Ancient forest frozen in lava rediscovered near Bend

BEND — Lauri Bonn's lava cast adventures began with the discovery of an old newspaper clipping.

The 1948 article, headlined "Oregon's new natural wonder: Lava cast forest discovered in Bend area," featured a picture of Bonn's father, Paul Bonn, perched in a rock formation created thousands of years ago when lava hardened around a big tree.

That was when an old family story clicked for Lauri Bonn.

"I knew, I knew he discovered something," the Bend resident said, article in hand. "With this, I decided — now I'm on a mission."

The casts are technically molds. They are created when flows of lava encase a tree trunk that is thick enough and has enough moisture content to hold strong until the lava hardens around it.

The tree eventually burns out, leaving a tree trunk-shaped hole in the lava.

Bonn had grown up believing that her father had discovered the Lava Cast Forest, 15 miles south of Bend and then 10 miles east on a dirt road. Reading through the clipping, she realized that Paul Bonn's lava cast forest was different — and much easier to get to.

But it also seemed to have faded from people's memories.

So, in the last month and a half, she has been scouring the lava flows, identifying casts and calling everyone she could think of to raise interest in developing a little trail system or interpretive site to mark the geologic features her father found.

"If he did discover this, and it's been lost, people need to know about it," Bonn said.

Bonn grew up in Bend, where her father was the big game biologist for the Oregon state game commission.

Paul Bonn, who died 30 years ago, roamed the forests around Bend for his entire career.

And according to news reports published in The Bend Bulletin, The Oregonian and the now-defunct Oregon Journal, one January day when he was studying winter forage conditions, Paul Bonn found lava casts "within a stone's throw of an arterial highway, not far from Lava butte," The Bulletin noted.

The local Deschutes Geology club estimated the casts were more than 2,000 years old, according to The Bulletin, which noted that the lava casts could be the most easily accessible in the western United States. A couple of articles mentioned the Deschutes National Forest intended to improve roads to the area, but although the lava casts made it onto a 1960s Forest Service brochure, the agency didn't fix the road.

"Over the years, I think people just forgot it was there," Bonn said.

But after she and her sisters found the article on the lava casts, Lauri Bonn got to work.

Lauri Bonn looked up old articles in the Bend Public Library, while her sister Eileen Spencer hit a library in Multnomah County.

Bonn went to the Oregon Department of Fish and Wildlife and looked up her father's old field notes from 1948. There were no mentions of lava casts written in her father's distinctive handwriting.

She talked with geologists at the Lava Lands Visitor Center and staff members at the Deschutes National Forest. None had seen the lava casts just across the highway from Lava Butte.

And she started searching for the lava casts themselves.

She got turned around on the first trip, but after spotting lava flows from the top of Lava Butte, she narrowed her search.

After that, her expeditions were more successful. She explored the wobbly rocks of one lava flow, and found two holes where trees had once stood, thousands of years ago.

"That got me excited," she said.

She kept coming back and looking for the hollowed-out areas among the gray lava rocks, and kept finding more casts on the half-dozen trips she made to the site.

"I loved being out there," she said. "I could kind of get a feel for what my dad was doing."

Finding lava casts can be addictive, she said as she stepped across a lava flow, peering around trees and piles of rocks to see if any had slipped her notice on earlier trips.

"That could be a little one," she said, pointing to an indentation. "Every time I find one of these it's like 'Oh, I've got to go find another.'"

Lava casts are not common, said Bart Wills, geologist with the Deschutes National Forest — Central Oregon features the right ingredients for them to form.

Bonn has talked to Wills and others about improving the road to the lava flows so others can see the lava casts, and maybe even setting up an interpretive path that could wind between the rocks and ponderosa pines.

There's a lot of steps to go through to get to that point, Wills said, including figuring out how to build and maintain a trail.

If built, the site would be a good addition to the other geological attractions in the area, said Larry Berrin with the Lava Lands Visitor Center.

"It might actually be the perfect spot to set up a little interpretive trail," Berrin said, noting that the reconstruction of U.S. Highway 97 in the area will route an access road close to the site.

Now, when staff members at the visitor's center recommend activities for out-of-town guests, they usually recommend Lava Butte and Lava River Caves, Berrin said. But staffers don't suggest the established Lava Cast Forest, unless people have more than one day to explore, even though the casts there are "beautiful," he said.

"The Lava Cast Forest is for those who have a little more time," Berrin said. "It just takes you out of your way."

The newly rediscovered lava casts, however, could be a closer and more convenient option — and one that comes with a story.

"It's sort of a lost forest," he said.

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