PORTLAND, Oregon (AP) —

As a result of climate changes causing the decline of native trees in the Pacific Northwest, the U.S. Forest Service, based in Portland, Oregon, and various citizen groups in the Puget Sound area are utilizing a seemingly straightforward approach known as “assisted migration” for climate adaptation.

Due to the increasing global temperature, it is projected that tree growing areas in the Northern Hemisphere will shift towards higher latitudes and altitudes.

Assisted migration is intended to aid trees in reaching their new climates, as they are unable to relocate on their own.

The concept is that people can assist trees in adapting to climate change by relocating them to suitable environments at a quicker pace than they could naturally migrate.

There is disagreement among individuals regarding the necessary form of assisted migration for the area and whether it is always beneficial.

In the northwestern region of the Pacific, there is a split among organizations supporting assisted migration to aid struggling native trees. Some propose introducing trees from the south, such as coast redwoods and giant sequoias, to replace the native species on the land.

Michael Case, a forest ecologist from the Nature Conservancy in Virginia, stated that there is a significant distinction between aiding the migration of populations and aiding the migration of species.

At the moment, Case is conducting a study on assisted population movement at the Ellsworth Creek Preserve in western Washington, under the Conservancy’s supervision.

Assisted population migration involves moving a native species’ seeds, and by extension its genes, within its current growing range.

On the other hand, assisted migration of species entails relocating a species to a location significantly beyond its current range, for example by introducing redwoods and sequoias to Washington.

One type of supported relocation, known as “range expansion,” involves moving a species slightly outside of its existing growth range.

Case is conducting a project to examine the potential use of native Douglas fir and western hemlock breeds from drier regions of the Pacific Northwest in aiding the adaptation of western Washington forests to climate change. He explains that the Nature Conservancy is prioritizing population migration due to lower ecological risks.

Case explained that planting something in an unfamiliar area raises the chances of it not succeeding. It also has the potential to disrupt important ecosystem functions and processes.

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This article is a result of a partnership between The Associated Press and Columbia Insight. It delves into the effects of climate change on trees in the Pacific Northwest.

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According to Dr. David Lytle, deputy chief for research and development at the Forest Service, the only type of assisted migration currently in use across the country is population migration.

Lytle stated that they are extremely careful and do not participate in the transportation and introduction of plant material beyond the original range of a species.

The Forest Service is implementing assisted population migration as it is expected to have minimal or no adverse effects on ecosystems, according to the spokesperson.

According to Douglas Tallamy, a professor specializing in insect and wildlife science at the University of Delaware, the movement of species could have a detrimental effect on native caterpillars, as they may not be able to consume the leaves of non-native trees that have migrated. This could have a ripple effect on the food chain as caterpillars are an important food source for birds and other animals.

Tallamy pointed out that this scenario could occur if the City of Portland relocates oak species from southern regions. He emphasized that oaks are crucial for supporting wildlife in North America, but moving them beyond their natural range would limit access for organisms that rely on them as a food source.

The Urban Forestry program in Portland is currently conducting a trial of assisted migration for 11 types of trees, including three types of oak trees, towards the southern region. These oak species include California black oak, canyon live oak, and interior live oak.

In response to an email inquiry about potential ecological disruptions, Jenn Cairo, the City Forester and Urban Forestry Manager of Portland, stated that they utilize research from universities, state and federal sources, as well as insights from local and regional field practitioners.

PropagationNation, a citizen-led organization in the Puget Sound area, is a proponent of species migration. Their website states that they have planted trees in multiple Seattle parks and have set a lofty objective of introducing a million coast redwoods and giant sequoias to the Pacific Northwest.

The PropagationNation website suggests adding redwood trees to locations where native species such as western red cedar, western hemlock, Sitka spruce, and big leaf maple are already present.

In recent years, there has been a decline in growth and an increase in die-offs among western red cedar, western hemlock, and big leaf maple due to the changing climate.

Philip Stielstra, the founder and president of PropagationNation and a former Boeing employee, chose not to provide a statement for this narrative.

According to David Milarch, the creator of Archangel Ancient Tree Archive in Michigan, which has provided PropagationNation with redwoods and sequoias, his trees are not meant to substitute for the native species in the Pacific Northwest.

Milarch stated that their efforts involve expanding the territory of redwoods and sequoias towards the north, with the goal of ensuring their survival for the next 100 to 200 years and preventing them from becoming endangered like other tree species.

Robert Slesak, a research forester with the Pacific Northwest Research Station, is in charge of the ENAMES project for the Forest Service. This project manages sites for population migration in Washington, Oregon, and California.

Slesak expressed caution towards the idea of relocating redwood trees to the north, stating that he has significant doubts about the effectiveness of assisted species migration and the lack of scientific testing in such efforts.

According to Slesak, implementing widespread assisted species migration without sufficient experimental evidence can be a risky endeavor. While it is widely acknowledged that action needs to be taken to address climate change, there is a potential danger of exacerbating the issue.

However, as the impacts of climate change continue to intensify, the responsibility for addressing them is being taken on more and more by both public and private organizations in the Pacific Northwest region.

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Nathan Gilles is a journalist and author who specializes in science and is located in Vancouver, Washington.

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Columbia Insight is an Oregon-based nonprofit news website covering environmental issues affecting the Pacific Northwest.

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The Associated Press receives backing from multiple private foundations for their coverage of climate and environmental issues. Learn more about the AP’s climate initiative here. The AP is solely accountable for all of its content.

Source: wral.com