: surveying for the presence of rare species to promote stewardship and protection of local populations while documenting and creating “herbarium vouchers” or plant pressings to study the taxonomy of the species; the collection of germ plasm from those trees, be it seeds or cuttings; and finally, the collection of seeds from the mature trees grown on site for distribution in restoration efforts.
Depending on the year, and the weather, the species can differ in size, meaning maintenance sometimes requires climbing and ladder use. For one sycamore that Fox says is about 63 feet high, a boom lift donated by Guelph’s SkyJack came in extremely handy.
While maintaining these beautiful woody trees and the gene bank itself is only a part of what the Arboretum does, the importance of the work is not lost on staffers. They are aware of those dedicated people before them and moreover, what is still to come.
“I certainly came up loving gardening and plants, so it’s nice to be able to create something beautiful and enjoy doing what you do,” says Fox. “But when you’re involved in a project that people well before me set up, I feel like I’m a steward into the next phase because these trees will be here long after I’m gone. You’re contributing to something. Those seeds that are getting sent off to seed banks across the country and are used for restoration, it creates a little bit more sense of importance as opposed to just making the site look pretty.
“It makes these formal plant collections worth something more to researchers and conservation practitioners.”
Earley’s job is to spread the word. Not just the information about the plants, but the reciprocal relationships they have with their pollinators, be it birds or insects.
“Hopefully, people realize how important all these species are so that they have a sense of responsibility for protecting them, for funding programs that would help these species, as well as allowing themselves and their children to internalize that they are part of nature,” he says.
“We are the stewards for the time that we are here and we want those positive feelings about the natural environment to be passed on from generation to generation so that they will be protected.”
For the Rare Woody Plant Gene Bank the Arboretum staff would visit sites where rare trees had been reported and often find the site bulldozed for agriculture or housing. There have been many cases of rare species loss in southern Ontario. Examples include:
A complete loss of a stand of Kentucky coffee trees in Essex County.
A soybean field in Lambton county where a stand of pawpaw once grew.
A corn field in Kent County where an outstanding, hardy population of flowering dogwood once grew.
All but one chinquapin oak was cut to make way for a housing development in Hastings County.
The Arboretum was one of the first institutions to commence establishment of a living gene bank of all known populations of rare woody plants in 1979.
At that time, the Arboretum launched its Ontario Rare Woody Plant Program, called Picking up the Pawpaws. The goal was to survey and document the status of over 20 species of rare woody plants in Ontario and inform the landowners of the significance of the plants on their property.
Seeds or cuttings were also collected from most of the wild populations or individuals with the goal of establishing an ex-situ conservation stand for each species just in case the in-situ conservation education didn’t work for some remnant populations. Most landowners were thrilled to be part of the conservation efforts and some didn’t know they had an unusual tree or shrub species growing on their property.
More than 20 species have much of their genetic diversity archived in the Arboretum Gene Bank and other collections. The gene bank holds a representative amount of the genetic diversity of such rare species as the cucumber tree, an endangered species in Canada, to the relatively common chinquapin oak (though few may ever see one). The gene bank orchards are now producing crops of seed that will ultimately reduce the seed-collecting pressure from wild populations and provide the seedlings needed to assist restoration of these species where they are in decline.
So yeah, grow local.