The Sakonnet Greenway trail has been eight years in the making, but in just a few months, the final stretch will be finished and joggers and walkers will have five full miles of trail to explore.

Until then, the Aquidneck Land Trust needs your help.

The Land Trust announced yesterday that it has been awarded a $40,000 “challenge” grant from The Nature Conservancy through The Champlin Foundations. The trust is asking the public to match the grant with donations by a Nov. 1 deadline.

The combined $80,000 will help the land trust pay for the Greenway’s newest trail segment, 1.2 miles, which is now under construction. That stretch will result in two completed trails: one that winds from The Glen recreational complex in Portsmouth, behind The Pennfield School, across Sandy Point Lane and around farmland at the Three S property, and the other that loops around the Newport National Golf Club.

The newest connecting section will travel through woodlands and wetlands, over boardwalks and bridges, and should be completed by Nov. 1.

“The pressure is on for us to raise the money,” Edward S. Clement Jr., the trust’s executive director, said yesterday. “We’re talking about the island’s largest nature trail, free and open to every single person that wants to utilize and enjoy it. I think it’s a very captivating project and it will provide some tangible benefits for all this conservation.”

The Sakonnet Greenway is Aquidneck Island’s largest public nature trail, winding through the middle of the island along fields, woods and farmland. The completed sections are already popular with dog walkers, joggers, horseback riders and cross-country skiers. The trust calls it a “living classroom,” providing a scenic respite for residents and visitors.

But the trail will continue to expand even after this latest segment is finished. The trust expects that a final section connecting the Newport National loop to the Middletown recreational complex on Wyatt Road will be completed by 2010. The trust is still estimating the costs to build that section, which will bring the Greenway’s length to seven miles.

The trust is also eyeing an ambitious extension of the trail south of Wyatt Road, all the way to Sachuest Point, although the idea is purely conceptual now, Clement said.

The Sakonnet Greenway was merely a vision when Clement joined the trust in 2000. As of today, the trust has raised $250,000 to pay for its construction and secured 10 conservation and trail easements. Clement marvels at how far the project has come.

“It’s very real,” he said. “Oftentimes you see plans that never happen, but this has literally materialized before our eyes.”

The trust will now turn its attention to continuing land-conservation efforts, Clement said, including protecting the Boulevard Nurseries property in Middletown and Swan Farm in Portsmouth. By the end of the year, the trust may conserve an additional, undisclosed 125-acre property.

“We only have so much time left to preserve the remaining great places on the island,” Clement said.

The trust has conserved nearly 2,000 acres on Aquidneck Island since its start in 1990.

mwims@projo.com