Going, going, gone: Death of a species as Kawartha Lakes set to lose 24,000 trees
Peace Park sits on a small, irregular plot of land just north of Central Senior Public School. It’s bordered by Albert Street., Peel Street W., a parking lot used by LCVI students, and a home. You might not have been aware it’s a park: there are no benches or play equipment. Until very recently what it consisted of was a stand of trees. There were thirteen of them, all planted in 1992, which is the year the park was dedicated.
The number 13 was significant, as a plaque explains: “The trees are symbolic of Canada’s Provinces and Territories and represent a link with one another, with nature, and as a symbol of hope for the future.”
A lovely gesture. And for years a pleasing sight. Until it wasn’t. All the trees were green ash, all were infected by emerald ash borer, and all were this year reduced to dying crowns, many dead and blackened branches, some wilted leaves, and “epicormic shoots” (suckers sent out as a response to stress).
In late August the Parks Department arborist and his helpers put all thirteen out of their misery. The trees were “removed,” anything under six inches in diameter put through a chipper (which would kill off any insects), and larger chain-sawed pieces left in neat stacks for any homeowner looking for what was still good quality firewood.
All that remains is a desolate-looking, open space with scattered ground-level stumps, spray-painted orange.
The Bigger Problem
The denuded park is a disturbing instance of a problem much larger in scale: the emerald ash borer (EAB) invasion.
Native to Asia, the beetle likely arrived in North America in wood packaging materials. In 2002, it crossed into Ontario at Windsor and has since then slowly but inexorably spread through the movement of infested materials such as firewood or woodchips. (“It’s a lazy insect,” explains Katrina Van Osch-Saxon, Coordinator of Fleming’s Arboriculture Program and instructor for their Tree Health course. “We move them.”)
It was first found here in City of Kawartha Lakes about five years ago.
The metallic blue-green beetle feeds on ash leaves and lays eggs in crevices in the bark. It’s the larvae that hatch out and bore into the tree that are the real problem. Tom Mikel (Van Osch-Saxon’s colleague and Coordinator of Fleming’s Urban Forestry Programs) explains.
“The larvae do all of the damage just below the bark where it cuts off the circulation of the tree through girdling it, interrupting its nutrient cycling, hence starving the tree.” ((This video featuring Van Osch Saxon shows what happens).
The first signs of an infestation include canopy die-back, cracks and peeling away of the upper bark, fewer leaves, and woodpecker activity.
The beetle has no natural enemies and very little can be done to protect the ashes. “It is expected that every ash tree will die,” says Mikel, “There may be some rare survivors or isolated trees that are missed but as we have seen throughout western Ontario the chance of any survivors is very slim. The greatest loss will be noticed in parks, along rural roadsides and on private property and woodlots.”
Ash have been a very popular choice for urban tree plantings. Once again, Mikel explains: “They can tolerate growing in poorer quality soils often found in urban spaces, they are fast growing, they have relatively strong wood, they provide adequate shade and they are a native species.”
Ryan Smith, the City’s Parks and Open Spaces Supervisor, adds some additional reasons for past mass plantings of ash: “The price point on ash trees was reasonable; they were hardy, climate wise.” Ironically, they were commonly planted as a replacement for Elm trees that succumbed to Dutch Elm Disease.
Losing every ash tree means losing a lot of trees. Estimates are that there were 24,000 in public spaces alone here in City of Kawartha Lakes (perhaps 5-10% of the total tree population).
What’s being lost are all those good things that trees confer. Van Osch-Saxon, off the top of her head, provides a lengthy list that includes their aesthetic value, cooling and heating effects, ability to soak up rainwater during downpours (storm water interception) and to absorb carbon dioxide and store it as carbon (carbon sequestration) — not to mention their proven health and social benefits, and providing habitat and food for other species.
And unlike roads and other “grey infrastructure” that depreciates and costs more and more money over time, “green infrastructure” (i.e. trees) becomes more valuable and has increased benefits over time. (In a city that’s seen a 90% increase in investment in roads over the past 10 years and in which 35% of our taxes is allocated to roads, this feels like a persuasive argument for protecting and investing in our trees.)
The Response
Lindsay is uniquely advantaged in being home to Fleming’s School of Environmental and Natural Resources Sciences. The Arboriculture, Urban Forestry, and Ecosystem Management programs mean expertise and resources.
Fleming began with inventory of ashes on their own campus and taking down affected trees. Under the direction of Ecosystem Management Program Technologist Jason Kerr the college has created an arboretum that includes a roof-top nursery and close to 100 tree species planted out on campus. It’s a way both of preserving locally-grown species and testing the viability of additional species. (Climate warming may accelerate the emerald ash borer problem by allowing two generations of the insect in a single year, but it also means that warmer-climate trees such as the Tulip tree can now be grown here).
The College has also been assisting City staff. Urban Forestry students helped inventory and remove local affected trees (in Memorial Park, for example).
They also assisted in development of an Ash Tree Management Plan. In April 2017 six Fleming students, Ryan Smith, and Rod Porter (Supervisor Capital and Special Projects) presented their 5-step plan to Council. They explained the benefits of a proactive program, indicated required resources, set out a replanting program, and a budget.
It was estimated that full implementation would cost $3.1 million. Council felt they couldn’t afford to proceed so they “received” the plan but gave no direction to City staff to put it into effect and no money specifically for the problem was included in operational budgets.
The result has been a scaled-down response. Bryan Robinson, Public Works Director, sets out some of the measures: “conducting an inventory of ash trees, participating in Emerald Ash Borer training, monitoring Emerald Ash Borer traps, removing pests from Ash Trees where identified and planting replacement trees that does not include the ash species.”
His own department focuses on impacted trees within road allowances and has what he terms a “nominal annual budget” to do this.
The Parks Department’s response began five years ago when the problem began. That’s when a park tree planting program to offset current and future losses of ash began. They concentrated initially, says Smith, on sites with mass plantings of ash. Remove, replant, and diversify was the approach.
Which brings us back to Peace Park, where we see this in action.
Peace Park
In October the stumps will be removed by the “stumper” the Parks Department rents each year and after that they will plant a mixture of 50 mm caliper trees, approximately ten feet in height depending on the species.
Last year in Victoria Park, just a few blocks away, the Parks Department attempted a version of the Peace Park vision. When work was done on the Armoury, they replaced the provincial and territorial flags that lined the building with specimens of the official provincial and territorial trees. There’s a tamarack for the Northwest Territories, a balsam fir for New Brunswick, and others.
But, Smith reports, “a few of the provincial trees have been difficult to obtain.” For Peace Park, then, he will replant with a variety of native deciduous trees.
The dangers of planting a monoculture have been learned, the hard way.
What you can do
If, by some miracle, you have a big healthy ash tree with a good set of keys, Van Osch-Saxon would encourage you to contact the Forest Gene Conservation Association (fcga), an organization that is working to identify and collect seed from trees that may have a genetic tolerance to the emerald ash borer.
If you have an ash tree that has been infested you have a decision to make. If you catch it early and the tree is of high value or emotional significance to you, you could hire a tree care service to inject a Canadian-produced insecticide called Treeazin; however that’s expensive and has to be reapplied every few years.
The other option is to do what Fleming College and the City have been doing: take the tree down, dispose of it responsibly, and replace it.
Any planting of trees to add to and diversify the urban forest is a good idea, if for no other reason than contributing to climate change mitigation. But it’s important to choose a species than can survive. There are stressors in an urban environment, and as Tom Mikel, points out, urban soil conditions are a limiting factor. “We badly deplete the biological health of urban soil through land development. Many tree species cannot survive in poor soil.” Peterborough County has a useful starting point for selecting appropriate species.
The ash may be all-but-gone, but a city with lots of gingkos, Kentucky Coffee, bur oak, and others? That would be some comfort.
