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Big tree-cutting machine put to the test on steep slopes around Breckenridge

Summit County wildfire mitigation work aims to protect homes, improve forest health and protect water supply.

On the north side of Breckenridge in late summer rolled a large machine that looked a bit like an industrial-sized Mars rover climbing up and down the steep terrain.

The machine is part of the Peak 7 Hazardous Fuels Reduction Project — an effort to remove and thin 522 acres of overgrown forestland in parts of Summit County.

“This project is a proactive step in treating forested areas near homes and businesses to keep communities and first responders safe in the event of a wildfire,” said Bill Jackson, Dillon District Ranger, White River National Forest. “This work will create a 400- to 600-foot fuel break between homes and trees in areas with an elevated risk of wildfire.”

The work also is important in protecting forest health and the watershed that feeds into Denver Water’s Dillon Reservoir, which is used for Front Range water supply.

Through a Good Neighbor Agreement, the Colorado State Forest Service is overseeing the project on Summit County and U.S. Forest Service land. Forty acres of the project are being done with a unique machine called a Ponsse Ergo Harvester.

The harvester looks like a cross between a tractor and a crane with a large mechanical arm at the front equipped with a claw and a saw.

A Ponsse Ergo Harvester remove trees on steep slopes in the Peak 7 area of Breckenridge in August 2020. Photo credit: Denver Water.


The machine can traverse steep slopes without rolling over due to its long, 2-section design, along with its six wheels and tank-like tracks. It’s also able to grab live and dead trees with its jointed arm and strip the trees of its branches.

This is the first time the machine has been used for wildfire mitigation on public lands in Colorado.

“In the past, a project like this would have required a helicopter, which was expensive, or a hand crew, which would have taken much longer to do the work,” said Bill Wolf, forester with the Colorado State Forest Service.

Another benefit of the harvester is that it can cut down trees and remove the limbs all in one process. Crews use another machine to haul away the downed timber. The logs are eventually sold locally for fence posts and firewood.

Removing the downed timber eliminates the need to have crews return in the wintertime to burn hundreds of slash piles.

After the harvester has treated the land, foresters leave some downed logs and woody debris on purpose. The pulpy remains are used by wildlife and will help prevent erosion as wildflowers, aspens, pine and spruce trees reseed the area. The leftover debris also will provide nutrients for the next generation of the forest.

The Ponsse machine removes limbs from the downed trees and stacks them. The trees are typically used for firewood and fence posts. Photo credit: Denver Water.


Building a healthy forest

The Peak 7 area, like many parts of Colorado forestland, has become overly dense during the past century due in part to fire suppression — when fires are put out as quickly as possible. This practice, however, has led to unhealthy forests because fires are part of the natural cycle of the forest ecosystem.

Compounding the wildfire issue is that many homes and communities have been built right up against the forest in an area referred to as the wildland-urban interface. This puts them more at risk of damage if a wildfire broke out.

Unhealthy forests are also more prone to diseases, beetle outbreaks and subsequent tree mortality which fuels large, high-intensity wildfires such as the ones that erupted across parts of Colorado in 2020.

By thinning the forest and creating fuel breaks with projects like Peak 7, fires are less likely to spread as fast, giving firefighters a better chance to control a blaze before it runs into neighborhoods.

Fuel breaks played an important role protecting homes during the Buffalo Fire on June 12, 2018, in Summit County. Photos credit: U.S. Forest Service.


“People often ask me why we are cutting down live trees as well as dead trees,” said Dan Schroder, director of the Summit County CSU Extension. “These dense stands of lodgepole pine are over 100 years old, no longer healthy and are now serious fire hazards.”

Along with reducing the risk of large fires, forest treatments like the Peak 7 work mimic what would happen if a smaller, beneficial fire happened. This leads to an overall healthier forest ecosystem by promoting new plant growth and diversity.

Shared stewardship

The Peak 7 project is being funded and supported by the Colorado State Forest Service, Denver Water, the U.S. Forest Service and Summit County.

The project also serves as an example of the U.S. Department of Agriculture’s Shared Stewardship Strategy with Colorado, which looks at cross-boundary collaboration to improve forest health and protect at-risk communities and watersheds across all lands.

One source of funding for the Peak 7 project included Summit County’s Strong Futures Fund; a measure approved by Summit County voters in 2018 that includes up to $1 million annually for wildfire mitigation measures. The measure passed after recent wildfires in the county raised awareness about the impact of wildfires on the community.

In addition, From Forests to Faucets, a forest management partnership between Denver Water, the U.S. Forest Service, the Colorado State Forest Service and the Natural Resources Conservation Service also contributed to the project.

The partners look to pool money and resources to treat areas with common interests such as homes, infrastructure, trails and watersheds.

Watch a video about From Forests to Faucets with Denver Water's Christina Burri:


Denver Water invests in projects like Peak 7 because of the threat a large fire would pose to the utilities’ water supply.

“Any rain or snow melt that comes off that area will flow down into the Blue River and eventually make its way into Dillon Reservoir,” said Madelene McDonald, a watershed planner at Denver Water. “If that water passes through a healthy forest, the trees act as that first line of filtration before the water even reaches the river.”

Since 2010, the From Forest to Faucets partners have invested nearly $66 million in forest health projects in Boulder, Douglas, Grand, Jefferson, Park, Summit and Teller counties. Funds have helped plant 1.4 million new trees in burn areas and treat about 120,000 acres of forest land as of July 2022.

“About 8,000 of those acres are right in Summit County in the Upper Blue River watershed,” McDonald said. “Denver Water only owns about 2 percent of the land in its watershed. So we're relying on our partners to help us with this cross-boundary work and achieve forest restoration on public and private land.”

The loss of trees in burn areas leads to high amounts of sediment flowing off hillsides after heavy rains. The sediment ends up in rivers and streams that eventually flow into reservoirs.

High amounts of sediment can take up storage space in reservoirs, damage infrastructure, impact watershed health, and require more extensive filtration in the water treatment process.

Debris filled Strontia Springs Reservoir after the Buffalo Creek fire and flood of 1996. Photo credit: Denver Water.


Looking ahead

Both the U.S. Forest Service and the Colorado State Forest Service have been impressed by the Ponsse machine and its potential to be used in other steep slope areas across the state in the future.

The Peak 7 work was scheduled to wrap up in the fall of 2020. The project is part of an ongoing forest management and fuels reduction effort in Summit County that dates to 2004.

“The treatments will not only protect the community, but they also will create a healthier forest that is less susceptible to large, high-intensity fires, insect infestations and disease,” said Christina Burri, watershed scientist at Denver Water. “Creating a healthy forest creates a healthy watershed, so this project benefits people on both sides of the Continental Divide.”