OTTAWA — Future trees will still look like today’s trees as the climate warms, but they’re going to need a whole new set of genes.
“In my opinion the single biggest threat to Canada’s forests is climate change,” says forestry professor Sally Aitken.
“And there are things that we can change ... to make that forest more resilient in the face of climate change.”
She’s a forest geneticist at the University of British Columbia. This week she’ll tell scientists, MPs and senators in Ottawa about the unseen differences among trees of the same species.
Genetically, a pine tree in Ottawa is different from one in Toronto or one in Sudbury. Each has evolved to suit its local climate.
That means there are already trees suited to the warmer climate Canada is likely to have in the near future, Aitken says, “but those genes are in the wrong places.” They’re in trees hundreds of kilometres south of us.
“So my research is focused on the best way to better match trees with new and future climates, to assist the movement of that genetic material through reforestation.”
Foresters have always chosen local seeds because they survive better, she said. “Local is no longer your best bet.”
The trouble is that it’s unclear which tree will be best adapted to a given place. Will trees from Ohio suit a future Ottawa? Or trees from Kentucky? No one knows.
“The climate is warming but we don’t know what trajectory we are on,” she said.
“The other thing is, we need to figure out what specific aspects of climate the trees are adapted to.”
For instance, no one knows whether the most important factor is average temperature, or summer heat waves, or extreme winter lows, or patterns of rainfall. It may be a mix.
Some species will move north, she believes.
Properly managed with new breeding stock, “the forest shouldn’t look fundamentally different. Now what will look fundamentally different is forests that aren’t managed, (which) are hitting tipping points.
“And so we’re seeing changes in forest health around the world associated with increased temperatures, drought stress, heat stress, (and) insect outbreaks.
“We have generally reforested with seed from a single population. In managed forests we’ve often replanted with a single species. And we need to think about increasing diversity because of the uncertainty.
“For a given species, we may need to mix seed from different sources” to learn which works best.
Aitken will speak Wednesday and Thursday to Genome Canada, which funds her work along with the Natural Sciences and Engineering Research Council; and to the Conservative forestry caucus and the Partnership Group for Science and Engineering.