Bruce Pit teeming with life after tornado felled forest, but it's not all good news

After a tornado ripped through Bruce Pit off-leash dog park in 2018the woodland is lush with new growth, and it provides a good example of what derecho-ravaged forests on other National Capital Commission (NCC) landwill likely look like in a few years.

But not all of the work done in Bruce Pit theselast four years, or in NCC-owned Pine Grove and PinheyForest after the derechoin May,areecological best practices, according to an urban forestry expert with the University of British Columbia.

While the NCC says it takes a mostly hands-offapproachin its woodlands to allow natural processes to unfold, thatexpert and Tree Canada sayif the commissionwants its woodsto better stand up to climate change, more work and maintenance are needed.

On Sept. 21,2018, disaster struck Bruce Pit and neighbouring Arlington Woodswhen a tornado described by Environment Canada as a "high-end EF-2" with winds up to 220 km/h touched down in southern Ottawa.

The towering eastern white pines planted as a monoculture more than a century ago the hallmark ofBruce Pit and Arlington Woods snapped like matchsticks.

Four years laterthose scars still show, but they're beginning to fill in.

Poplars shootup naturally

The fallen trees exposed the woodland floor at Bruce Pit to light, andhundreds of balsam poplarssprang up on their own. Four years later, they are4.5 to sixmetres tall and too denseto walk through.

The poplars will eventually make wayforlonger-lived native species to move in: such asmaples, hemlocks, oaks and beeches, said Andrew Almas, an associate professor and urban forestry expert at the University of British Columbia.

This is good natural work, but there are differingschools of thought about what should be done with areas stripped of trees: leave them untouchedto regenerate naturally, plant trees throughout by hand, or some combination of the two.

"The most common thing you would hear is ...leave it alone, but practise a little bit of ecological restoration" by planting some trees to introduce diversity [of species, age, and genetics]to the canopy, Almas said.

Asugar maplein Ottawa is not genetically identical toa sugar maple growing in the warmer, southern end of its range in Lexington, Kentucky. Introducing southern tree DNA couldgive Ottawa's urban forests a better shot at long-term success as the climate warms.

Most trees planted don't check diversity boxes

About3,600 trees have beenplanted in Bruce Pit and Arlington Woodssincethe tornado, but most of them don't achieve any diversity benchmark. They're eastern white pineseedlingsgrown at the same timesfrom seeds collected in Arlington Woods by a neighbourhood man.

Almas also said thespecies is "noted as being a little bit on the decline." In nearby Massachusetts, a university has noted "widespread health issues" in white pinessince 2009.

James O'Gradygrew up in Arlington Woods and has a deep fondness for the white pine woodland he played in as a child. When he noticed years ago that somepinesin the area were struggling with road salt, he approached a tree nursery in Kemptville, Ont., about how to replace them.

The nurseryadvised him to collect cones, and in 2015it harvested their seeds and grew about 2,000 seedlings,O'Grady said.

Then the tornado struck. O'Grady calledthe nursery, and the community managed to raiseenough money to buy back and plant about 1,800 of the seedlings in 2019. In 2020 O'Grady brought the nursery even more cones, and another3,500 seedlings were grown. Earlier this year, the community bought back andplanted700 of them.

The city didn't allow most of thewhite pine seedlingsto be planted on itsland, saying they would be vulnerable to mowing bycrewsand thatspecies diversity was needed,O'Grady said, but the NCCwelcomed most of the remaining 2,400 seedlings with open arms.

Most wereplanted along paths in Bruce Pit under the NCC'sdirection,as well as on private properties.O'Grady said about 50 to 60 per cent have survived so far.

Aside from the community-suppliedseedlings, 106 plants were provided by the NCC. They are "high-quality" trees, shrubs and vines "representative of the forest around Bruce Pit," the NCC said in an email Friday.

Most of the treesare, again,eastern white pines. Other NCC-provided tree species includemaples,birches, beech,oak, spruce and hemlock, the NCC said.

"Itreally comes down to money," said Almas,"because if you're going to plant some genetic diversity, then you're going to have to pay for those trees and you're going to have to pay for the people that plant those trees."

Almas was also concerned about sections of felled and healthy trees alongside trailsbeing cut down, mulched and left onsite to decompose after the May derechoin Pinhey Forest and Pine Grove, which the NCC said was necessary to protect the publicandforestry crews.

The better thing to do is leave some standing dead wood to provide valuable habitat, Almas said. Indeed, the NCC left some in Bruce Pit, which it said has attracted"native and rare species"including pileated woodpeckers andflycatchers.

"The dead wood is probably the most important habitat space that we could have in the forest," Almassaid.

Tree Canada is a non-profit working to get more trees in the ground and care for trees in both urban and rural spaces. Its director of operations, Michael Petryk, said more work needs to be put in to care for woodlands like Bruce Pit if we want resilient urban forests.

"I think that the staff that the NCC has is doing the best with what they have, but you're talking two or three staff members managing huge swaths of land," he said.