Assisted Migration Strategy: Is it the Solution for Pacific Northwest Native Trees?

The native trees in the Pacific Northwest are facing a mortality problem due to climate changes, and researchers and tree experts are turning to a strategy called “assisted migration.” However, not everyone agrees on what type of assisted migration the area needs – or that it is always a good thing.

What is Assisted Migration?

The idea of assisted migration is to help trees keep up with climate changes by moving them to more suitable environments faster than they can migrate on their own. However, not everyone agrees on what type of assisted migration the area needs – or that it is always a good thing.

Types of Assisted Migration

There are three main forms of assisted migration:

1. Population migration: Involves moving seeds of native species and thus shifting their genetics within their current growth range.
2. Species migration: Involves moving a species to an area outside its current range, such as relocating redwoods and giant sequoias to Washington.
3. Range expansion: The species is moved slightly beyond its current range.

Challenges and Risks

Assisted migration faces potential challenges and risks, including:

• An increased risk of failure when planting something in an area where it does not occur locally, which raises the danger of disrupting potential ecosystem functions.
• The possibility that local larvae may not feed on the introduced exotic tree leaves, leading to disruptions in the food web.

Different Perspectives

There are varying perspectives in the Pacific Northwest regarding assisted migration:

• Some groups support assisted migration to help struggling native trees.
• Some groups believe that assisted migration could lead to the replacement of native species in the ground with southern trees, including giant sequoias and redwoods.

Experiments on Assisted Migration

Experiments on assisted migration are being conducted in several locations in the Pacific Northwest, including the Ellsworth Creek Preserve in Washington. These experiments aim to test whether native Douglas firs and western hemlocks from drier parts of the Pacific Northwest can be used to help western Washington forests adapt to climate changes.

Warnings and Concerns

Assisted migration of giant sequoias and redwoods is seen as fraught with risks. Researchers suggest that assisted migration for these species could be “a risky proposition,” and there is a real danger of exacerbating the problem rather than solving it.

Conclusion

As the impacts of climate change increase, public and private groups in the Pacific Northwest face the risks of assisted migration. However, assisted migration should be implemented with caution and based on the results of guiding experiments to avoid exacerbating the problem and achieving the desired outcomes.

This article was written in collaboration between the Associated Press and Columbia Insight, both of which are interested in studying the impact of climate change on trees in the Pacific Northwest.

Source: Nathan Gilles, Columbia Insight

Source: https://apnews.com/article/pacific-northwest-trees-dying-climate-change-migration-0c060e68e111ca06f51fc9e8e61e66b8