Natural disturbances in the boreal forest


Marty Alexander: My name’s Marty Alexander. I’m a Senior Fire Behaviour Research Officer with the Canadian Forest Service and I’ve been undertaking research in the boreal forest for the past 33 years.

Jan Volney: My name is Jan Volney. I’m a Research Scientist with the Canadian Forest Service of Natural Resources Canada. And I’m very proud of that.

My training is in entomology and forestry, but I’ve taken a larger view of things, looking at boreal forest sustainability and integrity in my research.

Marty Alexander: Well fire in the boreal forest has multiple roles. First of all it affects the forest vegetation, its structure and composition, in turn, that would influence wildlife habitat patterns and populations, as well as forest insects and pathogens.

Jan Volney: The boreal forest is a disturbance driven forest, so the business of having disturbance for renewal is tremendously important. So some insects cause damage, they kill trees. This is quite normal. However, this allows other trees to populate and thrive in the boreal forest. And so this constant process of renewal and death is a characteristic of this disturbance that we see so common in a boreal forest. It structures the forest. And this diversity itself supports biodiversity.

Marty Alexander: Fire is good in the boreal forest, it rejuvenates the forest. It’s part of the natural processes.

Jack Pine and Lodgepole Pine are probably the most classic examples. Their seed is stored in cones that are only released when they are exposed to the flame and heat from a forest fire. And because the seed is released then it starts a new forest.

From a standpoint of the interaction between fire and wildlife, a good example of something that’s beneficial to wildlife would be the case of moose. They’re dependent on young Aspen forests and older Aspen forests are just not accessible as a food source. So when a fire burns through an Aspen forest it starts a process of sprouts, young sprouts that are accessible as food now for the moose.

Jan Volney: There’s a myth about the boreal forest that it’s like a cathedral, it doesn’t change. But in fact, because it’s a living community of living organisms, several species involved, there’s this constant change going on. For things to thrive they have to have movement of nutrients and insects are part of this. And this disturbance is integral to the boreal forest. Many of these stands are so young that they never get past a certain age, hundred years. Some of them last on the landscape for a very long time. So what you want to do is maintain that balance. But the thought that these stands will stay in this condition forever is a myth. It doesn’t happen.

You’ll find that by far the largest influence in this forest in terms of volume loss is from insects. OK, the Mountain Pine Beetle is a staggering example of this. The point is that far more wood is lost through fire and insects than harvesting. Especially in the boreal forest.

Marty Alexander: My motivation for undertaking research in the boreal forest has really been that I’ve always had a deep interest in fire behaviour and I want to be able to see that information transmitted not only to fire management agencies, but also to the public so that we can effectively co-exist with fire, rather than attempting to continually fight it.

Jan Volney: The thing that keeps me motivated in this work is a passion for insects and forests. The second thing is that people derive a lot of benefits from forests. OK, it’s not only about wood and timber products, I think if you look at the art in Canada, you know the Group of Seven, these guys painted forests. I mean this is something that’s embedded in the psyche of this country. And as an immigrant, this is tremendous. I couldn’t think of a better profession.