On naked patches of land in western Canada and United States, scientists are planting trees that don’t belong there. It’s a bold experiment to move trees threatened by global warming into places where they may thrive amid a changing climate.
Take the Western larch with its thick grooved bark and green needles. It grows in the valleys and lower mountain slopes in British Columbia’s southern interior. Canadian foresters are testing how its seeds will fare when planted farther north — just below the Arctic Circle.
Something similar will be tried in the Lower 48. Researchers will uproot moisture-loving Sitka spruce and Western redcedar that grace British Columbia’s coastal rainforests and drop their seedlings in the dry ponderosa pine forests of Idaho.
Deliberating moving a species has long been opposed by some, who believe we should not play God with nature and worry that introducing an exotic species — intentionally or not — could upset the natural balance and cause unforeseen ripple effects. It has happened before with dire results. Two decades ago, zebra mussels were accidentally introduced into the Great Lakes and millions are now spent every year removing the pest from water pipes.
The notion of relocating species as a pre-emptive strike against climate change has been largely theoretical. In recent years, some groups have tried assisted migration on a limited basis, most notably the effort by volunteers who last year planted seedlings of the endangered Torreya tree found in Florida to the cooler southern Appalachians.
The Canadian experiment currently under way will cover a broad swath, with tree plantings dotting the Yukon near Alaska to southern Oregon.
Past warmings have forced species to migrate to survive without human help. While some have learned to adapt to new surroundings, other have gone extinct. Faced with the possibility of much more rapid climate change, scientists say, some species may not be able to move fast enough to their new destinations and may need a little power boost to preserve biodiversity.
In North America, some critters have already started their march north. The Edith’s checkerspot butterfly, which vanished from its southern range, is now fluttering 75 miles higher in elevation. Red foxes have encroached farther into northern Canada and evicted the arctic foxes.
Last year, the British Columbia government took the first steps toward ensuring that trees in the province are adapted to future climates by relaxing its seed rules for timber companies when they replant on logged land. Seeds of most tree species can now be planted up to 1,600 feet higher than their current location.
The government’s latest experiment will study how humans can help trees move to more northerly spots where they do not currently grow, but may find themselves existing there years from now. It will not deal with introducing foreign tree species, O’Neill said.
This spring, crews fanned across rugged mountains and began the first dozen plantings on cleared forest land in British Columbia’s southern interior and on a private plot near Mount St. Helens in Washington state.
The project will eventually include 48 plots around British Columbia, Washington state, Oregon, Montana and Idaho. It will test the ability of 15 tree species to survive in environments colder and hotter than they’re used to.