The vision
The old tree said:
Burr of blade and clash of clan broke embraces held for centuries. My forest – seeded before memory – emptied itself of life by the sound and fury of sawing.
Alone I saw how seasons grow erratically. Alone I watched ripe flowers whip. Alone I saw how heat deepened and lingered. Alone, I lost hope of restoring the forest.
Then the people returned. With shovels instead of saws, they broke the ground again. In wounds reopened they sowed you whose roots embrace all mine, you who taste of lands unknown.
Together we can resist these changes.
— a drabble by Syris Valentine
The spotlight
On an almost cloudless August day, I arrived at a waist-high iron barrier gate in Washington’s Marckworth State Forest, accompanied by staff from the Mountains to Sound Greenway Trust, a Seattle-based nonprofit that preserves and restores land from the most eastern edge of the Waterfall mountains to the Puget Sound — an area known as the Mountains to Sound Greenway National Heritage Area. In 1900, Weyerhaeuser — the second largest lumber company in North America — bought his first 900,000 acres from timberland into what is today the green road. “The birth of industrial timber was here,” said Jon Hoekstra, the trust’s executive director, “for better or for worse.” For 35 years, Hoekstra said, conservation groups and nearby tribes have made intense efforts to save the devastated forests back together through many different projects.
On this particular day, Kate Fancher, the trust’s restoration project manager, took me into the woods to the Stossel Creek reforestation sitewhich lies about 20 miles northeast of Seattle in the foothills of the Cascade Mountains. Stossel Creek is unique among the approximately four dozen projects that the trust currently manages. Here, Fancher is overseeing a multi-year experiment on an urgent new approach to forest management: assisted migration. The strategy involves deliberately shifting the range of certain trees to make forests more resilient to climate change.
“I’m not used to doing this type of experiment. Normally it’s more informal,” she said. “But I think it’s very important to see what we can take away from this and then possibly link that into our restoration work going forward.”
Fancher (right) walks to the Stossel Creek restoration site in August, with Sarah Lemmon, a public relations consultant hired by the trust. Syris Valentine / Grist
For the past several decades, standard best practice for reforestation projects has been to source native tree plants from local nurseries that collect seed from nearby forests. Forest managers learned the hard way that local seedlings have a better chance of survival, forest geneticist Sally Aitken later told me. During early large-scale reforestation campaigns, seedlings derived from native but non-native trees had a much more difficult time establishing themselves in environments to which they were not adapted. Many died. Those that survived often did not manage to grow as tall or healthy as their local counterparts.
“Forest geneticists have spent decades and decades trying to convince foresters that they should use local populations of trees to get their seeds for reforestation,” says Aitken, who has studied the implications of climate change for trees since the early 90s.
But as the changing climate has created both new extremes and a new normal beyond what local species have evolved to withstand, some forest managers are pushing for an approach that replants with trees not adapted to the current climate. but to the future one.
While this may mean introducing species into ecosystems they have never inhabited before, in most cases, such as Stossel Creek, the species are the same species already in the forest, but the individual seedlings are transported from other regions , selected based on the environments they have adapted to.
The trust and its partners seeded the Stossel Creek area with trees sourced from warmer, drier climates similar to what the Pacific Northwest can expect in the future. Some of the 14,000 seedlings planted at the site traveled more than 500 miles north of California to reach their new home.
This experiment came about after Seattle City Light, the city’s electric utility, bought 154 acres of land in 2015 that a logging company had cleared three years earlier. City Light acquired the land to to conserve salmon and steelhead habitat as part of its extensive commitments to environmental stewardship, and the utility partnered with the trust and several other organizations to coordinate a mass planting of climate-adapted trees in 2019. The hope is that by reseeding the fields with trees adapted to warmer and drier environments, planted among locally sourced seedlings, the emerging forest will be “more resistant to heat, drought, pests, disease and wildfires,” he said. a report written by Rowan Braybrook, the program director at Northwest Natural Resource Group, one of the trust’s partners in the project.
To find out where to source trees that might be well adapted to the future climate of this particular forest, the project’s designers Seedlot selection tool developed by the US Forest Service, Oregon State University and the Conservation Biology Institute. The tool allows researchers and practitioners to experiment with a wide range of scenarios to determine where they can find seeds for the selected climate scenario. In the case of Stossel Creek, the project designers went to the worst-case climate projections for the next few decades to identify regions and nurseries in southern Oregon and northern California that will provide the best seedstock.
The specific portions of those two states were selected primarily based on two metrics: the “summer heat-humidity index,” to capture the increasing dryness of Northwest summers, and the “average coldest month,” a key consideration because Douglas firs a good winter cold to grow in the spring. Choosing seedlings from across this range, Braybrook said, allowed them to use the Stossel Creek experiment to “stress test” assisted migration.
“If you move too far, too fast,” Aitken said, “the biggest risk is frostbite.” While climate change is warming things up on average year after year, it has also made sudden and severe cold snap more likely, which can damage or kill trees born for the California sun.
But after walking with Fancher on the Stossel Creek site itself, weaving through rows of baby trees surrounded by plastic mesh skirts to protect them from grazing elk and deer, and later the data collected in the four years after the big 2019 planting was collected, I was surprised by how much the Douglas firs of California seem to love the new climate emerging in the western Cascade foothills.
Of the three seed beads – one each from Washington, Oregon and California – the California Dougs survived the best and grew the fastest, followed closely by the Oregon spruces. On average, more than 90 percent of the spruces originating from those southern neighbors survived through 2023. Meanwhile, those from Washington’s own iconic evergreen forests fared worse, with only 73 percent surviving, according to data collected through last September. According to a report published last year by the Northwest Natural Resource GroupIt’s still too early to draw big conclusions from the experiment — but these early results seem to suggest that planting for the climate of the future could bolster reforestation efforts.
Left: A row of Douglas firs planted in one of Stossel Creek’s test plots leading to a weather station. Right: A riparian pine planted next to a log on one of the trial plots. Syris Valentine / Grist
Despite the results of experiments such as Stossel Creek, and others conducted in the Eastern USA as well as Canada and Mexicoassisted migration is still a controversial practice. “The Forest Service still requires us to use local seed stock for most of our restoration work,” said Jon Hoekstra, aiming to preserve local adaptations. Hoekstra, Aitken and others increasingly realized that those local adaptations might not match the future climate. Still, they said, forest managers can be averse to assisted migration because they are often focused on reducing short-term risks. “The safest thing to establish the trees today is not necessarily the best thing for the longer term,” Aitken said.
Supported migration essentially goes against decades of conservation wisdom – and it represents a level of intervention that makes some uncomfortable. Aitken also noted that this is not going to be the right approach in every circumstance. “If you have an established, intact forest ecosystem that’s not suffering some massive hit from climate or pest, disease, et cetera, I don’t think you want to intervene at this point,” she said. She also advises caution when it comes to moving species outside their established range – for example, planting redwoods in Washington. “It’s going to fundamentally change that ecosystem.”
But ultimately, ecosystems are changing—and, as Grist previously coveredsome believe that approaches such as assisted migration may be the best way to recognize and direct the profound changes that people already have in the landscape. As forest managers plan and implement conservation projects, Aitken said, “We have to balance the risks of movement against the risks of doing nothing, and the right decisions are going to be different in different situations.”
– Syris Valentine
More exposure
A parting shot
Supported migration is also being considered as a potential strategy to help animals whose homes are threatened by climate change – like the key deer, a subspecies of white-tailed deer that lives only on the islands of the Florida Keys. Only about 1,000 remain in the wild, and some are advocating the species’ relocation as sea level rise threatens its home. Here, a doe (smaller than her cousins on the mainland; about the size of a golden retriever) crosses Key Deer Boulevard on Big Pine Key.
