Editor's note: Mountain Bike Trail Guide, by Bulletin outdoors writer Mark Morical, features various trails in Central Oregon and beyond. The trail guide appears in Adventure Sports on alternating Fridays through the riding season.

One of the oldest mountain biking trails in Central Oregon, the Black Rock Trail south of Bend is a relatively short (4½ miles) ribbon of dirt singletrack that skirts a truly dramatic landscape.

The trail could serve as a field course in geology. It parallels the edge of a vast lava-rock field that covers more than 9 square miles from U.S. Highway 97 east to the Deschutes River. The field — for whose jagged black lava formations the trail is named — was formed by the eruption of the Lava Butte cinder cone some 7,000 years ago, according to the U.S. Forest Service.

The Black Rock Trail was rerouted from its original path about 10 years ago. But on a recent ride, I could see why some of Central Oregon's mountain biking pioneers considered it one of their favorite trails in the early 1980s.

“It was one of the first ones around,” said Kent Howes, who serves on the board of directors for the Central Oregon Trail Alliance. “It sort of got put away for a while, and didn't really get worked on, and then came back about 10 years ago. It just didn't get used much (before that).”

I started the ride Monday from the Deschutes River Trail at Dillon Falls, planning an out-and-back ride of about 17 miles. About four miles into the trip, I arrived at Benham Falls, its whitewater shimmering in the sun on a bright spring day.

Above the falls, the trail widens and comes to a wooden bridge. After crossing the bridge, bikers have a choice of heading west (right) to continue along the river trail to Sunriver, or going southeast (left) onto the Black Rock Trail.

I turned left and began a gradual climb to the southeast, nothing too strenuous or technical.

The trail is flanked by a wall of black lava rock. To truly appreciate the geologic wonder, riders can dismount and scramble up the rock, or turn onto an old dirt road that runs up and over the lava field.

I made that turn, about halfway to Lava Butte, and soaked up a view that is unique to Central Oregon: a never-ending field of lava rocks with the snowcapped Cascade mountains in the background. Here and there, lonely trees grew out of the rock as if sprouting out of the African savanna.

Back on the trail, I pedaled my way to Lava Butte. The gradual climb required some bursts of power from my legs but was generally easy. Once at Lava Butte, I turned around to begin the trip back to Benham Falls.

The mostly downhill ride back to the falls was fast and fun, a smooth trip with a few extremely brief technical rock sections.

As I made my way back toward Benham Falls, I noticed small wooden stakes with pink flags paralleling the trail, as if a new path might be in the works. Turns out, it is.

The U.S. Forest Service and the Oregon Department of Transportation are planning to build a 10-foot-wide, 11-mile-long paved path that runs from Lava Butte to Benham Falls, and from the falls to Sunriver. Much of this paved road — planned to be completed by fall 2013 — will parallel the Black Rock Trail.

Marv Lang, a recreation forester for the U.S. Forest Service in Bend, told me the new path will provide a way for folks in Sunriver to reach Benham Falls and the Lava Lands Visitor Center at Lava Butte via bike or foot.

“It's an area we haven't tapped into much yet,” Lang said. “It's really more for families. We expect to see most of the use from Sunriver to Benham Falls.”

I have mixed feelings about this project. I wonder if the tourist crowd from Sunriver would take away from the solitude and scenery of the Black Rock Trail. But on the other hand, I would not be against taking my young children — too young for mountain biking — riding along a paved trail in such a spectacular location.

I guess the project will provide more access to the Lava Lands to more visitors, and in the long run, maybe that's not such a bad thing.