Rigo 23’s One Tree may be San Francisco’s most iconic street art.

Created in 1995, it transforms the image of a simple black-and-white traffic sign into a giant Pop Art piece. When Rigo 23 made the piece on a blue wall, it pointed to a mature tree — an art directional that was funny and poignant, a commentary on urban living that pedestrians, drivers, and art-goers enthusiastically applauded. The Library of Congress has a photo by celebrated photographer Carol Highsmith that shows One Tree in 2012, after other trees had joined the original tree. In Highsmith’s capturing, the artwork’s blue wall is still blue, and One Tree is still on the wall’s upper far left.

Much to Rigo 23’s dismay, the building’s new property owner — or someone with the owner’s authority — has changed One Tree.

Dramatically.

The art has been moved to the far right. No longer does it point to a tree. Instead, it points to the nearby freeway onramp. And no longer is the wall blue. Instead, it’s brown. The changes, which apparently happened in the last year, have upended the entire foundation of One Tree. It’s as if someone repainted the Golden Gate Bridge mud-brown without telling anyone beforehand.

“If I were more agile in my administrative end of things, I’d be suing the people who bought the building,” Rigo 23 tells SF Weekly. “What has happened to the One Tree mural is very indicative of some of the changes that San Francisco has been going through, because the people who purchased the building and redeveloped it — they took out the portion of the mural with the arrow that said ‘One Tree,’ they redid the building, and then placed it back behind the tree. Their actions indicate that they knew it was a work of art, that people cared about it — yet they never contacted me, they never contacted the gallery in San Francisco that represents me [Anglim Gilbert]. They destroyed the work.”

The commercial property company that brokered the property didn’t respond to SF Weekly’s request for comment.

Rigo 23, who’s based in San Francisco and is a co-founder of the longtime Clarion Alley Mural Project, found out about the changes several months ago from a friend in Barcelona. So he visited One Tree in person.

“I couldn’t believe it,” he says. “I was heartbroken.”

He says the people who changed the work violated the Visual Artists Rights Act, federal legislation passed in 1990 that protects an artist’s work from “intentional distortion, mutilation, or other modification.”

“It protects artists from such an event happening to their work,” says Rigo 23, whose other works include Truth, which is atop a building on Market and Seventh streets that overlooks United Nations Plaza. “I truly believe in public art. When I put art in public, I want the public to have a genuine relationship with the works. In the past, when people have alerted me to things — like someone selling photographs of the One Tree mural or this and that — I never felt compelled to do anything about it because the work is in the public realm. It’s publicly looked at, it’s publicly enjoyed, it’s a collective relationship.”

Adds Rigo 23: “I think this is the relationship that ‘newcomers’ to the city have toward what was there before they arrived. The mural was not just the arrow. The mural was the natural limits of the architecture. The entire blue wall was as much a part of the mural as the arrow part. It’s so moronic. I don’t understand it. I imagine it was a substantial financial effort on their part to move it, store it somewhere, and place it back. It almost signals a kind of care toward the thing. But it’s such an entitled and dismissive attitude to take toward a work of art. I put it up 22 years ago. I met a curator recently who said, ‘I remember that work as a child.’ ”

But Rigo’s other works remain as they were intended in San Francisco, and 2002’s Truth is another art piece that uses words and imagery to make a bigger point. It honors Robert H. King, a former member of the Black Panther Party who in 2001 was released from prison after 31 years — 29 of them in solitary confinement — when his conviction was overturned. Truth, painted after the start of the U.S.-led war in Afghanistan and the wake of 9/11, features a barcode that suggests the truth is for sale.

“In the old gas stations, when you see the numbers rotate, I made a drawing where the ‘T’ is rotating upwards, the same with the ‘H,’ and the top of ‘N’ and a ‘P’ are coming up,” Rigo 23 says. “I was thinking that truth is the first casualty in a time of war. Then Robert King got released, and I got quite close with him, and I thought I’d dedicate the mural to him. It’s a story of personal vindication on his part and also the ability of truth to prevail against incredible odds.”

Like One Tree, Truth has inspired other art. “Robert King came to San Francisco, and we had a public ceremony in United Nations Plaza,” Rigo 23 says. “The Board of Supervisors declared that day — April 22, 2002 — Robert King Day. The president of the Arts Commission handed Robert a plaque. And then the Luggage Store Gallery, who are old friends of Robert, had a aerial acrobatic performance group that did a dance in front of the mural. They were suspended from ropes. It was a beautiful celebration. And we gave out over 200 bags of free groceries. It was a very special day. Robert King got onto the roof the building, and we took a photograph — and that photograph became the cover of his autobiography.”

And people are making sure that Truth doesn’t change the way One Tree did. The management of the Odd Fellows building, on whose property the mural is on, “are looking after it,” says Rigo 23, “and have given me assurances that they plan to keep it there.”