The Emerald Ash Borer (EAB) is an invasive species that originated in China, because it has no natural predators in North America, it has become a devastating problem for North American ash trees (Fraxinus). Cities in Eastern Canada have been severely affected and are losing thousands of ash trees to EAB. Several Canadian cities, organizations, and scientists are trying to combat the problem and save the ash trees.
Ontario and Quebec are currently the only provinces in Canada infested with EAB. Other provinces are preparing for it to spread across the country. The City of Ottawa, Ontario, has been majorly affected by EAB. Ash trees account for 20-25% of Ottawa’s urban and rural forest (City of Ottawa EAB Strategy, 2013). Tree Ottawa says that in the next 3-5 years, Ottawa could lose 25% of its tree canopy (Ecology Ottawa). Another city that has been impacted by EAB is Montreal, Quebec. As of October 2016, more than 13,000 ash trees have been killed by EAB in Montreal (CBC 2016). One in five trees in Montreal are Ash and the City says that the 200,000 ash trees on public property are at risk for EAB (CBC, 2016). Cities are doing a lot of things to save ash trees, even cities that have not been hit by EAB are preparing for the beetles’ arrival.
Many cities and municipalities are including EAB control in their urban forestry management plans (UFMPs). The Cities of Ottawa and Montreal are experiencing urban canopy loss due to EAB. Both cities have included strategies for dealing with the pest in their UFMPs. The City of Ottawa’s EAB Strategy says to manage the impact of EAB, they will engage in “proactive and replacement tree planting, selective tree injections, tree removal, wood movement and disposal, and public awareness and outreach” (City of Ottawa, 2013). The City of Montreal, Quebec has a by-law to help mitigate the spread of EAB. The by-law has information on how to identify EAB, how to treat EAB, and how to dispose of infested Ash. The by-law also includes subsidies to help the public get rid of dead ash trees. Both cities have also included ash wood in their urban planning, with Ottawa using the felled ash trees in the construction of light rail stations, and Montreal using the Ash for public benches and flower boxes (CBC, 2016).
EAB has not reached Manitoba or Nova Scotia yet, but cities within these provinces are already including EAB mitigation in their UFMPs. The City of Winnipeg, Manitoba has already included steps in its UFMP to try and mitigate Ash loss and save the urban tree canopy. The City of Winnipeg’s Urban Forestry Branch is counting all the privately-owned ash trees to see how much urban canopy they will lose. The City of Halifax, Nova Scotia includes in their UFMP that the threat of EAB is “on the horizon” (City of Halifax, 2013) and are taking steps to prepare their urban forest for EAB. Organizations are also helping in the fight against EAB by providing subsidies and programs to help treat ash trees.
Two Canadian, non-profit organizations that are helping to mitigate the impacts of EAB, are Tree Canada (national) and LEAF (local to the City of Toronto). At the national scale, Tree Canada is offering incentives and pilot programs. In 2016, Tree Canada offered private ash tree owners $3 per centimetre of trunk diameter to treat with TreeAzin, an insecticide that kills EAB. LEAF (short for Local Enhancement and Appreciation of Forests), a Toronto-based non-profit, offers a Youth EAB Ambassador program, a workshop that teaches children the importance of urban forestry and the threat EAB poses. Along with cities and organizations, scientists and researchers are also helping ash trees.
Researchers and scientists across Canada have been trying to solve the problem of EAB. EAB is an invasive species and has no natural predators in North America. But a parasitic wasp, called Tetrastichus, bred in Sault Ste. Marie by the Great Lakes Forestry Centre, offers some hope. The wasps will help curb EAB by laying their eggs in the larvae, preventing the EAB larvae from reaching maturity. While it is not a solution to the problem, the wasps will help mitigate the impact of the invasive EAB. Tetrastichus have gone through extensive testing to ensure they will not negatively impact the environment or harm humans. The Great Lakes Forestry Centre hopes to rear about 12,000 of the wasps (CBC 2017). Besides subsidies, research, and programs there are other ways to control EAB. Natural Resources Canada (NRCan) has plenty of information about mitigating EAB; suggested treatments include selective pruning, EAB traps, and insecticide.
EAB is mainly spread by humans through the movement of firewood and other Ash products like wooden packaging; as such the likelihood of the beetle spreading to the rest of Canada is high. According to NRCan, the infestation of already-overrun regions is likely to increase. NRCan also says that most cities in Canada have a high concentration of ash trees in urban areas, therefore they expect most urban forests to be significantly reduced. The National Capital Commission for Ottawa, Ontario, plans to cut down almost 12,500 infected ash trees by 2018, and replace them with over 13,000 new trees (Ottawa Citizen, 2015). Although the outlook is grim, treatment and replanting is helping to replenish urban tree canopy.
While many ash trees are being cut down because of EAB, they are being replaced with other species of trees, ensuring that Canadians will still have green spaces to enjoy. With the help of scientists, and the inclusion of mitigation techniques into municipal UFMPs, ash trees will continue to be part of our urban tree canopy cover. Hopefully, someday soon, EAB will be at controllable populations and ash trees will thrive again.
- The City of Ottawa EAB strategy: https://documents.ottawa.ca/sites/documents.ottawa.ca/files/documents/eab_strategy_en.pdf
- The City of Winnipeg EAB strategy: http://www.winnipeg.ca/publicworks/parksOpenSpace/UrbanForestry/EmeraldAsh.stm
- The City of Halifax Urban Forest Master Plan: http://www.halifax.ca/property/ufmp/documents/secondeditionhrmufmp.pdf
- The City of Montreal EAB by-law: http://ville.montreal.qc.ca/portal/page?_pageid=8797,142106032&_dad=portal&_schema=PORTAL#subvention
- Montreal using ash trees: http://www.cbc.ca/news/canada/montreal/montreal-emerald-ash-borer-public-1.3807627
- Tree Canada EAB incentive: https://treecanada.ca/en/programs/operation-releaf/emerald-ash-borer-releaf/
- LEAF EAB youth ambassador program: http://www.yourleaf.org/youth-eab-ambassador-program
- Canadian government website with information about what is being done for EAB: https://www.nrcan.gc.ca/forests/fire-insects-disturbances/top-insects/13377
- CBC News, killer wasps EAB: http://www.cbc.ca/news/canada/sudbury/canadian-wasps-on-battlefront-1.4032275
- CBC News, killer wasps EAB: http://www.cbc.ca/news/canada/manitoba/wasps-fight-emerald-ash-borer-beetles-1.4035333
- Emerald Ash Borer Information Network: http://www.emeraldashborer.info/index.php
- Ottawa Citizen, NCC replacement trees: http://ottawacitizen.com/news/local-news/ncc-wont-replace-most-diseased-ash-trees-it-cuts-until-2018-or-later-report-says-with-video
- Ecology Ottawa: https://ecologyottawa.ca/tree-ottawa/