Tree-moving due to global warming is debated

LOS ANGELES — 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 red cedar that grace British Columbia's coastal rainforests and drop their seedlings in the dry ponderosa pine forests of Idaho.

All of this swapping begs the question: Should humans lend nature a helping hand?

With global warming threatening the livelihoods of certain plants and animals, this radical idea once dismissed in scientific circles has moved to the forefront of debate and triggered strong emotions among conservationists.

About 20 percent to 30 percent of species worldwide face a high risk of becoming extinct possibly by 2100 as global temperatures rise, estimated a 2007 report by the Nobel-winning international climate change panel. The group noted that current conservation practices are "generally poorly prepared to adapt to this level of change."

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.

Others counter that given the grim realities of a warming planet, it would be irresponsible not to intervene as a conservation strategy. Otherwise, trees may suffer from ravaging disease epidemics while critters unable to head north may find themselves trapped in a declining landscape.

"A tree that we plant today better well be adapted to the climate for 80 years, not just the climate today," said Greg O'Neill, a geneticist with the British Columbia Ministry of Forests and Range. "We really have to think long-term."