Scientists Are Migrating Trees To Save Forests From Climate Change. Will It Work?

July 24, 2020

One of the things that make the climate crisis so destructive is that we can’t evolve quickly enough to keep up with it. Evolution is a carefully-perfected process that occurs over millennia—it cannot be condensed into a matter of a few decades. As such, flora and fauna are being pushed to the brink. They rely upon conditions that no longer exist, but are unable to adapt to what has replaced them before survival is threatened.

Many plant species across the world face inhospitable conditions as a result of drought and desertification. While preventing emissions in the first place is key, one project is trying something a little different. Adaptive Silviculture for Climate Change (ASCC) is a collaborative effort between the U.S. and Canadian agencies and universities trying to prepare North American forest ecosystems for climate change. The group is working to establish a series of experimental silviculture sites across the region to better understand on-the-ground actions that we can take to manage our forests.

What is Silviculture?

Silviculture can be defined as the practice of controlling growth, composition, and health of forests to meet the needs of land-owners and wider society. It’s about more than timber alone, though this is certainly an important resource. Other values of forests and woodlands include water resources, wildlife habitat, recreation, and, of course, carbon sequestration. The practice includes activities ranging from establishing new trees to pruning and organized burning. In the face of the climate crisis and the extra efforts demanded, the ASCC is trying to get creative.

The Strategy

ASSC focuses on 3 adaptation strategies:

  1. Resistance—This focuses on forest defenses in the face of rapidly changing conditions, so as to allow the basic architecture of the habitat to remain relatively unchanged over time. This involves looking at what resources can be invested in the existing landscape.
  2. Resilience—This plans for some change, but encourages a return to the prior (benchmark) condition following disturbance.
  3. Transition—This manages woodlands from the perspective that it’s best to take action in response to change. No longer trying to plan for a return to benchmark conditions, this uses the future-oriented logic of adaptation based upon expertly-diagnosed trajectories of where we’re going.

When a new site is identified, a workshop is held on-location for leading scientists, land managers, and community stakeholders. Data is collected as a kind of initial inventory before the experts discuss appropriate mitigation strategies. Everyone is brought up to speed on trends in climate change and climate science so as to highlight the importance of proper land management. Then, they begin to develop a plan taking into consideration the over-story, mid-story, and under-story forest layers. One plot of experimental land is subjected to the resistance strategy, another resilience, the third transition, and the fourth without treatment. After the treatments are implemented, the land is measured in 3, 5, and 10-year intervals. The teams are interested in observing species composition and various parameters of forest health (including things like crown density and invasive species) before finally measuring changes in overall biomass.

Where is this happening?

Experimental plots can be found across North America in a variety of forest types. On Jackson Mountain in the San Juan National Forest in Colorado, white fir are being thinned and removed, while drought- and fire-resistant ponderosa pine and Douglas fir are being planted. Warmer weather in recent years has driven fires further into this forest, along with invasive species like the western pine beetle. Increasing structural heterogeneity breaks up fuel sources, leading to more manageable burns.

In the Cutfoot Experimental Forest, nestled within the Chippewa National Forest in Minnesota, scientists are working hard to combat the same drought and wildfire stress being felt across the continent. Less-resistant red pines are being replaced by eastern white pines, red oaks, and red maples. As well as monitoring tree survival in the coming decade, researchers are using songbirds as representative of ecosystem health.

In the Northern Rockies, deep in the Flathead National Forest of Montana, the Coram Experimental Forest is influenced by a combination of wet maritime airflows from the Pacific as well as cooler, drier Canadian air. It provides an important habitat for grizzly bears, as well as lynx. As an adaptive strategy to mitigate wildfires, near-ground surface fuels are being cleared, while fire-adaptive species are being planted. These include roughly equal parts western larch, western white pine, and ponderosa pine.

In the southeastern Coastal Plain of the U.S., the Jones Center at Ichauway in southwestern Georgia is home to diverse ecological communities. From depressed wetlands to riparian hardwood forests and even human cultural zones, the team is working to remove mesic oaks that consume a lot of water and replacing them with turkey oaks and wiregrass, as well as incorporating biennial burns into the plan to reduce catastrophic wildfires.

There are a variety of other ASCC sites across North America, including Ontario, Mississippi, and New Hampshire among others. One of the more interesting stories I’m following is how small mammals are distributing mycorrhizal fungi in northern New Hampshire. These fungi are important symbionts that colonize tree roots and increase water uptake. They also play an important role in tree-to-tree communication, forming what world-renowned mycologist, Paul Stamets, has called, “Earth’s natural internet” or, my personal favorite, “the wood wide web.”

Criticism

While the intention behind the ASCC is good and the teams involved considered experts in their fields, not everyone has been in support of the project. Critiqued as playing “the hand of God” in this form of “ecological gambling,” some ecologists have expressed concern about the unknown consequences that can result from reforestation based purely on current predictions. What about all the possible unforeseen, undesirable outcomes that may occur? Others acknowledge the labor-intensive process of relocating trees and question whether time and resources could be better spent. Only time will tell on that front.

So should we do assisted migration of trees—or not?

While much remains up for debate on how best to tackle the loss of biodiversity that is resulting from the climate crisis, the need to do something—anything—is clear. If not habitat migration, then an immediate reduction in emissions. At the start of the pandemic in March 2020, we saw nitrogen dioxide (NO2) levels fall significantly in several parts of the world. Air pollution improved, thought by experts to offset some of the respiratory-related deaths caused by COVID-19. However, as lockdown restrictions have eased and more of us have been returning to work, we’ve seen a boomerang in these pollutants.

Walkable cities and zero-carbon transport are more important than ever before. So too is work flexibility, with employers allowing more staff to work from home. Prevention is the best treatment, after all. The forests would rather stay where they are, I’m sure.

What are your thoughts on the mass migration of forests in the face of climate change?

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Photo: kazuend on Unsplash

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Kat Kennedy is an explorative writer, Physiology PhD student and holistic health advocate breaking down the barriers in science. You can read more of her articles on her blog, Sphynx Kennedy, or keep up with her on Instagram @sphynxkennedy.

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