Survival of the fittest: Program aims to give aspens an edge over pines in the competitive Prescott National Forest
In the battle for survival in the arid Prescott National Forest, the towering and prolific ponderosa pines have a natural advantage over the rarer and treasured stands of aspens.
Experts say the ponderosa pine trees, which grow densely throughout much of the Prescott National Forest, tend to crowd out the more fragile aspens for crucial resources such as water and sunlight.
That is a concern for foresters, who hope to protect the two small stands of the picturesque white-trunked aspens that exist in the forest.
To that end, an ongoing effort by the U.S. Forest Service and the National Forest Foundation aims to level the playing field a bit in the aspens’ favor.
“The aspen – we love it, and we’d love to have more of it,” Ben Roe, a forester with the Prescott National Forest, said this week as he walked among the gold-on-white fall colors of the aspens in the small stand along Copper Basin Road.
“It’s a pretty special part of the Prescott National Forest,” he added.
Without some intervention, however, Spencer Plumb, the Southern Rockies Program Associate for the National Forest Foundation, says, “The pine trees come back in excess, and they can out-compete the aspens.”
It was with that in mind that the non-profit National Forest Foundation acquired a $100,000 grant from U-Haul International to help with the Aspen Restoration project. The foundation then partnered with the Prescott National Forest on the project.
Over the past year or so, the project has been at work thinning out the ponderosa pines in the acreage surrounding the 20-acre stand of aspens along Copper Basin Road.
Signs of the work currently can been seen along the road, where piles of cut pine tree trunks and limbs appear periodically, as do charred areas where the piles have been burned.
In other areas, stripes of orange paint are visible among thick stands of ponderosa pines. Roe said the orange stripes indicate the “leave trees” – the ones that will remain after the thinning.
“The project is aimed at giving more space for the aspen,” Roe said.
He and Plumb both point to the practice of suppressing forest fires for the first 80 years or so of the 1900s as one of the problems for the aspens.
Roe said the aspens gain an advantage after forest fires. “It competes better when there’s fire,” he said of the aspen stands, noting that regular fires “open up space and bare mineral soil.”
During the era of widespread fire suppression in the forest, the ponderosa pines were able to gain ground, Roe and Plumb said.
Noting that the National Forest Foundation focuses on “treasured landscapes,” Plumb said the organization looks for ways to help protect those areas.
“We do projects like this all across the state,” Plumb said. Based in Flagstaff, he has been making regular trips recently to the Copper Basin area to watch the progress of the Aspen Restoration thinning contract.
Plumb stressed that the Prescott National Forest’s aspen stands add to the diversity of the forest, which, along with the ponderosa pines, also has three types of oak trees, as well as Arizona walnut trees. “It is a spectacular forest for a lot of reasons,” he said.
Roe said the current thinning project is the second phase in the restoration project. The first phase occurred about a year ago.
In recent weeks, he said, the fairly wet weather has allowed for the safe burning of many of the piles of cut pine trees. Along with protecting the aspens, the tree thinning also helps to guard against infestations of bark beetles, Roe said. After the thinning, the remaining pines have less competition for water, and therefore will be healthier and better able to withstand the effects of the bark beetles.