Carissa Brown doesn’t mind people barging into her office.
Working from the back of a truck on the Dempster Highway last summer, the 30 year-old researcher from the University of Saskatchewan is used to people stopping for a break during the long slog to Inuvik.
“It’s funny, sometimes you feel you’re in such a remote setting,” said Brown. “But sometimes you’ll be out working in a burn and someone in an RV will stop to talk to us and it will be tourists from Germany or Texas.”
“The Dempster is kind of a funny place to work, we meet all kinds of people.”
Last summer, Brown and her research assistant spent most nights in the cab of the truck because of the rain. It was their second summer collecting information on the tree line.
“We’d usually get up at around seven or 7:30, have a quick breakfast, and then go out and do the tree sampling, dig soil pits or collect pine cones,” said Brown. “We’d usually finish at five and make dinner.”
“It was a pretty regular nine-to-five kind of job,” she said.
They would take a break once a week for showers and groceries in Dawson, and then it was back to work trying to settle one of the most pressing predictions of climate change - are forest fires becoming more frequent?
Northern Canada is a testing ground for climate change predictions, where the volatility of the Arctic is a plus for researchers who try to separate myth from reality.
For all the plants and animals that depend on fires to renew their ecosystem, it could be the biggest decider of who lives where for centuries to come.
The Present Processes, Past Changes, Spaciotemporal Dynamics Arctic research program, which provided Brown’s funding, examines the structure of the tree line across Canada. Brown dealt specifically with the increase in fire patterns due to climate change and the effect on the tree line.
Brown worked on burn areas near the Eagle Plains gas station.
Usually, there will be 50 and 150 years between fires, she said.
“As things get warmer and drier, there might be fires more often and they might have big changes for what kind of trees are up there.”
The Eagles Plains area has sparse populations of white spruce, Alaskan birch and balsam poplar huddling near the rivers.
“But really, it’s like 99 per cent black spruce up there,” said Brown.
“Black spruce need a long time to make their cones and make seeds to be able to regenerate,” she said. “So if a fire happens too soon then they’re not going to be able to replace themselves.”
“So a black spruce stand might not be a black spruce stand again after a fire.”
It takes at least 30 years for a black spruce to reach puberty in the North, when its seed-filled cones begin to develop.
“In northern climates, everything grows a lot slower,” said Brown. “There are less nutrients so it takes at least 30 years.”
The rest of the ecosystem depends on the delicate survival conditions of the black spruce.
“In these recently burnt areas, there’s a lot of moose,” said Brown. “They really like to browse on the willows coming back (after a fire). There’s also lots of voles and lemmings that the wolves come and snack on.”
“They all use these burnt areas a lot.”
It’s difficult to determine if forest fires are actually happening more frequently, said Brown.
“One of the problems with research in the sub-Arctic is we don’t have fire records,” she said.
Brown said she believes the natural cycle is in northern Yukon is in the 50- to 150-year range, but being any more precise than that is tough.
“We’re trying to figure out if (the increased frequency in forest fires) is something that has happened in the past or whether it’s something completely novel,” said Brown.
Instead of fire records, she looks at tree cores, or stem disks, to age the trees.
“If you age the tree stands and find that all the trees established themselves at around the same time, then that’s probably because a fire came through,” she said.
Tree aging, or dendrochronology, can be done by drilling or cutting a cross-section of a tree trunk.
“One of the areas I studied burned in 1991 and again in 2005,” said Brown. “Right now, that looks like a grassy meadow. I’m trying to figure out what kind of trees would grow back there and what is growing there.”
“Right now it looks like not a lot of trees coming back at all. So it might turn into shrubby tundra.”
This, in turn, might alter the kinds of animals that flourish in Eagle Plains.
Not only that, but an increase in forest fires will have a number of feedback effects that will both encourage and slow climate change.
“Even after a forest fire you still have all those black spruce trees standing,” said Brown. “So you’re going to have changes in how strong the winds are through that area and that’s going to change snow depth.”
“After a fire, all that burnt, black and charred material really absorbs a lot of heat from the sun. But a field of light-coloured grass is going to reflect the sun a lot more.”
“That might make for cooler soils.”
Brown’s research may one day be used to see if other parts of the world will experience fire pattern changes.
“If a more frequent fire pattern has happened, and because it’s predicted to happen more, I can look at this one situation and use that to predict what might happen if we get more severe fires.”
Much of this Arctic research is looking at what has happened. But because the Arctic is ahead of the rest of the world in terms of climate change, the research can be predictive toward changes elsewhere.
Any jurisdiction where fire is part of an ecosystem, such as Yellowstone National Park in the US, might find her research useful, said Brown.
Brown grew up in Thunder Bay and earned her master’s degree at Ottawa University. Back then, she worked the summers in Ontario’s hinterland for that province’s Department of Mines and Natural Resources.
But Yukon work marks the first time she did research from the back of a truck.
“If I was feeling down, all I would have to do is look up and see the Ogilvie Mountains, that would always cheer me,” said Brown.
“I’ve been telling people down here if they’re going to do a trip up North to forget Alaska and the Northwest Territories,” she said. “The Yukon has amazing sites no matter where you are, whether you’re around rivers or the mountain ranges.”
“It’s an amazing place.”
Brown will be returning this summer and in 2010.
The natural resources management class from Yukon College stopped by to look at her research last summer, and Brown wants to make sure anyone who is interested in the fire cycle can drop by.
“I don’t want to just come from southern Canada and do this research and bring that research back down here with me,” she said. “I like to try and share it with people up North since it’s their home I’m working in.”
“If anyone sees me one the side of the highway this summer, they’re always welcome to stop by and chat.”
Contact James Munson at