A Michigan State University researcher has received a $500,000 grant from the Michigan Department of Natural Resources to explore assisted tree migration as a way to protect the future productivity of Michigan forests.
Assisted migration is a process by which trees are intentionally moved within their native range or to new areas in which they are better suited.
The project is led by Jeremy Johnson, an assistant professor of forest genetics in the MSU Department of Forestry. He said that many of Michigan’s most important tree species, such as red pine, are at the southern end of their native ranges. As temperatures increase and precipitation becomes more unpredictable, these species may struggle to adjust.
In addition to his research role, Johnson serves as director of the Michigan Cooperative Tree Improvement Program.
Founded in 1974, MichCoTIP is a partnership among MSU, the DNR and the Michigan forest industries to genetically improve tree species for public and private stakeholders. Two species that have seen significant boosts through MichCoTIP efforts are the red pine and jack pine.
“There are important environmental and ecological reasons for increasing tree resilience and diversity,” Johnson said. “The ecosystem services trees provide are extremely important — carbon storage, air and water filtration, and creating wildlife habitat. To preserve Michigan forests, it may mean improving the genetics of our current species, but there may also be species present in more southern locations that could thrive here in the future.
“In addition to the environmental benefits, trees are also important economically to Michigan. The forest products industry relies on healthy populations of a variety of species, and as we see more unpredictable weather, we need to understand which ones are likely to thrive in the future.”
According to the DNR, the Michigan forest products industry directly or indirectly supports more than 90,000 jobs and generates roughly $26 billion in annual economic output.
For the new project, Johnson and his team will monitor how climate and soil type affect tree growth using a common garden model in which several tree species are grown together under the same conditions.
Six conifer species and American Chestnut were identified for planting at nine common gardens across Michigan. In the seed collection process, 50 families will be represented for each species.
Johnson said that for assisted migration to be most effective, the selected species must meet these criteria:
- Enough individuals from a species must be introduced to avoid depression from inbreeding. When possible, the trees must match the climates and competitive environments to which they’re being introduced.
- Testing must use species assemblages, not just single species.
Researchers will propagate the seeds in the MSU Tree Research Center greenhouses for up to two growing seasons, then transfer the seedlings to the common gardens.
The common garden locations represent three distinct climate regions — the western Upper Peninsula, northern Lower Peninsula and southern Lower Peninsula — and three site types — xeric (with very sandy, dry soils), dry mesic (with sandy, moderate-moisture soils) and mesic (with rich, moist soils).
The team will assess height, diameter, phenology (recurring biological events) and survival in the first, third and fifth years after planting. After that, measurements will be taken every five years for the duration of the trials, roughly 20 years total.
Tree performance will be analyzed with statistical models using current and predicted climate data to determine the best matches for species and location.
Additionally, genomic sequences will be assessed to identify genes associated with adaptive traits that may allow trees to persist within the test environments. Johnson said the traits measured in the common gardens and the genomic data will be used to model patterns of maladaptation across the different species’ ranges to inform management goals.
The overall goal of the project is to inform the DNR on which species are able to withstand predicted future climate conditions, and how those trees perform important ecosystem functions and propel the Michigan forest industries forward.
“Tree improvement has focused historically on biomass production, which is growing big trees as quickly as possible and harvesting them for timber,” Johnson said. “However, the broader need now is ecological and climate-based. Weather is getting more unpredictable, and there are new and enduring pests and pathogens, so there is a lot of stress on trees. We need to focus on which trees can stay on the landscape long term because they’re adaptable.”
Johnson’s work is supported in part by MSU AgBioResearch and the Partnership for Ecosystem Research and Management. PERM is a joint effort between MSU and the DNR to address chronic and emerging threats to Michigan’s wildlife and natural resources.
This story originally featured on the College of Agriculture and Natural Resources website.
