70% of upper tree canopy lost in Pine Grove and Pinhey Forest, NCC says

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Snapped and uprooted trees line the floor of Pinhey Forest on Monday, more than three months after the devastating derecho windstorm. They'll be left to decompose for decades to improve soil and contribute to the growth of species like balsam poplar. (Alexander Behne/CBC - image credit)
Snapped and uprooted trees line the floor of Pinhey Forest on Monday, more than three months after the devastating derecho windstorm. They'll be left to decompose for decades to improve soil and contribute to the growth of species like balsam poplar. (Alexander Behne/CBC - image credit)

About 70 per cent of the tallest trees in Pine Grove and Pinhey Forest were lost to a devastating windstorm in May, according to the National Capital Commission (NCC).

To put that in perspective, the area of upper canopy loss (about 1,890 hectares) in those two Ottawa Greenbelt woodlands alone is nearly the size of five Central Experimental Farms.

The farm sits on about four square kilometres of land.

About 180 hectares of red pine in those two woodlands — planted in straight lines by the province in the 1950s and '60s to be harvested for utility poles — were particularly battered by the derecho, added NCC biologist Alexander Stone.

Red pines have no central taproot, making them more susceptible to toppling by wind, Stone said. The NCC no longer plants this species.

(Natural Resources Canada said red pines do sometimes have taproots and calls the trees "windfirm." The province says their roots "go fairly deep into the ground and are widespread; this means that the tree can withstand strong winds without blowing down.")

Regeneration will take decades

Storms are part of nature, clearing out older trees and opening up the canopy for "early successional species" to grow, Stone said.

In two to three years we can expect "a lot more balsam poplar" to shoot up in derecho-ravaged spaces, he said. They can grow up to about three metres by their third year, as the NCC saw at Bruce Pit after tornadoes swept through Ottawa and Gatineau in 2018.

But it'll take decades, maybe even 100 years, for Pine Grove and Pinhey to look the way they did before the storm. Stone said there are plans to help nature along with some tree planting as happened in Bruce Pit.

"We hope to have a good replanting strategy for those areas," he said.

Alexander Behne/CBC
Alexander Behne/CBC

Natural regeneration preferred, forester says

Bruno Chicoine, an NCC forest engineer, said the first step is to evaluate what will naturally regenerate.

"We know that natural regeneration is usually more [preferred] than planted trees and it's cheaper, of course," he said.

And while the NCC recently committed to planting 100,000 trees as part of its 2021-2026 forest strategy, it focuses more on expanding the urban canopy, Chicoine said.

Alexander Behne/CBC
Alexander Behne/CBC

He also described the forest strategy as an "intention" document about wishing to expand the canopy.

"So of course, that storm is a major step back, if you will. But it doesn't change the fact that the NCC recognizes the importance of forests and trees on its land, and wants to … get better in this direction," Chicoine said.

No plan to get rid of assets

In a recent climate vulnerability and risk assessment, the NCC said "If climate risks are not proactively managed, the NCC will need to seek more funds, decrease service level standards, and/or abandon assets and programs."

Horticulturalist Marc-Antoine Poitras, the NCC's contract management officer of Ontario urban lands and the Greenbelt, said Monday that "there's no plan to divest ourselves of assets.

"Obviously this storm was a significant impact but it's definitely something what we can manage," he said.

The NCC generally doesn't do much work in woodlands to allow natural processes to unfold, he said, and while intervention is needed after this storm "it's well within our capabilities" and funding will be sought from the government.

WATCH | A timeline update from the NCC: 

The first priority was cleaning up residential properties bordering NCC lands. Most of that work took about six to eight weeks but is ongoing, Poitras said.

The next focus was trails and sites such as dog parks.

The work has run the gamut, Poitras said, from contractors handling small-scale debris with chainsaws to more specialized work involving crews of arborists, as well as large-scale forestry operations using heavy equipment in Pine Grove and Pinhey Forest.

The NCC did its best to triage the work that needed to be done amid labour shortages and the "huge" scale of the damage, he said.

Poitras added that the NCC hopes to have all trails open in three to four weeks.