Acting Their Age : The junior thespians who star in the Northridge Park Players production of ‘The Wizard of Oz’ are treated like young professionals.

The mayor of Munchkinland is a pint-sized 13-year-old boy who wouldn’t spend his summer in any other fantasy.

Dorothy is an older woman--15--who is amazed that she got the part.

The Wizard is an ambitious teen-ager who already has discovered the stage as the best place to express himself.

Such are the stars of the Northridge Park Players production of “The Wizard of Oz,” opening tonight. Some dream of Hollywood glamour, others come back every year to see old friends. Whatever their motivations, these youngsters have exchanged more traditional summer activities for the thrill of theater.

“I’d be propped up in front of the TV doing absolutely nothing,” said Howard Friedman, the Munchkin mayor. “Here, I can put everything in my life aside and take another person’s life and become someone else. I can go from normal Howard to whoever.”

Normal Howard and the rest of the young thespians--45 in all, ages 7 to 18--began four hours of daily rehearsals in late June and continue through next week. They arrive at 1 p.m. and go right to work.

Carol Allen, who took over in 1989, acts as director and cheerleader. Having directed adult groups and teens, Allen teaches drama at the Northridge Park Recreation Center during the rest of the year. The center also sponsors the summer workshop.

“Speak slower!” she said during rehearsal to Andrew Lewis, 14, who plays the Wizard. Andrew just got an agent and hopes to make acting his profession. First, though, he’ll have to enunciate better, according to Allen.

“It won’t matter how cute you are if nobody can hear you,” she said.

Allen and her assistant teachers have their standards.

“This isn’t about doing little kids’ shows where Mommy can say, ‘There’s my kiddie,’ ” said Jack Stauffer, one of the teachers and an actor who has appeared in numerous small TV roles. “The object is to knock them on their tushes . . . . I treat them as the young professionals they are, not some kids that Mom shipped off to drama to get rid of for four hours.”

The actors approach the task with the same seriousness. That was especially evident in the auditions for the part of Dorothy.

“Every girl here wanted to be Dorothy,” said Allen, adding that she finds casting difficult because she hates to hurt anyone’s feelings.

Ultimately, the choice came down to two talented finalists--Pauline Yasuda and Gina Speciale. Gina appeared to be the early favorite; she’s nailed almost every female lead the group has offered over the last few years. But the role went to Pauline, who still can’t believe it.

Allen said it could have gone either way.

“They both have strong voices,” she said. “In fact, there are about six or seven girls who could’ve done a good job.”

Gina, naturally, was a little disappointed, but it wore off quickly. “It wasn’t fair for me to keep having the lead,” she said.

These kids don’t minimize any part. Jennifer Steinberg, 11, went with her family on a recent cruise in the Caribbean. Call it a working vacation.

“I took my script everywhere,” said Jennifer, who plays one of the three wicked witches. Allen has added a witch in her version of the play.

She also gave the Wizard a much more prominent role. “I’ve always thought the Wizard was a misunderstood character. He has compassion. He’s not just a scary guy,” she said.

And the Tin Man has become the Tin Woman. Of the 45 young actors, only nine are boys, which limits options.

But Andrew doesn’t mind. “It’s good because you always get the main guy parts,” he said.

For Andrew, acting has become the place to work out the raw emotions he can’t resolve in real life.

“I have a real problem with anger,” he said. “But I can show it here.”

Andrew seems to be the exception. “The hardest thing for them is to let go,” Stauffer said. “We keep telling them that the only bad choice is to not make a choice. We want them to let go of that imagination they keep bottled up.”

They have no trouble making friends. About half a dozen of the youngsters have been attending the program, which costs $225, for five or six years. Whatever their social obligations during the school year, summer is reserved for other bonds.

“We see each other around school,” said Pauline, “but we don’t talk much to each other because we have different friends, and we’d have to break from them to be with these friends and it becomes really complicated.”

Over the last four years, Allen has become very familiar with her crew. She can practically cast the show before auditions.

The transformation among the youngsters that takes place from year to year, and even over the course of a summer, is what keeps her coming back, even though the plays never seem like they’ll be ready for opening night. This summer, using the same kids, she also has put together “Broadway Remembered,” an original musical by Allen, featuring 32 songs from 11 popular shows, including “Annie,” “The Music Man” and “Fiddler on the Roof.”

“Broadway Remembered,” which tells the story of a theater manager reminiscing as his beloved building faces imminent closure, was presented earlier this week.

Allen ensures that every youngster has a speaking or singing part in both productions.

“I love to see the little ones who can’t do anything get up at the end of the summer and show something,” Allen said. “They gain self-confidence that they didn’t have before. Let’s face it, these kids aren’t going to be pros, but that little moment of glory will probably affect them for the rest of their lives.”

WHERE & WHEN What: “Wizard of Oz” at the Northridge Park Recreation Center, 18300 Lemarsh St. Hours: 7:30 p.m. Fridays and Saturdays, 4 p.m. Sunday, Aug. 13-15, 20-21. Price: $3 to $5, depending on seating. Call: (818) 349-7341.