Harsh winters, dry summers stressing trees

Branfordexpositor.ca
Sept. 9, 2015
By Heather Ibbotson

Brantford's trees are in need of some love from Mother Nature.

Successive years of punishing weather, including a 2012 drought, a harsh winter and ice storm in 2013 plus another bad winter in 2014 have been hard on trees, said Kat Hodgins, an urban forestry technician with the city.

And during this hot dry summer, many trees are "showing drought stress," exhibited by brittle, droopy leaves that may be already falling prematurely, she said.

Trees that are stressed are also more susceptible to other problems such as fungus, Hodgins said.

Added to all the climate woes are other factors that can cause harm, such as road de-icer runoff, vehicle exhaust and disturbance or damage to root systems caused by construction.

And then there's the curse of the emerald ash borer.

The alien insect, imported to North America from Asia, was first detected in Canada in 2002 at Windsor and has since spread rapidly across Ontario, tolling a death knell for the popular and oft-planted ash tree.

Brantford has an identified inventory of between 4,000 and 5,000 ash trees located on city streets, not including those in park areas. Removal of affected ash trees has been tracked since 2011.

"They are all to be taken down. Every ash on streets and in parks," Hodgins said.

The infestation is throughout the province and, at this point, there is really nothing left to do," she said.

"We try to triage and (take down) the worst trees first," she said.

More than 500 ash trees have been cut down in the city this year.

"Ash were amazing, wonderful trees up to the time the bug came to North America," Hodgins said.

"They were hardy, resilient, with gorgeous colour. They were a perfect street tree 'til the bug came."

Hodgins said that the loss of the ash is comparable to that of the elm, the stately species that largely succumbed half a century ago to the imported scourge of Dutch elm disease.

The main difference between the two plagues is one of time, she said.

It took 30 to 40 years for Dutch elm disease to creep across the province and destroy the shady trees that once graced streetscapes, country lanes and farm properties.

Ontario was hit hard in the 1960s, and Brantford's elms were struck full force by 1964. By then, 123 of the city's elms had been affected and doomed.

In the face of such destruction, it was decided to include a variety of species in plantings slated for what was then the new Mayfair Gardens subdivision just north of Highway 403 near Tollgate Road.

"If a disease strikes a tree the whole street will not be wiped out as is the problem with the Dutch elm disease," said Len Joylyn, then assistant parks superintendent, in 1964.

Now, a half-century later, Joylyn's foresight has proven its worth.

The emerald ash borer is obliterating ash trees within five to eight years, Hodgins says. "The mortality curve moves very fast."

Luckily, neighbourhoods planted in the wake of the elm disaster have more variety and are less likely to be left barren after the ash are taken down.

Still, the loss of the ash has had a huge impact, Hodgins said.

"It's about 7% of our forest cover from a municipal standpoint," she said.

Overall, Brantford's tree canopy sits at about 24.5%, meaning that, from a bird's-eye view, about a quarter of the city shows the tops of trees, Hodgins said.

"That's pretty good for an urban environment" and the city is committed to increasing it, she said.

The hoped-for target would be about 40% but it will take a while to get there.

"We're making headway. We're planting more than we cut down. But young trees take a while to catch up from a canopy standpoint," she said.

Meanwhile, the continuing loss of the ash has widespread negative economic impact. It touches the landscape industry, forest and wood product industry and even sports because many baseball bats are traditionally made from ash, Hodgins said.

Locally, the work involved in identifying ash trees on municipally owned land and then removing them also impacts other work on the plates of city parks staff, she said.

And there is an emotional impact often overlooked.

"No one gets into this line of work to cut down trees. We want to make the world greener. It's hard when this happens. It hits when you go home," she said.

The city is committed to replacing the ash trees taken down with new plantings of mostly native trees, including maple, hackberry, serviceberry and oak (in areas with enough room), Hodgins said.

Neighbourhoods are not getting just two or three species in new plantings, but a healthy mixture.

"Just in case this happens again," she said, echoing the sentiment of her city parks predecessor of more than a generation ago.