Time To Trim Your Elm Trees Is Now
With all of the talk about Covid - 19 and everyone trapped in their homes and their yards there is one task that people can perform and still maintain social distancing and that is trim and prune their elm trees prior to the April 1st deadline.
The April 1st deadline is to protect the trees as the cutting may attract Native Elm Bark Beetle which can carry the fungus which causes Dutch Elm Disease.
What Is Dutch Elm Disease?
Dutch Elm Disease (DED) is caused by a fungus that was brought over to Europe from the East Indies in the late 19th Century. It was first identified in the Netherlands in 1919. The first case in North America was reported in Ohio in 1930. It was believed to have crossed the Atlantic in a shipment of wood for a furniture maker.
The fungus blocks the conductive tissue of the tree, blocking the flow of nutrients and water to the tree, thereby killing the tree. It can destroy a tree in as little as 3 weeks or take as long as 3 years.
The primary vector of Dutch Elm Disease in the province is the Native Elm Bark Beetle. This beetle occurs naturally in the province and is part of the natural decay process of our urban forests and wood lands. The Dutch Elm Disease fungus sticks to the beetle and is spread from tree to tree while the beetle feeds.
Native Elm Bark Beetle - photo credit Natural Resources Canada
As a species indigenous to North America and a vector of the Dutch elm disease fungi, the native elm bark beetle plays a leading role in the transmission of this disease, which wiped out the American elm population in eastern North America, Natural Resources Canada website says. The insect is monitored by many municipalities and some municipalities apply preventive measures - including the City of Moose Jaw - under an integrated pest control program with the aim of preventing the spread of this insect and hence the disease.
When Did Dutch Elm Disease Arrive In Moose Jaw
Dutch Elm Disease was discovered in the city on July 11, 2001.
It is a major threat to the not only the City’s owned urban forest consisting of approximatey 5,000 elm trees out of a total estimated 15,000 City-owned trees and privately owned elms as well.
Elms make up about one-third of the publicly owned urban forest. It is unknown how many privately owned elm trees there are in Moose Jaw.
There are City-owned elm trees thoughout the city with the highest concentration in the in the Avenues from Willow to 7th Avenue NW and from Caribou to Laurier and/or Saskatchewan. These are the trees which draw many residents to live in the shaded Avenues.
Elm varities are American Elm and Siberian Elm. With the City still ordering and planting elms but a variety that is more resistant to DED such as the Discovery Elm.
There are many elm trees which are 75 to 100 years old with the natural lifespan about 200 years.
In the past five years Dutch Elm Disease has been detected in the city. It is not eradicated from the City and control measures continue to keep it from spreading and devestating the city’s urban forest.
In 2015 there were nine trees with Dutch Elm Disease detected in the city, in 2016 there were 19 infected trees detected, in 2017 there were 11 infected trees detected, in 2018 there were 18 infected trees detected, and in 2019 there was the largest number of trees detected with 27 infected.
Once a tree is infected with Dutch Elm Disease it must be cut down. There is no way to save the tree and not cutting it down raises the potential of other nearby trees becoming infected.
Why The Need To Trim And Why Now?
The need to trim dead and dying parts of healthy elm trees is because the Native Elm Bark Beetles breed under the bark of dead or dying elm wood. If that wood contains the DED fungus, each new generation of beetles can infect healthy elms. By trinning this from elms it prevents the beetle from having a place to breed. It is also the reason why elm cannot be used for firewood under Saskatchewan law as the woodpile can be a major breeding ground.
“Provincial regulations prohibit pruning of elm trees from April 1 to August 31 each year. The beetles are most active then, and fresh cuts attract them, increasing the chance of infection,” said Daily Lennox parks supervisor for the City of Moose Jaw.
In order to prune their own tree and dispose of the trimmings at the landfill a resident must first get a free elm wiid disosal permit available from the City’s Parks and Recreation Department. There is no cost for the permit.
After being cut there is nothing a person can apply to the cut on the tree, Lennox said.
The trimmings and all elm wood should be hauled to the City’s landfill for disposal where it will be buried to prevent the potential spread of the fungus.
Although it is Winter now is the time to trim your privately owned elm trees - MJ Independent photo
What Is The Cost?
Lennox said the cost to protect the City’s elm trees is not broken down from the overall urban forest management budget.
“We do not have a breakdown of costs specific to the protection of elm trees as many of the efforts include all tree species. Methods include pruning, surveillance, erecting and monitoring Elm Bark Beetle traps, basal spraying, sampling, DED removal, trenching between neighboring trees, etc… Our annual urban forestry maintenance budget was $117,000 in 2019 and was increased to $172,000 in 2020,'“ she said.
The Province at one time contributed heavily to preserving the elm trees but there has been cutbacks over the years.
“In the early 2000’s the province provided funding for surveillance and inventorying our elms. They still fund the Elm Bark Beetle trapping, and they still look after the Buffer Zone in the Buffalo Pound Valley north of Moose Jaw. They send in a crew every fall to remove any dead elm or elm showing symptoms.”
Without the control measures the City has now it is likely the elm trees - both public and private - would be devestated in Moose Jaw.
“It is difficult to estimate how fast we would lose all of our elm without the controls we have in place now, but we would certainly lose all of them in time without control measures in place. Eastern Canada is a good example as there are very few because they were lost to DED. A good Dutch Elm Disease program typically loses one per cent of elms per year and we continue to be well under that target which is a sign of a successful program,” Lennox said,
What Can You Do To Help The Elms?
Although all City-owned trees under the Boulevard Bylaw must be trimmed by City crews people can still help out by informing the City of any trimming needed to be done as well as other proactive measures such as trimming your privately owned trees.
Do not store or use elm firewood.
“Keep their elms as healthy as possible: which can include additional watering during dry weather, regular pruning of dead wood, and monitor and protect against insects, such as cankerworms,” Lennox said.
What About Trimming At Other Times?
If an elm tree becomes infected after April 1st and needs to be removed the City needs to be notified and a permit obtained first. Otherwise fines may be assessed.
“Permission may be granted it an elm poses a threat to property damage, public safety or is infected. Application must be made to the City and approval will come from one of the designated municipal inspectors. If permission is granted, an Elmwood disposal permit is issued to dispose of the wood at the City of Moose Jaw landfill and followed up on,” Lennox said. “They must obtain a free Elmwood disposal permit from Parks and Rec and dispose of them at the landfill.”
How Does The City Control The Beetle?
At present time the City uses the chemical Pyrate 480 EC to help control the beetle population. The chemical is applied under low pressure to the bottom 50 centimetres of the elm tree, minimizing the possibility of drift.with annual goal to treat 2,500 trees or about half of the City-owned trees.
They do not spray private trees which, of the tree’s owner wants it done, they must make arrangements with a licensed spraying form to apply the pesticide.
“We regularly review our options and decide what the most effective means of controlling our elm beetle population would be at that time based on factors such as public safety, environmental impacts, cost, resources required and effectiveness,” Lennox said.
Although Pyrate 480 EC is officially licensed to control specific bugs in golf greens and not intended to be used in urban settings and near homes the federal government does allow and license its use in provincial Dutrch Elm Disease programs.
Warning sign prior to last Fall’s spraying to control Native Elm Bark Beetle - MJ Independent file photo
In an email response to MJ Independent on the use of the pesticide Health Canada in Ottawa said “Pyrate 480 EC is a Restricted Use Product that is to be used only under a provincial Dutch elm disease program. Label directions specify that the product is to be applied in a manner that is safe for both applicators and bystanders.”
“There are no health concerns from the use of this product provided that label directions are followed. Label directions specify that the product is to be applied in a manner that is safe for both applicators and bystanders. One of the label requirements is that bystanders should be advised to keep away from treated areas until residues are dry,” Health Canada responded in an email.
Although Pyrate 480C is determined as being safe to help control the beetle which spreads the fungus causing Dutch Elm Disease the active ingredient was under review last Fall.
“Health Canada is re-evaluating chlorpyrifos, the active ingredient in this product. The consultation completed by Health Canada received additional information which will allow for the assessment of whether specific uses will be indicated on the label or phased out in light of confirmed environmental concerns. Until a final decision has been made, the use of Pyrate 480 EC according to label directions can continue, including for the control of the native elm bark beetle,” Health Canada’s email stated.
More Information On Moose Jaw’s Urban Forest
“We plant a wide variety of trees: Ash, maple, linden, alder, birch, tree lilac, ornamental Crabapple, hawthorne as well as more DED resistant elm.” Lennox said.
For more information about Moose Jaw’s urban forest check out: https://moosejaw.ca/parks-recreation-culture/trees-of-moose-jaw/