One woman's determination unlocked science behind reforestation on an arid southwest forest

Laura Rabon
Thu, November 18, 2021

ALAMOGORDO — Tucked back in carefully chosen locations on the Lincoln National Forest, you can see baby trees poking up from the ground among the blackened logs

remaining from fires that laid bare patches of the forest. These fledgling trees aren’t here by accident. They are here because of one woman’s determination to unlock the science behind reforestation in the arid southwestern forest.

Forest Service silviculturist Marisa Bowen has spent the last five years coordinating the planting of 170,000 trees.

Forest Service silviculturist Marisa Bowen, known as Reese to her friends and coworkers, revived the tree planting program on the Lincoln National Forest after others had given up 20 years ago. Previous efforts to replant trees in fire scars on the Lincoln National Forest showed only mild success. Forest staff began to wonder if the limited returns were worth the hours and money spent on the program. In 2017 Bowen began researching the old methodology and successfully tweaking how, what, where and when the trees were planted.

Since then she has coordinated the planting of 170,000 trees in the Little Bear (2012) and Scott Able (2000) fire scars and learned the little details that make a big difference when doing reforestation in a drought-stricken forest.

“Everyone thinks it’s an easy, straightforward process. Just get some seeds and plant them, right?” Bowen smiles and says. “Turns out it’s a bit more complicated if you want the trees to survive.”

While the Forest Service acknowledges it has too many trees in some part of the forest, it also has too few in other areas. Prompt reforestation in these areas allows for the accelerated regeneration of the woods after natural disturbance, such as wildfire, climate change, and insect and disease infestations. Reestablishing forest cover provides wildlife habitat, clean and abundant water for animals and humans, carbon sequestration, future timber that can be responsibly harvested, forested recreation opportunities, and prevents soil erosion.

Finding the right sites

Five years ago, Bowen and the GIS department at the Forest Service mapped the terrain burned by fires over the years. They were searching for areas where replanting trees was most needed and where they had a shot of survival. After a careful review, they chose 8,315 acres of severely burned forest at various locations across the forest.

The sites were in areas where all the trees were destroyed, and with them, the seed source that would have naturally replenished the trees. They also considered the state of the soil, access to the area, and nearby private land. It is also worth noting official wilderness areas are not eligible to be replanted per wilderness regulations. In just five years, they have successfully replanted 20 percent of the area with Ponderosa pine,

Douglas Fir, Engelmann spruce, and southwestern white pine.

Bowen inspects a three-year-old ponderosa pine seedling.

“Fire burns in a mosaic pattern. It doesn’t burn uniformly,” explained Bowen. “In the same fire you can see patches of forest that were completely untouched next to burned areas. If some trees survive in the area, it has hope of coming back. I was looking for areas with total overstory removal and no seed source remaining, but with soils that were still able to support vegetation.”
The art and science of seed collection

Success is in the details. Trees, like humans, have their own genetic makeup passed down from tree to seedling. Bowen only uses seeds collected from the same elevational levels on the same forest. Using seeds already adapted to the unique ecosystem of the Lincoln National Forest in southern New Mexico gives the tree the best shot of long-term survival.

Seed collection is an exercise in patience. It turns out conifer trees only produce a good seed crop every 7-15 years, depending on the species. For the first few years of the program, she relied on seeds collected decades ago, some from as far back as the 1970s that had been stored at a Forest Service nursery in Idaho. The trees would produce some cones each year, but when Bowen opened the cones, she discovered underdeveloped seeds that weren’t viable for collection. However, nature was on their side because, in 2018, the trees produced a mast crop with huge cones and plenty of seeds.

Specially trained tree climbers from the Lincoln National Forest and nearby Mescalero Apache Tribe climb to the very top of dozens of trees to carefully clip the cones.

Specially trained tree climbers collect cones from dozens of trees to ensure they have enough genetic variety.

“I love it, but you can’t be scared of heights,” joshed tree climber Wells Viana. “It’s slow, technical work, but it’s rewarding. You’re attached to the tree and covered in sap. When the wind blows it feels like the rest of the world is moving and you’re staying still, when in fact, it’s the opposite. The tree climbers collect cones from multiple different trees of the same species.

“We want to make sure to get a genetic variety for each species, which wouldn’t happen if we only used seeds from one tree… and of course, we leave some so the forest can regenerate itself,” explained Viana.

The seeds are also an important food source for wildlife.

Once collected, cones are placed in burlap bags and rotated daily to avoid rot until refrigerated trucks arrive to take them to Forest Service nurseries. Forest Service nurseries and seed extractories remove the seed from the cones and grow seedlings for planting. The seedlings are shipped back to the forest in the late summer of each year.

Forest staff use recently collected seeds to replant the southwestern white pine, once a staple species in the forest. In the 1980s, its numbers began to dwindle after an outbreak of White Pine Blister Rust hit the forest. The fungus attacks white pines and kills more than 95 percent of the trees it infects by cutting off pathways for water and nutrients.

White pines are large trees that can live up to 450 years if undisturbed.

“It’s tragic. You’ll find one white pine in a sea of dead ones that survived the outbreak. The hope is that tree has a genetic resistance to the Blister Rust. By using its seeds, the seedling may get those genes that allow it to survive when it is exposed to the fungus, which almost always happens.” Bowen said.

The U.S. Forest Service estimates 3-5 percent of white pines are resistant to the devastating effects of the pathogen.

Plant in summer, not the spring

For the past five years, a crew of tree planters has arrived from Oregon in late summer or early fall. They move quickly across the landscape digging holes, placing seedlings inside, and installing beige tubes around the baby tree called sentry tree shelters. The reusable shelters garner attention from forest visitors who aren’t quite sure why they are there. The shelters stay on for two years, and dramatically increase the rate of survival for the tree. The shelter helps retain moisture, shades the plant from the harsh New Mexican sun, and protect the new seedling from being eaten by the hearty population of elk and deer.

Conifer cones are cut in half to inspect the viability of the seeds inside.

Trees used to be planted in neat, tidy rows, giving the forest an unnatural row-crop feel.

“I’ve stood in those older reforested areas, and it’s creepy the uniformity of it all,” said Bowen. “It’s supposed to be a forest, not a farm.” Today, the crew plants the trees in clusters to mimic how natural forests develop, which isn’t in straight, clean lines.

Foresters also thought the best time to plant was in the spring before the monsoons arrived, but almost all the trees died.

Bowen explained, “The soil is bone dry in spring on the mountains. Usually, we haven’t gotten rain for months, and we don’t have the snowpack we used to. Now we plant in August and early September after the heavy monsoons when the soil is wet, the temperatures aren’t as hot, and we will likely get a few pulses of moisture.”

It’s working too. Depending on the site, the tree survival rate averages between 60-80 percent, beating Bowen’s expectations of 50 percent. A high level of tree mortality is always anticipated when doing reforestation.

Forest staff chooses severely burned sites with no surviving trees, like this hillside burned by the Scott Abel Fire 20 years ago.

“Think of it this way; trees produce an enormous number of seeds because they know the vast majority of them won’t make it. We are replicating a natural process, so some level of tree mortality is inevitable,” Bowen stated.

Next year will be a big moment for Bowen and her crew. Six years after planting the first seedlings, the initial area can officially be called “reforested.” It will take another 20 years for the trees to reach full maturity and begin producing their own seeds, a reminder of how long it can take a landscape to recover.

“Coordinating the reforestation program takes a lot of time and work, but it’s one of the most rewarding part of my job,” Bowen said. “In the future, I’d like to see the program grow and to identify more areas that could benefit from reforestation.”
Money doesn't grow on trees

Reforestation is expensive. Bowen estimates she spends $200,000 a year on the program, and she relies heavily on partner organizations to help fund the work. The Lincoln National Forest partners with four organizations that help fund the tree planting efforts: The National Forest Foundation, American Forests, One Tree Planted, and the Arbor Day Foundation. The forest has been awarded money each year from one or more of the organizations, which is partly why the program has accomplished so much in such little time.

American Forests is the oldest national nonprofit conservation organization in the United States, founded in 1875. It has helped to fund replanting efforts on the Lincoln National Forest every year since 2018.

“We loved everything about this project, and so did our donors,” said American Forests Forest Restoration Manager Austin Rempel. “Locations like the Lincoln National Forest are so important. They are forested sky islands isolated by desert on all sides. Every tree counts in that scenario. A small project in these areas can have an outsized impact,” he added.

Reforestation in the face of climate change

The race is on to establish healthy mature trees sooner rather than later. As temperatures continue to rise and drought continues, the types of trees that thrive at certain elevations has already begun to shift. Historically, pinyon and juniper trees grew at lower elevations on the

Lincoln National Forest and then transitioned to ponderosa pine and eventually mixed conifer of pine, fir and spruce trees at high elevations. After a landscape altering event, like a wildfire, the lower elevation tree species are being seen at increasing higher and higher elevations, as they seek out terrain with the water and temperatures they have adapted to over millennium.

Reforestation presents opportunities to address the effects of climate change by managing plant genetic diversity and capturing carbon to counter greenhouse gas emissions.

The Forest Service National Forests Genetics Program is working to improve reforestation efforts in the face of climate change. Climate change is fueling extreme droughts and severe wildfires. Trees that aren’t killed by these threats are weakened. This leaves them vulnerable to disease and pests. The program identifies genetic variations in tree species that make them more resilient to higher temperatures and leads the development of trees with resistance to insects and diseases.

The program manages 70 highly productive seed orchards of many species developed through selection, breeding, and testing. These seed orchards cover over 25,000 acres, and include species such as Douglas fir, western larch, western white pine, ponderosa pine, sugar pine, white fir, eastern white pine, shortleaf pine, longleaf pine, slash pine, and whitebark pine. The program also conserves forest tree genetic material (primarily through collecting and long-term storage of seeds) before it is lost to climate change, pest and diseases, wildfire, and other natural disasters. The Forest Service works on over 100 species, including non-commercial conifer and hardwood tree species, native grasses, and wildflowers.

This article originally appeared on Ruidoso News: One woman's determination unlocked science behind reforestation on an arid southwest forest