Sat. Mar 2nd, 2024

Today’s post comes from Isabelle Moy, Discovery Naturalist at Killbear Provincial Park.

As many loyal Killbear campers will remember, seven years ago our camping landscape changed dramatically with the felling of many American beech trees due to beech bark disease.

Unfortunately, Killbear has once again been infested by an invasive species.

This time, it’s the emerald ash borer (EAB), an invasive beetle that weakens and kills ash trees. Just like that, Killbear’s landscape will change once again!

Signs of the Emerald Ash Borer

Park staff first discovered evidence of EAB at Killbear in the fall of 2019.

Native to Asia, this iridescent green beetle has been decimating ash trees throughout southern Ontario and is steadily moving north.

Emerald ash borer

Interestingly, it is the larval (baby) form of the ash borer that damages ash trees.

The eggs are laid hidden in the bark of an ash tree. When the larvae hatch, they begin to devour the layer beneath the bark where nutrients flow up and down the tree.

The larvae grow and eat more and more until they pupate and finally emerge from the tree as adult beetles a year or two later. Occasionally small “D” shaped exit holes can be found in the bark from which the adults emerged.

Beneath the layer of bark, undulating “feeding galleries” can be seen, marking the progress of the larva that grew there.

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Ash trees infected with EAB will experience crown dieback, which means fewer leaves at the ends of their branches.

holes in the bark

Because these trees cannot send food and water to the canopy, they will often produce “epicormic shoots.” These thin, misplaced branches along the trunk help the tree continue to collect sunlight and produce food despite the infestation.

Woodpecker holes and peeling bark are other signs of EAB.

Preparation for the future

Just as Killbear looked a little different after the beech bark disease cut, the cut that took place this year has changed things again.

Campsites may be a little sunnier and the forest may seem a little thinner.

piles of logs

Fortunately, the forest will adapt.

Other tree species will take advantage of the light and space and grow more quickly, filling gaps for the future.

Meanwhile, the noise of wood chippers has become an everyday sound, as maintenance teams work hard to get the park ready as soon as possible.

In the end, Killbear will remain the same park you know and love.

Burn where you buy!

We all have a role to play in stopping the spread of EAB. What happened in Killbear does not have to happen in other parks and natural areas in Ontario.

An individual BEF beetle can only fly a few kilometers.


The reason EAB has been able to spread so quickly across Ontario is because people move infested firewood to different areas.

Remember to burn your firewood where you buy it! Do not bring wood products from other areas of the province to the parks.

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Learn more about invasive species in Ontario parks.

Together we can prevent the spread of the emerald ash borer.