A stand of aspen trees along the popular Mid-Mountain trail near Deer Valley is experiencing extensive die-off. Keith Clapier is a master arborist and was contracted to prepare a report about the area earlier this year.
The popular Mid-Mountain hiking and biking trail crosses Guardsman Pass Road above the new project. Due to the construction, the trail ultimately will be rerouted.

Clapier explained that the aspen stand has been isolated on three sides by the Guardsman Pass and Twisted Branch roads for many years. The process began decades ago when Guardsman Pass Road was constructed and later paved. His report indicates the Mid-Mountain trail has caused no impact on the trees in the area.
Clapier said years of development in the area contributed to these aspen trees being isolated from their broader root system. He said decades of resort development, road installation, drought, and water runoff weakened the stand.

“So now it's completely fragmented," Clapier said. "That's probably what was giving its life support because I think this column is part of that column on the other side. It went all the way up to halfway up Hawkeye. I think that was one tree. I mean, the damage was 3/4 done. It’ll progressively get worse over time unless mitigated.”
Clapier’s report identifies 276 aspens that should be removed, mostly mature trees. The tagged trees show distress, with the bark easily peeling off and exposing the infection underneath. Most are suffering from what’s called sooty bark canker fungus, which quickly grows vertically up the tree. Clapier said the fungus will eventually wrap, or girdle, the tree, killing it.
If the trees aren’t removed, they could fall during high winds and create hazards to people and property. Clapier said the most significant impact is on the wildlife that doesn’t like entering areas surrounded by hard surfaces. He said the area could recover if specific steps are taken.
“If they are going to be running skid steers and cement mixers and whatever in here, they could protect the existing root system by buffering it with mulch and old sheet plywood," Clapier said. "First, you flush cut it [leaving stumps] and then just try to protect the root.”
Aspen trees are connected in vast underground root systems. Clapier said that when hiking or riding through an aspen forest, we see the organism's stems, not trees. He referred to the aspen forest in the Fish Lake area in central Utah.

“It’s the oldest in the world and it’s the largest organism on Earth. I think it's somewhere around 1,000 acres or something. One tree," he said. "So, this is roughly about 10 acres approximately. That seems to be about the average size of a clone in the Wasatch Mountains. They vary in size, but they can be anywhere from 1 to 10 acres in size.”
Clapier recommended that 276 dead aspens be cut and removed from the site. He said stumps should remain because they can stimulate growth and help remove the cells of the sooty fungus. He suggests installing fencing around the living aspens and irrigating the land during the hottest, driest months to alleviate stress from drought. He also proposes that builders use designated construction routes to minimize hard-packing dirt and severing roots.
Clapier believes that if those recommendations are followed, the root and remaining aspens could be preserved.
The Park City Planning Commission considered the findings in the March 9 meeting.