Life after wildfires: NMSU researchers work to restore fire-damaged forests

Life after wildfires: NMSU researchers work to restore fire-damaged forests
DATE: 02/18/2019
WRITER: Jane Moorman, 505-249-0527, jmoorman@nmsu.edu
CONTACT: Owen Burney, 575-387-2319, oburney@nmsu.edu
Catastrophic wildfires in the Southwest in recent years have impacted approximately 118,000 acres of federal forest lands in New Mexico and Arizona. The damage is categorized as high burn severity, according to a white paper by the U.S. Forest Service.

New Mexico State University’s College of Agricultural, Consumer and Environmental Sciences is actively involved in researching many aspects of these fires’ impact.

As various federal and state agencies work to prevent future catastrophic fires with prescribed burns and thinning of the remaining forests, other agencies and groups are developing a plan for the restoration of the large-scale fire areas.

James Cain, an affiliated faculty with the college’s Department of Fish, Wildlife and Conservation Ecology, is answering the question of how the fires, both prescribed and high severity devastation, and thinning of forests impacts the wildlife habitat of the Jemez Mountains and Valles Caldera in northern New Mexico.

Owen Burney, NMSU associate professor and superintendent of the John T. Harrington Forestry Research Center in Mora, is researching how to restore the forest habitat throughout New Mexico and Arizona.

“We’re specifically looking at how mule deer, elk, black bears and mountain lions are responding to these aftermaths of these situations,” Cain said of the study, which is funded by a U.S. Forest Service and National Park Service grant. “We usually have 10 to 20 bears, about 50 elk and about 10 to 15 mule deer with GPS collars at any given time allowing us to see where they’re moving throughout the landscape.”

Analysis is still being conducted on the data that has been collected.

“We have some early findings for the mule deer and elk, as well as the black bears,” said Cain, who is the assistant leader of the U.S. Geological Survey’s New Mexico Cooperative Fish and Wildlife Research Unit. “So far what we’ve found is that the elk are really responding to the wildfire burned areas, because they like the new grass growth.”

The mule deer avoid the wildfire areas completely after the fire, likely due to the reduction in browse. They will visit prescribed burn areas, particularly those burned within the previous two years. Deer select thinned areas, but only those thinned more than five years previous, once the shrubs have grown back. They avoid more recently thinned areas.

Thinning and wildfires also have the potential to disturb black bear bed and den site selection.

“We found horizontal cover or security cover the biggest driver for the bears’ selection of bed sites where they rest during the middle of the day,” Cain said. “Those that were in the thinned area were where the thinning crews were unable to access the area because it was too rocky or too steep. Most of the bed sites in the wildfire burned area were where the security cover was not damaged.”

The researchers found similar patterns for den sites.

Burney is working with forestry professionals in the Southwest, including the U.S. Forest Service, The Nature Conservancy, Forest Stewards Guild and Northern Arizona University. The goal is to develop strategies to put the forest back on the right trajectory after a fire, and work to ensure the forest is resilient to future fire conditions.

“We are developing a nucleation strategy where tree islands, or small planting plots, will be replicated in natural patterns across the landscape,” Burney said. “The area between these islands can be seeded with native grasses and shrubs. And in the long-term, these gaps will begin to fill in with native trees from mature trees within the established tree islands.”

One of the first issues the foresters are facing is the huge number of seedlings needed to restore these U.S. Forest Service burned forested areas – between 30 and 60 million. This number increases each year with every new forest fire.

“NMSU’s Mora facility has the largest forest tree seedling nursery in New Mexico that is producing seedlings for restoration,” Burney said. “Our production capacity is 270,000 seedlings per year. There is a large gap in both nursery capabilities and overall planting efforts to address the growing planting deficit to restore these landscapes.”

The second part of the seedling issue is survival rate once planted. Historically, seedlings that thrive in the nursery have had an average survival rate of 25 percent in the field. Many things play into the lack of survival, including growing and planting techniques, climate and precipitation, temperatures and animal activity in the area.

Another aspect of the lack of survival is that the nursery seedlings are physiologically not ready for the harsh environment where they are planted.

“Usually after the fires, the Southwest environments are dry and difficult to get plants established,” he said. “The traditionally grown seedlings struggle.”

At Mora, a nursery cultural practice of “tough love,” or stress conditioning, has been used while growing the seedlings. “By decreasing the irrigation in the nursery, plant hydraulics are altered to provide improved water conduction in the xylem as well as a buffer against drought stress,” he said. “In the field we are seeing an increase in both growth and survival of these conditioned seedlings.”