How volunteers are restoring Pennsylvania’s trails to withstand climate change

• Unnati Akhouri
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On a muggy August evening at Wizard Ranch Nature Preserve in York County, a lawyer, an insurance officer and a new grandma were among the trail-worker volunteers surrounded by thorny locust trees and invasive plants.

Two years ago, the group was here bushwacking, following deer paths and the sound of the creek. Since then, they’ve worked on the dilapidated trails to prepare them to withstand challenges that come with Pennsylvania’s climate getting warmer and wetter. 

The team, led by Keith Williams of the Lancaster Conservancy, is restoring roughly 1,000 acres of land in east-central York County. Pennsylvania has more than 2.2 million acres of forest and over 12,000 miles of trails that are facing similar risks as the climate changes. 

 

 

On the trail, Williams pointed out one of the impacts: overgrowth and abundance of invasive plant species like multiflora rose, privet and tearthumb. 

They can spread quickly and out-compete native vegetation if the climate favors their growth. The average temperature of Pennsylvania has gone up by 2 degrees and annual rainfall is up by 10% in the last century. That, combined with the increased carbon dioxide, makes the climate more suited for these species, Williams said. 

He said, on top of that, these introduced species do not have any natural predators to keep the population in control, “so, it’s like a double whammy.”

Along the trails, the overgrowth can create safety hazards. In one area of the forest, vines starved native trees of sunlight until they fell from the weight. Williams said that’s occurring more often, and sometimes means trails have to be re-routed.

 

 

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Trail managers across the country are rethinking management strategies.

 “At this point trail managers think about when some climate-related event will happen to their trail network, not if,” said John Winn of USDA’s Forest Service. 

For a path like the one in Wizard’s Ranch that is home to floodplains along the Susquehanna River, that means planning and preparing for how the land will respond to increased rain and floods, Williams said.

Floodplains, he said, usually slope gradually toward the river and are “like a sponge that holds floodwaters and slowly trickles it back.” 

But here, the riverbanks are raised by sediment runoff from farming. There are narrow gullies about 4 feet deep in the floodplain, where the river has cut channels into the banks.

During a 2018 heavy rainstorm, the floodplain failed. 

“Took out one and a half houses, took out two roads,” Williams said.

 The price tag on the disaster was $1.5 million. 

Climate change is expected to bring more frequent and heavier rainfall to central Pennsylvania. That brings more frequent erosion and trail loss. 

Historical trails that were often originally deer and horse paths are not designed for today’s extreme weather events. Now, Winn said, trail managers are considering what 50-, 100- and 500-year flood predictions look like.

Williams said they look at “which way is the water going to flow, and putting the tread in such that it’ll shed the water quickly and keeping that trail up out of the floodplain, as much as we can.” 

As for the excess sediment, he said, they will smooth the banks so that water can spread onto the floodplain during heavy rain.  

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On a steeper part of the preserve with light tree coverage – almost as if the forest had a bald patch – there are damp charred logs and a thin layer of gray ash mixed with mud. 

It’s leftover from the conservancy’s first controlled burn almost two years ago. 

 

 

The fire, a native forest management strategy, burns and eliminates the invasive seed bank. Once cleared, the team can “get down to mineral soil and start planting trees again, native trees and shrubs,” Williams said. 

 

 

The group has started re-planting native trees, but not just any species.

A forester chooses southern species for the northern end of the range, keeping future climate in mind. That’s to “have survival into the future,” Williams said.

But not all burnt land is being planted to be a traditional forest. A section is set aside for grasslands that provide habitat for birds and help manage stormwater. They are also “amazing ecosystems for storing carbon under the ground,” Williams said.

Back at the base of the slope, volunteers have piled chopped trees as they clear part of the burned land where trees have regrown. 

 

 

Despite the burn, locust, a native tree, and some invasive species have come back and need to be uprooted. Williams said that has to happen before the forest and its trails can be safely opened to the public. 

But he sees one good thing: All the tearthumb, an invasive that had dominated the land before, is gone. 

Between the overgrown locust and invasive trees, a few magenta-stemmed young trees with a peppery aroma are taking root. They are pawpaws, small fruit-bearing native trees beneficial for wildlife. They came in on their own, Williams said.

By late evening, the volunteers had been at it for three hours. One patch of the slope was cleared. The results included three piles of chopped trees, each 5-6 feet high. 

 

 

Williams wiped away the beads of sweat streaming down his temples and looked at the horizon – more forests infected by invasives.

“We’re never going to be done. It took generations for this to get into this. It’s going to  take generations for us to reverse that,” Williams said. 

The volunteers will be back in less than a month, tackling one patch at a time–chopping, mowing and altering water flow–to build forest trails that can withstand the challenges of a changing climate. 

 

 

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