A UNB researcher hopes to unlock the secrets of 500-year-old hemlocks

Loïc D’Orangeville walks a dirt trail deep within Fredericton’s Odell Park. Looking up, he’s surrounded by the tall trunks of hemlock trees, some of them hundreds of years old.

Another man crosses his path on the trail. Unprompted, the man says the city needs to cover the trail with gravel.

D’Orangeville disagrees, saying this space is protected. The University of New Brunswick associate professor is one of those trying to make sure it stays that way.

Loïc D’Orangeville is an associate professor, specializing in tree biology and silvics at the University of New Brunswick. His project includes collecting samples and documenting the age of old growth trees. (Mrinali Anchan/CBC)

D’Orangeville is working on a project to collect core wood samples from the trees and to study the width of the rings within them. That will help confirm the age of the towering trees.

So far, his research suggests these old growth hemlock trees are among the oldest in the province, some still standing tall 500 years after erupting from their seeds.

If his research can prove their age, he hopes “we can perhaps better protect them from future threats.”

Old growth trees are special because they haven’t been impacted by humans or natural disturbances for multiple centuries. (Mrinali Anchan/CBC)

Old growth trees are special because they haven’t been affected by humans or natural disturbances for multiple centuries.

The idea for the project came while he was out for a walk.

“I was with my colleague and friend Anthony Taylor and we were just noticing those fallen trees [in the forest] and how very old it might be,” said D’Orangeville.

Threats to forestry

D’Orangeville hopes some of the information he gets from the trees will also help understand how climate change and warming temperatures affect the forests.

“The warming allows for new insects and pests to actually migrate here. The winter has been putting a lot of insects and pests at bay and now they’re moving north.”

One of the most concerning pests for this grove of protected trees is the hemlock woolly adelgid, a small insect originally from Japan, but which has now made its way as close as Maine and parts of Nova Scotia.

Hemlock woolly adelgids are shown on hemlock tree needles via a microscope in this October 2016 file photo. (Elise Amendola/Associated Press)

“We don’t have it here yet, but scientists are pretty confident it’s going to happen at some point.” said D’Orangeville who stresses the importance of having a good monitoring system so experts know when the insect creeps into New Brunswick.

City collaboration

The research project is happening in collaboration with the city of Fredericton.

Keanen Jewett is foreman with the Parks and Trees department.

“We take very good pride as good stewards of Fredericton’s trees and it is important as our natural assets. With hemlock woolly adelgid right next door, Nova Scotia, it’s something that we want to be completely prepared for,” said Jewett.

He said part of that preparation includes learning more about the trees that have stood for hundreds of years.

“It would be really great to see actually, what the true ages are [of the trees],” said Jewett who noted that old growth forests like the one in the 160 hectare park are becoming increasingly rare.

“Very old trees have something that’s beyond the science.” said D’Orangeville.

“We know about the climate in the last four or 500 centuries and more from those old trees … But in terms of other values, social values … there’s something more to it.” said D’Orangeville.

He hopes to have the team’s project and results published formally next year.

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