The Bay Circuit Trail, a generations-old vision of connected recreational walking paths, is nearly complete, though its future grew uncertain in recent years with the impending retirement — from an unpaid post that had been his passion for more than 20 years — of 80-year-old Alan French of Andover. 

Now two regional conservation groups are collaborating on a plan to help finish the trail, first envisioned as an “outer ­Emerald Necklace” along the lines of Boston’s chain of parks 83 years ago.

The Appalachian Mountain Club and the Trustees of Reservations are working together to help the trail’s all-volunteer coalition, the Bay Circuit Alliance, secure permanent easements and other protections for properties that will forge a continuous path through conservation areas, private land, and the occasional suburban street in 37 communities.

“Closing those gaps is a priority for all of us,” said Wesley Ward, a founding member of the trail alliance’s board and vice president for land and community conservation for the Trustees of Reservations nonprofit organization.  

About 17 miles remain to be dedicated for recreational use on the main path, which runs chiefly between the corridors of Interstate 495 and Route 128/Interstate 95. Other sections of the main path carry temporary easements that the alliance hopes to make permanent. In addition, the group hopes to add spurs to connect with interesting destinations, such as Crane Beach in Ipswich and the village of North Easton.  

French, who is stepping down at the end of the year as the Bay Circuit Alliance’s executive director and board chairman, is pleased with the new partnership. He had been asking the board, of which the AMC and Trustees of Reservations are members, to decide on a succession plan for six years, he said.

“I’m not getting any younger, and the project, frankly, needs staff now,” he said. The work ahead includes complex negotiations with corporate and private landowners as well as municipalities.

The alliance will continue to act as a 501(c)3 tax-exempt organization, but will have new blood and resources, French said. It has about 50 member organizations, both public and private, including nonprofit land trusts and municipal conservation commissions.

Ward said eliminating gaps in the main path will probably take three to five years, but permanently protecting the land could easily require 10 years. Beyond securing access, the groups hope to provide more consistent maintenance and signage, move certain sections off public roads onto undeveloped land, and promote public awareness of the trail. They have not put a price on the task, partly because they don’t expect the cost to be high, he said.

Many sections overlap trails on other conservation property, such as the Massachusetts Audubon Society’s Moose Hill Wildlife Sanctuary in Sharon. People who walk the local trails may not know they are part of the Bay Circuit, said Stephen Sloan, the Trustees of Reservations’ Greater Boston regional director. The Bay Circuit is identified by name at some of the trail heads, but generally not on blazes along the paths.

Local residents looking for a four-hour nature hike don’t always think they can find it near Boston, he said, but they can do that and more. “I love the vision of it,” he said. “I’m hoping it will encourage more people to spend time outside.”

Dedicating a 10-foot section of trail can be as difficult as a 3-mile section, depending on the ownership, and in some cases, the ownership may have to change before the alliance gets permanent permission to use the land, Sloan said.

In some places, a temporary trail has been drawn over suburban streets to allow hikers to pass between sections. One such spot is Route 1A in Rowley, an arrangement that Ward said must be eliminated because the road is too busy. Elsewhere in Rowley, a temporary trail bypasses an area of severe flooding, aggravated by beaver activity, at a crossing of the Mill River.