The jack pines and scrub oak of the New Jersey Pinelands may be green, but the folk music of these woods runs to bluegrass.

Next month, the folks who dig that music's place in "piney" culture will mark the 20th anniversary of Waretown's legendary Albert Music Hall with a special concert.

Hosted by the Pinelands Cultural Society, the Jan. 7 program will honor the hundreds of volunteers who built and maintain the performance hall, sometimes called the "Grand Ol' Opry" of the Pine Barrens.

Doors will open at 6 p.m., and the program will start at 7 with a video made during the hall's construction in 1996. The concert, featuring a half-dozen bands, is scheduled to run to 11 p.m.

A simple frame building with a stage, seating for 350, practice rooms, and a "picking shed" out back, Albert Hall has a pre-history reaches back to the 1950s, when brothers Joe and George Albert began playing for their own enjoyment in a hunting cabin on their 51-acre woods outside the Ocean County town.

George played the fiddle. Joe played washtub bass.

Lighted by gas lamps and heated by a wood stove - there was no electricity, and water came from a hand pump - the brothers called their cabin "the Home Place." As word of their musicality spread, they began to draw performers and crowds from miles around.

Just about anybody with a bluegrass instrument - be it mandolin, dulcimer, dobro, banjo, fiddle, guitar, or bass - was welcome to join in.

"It was a different life back then," said Elaine Everett, spokeswoman for the cultural society. "This was before the Garden State Parkway, so it was very remote, with dirt roads in the rural areas."

Those Saturday night gatherings continued for a time after George died in 1973, but the size of the crowds and their sometimes raucous behavior became too much for Joe, a former DuPont Co. employee then in his 80s. He closed the doors to the Home Place in 1974, but a few months later, his friends created a new gathering spot in a building at the Waretown Auction.

That led to creation of the Pinelands Cultural Society, which took charge of inviting performers to the Saturday night concerts. It also also started charging a small admission fee.

When a "disastrous fire" destroyed the auction building in 1992, the society resumed concerts first in the parking lot outside the ruins, then at a nearby elementary school.

Meanwhile, said Everett, it began planning and raising funds for a permanent home, with some nationally known artists like folk singer Pete Seeger performing fund-raiser concerts.

In May 1996, it broke ground for the new building at 131 Wells Mills Rd., which Everett's husband, Roy - an engineer and president of the cultural society - had designed.

Hundreds of volunteers turned out that year to help with its construction and painting, and on Jan. 5, 1997, 1,100 people crowded in and around the new Albert Music Hall for its inaugural concert, which featured 44 bands playing two-song sets.

The stage's backdrop is painted to look like the woods that surrounded the Home Place, and the hall is governed by a strict set of "family-friendly" rules, according to Everett.

"No smoking, no drinking, no dancing, no cursing, and we don't rent it out," she said. Except for the weeks of Christmas and New Year, it hosts a concert every Saturday night, and the music style is "never modern," according to Everett.

"It's country and bluegrass, mostly from the 1950s to the '70s" she said, "because that's what our audience likes." Admission these days is $5 for adults. Seven different bands typically perform, with each playing about 30 minutes.

The society's board gets many requests from many groups and artists seeking to play Albert Hall, said Everett, but selects only those whose style and level of playing adheres to its standards.

"We've got about 1,000 performers we choose from," she said. "We're booked about six months in advance."

Yet some of the bands that make it onto the stage can be quite green, formed in the "picking shed," where musicians of all different skill levels are welcome to play, listen to one another, form friendships, and "start playing together."

"So that's how it's been for the past 20 years," said Everett, a retired schoolteacher. Like her husband and everyone else who works at the hall - cooking food for the snack bar, taking tickets or manning the lights - she is unpaid. "And it's a lot of work."

"For a while we thought we'd never see this building," she said. "And now here we are, up and running for 20 years, all thanks to volunteers. So we think it's time to celebrate."