When the locally filmed drama “One Tree Hill” first hit the airwaves, its producers, actors and crew had few lofty expectations, executive producer Gregory Prange said.

So there was a definite sense of satisfaction when Prange learned that The CW Television Network recently renewed “One Tree Hill” for an unprecedented seventh season. If all 22 episodes that have been ordered are produced, “One Tree Hill” will become the longest-running project to be filmed in North Carolina, surpassing the venerable “Dawson’s Creek.”

“Literally, on this show from the beginning we never knew if we were coming back. We kind of labeled ourselves as the little engine that could,” said Prange, who served as an executive producer of “Dawson’s Creek” before being hired in 2003 to work on the fledgling “One Tree Hill.”

The show is very successful at attracting the network’s demographic target of women between the ages of 18 and 34. And because it now also airs in syndication on Soap Net and other overseas venues, “One Tree Hill” is reaching an ever-growing audience that includes fans from around the world.

“We’ve been getting good numbers and they want us back. We thought it could be possible. We’re very happy,” Prange said.

“One Tree Hill” airs at 9 p.m. Mondays on The CW. It has filmed in Wilmington since 2003. The show was originally on the WB Television Network until a 2006 merger with UPN, which resulted in the formation of The CW. EUE/Screen Gems Studios serves as its home base.

The network’s February renewal confirmation affords “One Tree Hill” producers a rare luxury.

“We’ve never had this early of a pickup before so we’re able to make a plan for the seventh season to some degree,” Prange said.

Early on, there was not much of a budget for promoting the show, which was fast-tracked by The WB in 2003 from a mid-season replacement to the fall schedule.

“We were in a rush mode literally with this show from the beginning,” Prange said. Its primary cast members, which include Chad Michael Murray, Hilarie Burton, James Lafferty, Bethany Joy Galeotti and Sophia Bush, were all barely out of high school themselves when “One Tree Hill” first aired.

Unlike “Dawson’s Creek,” which used Wilmington to recreate a New England setting, “One Tree Hill” is set in a small fictional North Carolina town. The versatility of Wilmington and the surrounding area allows producers a great deal of latitude when it comes selecting shooting locations.

“I think the show has really embraced the North Carolina reality,” Prange said. “Wilmington is a beautiful place to film. This is an incredibly viable place and once you shoot here you want to come back and shoot again.”

The series’ young actors were able to develop their skills without the overbearing sort of media attention they might encounter in New York or Los Angeles, Prange added.

“Wilmington is a nurturing place. It’s still a young film community and everybody is really still passionate about doing their work,” he said. “It’s an inviting place for talent. You rent a place on the beach and it’s not so bad.” 

The show took a radical turn at the beginning of its fifth season. Series creator and executive producer Mark Schwahn had the innovative idea of advancing the lives of the high school classmates four years to portray their struggles with the challenges of young adulthood.

Schwahn said in a 2007 interview with BuddyTV he was “very passionate” about the concept, despite concern on the part of the network and studio.

“Initially, I think they were all afraid of it because it’s unprecedented and it’s brand new,” he said.

Not everyone was convinced the show’s core viewers – young women – would accept the change.

“We’ve definitely been able to do that,” Prange said. “Mark Schwahn had a lot of forethought. I think we pulled it off.”

Shooting of the sixth season of “One Tree Hill” wrapped earlier this year. Production of the 2009-10 season gets under way in June.

Prange does not see any major cast changes for season seven.

“We anticipate all the (actors) will come back,” he said.

The CW’s order for a 22-episode seventh season will give the series 152 episodes in total and surpass “Dawson’s Creek” by 24 episodes, according to the North Carolina Film Office.

“I think when you have over 150 episodes you’ve got pretty good legs,” Prange said.

With worldwide syndication, “One Tree Hill” is finding a much wider audience. Last month Schwahn and series co-star Lafferty went to Paris to promote the show, Prange said.

“It has rabid fans there and it has rabid fans in Australia. I was thinking about season seven and they come from all over the world to watch us (film). It’s astounding,” he said.

The producers of “One Tree Hill” remain focused on the series’ seventh season and haven’t given much consideration to the future, Prange said.

“I don’t know if ‘One Tree Hill’ will spin off,” he said. “I don’t think the studio and guys I work with would be averse to bringing another show to Wilmington.”

New state-generated initiatives to attract film and television projects such as an increased tax incentive for productions “probably is a good idea,” Prange said.

The N.C. Film Office estimates that “One Tree Hill” has generated more than $135 million in spending across the state over the life of the series.

Johnny Griffin, director of the Wilmington Regional Film Commission, said The CW’s renewal of “One Tree Hill” will provide a welcome boost to the local economy.

“Another season means jobs for approximately 125 folks and about $23 million which will be spent locally,” Griffin said.

A seventh season of “One Tree Hill” will additionally serve as a “great marketing tool” for the area’s film and television industry, Griffin said.

Aaron Syrett, N.C. Film Office director, said the state’s film tax incentive program was a factor in keeping “One Tree Hill” from relocating elsewhere.

“But if we want to keep these high-paying jobs coming into the state, we need to continue to be competitive with our incentive program. Other states are offering a lot more than we are,” Syrett said.

Current incentives offered by North Carolina include a 15 percent tax credit on productions spending a minimum of $250,000 in-state.