Within minutes of leaving behind a cluttered commercial stretch of gas stations, motels, package stores, pizza parlors, office buildings, shopping plazas and department stores, our small group of hikers traipsed among ledges, old stone walls and streams in a densely wooded section of Groton earlier this week — reinforcing the point that those who live and work in busy neighborhoods don't always have to drive far north to savor a slice of nature.

After passing a giant boulder — a glacial erratic left behind from the last ice age some 12,000 years ago, Sue Sutherland, a director of the Avalonia Land Conservancy, pointed to a beech tree.

"Look at the holes," she said. "That's from a pileated woodpecker."

We were roaming through the conservancy's newest acquisition, a 41.48-acre undeveloped tract south of The Gold Star Highway and west of Buddington Road.

More than a decade earlier. a developer had proposed building a 200,000-square-foot Walmart superstore there, prompting a contentious legal battle that ended in 2008 when a Superior Court judge ruled that the town Planning Commission properly rejected the project because of potential harm to a nearby reservoir.

In subsequent years, the land has remained largely quiescent, though hikers and mountain bikers apparently have on occasion been traversing unofficial trails.

Then, late last year, Sutherland, who is head of Avalonia's acquisitions committee, received a surprise phone call: Property owner Leo Antonino decided to donate the land to the conservancy.

A founder of the Antonino Auto Group — one of his company's nine dealerships is located on the Gold Star Highway a short distance from the property; another is across the street — Antonino has been a longtime Avalonia supporter, Sutherland said.

The conservancy announced in a prepared statement that the property "will be called the Leo Antonino Preserve in honor of Mr. Antonino's tradition of giving back to his community. The land will be conserved in its natural state and open to the public for passive recreation."

"It's a beautiful piece of land, virtually untouched," Antonino said when reached by telephone. "I've walked back there for years. It's like walking back in time."

Antonino said he had tried to sell the property in the past but eventually concluded it would be better to give it to Avalonia "so that the whole town will be able to enjoy it."

Avalonia said that the preserve's rugged features "make for a wide diversity of habitats for wildlife. The land is home to wood thrush, which require large forest blocks for survival, pileated woodpeckers, and other rare Connecticut species."

The new preserve, accessible from the Antonino Road dead end, borders open-space parcels owned by the town and city of Groton, which, when combined with other contiguous tracts, comprise more than 100 acres of unfragmented forest.

Avalonia noted, "The less fragmented our forests, the more capable they are of absorbing carbon and mitigating the effects of climate change. This preserve's forest also helps protect Groton's drinking water. Its streams flow into the Groton Reservoir, less than 1/10th of a mile away."

Among those joining this week's hike were Janet Andersen, head of Avalonia's Groton committee; Carl Tjerandsen, who has helped establish trails at other preserves; and Bob Graham, an Avalonia member.

Tjerandsen and Sunderland had earlier blazed one section of a proposed new trail through the Antonino preserve, while Andersen plans to evaluate additional routes that might one day be used by school groups as well as by mountain bikers.

She relies on a Global Positioning System tracking and publishing application on her smart phone to photograph and keep a digital record of possible routes.

"As I walk if I see (what could be) a trail I stop, make a note and take a picture," she explained.

Eventually, paths in the new preserve could link with trails heading north into Ledyard and south to Bluff Point Coastal Reserve, Andersen added.

Tjerandsen said designing new trails require careful planning so that they not only lead hikers past interesting geologic and natural features but also don't intrude on wetlands and other environmentally sensitive sections, and remain safe in all seasons.

"It's always a complex compromise," he noted.

Once the trails are completed, the preserve will prove a worthy addition to Avalonia's growing inventory of almost 100 protected properties in the region that amount to more than 3,500 acres.

And for anyone who would have preferred a new Walmart, there's a perfectly good one only a few hundred yards away.