By Vivian Collings
If we don’t prioritize invasive species as a problem, we may not have an environment left to be worried about.
Invasive pests should be at the top of our list of concerns as Ontarians, said Malcolm Cockwell, managing director at Haliburton Forest and Wildlife Reserve and president of Forests Ontario.
“You’ve got to make sure there’s an environment to protect in the first place,” Cockwell said. “If you’re worried about climate change, you need to be worried about this. This is going to be the defining environmental issue for the next 100 years. If we don’t prioritize invasive pests, there will be no environment.”
He said no matter who you are or how you enjoy the Highlands, you should be concerned about invasive pests.
“Obviously, I am looking at it through the lens of a forester and a forest manager, but different people would prioritize different invasive pests,” Cockwell said. “Recreationalists would probably be really concerned about Giant Hogweed or possibly Garlic Mustard or Purple Loostrife. Waterfront owners would probably be concerned about something called Spiny Waterflea, Japanese Knotweed, or another aquatic pest that are likely to come in.”
Either way, he said, there’s no shortage of pests to be concerned about on a recreational level and by the affect it will have on our ecosystems.
There’s also no easy way to address invasive species.
Back in December, Dysart council heard a proposal to eradicate the five known patches of Giant Hogweed in the municipality; a weed that produces sap which can cause severe burns on skin that comes in contact with sunlight.
Total eradication would take multiple years and $55,000, and it was a debate council decided to defer until the budget was settled.
Cockwell highlighted the two invasive species he is most concerned about as a forester.
“The big one that’s already here is Beech Bark Disease. Once it’s fully run its course, it will probably have killed 10 to 15 per cent of the trees in Haliburton County. That’s a massive impact from that one alone. It’s already halfway done doing its damage in Haliburton County.”
As stated by the government of Ontario, Beech Bark Disease is a combination of beech scale insects and a canker fungus that together “cause severe cankering, deformation of the stem, and eventually tree mortality.”
The insects make punctures in beech tree bark, allowing for fungal spores to enter the tree. The fungus usually kills a large beech tree within 10 years.
Cockwell said there are two main effects of Beech Bark Disease that are of concern.
The first is that the disease will kill the majority of beech trees in the area.
“That’s concerning because beech is an important tree. They’re common, they’re everywhere, and trees are sequestering carbon, generating oxygen, and all kinds of good things, so inherently it’s bad if they die, but it’s paricularly problematic because beech is the biggest producer of mast in forests around here, and mast is food that animals eat,” Cockwell said.
Mast is the fruit, nuts, and seeds produced by trees.
“Beech produces beech nuts that humans can eat too, but at various times of year, beech nuts can account for the majority of caloric intake for some animals including bears. If you start to think through the repercussions of the death of the beech and the loss of the Mast, then you’ve taken away half of the food of the bears at certain times of year. What’s going to end up happening? Human/bear conflict, among other issues,” he said.
Cockwell said nothing can be done about this problem, and he thinks beech will never be a commercial species in Ontario.
However, the second issue with the presence of Beech Bark Disease can be addressed.
The second problem will likely start five years in the future.
“Beech tends to reproduce vegitatively as opposed to sexually, so most of the beech saplings that you see in the forest did not grow from a seed. They grow as a root sucker from the roots of another tree, so they’re clones of each other basically.”
Cockwell said this in itself is not a problem.
“The problem is that when you have a huge mortality event among beech, they get stressed. When they get stressed, they will reproduce, so they will send up lots and lots of root suckers into the forest. What you end up with is a huge amount of little beech saplings being created in the forest which prevents other trees from growing, so it reduces diversity, and then those little beech saplings are destined to die before they become trees because they will get beech Bark Disease,” he said.
Cockwell said this results in the formation of beech thickets that are a dead area where nothing else can grow.
“They are essentially a desert.”
Like many invasive species now present in Ontario, Beech Bark Disease originates in Europe, but he said the insect-fungus complex is not harmful to European beech trees because they are a slightly different species.
“The problem is that here, the beech did not evolve with this, so they are very susceptible and there is no protection against it.”
To help this issue in Ontario, Cockwell said harvesting methods that can encourage the growth of other tree species on top of beech can be successful. But even these solutions have some downfalls.
“It’s not pretty because it often involved doing a hardwood clear cut, but in doing a clear cut, you’re able to get other species like maple, cherry, ash, and oak to grow back,” he said.
Cockwell said the second way to prevent the long term impact is with herbicides which would kill all beech tree suckers which allows other species to become established.
Haliburton Forest and Wildlife Reserve has experimented with both and has had success, but said they are both very costly.
The second invasive species Cockwell is most conerned about is an insect called Hemlock Wooly Adelgid.
“That one’s not here yet, but it likely will be soon. It’s been noted in Southern Ontario, and if it gets established here, it will kill virtually all of Hemlock, which would represent another ten per cent of our forests. It would be particularly bad because the habitat types where Hemlock occurs are very sensitive and very important to most wildlife; birds and ungulates in particular,” Cockwell said.
He said although the subject is disheartening because there are no easy solutions, and sometimes there are no solutions at all, he hopes invasive pests will come to the forefront of environmental concerns.
“Nobody likes to talk about invasive pests because it’s a nasty subject. There’s no heroes in the world of invasive species. We need to get over that as a society. Everybody needs to realize that this is going to affect everyone in a major way, and the impact will be shared by everybody,” he said.