A fungus known to infect and kill oak trees could have devastating effects in Niagara-on-the-Lake if it spreads. 

Holmes Hooke is one of the founders of the Chautauqua Oaks Project, which has planted upward of 150 oaks around the neighbourhood.

He is one of several people concerned about the issue this year.

“It could destroy the neighbourhood,” he said.

The fungus was found for the first time in Canada near the beginning of June at a residential property in Niagara Falls after a sample came back positive for the fungus. 

It was also detected in Springwater, Ont., two weeks ago.

Hooke and neighbour Leslie Frankish started the tree-planting project in 2016 to try to save the area’s tree canopy.

“If you go up Shakespeare, you’ll see the massive, big trees there: they’re all oak,” he said.

He has another 70 in his backyard waiting to be planted this fall.

“We’ve worked incredibly hard; we grew our own trees from harvested acorns in the neighborhood,” said Hooke.

He said oak wilt could wipe out their work – which would be devastating. 

Nicole Mielewczyk, a biologist with the Canadian Food Inspection Agency, explained how large the threat of the fungus could be.

“While it is a slow-moving disease, if it becomes established, it could have a major impact on Canada’s natural resources and forest industries,” Mielewczyk said in an email to The Lake Report.

Oak wilt could also have a negative effect on Niagara-on-the-Lake’s property values, the ecosystem and wildlife habitats, said David Dutkeiwicz, an entomology technician at the Invasive Species Centre in Sault Ste. Marie.

“We buy properties because sometimes you have these giant, beautiful oak trees that are on the property and have been there for a hundred or so years,” Dutkiewicz said.

“If oak wilt comes in and takes out some of these big, giant oak trees that are in our parks (and) in our backyards, that’s going to be very detrimental to us as well as the ecosystem,” he added. 

Coun. Sandra O’Connor said not only do trees provide oxygen, shade and clean air, but they also have immense economic value.

“It increases property values not only on an individual’s property but in the whole neighbourhood,” she said. 

“Everybody shares in the increased land values when there are large mature trees,” she added.

Red oaks are more susceptible to the disease, while white oaks can become infected, but are less likely to, said Dutkiewicz.

Marah Minor, the Town of Niagara-on-the-Lake’s spokesperson, said as soon as oak wilt was discovered in Niagara Falls, the town reached out to the Vineland Research and Innovation Centre and requested information about what steps to take. 

The town has joined the centre’s Greening the Landscape Research Consortium, which provides the latest information on green infrastructure. 

Oak wilt will be discussed at the town’s next meeting, said Minor.

Many of Niagara-on-the-Lake’s trees are in what scientists call a “riparian zone,” said Dutkiewicz, a zone found in riverside areas that support things like wildlife, water quality and soil health.

Since oak trees are often found in those zones, the fungus could affect said zones significantly, especially in the Niagara region, Dutkiewicz said, where forests are more fragmented due to the agricultural land surrounding the town.

However, he said oak trees can still be found in areas all over southern Ontario, including private woodlots, conservation authorities, riparian areas, urban and rural areas and parks.

Dutkiewicz said the Invasive Species Centre is worried about oak wilt being found in rural and urban areas.

“If oak wilt is found in rural areas, it may have larger ecological impacts that can affect riparian areas around streams and rivers because oak trees are often found in those locations,” he wrote in an email.

The fungus would also have a massive impact on wildlife and different insects that rely on oak trees as a main source of food, especially during the winter.

Oak wilt can spread through the movement of firewood and through sap-feeding beetles. 

“I always say don’t move firewood out of 100 kilometres of where you got it from,” said Dutkiewicz.

A great example of how moving firewood could spread disease, or an insect, would be the case of the emerald ash borer. 

Many people moved ash trees from location to location to burn and spread the emerald ash borer without realizing it, he said.

Since 2014, the Town of Niagara-on-the-Lake has had to remove more than 1,000 ash trees due to the invasive insect, which originated from Asia. 

The disease can also be spread through the movement of sap-feeding beetles.

On oak trees, oak wilt creates a fungal pad underneath the bark that “presses on the hardwoods and the bark, basically peeling the bark away a little bit, and creates little cracks in the wood,” said Dutkiewicz.

It releases a fruity scent that attracts the beetles to come and eat the fungus.

The beetles then get spores on them that they can transfer to the next tree and infect it too. 

Dutkiewicz tells people not to prune oak trees between April and October, when the beetles are most active. 

Hooke has also been telling people in his neighbourhood not to prune back the oak trees, no matter how much they want to. 

The town is taking a similar approach and will not be pruning oak trees from April through October, except for safety reasons,said Minor.

Root grafting is another way the fungus can spread. 

“Below the surface of the soil, trees are pretty interconnected so usually trees will graft onto each other through their roots,” said Dutkiewicz. 

If oak wilt spreads, he is worried that it could “go throughout the entire oak range” and into places like Quebec, which has a large oak tree population. 

“Quebec has a very big oak forested area and they rely on that for a lot of lumber,” he said. 

More information can be found online at invasivespeciescentre.ca and the Canadian Food Inspection Agency‘s website.