Canadians asked to find ash trees in a bid to preserve the species

Donnie McPhee, Coordinator of the National Tree Seed Centre of Natural Resources Canada, holds a collection of Black Ash seeds in a deep-freeze vault that stores seeds of Canada’s tree species of conservational concern, in Fredericton, N.B., Monday, Aug. 26, 2019. (THE CANADIAN PRESS/Stephen MacGillivray)

HALIFAX -- An invasive insect from Asia is expected to kill almost every ash tree in Canada, but Donnie McPhee has a plan to preserve the species.

Co-ordinator for the National Tree Seed Centre in Fredericton, McPhee is asking Canadians to help him find mature stands where seeds can be gathered and later stored for future generations in the centre's deep-freeze vaults.

"We're looking to protect the genetic diversity of the species," McPhee said in an interview. "We're looking for natural stands of trees that are in seed .... We want Canadians to be our eyes -- to let us know they're out there."

And the time is right to start the search because the white ash and black ash -- two of the most common species -- are expected to produce a bumper crop of seeds this fall. The centre's website provides details on what to look for, but seed collecting should be left to experts.

"We've already had people showing up with big bags of ash seed ... but it's too early in the season," McPhee said.

Larvae of the emerald ash borer, a small beetle with an iridescent green hue, have already killed millions of trees in Canada and the United States, and the pest's population is still growing.

The larvae make tunnels underneath the tree's bark, cutting off nutrient flow to the canopy, which eventually kills the tree.

"The reports I've seen suggest that within 50 years, there might not be any ash trees anywhere in the country," McPhee said.

In the southern Ontario city of Windsor, where the beetle was first detected in 2002, more than 90 per cent of the ash trees have already died.

The insect, known to hitch rides on ships, trucks and cars, has also been found across southern Ontario, southern Quebec and in the New Brunswick communities of Edmundston, Oromocto and, as of last week, Moncton.

It was spotted last year in Winnipeg and in Bedford, N.S., where Natural Resources Canada has deployed experimental traps filled with a beetle-killing fungus.

The range for Canada's most common native ash species -- white, black and green ash -- stretches from Nova Scotia, across New Brunswick and to the southern reaches of Ontario and Quebec.

However, black ash can also be found in western Newfoundland, northern Ontario and eastern Manitoba. And green ash -- the most widespread species -- can also be found in southern Manitoba, southern Saskatchewan and southeastern Alberta.

Though ash trees are not native to much of Alberta and British Columbia, non-native trees have been planted in many cities across Canada, creating a lush urban canopy that is now under threat.

Jon Sweeney, a research scientist with the Canadian Forest Service, said the loss of ash trees also means the loss of the 44 species of insects and other organisms that depend on this particular type of tree.

"When the ash trees go, you lose more than the trees," said Sweeney. "You get complications."

As well, the dead ash trees may be replaced by invasive plants, which has already happened in the United States.

Aside from the environmental impact, there will be an economic impact as well, considering white ash is used to make baseball bats, hockey sticks, canoe paddles and many types of tool handles, ladders and furniture.

"It's going to cost municipalities millions, if not billions, of dollars to cover tree removal and replacement costs," Sweeney said from Fredericton.

"It can cost you $200 to take a tree down, or it can cost you $2,000 ... (And) if your house is no longer shaded, you'll be paying more for air conditioning."

Municipal officials in Edmonton, Toronto, Ottawa, Montreal and other cities are doing what they can to combat the voracious bugs.

McPhee said he's primarily interested in native trees, which means most of the tall, slender examples found on city streets -- typically introduced from elsewhere -- are not eligible for seed preservation.

"I've gotten close to 250 emails, and half of them are from people who have an ash tree that somebody planted on their front lawn," McPhee said. "That's of no interest to us."

McPhee's long-term plan is to have the centre retrieve the collected ash seeds from cold storage in about 40 or 50 years, when the ash borer population has dwindled and safe planting can begin.

"The population of the insect will drop way down because the food supply isn't there," he said. "At that time, we want to go in and put the genetic diversity of the population back to where it came from."