Scientists Build Network to Test Reforestation Practices for Climate Adaptation

Photo Credit

Laura Gonzalez Mantecon, USDA Forest Service.

Experimental Network for Assisted Migration and Establishment Silviculture current and planned sites as of December 2023.

As high-severity wildfires and other disturbances kill trees across the Western United States, climate change is complicating how land managers determine which species to plant during reforestation.

Changing climatic conditions raise questions about which seedlings will likely survive under rising temperatures and increasingly harsh conditions. 

Rob Slesak, research forester with the USDA Forest Service Pacific Northwest Research Station, and his colleagues set out to evaluate assisted population migration as a climate adaptation strategy to support reforestation. 

Assisted population migration refers to the movement of seed sources or populations of plants from their existing location to new, cooler locations within their habitat range. The hope is that future warmer climates at the planting site will be hospitable to the plants, but cooler temperatures in the near term will not be cold enough to kill the trees or hinder their growth. 

“It was a very kind of grassroots-type discussion among everyone involved: the need for climate adaptation strategies; recognition that assisted population migration was a good way to go; and everything just kind of clicked together,” said Slesak. 

Building Capacity Through Partnerships 

Slesak partnered with Jessica Wright and Chris Looney, a research geneticist and a research forester with the USDA Forest Service Pacific Southwest Research Station, as well as USDA Forest Service Pacific Northwest Region geneticists including Vicky Erickson, to test assisted population migration and reforestation practices. Erickson had already developed relationships with managers in several USDA Forest Service Pacific Northwest Region forests that led to a series of initial trials that the team used as models for a larger network that would span Oregon, Washington, and California. 

In 2022, the USDA Forest Service Pacific Northwest and Pacific Southwest Research Stations received funding from the agency’s USDA Forest Service Washington Office to establish the Experimental Network for Assisted Migration and Establishment Silviculture (ENAMES). The network researches potential answers to a major USDA Forest Service challenge—address a backlog of more than 4 million acres of needed reforestation. 

Photo Credit

Broderick DeAngelis, USDA Forest Service.

Seedlings planted at the Riverside experimental site in Mount Hood National Forest, Oregon.

Evaluating Seed Sources and Silvicultural Practices to Support Reforestation Success 

The objective of the ENAMES project is to evaluate short- and long-term success of reforestation treatments that use assisted population migration and silvicultural practices, such as reducing vegetation competition or planting density. 

Plantings were done at experimental sites in 2022 and 2023, with more plantings planned for 2024 and 2025. Some future planting experiments will look at seed sources that were bred for improved growth. The group is measuring seedlings after 1 year and plans to measure tree-diameter and height growth every 5 years thereafter to evaluate the success of the seed sources and silvicultural practices. 

The researchers intend to produce both site-specific and more broadly applicable results that they hope will inform adaptive management. 

Addressing Landowner Needs to Produce Actionable Science 

The ENAMES project is centered on a commitment to provide scientific findings that will be relevant to land management. To do this, the team is using a coproduction model that has scientists and stakeholders working together to design and implement research. 

The network has grown over time and now includes 37 sites, with more coming. Each of these sites represents a partnership with a manager who contributes to the objectives of the ENAMES project and provides input on the experiment. For instance, managers choose which tree species they want to plant. They are also encouraged to test silvicultural strategies that they would like to know more about. This provides managers with opportunities to expand their knowledge of seed sources and silvicultural practices that can help them achieve management objectives. 

Current and planned experimental sites are on lands managed by the USDA Forest Service, USDI Bureau of Land Management, Oregon Department of Forestry, Washington State Department of Natural Resources, and the Confederated Tribes of the Colville Reservation. Partnerships with private entities are underway. 

Challenges and benefits of co-production 

Slesak acknowledged that the coproduction of knowledge does require more time and resources than traditional top-down research, but he believes that its benefits far outweigh the drawbacks. He stresses that communication is vital, but once those communication lines are established it allows for an open sharing of ideas and information. Slesak said that the broad range of partnerships that the team has developed as part of this project highlights the importance of this approach to forestry, considering the many challenges land managers are facing with climate change. 

“We’ve got a large swath of the forestry community into this network and they're all… committed to evaluating the use of assisted population migration. So that's huge… It just elevates the importance of the network,” said Slesak. 

Photo Credit

Broderick DeAngelis, USDA Forest Service.

Seedlings planted at the Riverside experimental site in Mount Hood National Forest, Oregon.

Sharing Ideas and Disseminating Results 

Slesak estimates that to date, more than 100,000 seedlings have been planted as part of the ENAMES project. The team recently received additional funding through the 2023 Bipartisan Infrastructure Law and future research phases will be focused on measuring planted seedlings at the experimental sites. 

Researchers are using a variety of tools to disseminate their research results, including an online interactive tool that is currently in production. The tool contains geospatial information as well as site characteristics and measurement results from each experimental site. Slesak noted that the online dashboard is an ongoing project. 

“Over time, as we get more and more data, we’ll just be adding to that and it will become much more data rich as we continue the measurements going forward,” he said. 

The team is hoping that the data dashboard and other outreach tools will keep partners engaged with the research and generate more interest in assisted population migration and the ENAMES project.