What the Beatles are to pop music, what the Velvet Underground is to indie rock, Joni Mitchell is to singers and songwriters.

"I think a lot of people think of her as an influence, whether they sound like her or not," says Heather Kropf, one of the musicians performing Saturday in "It's Comin' on Christmas -- A Joni Mitchell Tribute Concert" at the Make Your Mark Artspace & Coffeehouse in Point Breeze.

Kropf will be joined by local musicians Brad Yoder, Clark Slater and Hayley. Joanne Juskus, of Baltimore, and Folk By Association, a duo from New Jersey, also are on the bill.

Mitchell's career spans five decades, dating back to her debut album, "Song to a Seagull," released in 1968. She is generally regarded as one of the most important musical figures of the 21st century, having paved the way for artists including Patti Smith and Chrissie Hynde, and influencing scores of young girls to pick up a guitar and compose songs.

"She definitely made spaces for people," Kropf says, "to write really personal songs that are art and not just pop, confessional tunes."

Nor is Mitchell's influence only on female musicians. Prince used to send her fan mail when he was a teenager. Elvis Costello has cited her work as charting a course for his music, and the Beastie Boys have used samples of her songs in their music.

Why are artists so in thrall to Mitchell's body of work?

Yoder thinks she's an artist who writes songs with unexpected twists that make complete sense.

"She does it on a macro level in terms of writing songs on specific topics, and she does it on a micro level with her choice of words and especially with her choice of melody," he says.

"I've ripped off tons of stuff from her," Kropf admits. "The whole arpeggiated bass line from her early stuff on the piano? She's more nuanced in the harmonics than I am, but I took that from her."

Kropf also says she has tried to copy Mitchell's ability to transfer images from visual art -- Mitchell is a painter -- to lyrics.

"There's also not being afraid," Kropf adds. "Her song 'Blonde in the Bleachers' starts off as a really simple piano song, then gets big at the end. So it's not being afraid to switch a song around and do something that kind of serves the song but doesn't seek to be very conventional."

Such is Yoder's admiration for Mitchell that when he gives guitar lessons, he often will pick one of her albums and loan it to his student to illustrate not only how to play guitar, but how to compose songs. Thus, many of the Mitchell albums in his collection have gone missing.

Not that her music can be replicated.

"If I was trying to play exactly like she does, that would be hard, in part because she uses all these alternate tunings," he says. "To take one of her songs and try to do something with it, I can do that. But it would be hard to try to equal the level of passion and commitment she has in her best performances."