Kamehameha Schools, the National Park Service, The Nature Conservancy and others are planning a sprawling 350-mile system of interconnected nature trails that would drape like a lei around Mauna Loa and the lower peaks of Kilauea and Hualalai.

A world-class trail complex would beckon the 25 percent of U.S. visitors to Hawai'i who seek out hiking opportunities and potentially draw many more visitors. At the same time, it could help develop a low-impact ecotour industry that could provide income for upland property owners, support conservation and give residents and visitors a first look at stunning landscapes.

The region includes dense native forests, vast pasturelands, fields of lava and much more, generally at elevations of 4,000 to 7,000 feet, but with sections that reach the 13,000-foot level of Mauna Loa.

"We all saw it as an opportunity to expose people to lands that have been virtually inaccessible," said Rob Shallenberger, Big Island conservation director for The Nature Conservancy.

Most of the trails already exist as walking paths or jeep roads; only about five miles of new trail would need to be built, he said.

The idea for such a trail system has been around for years, but it gained interest when Hawai'i Volcanoes National Park, with The Nature Conservancy's help, acquired the 116,000-acre Kahuku Ranch, which linked lands around Mauna Loa held by the park, Kamehameha Schools and other entities interested in the concept.

With the aid of a Hawai'i Tourism Authority grant and Kamehameha Schools funding, proponents went to the Mainland, New Zealand and Europe, looked at similar trail systems, and developed a feasibility report.

"What we learned in looking at other trail systems is that they become economic generators," Shallenberger said, with the building of eco-lodges, selling of backcountry tours, food and gear, and other goods and services.

Shallenberger and Peter Simmons, regional asset manager for Kamehameha Schools, said the project must be planned to protect resources and the interests of private property owners.

"We need the discipline of not rushing in to do something wrong," Simmons said.

Some areas, for instance, may be so culturally or biologically sensitive that only guided hiking would be allowed. In others, campers might hike 10 to 15 miles between overnight spots that could be a tent site with a water tank, a spartan bunkhouse or a mountain lodge where they can eat and sleep in comfort.

A couple of stretches of the system, mainly on National Park land up the slope of Mauna Loa, are ready for hikers now. But there's still much work to be done — resolving possible user conflicts, arranging the protection of resources and settling concerns of landowners. Among the user conflicts, for instance, are those between bikers, horseback riders, all-terrain-vehicle drivers, dog-walkers, hunters and helicopter tour operators.

Next steps may be the creation of a steering committee, perhaps with a trail system coordinator, and a volunteer program, as well as meetings with various communities. The park service has offered help through its Rivers Trails and Conservation Assistance program. Simmons and Shallenberger said it could be several years before all or most of the Mauna Loa Trail System is up and running.

Reach Jan TenBruggencate at jant@honoluluadvertiser.com.