Resilient forests for the future, part one

Oct 2, 2018

Scientists are developing made-in-Alberta solutions to keep our forests healthy

Part one of two

The smoke pouring into Alberta from wildfires in British Columbia this year gave many of us pause to consider the health of our forests. Then there’s the still-fresh memory of the devastating Fort McMurray wildfire in 2016, the situation in northwestern Alberta with large tracts of dead trees ravaged by the mountain pine beetle and increasing concerns about global warming and its effects on our forests.

Our forests are under threat. Can we do anything about it?

Most definitely yes, says Dr. Ellen Macdonald, professor of Forest Ecology at the University of Alberta. “While climate change, insect outbreaks and drought are occurring at an unprecedented rate, we have responded by developing innovative tools for forest management based on science. Now we must put these into practice to secure the future economic value of our forests. Communities across Alberta depend on the forestry industry.”

“And it’s more than economics. We also need healthy forests for less tangible reasons: their cultural significance to First Nations, biodiversity  plants and animals – associated with forests, purification of air and water, recreation, tourism and aesthetics.”

Dr. Macdonald says our province can’t simply rely on research done elsewhere because our unique ecosystems and geography dictate that the most effective solutions will be made in Alberta.

A case in point is her own research on the mountain pine beetle. This pest swept into Alberta from British Columbia in 2006 and has since decimated about 2.3 million hectares of our lodgepole pine forests. (One hectare is the size of an average sports field.) Dr. Macdonald is heading a five-year collaborative project on how best to manage the regeneration of these forests.

Unlike the lodgepole pine forests of British Columbia, Alberta’s pine forests don’t tend to have many other tree species in them. So while British Columbia’s beetle-killed pine forests have regenerated to white spruce and fir, that’s not likely to happen in Alberta. To be sure, there is black spruce in the pine forests of the foothills, but black spruce is not a particularly valuable tree from a forestry perspective.

Another difference between British Columbia and Alberta is the mortality rate in pine forests. Rates tend to be lower in Alberta, often with about 50 per cent of the pines left alive.

While this might seem to be a good thing, it’s not. In the half-dead stands left by the mountain pine beetle, the remaining trees shade pine seedlings, which inhibits their growth, and the understory vegetation grows vigorously and out-competes the pines.

Based on this evidence, the team has concluded that many beetle-killed lodgepole pine forests will need help to facilitate lodgepole pine regeneration. One method is to salvage logging by clearcutting and then either spread cones or plant seedlings. “This is how we’ve been harvesting pine in Alberta since the 1950s and we know it works,” says Dr. Macdonald. “However, it’s simply not realistic to expect companies to log all these forests.”

The team is evaluating other methods such as partial harvesting (where strips of forest are clearcut), underplanting with young trees and mechanical site preparation to reduce competition from understory vegetation. Another aspect of the research is assessing the fire risk of forests that receive partial harvesting and site preparation treatments.

Ultimately, the goal is to provide the Alberta government and forestry companies with a scientifically supported basis for making decisions about which beetle-killed stands to prioritize for treatment and which treatments to use. “We’re using science to ensure that the forests of 60-to-80 years from now are healthy for people to use and enjoy,” says Dr. Macdonald.

Next month in part two of Resilient forests for the future

Learn about the role genomics plays a role in forest health.