Assisted Migration Gains Traction in Pacific Northwest Amid Climate Change

As native trees struggle, different forms of assisted migration spark debate over ecological risks.

Assisted migration, a climate adaptation strategy, is being increasingly adopted in the Pacific Northwest to help native trees adapt to climate change.
There are three forms of assisted migration: assisted population migration, assisted species migration, and range expansion.
Assisted population migration, which involves moving a native species' seeds within its current growing range, is currently the only form practiced nationwide by the U.S. Forest Service due to its fewer ecological risks.
Assisted species migration, which involves moving a species well outside its existing range, is seen as risky due to potential disruptions to the ecosystem, such as native caterpillars not eating the leaves of migrated nonnative tree species.
Despite the risks, assisted migration is being increasingly adopted by public and private groups in the Pacific Northwest due to the growing effects of climate change.