As Salesforce Tower nears completion, the plaza that will accompany it has been shorn of two eye-catching features: a grove of redwood trees and a 40-foot-tall sculpture made from chunks of recycled concrete.

Instead, the half-acre space at Mission and Fremont streets will be handsomely paved but almost entirely open — a change instigated by Salesforce but agreed to by public officials. They welcome the idea of an uncluttered path to the new Transbay Transit Center, which should open next spring on the plaza’s south edge.

“In retrospect, 20 redwood trees are probably not the best thing to have” between Mission Street and what will be the transit center’s main entrance, said John Rahaim, San Francisco’s planning director. “This leaves a clear passage and sight lines at both ends.”

But it weakens the design links between the plaza, dubbed Mission Square, and the 5.4-acre rooftop park that in some ways is the transit center’s most anticipated feature. The park is supposed to debut simultaneously with the center’s bus service, though no opening date has been set.

One distinct connection will remain: the gondola that will glide up to the park from near the corner of Mission and Fremont streets. The retention of that feature, along with the emphasis on pedestrian ease, helped persuade the Transbay Joint Powers Authority to sign off on the changes.

“We wanted to make sure commuters have an unimpeded and convenient path,” said Mark Zabaneh, the authority’s executive director. As for the loss of the trees, “the neighborhood has changed a lot since the plaza was envisioned.”

That’s obvious not only in the burst of high-rise buildings near the transit center but in the highly visible presence of Salesforce. The software giant founded in 1999 owns one tower at Fremont and Mission and is the sole occupant of another. Salesforce Tower is being developed by Hines and Boston Properties, but the company will lease at least 36 of the 61 floors and have its own lobby facing Mission Square when the tower opens this fall.

Another change is that the original design was conceived for Hines, which won the rights to the block in 2007. Boston Properties now has 95 percent ownership of the project.

Last year, with Boston Properties’ blessing, Salesforce founder Marc Benioff approached local architect Mark Cavagnero to revisit the plaza, which was designed by Berkeley’s PWP Landscape Architecture.

Back to Gallery Salesforce Tower redesign trims trees, sculpture out of... 6 1 of 6 Photo: Mark Cavagnero Associates 2 of 6 Photo: Mark Cavagnero Associates 3 of 6 Photo: PWP Landscape Architecture 4 of 6 Photo: Mark Cavagnero Associates 5 of 6 Photo: Mark Cavagnero Associates 6 of 6 Photo: Pelli Clarke Pelli Architects











“When he asked me to look at this, I felt an obligation to do it,” said Cavagnero, who is best known for such buildings as SFJazz Center, but has done extensive work for Salesforce. “My approach was to fix what’s broken and keep what’s good.”

The new scheme will be shown Thursday on an informational basis to the city’s Planning Commission. It incorporates the original design’s elegant surface, alternating bands of steel grilles and stonework that have already been purchased. The tree grates will be retained as well — but with LED lighting beneath them instead of redwood roots.

The only trees in the revised design will be four maples along Fremont Street. This should allow considerably more sunlight to reach the plaza, Cavagnero said, plus flexibility to deploy tables and chairs outside of commute hours.

As for the gondola, Cavagnero has redone the surrounding 12-foot-high enclosure of glass and steel to echo the rounded form of Salesforce Tower. Outside, there will be an informal waiting area with grass and curved benches.

Early on, Cavagnero explored adding a large video screen to the transit center’s undulating white metal facade above the plaza. The idea was that Salesforce could use it for free broadcasts of things like sporting events or movies. But the concept of such a permanent installation met a cool reception from public officials.

“We were adamant that Mission Square truly read as a public space, not a Salesforce space,” Rahaim said. “I’m cautiously optimistic that it’s going to strike the right balance.”

The software firm has no desire to turn the plaza into a corporate quad, said Elizabeth Pinkham, Salesforce’s executive vice president for global real estate.

“We’ve just wanted it to be a really open space that works for the community,” Pinkham said. “When you think of all of the people that will be coming in and out of the transit center, it’s going to be an important piece of the city.”

As for the enormous Transformer-like sculptural figure, which artist Tim Hawkinson would have assembled from the remains of the Transbay Terminal that occupied the site until 2010, the Transbay Joint Powers Authority voted last month to cancel the planned installation.

Though the agency praised the Los Angeles artist for his “exceptional vision and effort,” there were concerns about the safety of a concrete collage looming over public space — especially since “periodic engineering stability evaluations were deemed necessary that represent potential long-term risks.”

Hawkinson already had selected the concrete chunks for his artwork, and they’re in a fenced lot off Folsom Street. They’re now likely to be recycled more conventionally.

John King is The San Francisco Chronicle’s urban design critic. Email: jking@sfchronicle.com Twitter: @johnkingsfchron