Assisted migration of forests in North America

[19] Regional climate change in the Sierra mountains of California made it possible for native bark beetles to kill drought-stressed conifer trees, which in turn led to expansive and catastrophic fires.

[21][22] The northern populations of temperate tree species ranges in coastal Washington and Oregon began to evidence abrupt decline and mortality over such large regions that news articles written for the public,[23][24] as well as academic papers, reported on this phenomenon in 2021 and 2022.

[28][29] A synthesis paper published in 2022 by a team of governmental and university forestry scientists in the United States warned that "climate change may represent the greatest challenge ever faced by forest managers, conservation biologists, and ecologists."

[30] A 2011 discussion paper in the British Columbia Journal of Ecosystems and Management offered this definition of assisted migration: "the purposeful movement of species to facilitate or mimic natural population or range expansion to help ensure forest plantations remain resilient in future climates.

[22] Beginning in 2004 and accelerating in 2007, researchers in conservation biology published papers on the pros and cons of supplementing traditional management practices for preventing plant and animal extinctions with species translocation tactics to accommodate the range shifts already becoming evident as a result of climate change.

[44][45][46][47] In the 1990s, forestry researchers had begun applying climate change projections to their own tree species distribution models, and some results on the probable distances of future range shifts prompted attention.

Isabelle Aubin and colleagues stated that "assisted migration is being proposed to reduce the impacts of human-induced climate change, an unprecedented situation in human history that brings with it entirely new environmental, societal and ethical challenges.

Rather, forestry forms of assisted migration would be undertaken for the purposes of maintaining the forests' ecosystem services as well as the extractive resource values of timber and pulp production.

[59][60] Communication in both word and images has also been honed in the United States, thanks in part to the Northern Institute of Applied Climate Science (NIACS), a collaborative group launched in 2010 by the U.S. Forest Service.

[62] A 2022 review paper that charted key words and lead authors in forestry publications concluded that "much of the research on assisted migration has been carried out in North America, where Canada and the USA have established strong collaborative networks."

[64] While climate adaptation may be a necessary consideration today, assisted migration is not a readily palatable option for Indigenous peoples, given the grounding in mutual relations with the ecosystems in which their cultures are enmeshed.

[69][70] Kimmerer is founder and director of the Center for Native Peoples and the Environment, hosted by SUNY College of Environmental Science and Forestry, which lists "Helping Forests Walk" as a five-year collaborative project launched in 2011[71] and completed in 2016.

[74] In 2024 a collaborative report presented Indigenous knowledge and forest management experience as meriting equal standing alongside the prevailing paradigm and assumptions inherent in forestry grounded in western science.

[76]As of 2021, the Little Traverse Bay Bands of Odawa Indians in northern Michigan have planted tree species common to more southerly ranges, including shagbark hickory, silver maple, black walnut, swamp white oak, sassafras, and pawpaw.

Traditional use of fire in managing local ecosystems for safety and for ensuring abundance of culturally significant plant and animal foods has drawn media attention to the climate-adaptive actions by the Karuk Tribe along the Klamath River of northern California.

Provenance trial locations poleward of native ranges or at higher (and thus cooler) elevations help forest managers determine whether, where, and when assisted migration as a climate adaptation measure should be implemented.

[86] Within the United States Forest Service, regional geneticists have recommended a "no regrets" approach to considering assisted migration and seed transfer as a climate adaptation strategy.

This project also entails standardized norms for labelling seeds by collectors and nurseries in anticipation that future reforestation and restoration plantings may begin to include various forms of forestry assisted migration.

The western larch was selected for assisted species migration because of its significant commercial importance and the fear that climate change and parasites such as the mountain pine beetle would considerably diminish its supply.

"[113] Assisted migration of oyamel fir is complicated by the necessity of planting this shade-tolerant species under nurse plants—especially because of the extreme solar radiation and the large differences between day and night temperatures at high elevations.

"[121] By 2023 two other land conservancies in Michigan were reported as also planting more southerly tree species including sycamore, pawpaw, blackgum, tuliptree, Kentucky coffeetree, honey locust, and red mulberry.

Because nursery stock had run short of native western red-cedar, project leaders chose to substitute a closely related conifer sourced from Oregon and northern California: incense cedar.

This attempt to ensure that a forest canopy will once again prevail in regional wetlands thus also entails an assisted range expansion form of climate adaptation for species including eastern cottonwood, American hackberry, and river birch.

In 2024 a Mexican leader who has long advocated for assisted migration to become a standard climate adaptation tool within North American forestry practices published a short paper concluding that the then-current El Niño had already pushed global temperatures to the 1.5 °C threshold of increase that generates self-reinforcing tipping points.

Jesse Bellemare and colleagues may have coined the term in a paper published in 2015: "It appears that a subset of native plants, particularly those with ornamental value, might already have had opportunities to shift their ranges northward via inadvertent human assistance.

In October, a lengthy New York Times Magazine article reported favorably on the group's distribution of redwood seedlings to tree farms, public parks, and private individuals in a broad region surrounding the city of Seattle.

The deaths caught scientists and national park managers by surprise during the next few years, as drought-weakened trees succumbed to bark beetle infestations in their thin-barked upper branches.

[159] Because the drought killed an enormous number of the common pine species and firs that surround the discrete groves of giant sequoias, a wildfire of catastrophic intensity, the Castle Fire, swept through the region in 2020.

[49] Two genera, Taxus and Torreya, within the ancient yew family called Taxaceae have been proposed as important understory components for their value in providing ecosystem services for forest restoration and climate adaptation projects in China.

Botanist Todd Rounsaville suggests, "There is an important need to study and report the ecological processes of tree naturalization in novel environments to guide policy making and forest management relating to climate change, species range-shifts, and assisted migration.