Quebec boreal forest could be climate change refuge: study

If you make your living in Canada’s boreal forest — whether you’re a logger or a songbird — you might want to consider a move to Quebec.

Research suggests a Spain−sized area of forest in the centre of the province will be one of the rare places where nature will ease the effects of global warming and preserve existing ecosystems.

"As the climate changes, it’s imperative that we find places that might be OK," said Harvard University ecologist Neil Pedersen, co−author of a paper published Thursday in Science.

Pedersen and his colleague Loic d’Orangeville at the University of Quebec at Montreal analyzed a huge database of about 26,000 trees in Quebec’s boreal forest to try to understand how it will react to climate change.

Forecasts suggest that greenhouse gases will cause large regions of North America to gradually warm and dry out. Scientists have also predicted those higher temperatures would increase growth in the boreal forest.

But studies in Western Canada haven’t found a link between warm years and unusual growth.

In an effort to understand why, the team correlated tree growth between 1960 and 2004 in a large region of Quebec with weather data. They used trends from that data to predict what could happen under climate change.

They found a split in the response roughly coinciding with the 49th parallel, about 200 kilometres north of Quebec City.

South of that line, they found higher temperatures were likely to slow the growth of black spruce, the boreal forest’s dominant tree. More warmth increased the growing season, but didn’t make up for the reduced precipitation and increased evaporation.

But to the north, it was the opposite. There, the forest gets so much rain and snow, the extra heat gives the trees more chance to use it.

It wasn’t temperature that was the limiting factor. It was water.

"Most scientists would think that it’s the temperature that controls growth in boreal forest, because it’s so cold and the growing season is so short," said d’Orangeville. "But if there’s not enough water to sustain that growth, the positive response to warming may not be there."

The theory also explains the findings from Western Canada. The east, said d’Orangeville, gets two or three times as much precipitation.

"There’s much more water available in the system."

D’Orangeville cautions the study doesn’t factor in other climate− change−related disruptions such as large wildfires or insects.

But Pedersen says the results suggest northern Quebec could become what scientists call a refugium — an area that preserves an older ecosystem while everything around it changes.

"We still need to try and locate the regions that we think might be just better for biodiversity in the next few years," he said.

Black spruce stands are home to millions of songbirds as well as many kinds of wildlife. Black spruce is also a major resource for forestry companies.

"The wood industry would be pretty happy to hear their trees might grow faster and productivity’s going to shift north," said d’Orangeville.

"I’m not sure what the whole story’s going to be in the future. (But) I think it’s good news, not only for industry, but also for biodiversity."