The summer of 1938, one of Vancouver Island’s hottest on record, set up conditions for the Bloedel Fire that destroyed more than 30,000 hectares of timber on the north Island.
Drought-stressed trees and debris left by the fire became a breeding ground for a Douglas fir beetle outbreak that further degraded the forest. TimberWest owns much of the forest land that is still recovering nearly 80 years later.
Could climate change trigger similar future events?
“There was a Douglas fir beetle outbreak in the ’30s which was related to drought and a fire, so there actually is recorded history of what happens if we’re not prepared,” said Domenico Iannidinardo, TimberWest vice-president of sustainability and chief forester.
To hedge against effects of climate change that can weaken forests and affect productivity for decades, forest companies rely on seed orchards, such as TimberWest’s Mount Newton Seed Orchard in Saanichton, where seeds are harvested from trees adapted for drier conditions and volume growth, quality and pest resistance. Seedlings from that seed are raised by private contractors, including Arbutus Grove Nursery in North Saanich. The province and companies trade surplus seed for research.
Greg O’Neill, climate change adaptation scientist with the Ministry of Forest Lands and Natural Resource Operations Tree Improvement Branch, said B.C. has some of the world’s strictest seed migration regulations.
He said climate adaptation programs aren’t in response to future rising temperatures, but to account a mean annual temperature rise across B.C. of 1.2 C over the past 150 years.
As a result, seed movement of a species is typically restricted to distances of 200 to 400 kilometres north and elevation changes of 100 to 200 metres – distances that would fall within the tree species’ natural distribution range. Conservative movements better ensure success of the program, but also mitigate risk of forest stress if temperature change reverts to a cooling trend.
“There’s this evolutionary lag that’s been created over the last 150 years that we’re trying to rebalance through assisted migration,” O’Neill said.
Seed movement and genetic research is watched over by the Forest Genetics Council, a Crown-corporate volunteer board with appointments made by the minister of forests. Iannidinardo is a director.
“Our mandate is to oversee the province’s assisted migration and climate change adaptation strategy. With that is the system that makes sure our orchards are growing the right kinds of cones and seeds and our nurseries are applying the best practices and ultimately that we monitor the success of the plan,” Iannidinardo said.
New technologies, research and data-gathering methods are currently helping scientist develop a more comprehensive system, called climate-based seed transfer, to be adopted by government to better refine assisted migration, but there is already evidence for what works on hand. In the 1960s and ’70s B.C. established field trial plots across the province – there are also plots in the U.S. Pacific Northwest and Alaska – to test-grow seedlings from multiple sources to identify superior seed for reforestation.
“Serendipitously, those trials now turn out to be ideal climate change laboratories … that now are guiding us in terms of what is a safe distance to go to procure your seed and what is a safe distance to move seed to account for past and future climate change,” O’Neill said.
The government is also encouraging planting diverse species on reforest sites.
“Foresters like to recreate what was there originally, so there’s even more emphasis on ensuring the species diversity is being maintained or expanded,” O’Neill said.