Science Moab talks to Henry Grover about how moss can help restore burned areas

After major fires devastate a landscape, the earliest restoration may come in the littlest form: moss. This week, we speak with Henry Grover, a Ph.D. student at Northern Arizona University who studies the native mosses that often colonize hill slopes after severe fires. His work explores both the ecology and application of these mosses as a way to restore burned areas.

Science Moab: Can you explain the different types of fires that occur on the landscape?

Grover: There are lots of different types of wildland fire. A low-severity fire is a surface fire that travels along in the understory and creates really beneficial impacts for the ecosystem; it helps with nutrient cycling and thins out small forest trees that would encroach on grasses and other super-helpful plants. A mixed-severity fire includes both low- and high-severity, where trees are getting burned in some patches, even really big trees, but not everywhere. High-severity fire is where you have a lot of trees all burning at once in this massive flaming. A “crown fire” is where the fire severely burns everything from the soil to the trees. Only certain plant species can sprout after those fires.

Science Moab: Why have the frequency, area, and potentially the severity of fires in the Southwest been changing?

Grover: The major reason is due to fire suppression in the Southwest, beginning in the late nineteenth century. The U.S. Forest Service tried to put out every single fire and became more and more successful as technology increased our ability to reach fires quickly. They've successfully suppressed fires for so long that there's been a huge buildup in fuels. Forests have become overgrown, and that increases the propensity for the high-severity fires we're seeing now. That's also coupled with climate change. The increase in temperature, as well as the droughts that we see, have led to more high-severity fire. These longer droughts, and much hotter temperatures earlier on in the season, are really good examples of how the potential for a year-round fire season is increasing in the Southwest.

Science Moab: How does fire intersect with your research on moss?

Grover: My research focuses on mosses that colonize severely-burned landscapes. Moss grows in a very different way than vascular plants. It aggregates soil super well and grows in a carpet, so it can really stabilize more soil per biomass than a vascular plant can.

It’s also a really understudied plant. Especially in the western United States, the mosses I work with are cosmopolitan: they grow everywhere, but they're common in burned areas. So, I'm exploring where and when the mosses colonized those burned landscapes. We’re interested in seeing the function that they add to a burned landscape, and how quickly that function is added. If mosses enter an ecosystem directly after that first monsoon season and can stabilize a lot of soil quickly and decrease erosion and runoff, then they're a really valuable tool. They could potentially be used as an emergency-response treatment for burned areas. I’m examining this combination of actively restoring burned areas with mosses, as well as natural recovery that includes mosses.

Science Moab: How do you study mosses in the field, and what kind of experiments do you do?

Grover: We go into a burned area months after the fire, and look at the moss cover there. We're looking at how the bare soil — the soil that hasn't been colonized by moss — relates to the moss-covered soils.

In these moss-covered soils, we've seen about a 100% increase in soil stability and infiltration, as well as soil “shear strength,” which is another metric of erosion resistance. It’s very promising. It shows that the moss does a good job of stabilizing the community and increasing infiltration, which is super important for reducing the amount of water that's running down a hill slope causing erosion.

To learn more and listen to the rest of Henry Grover’s interview, visit www.sciencemoab.org/wildfire-moss/. This interview has been edited for clarity.