Every day, employees of the New Jersey Department for Environmental Protection walk across a concrete plaza on their way to work. Most have no idea that underneath their feet is a celebrated piece of landscape architecture. But that might change soon. The fate of the plaza is the subject of an ongoing dispute between its creator, prominent sculptor Athena Tacha, and the New Jersey government. The conflict is emblematic of the challenges facing urban landscape architecture across the country, experts say. The crux of the problem? No one can agree whether or not to preserve these aging works as art or redevelop them as raw land.

In May, Tacha received a letter from the New Jersey Department of the Treasury stating that the plaza, located in Trenton and known as “Green Acres,” would be destroyed after August 1 unless she paid to have it removed. It had fallen into disrepair, the state wrote, but there were limited funds to restore it. The Treasury Department plans to replace it with a self-sustaining rain garden.

There was just one problem. Moving the work, according to Tacha, is tantamount to destroying it. “It’s not removable,” the artist told ARTINFO. “It was made for the site. It took two years and $400,000 to execute. It has foundations like a building.”

Tacha’s predicament, which parallels that of many outdoor sculptors and landscape architects from the 1970s and '80s, begs the question: How can a work of landscape architecture be preserved in a rapidly changing urban landscape? “This discussion really moves people out of their comfort zone,” Charles Birnbaum, founder of the Washington, D.C.-based Cultural Landscape Foundation, explained. His organization is currently lobbying the state government on Tacha’s behalf. “When people think about preserving landscape architecture, they think about Frederick Law Olmsted and the Monroe County Park System. They don’t think about the recent past.”

But even historic landscape architecture has few devoted supporters. Arts advocates are occupied with the (admittedly worthy) task of preserving land art like Robert Smithson’s “Spiral Jetty.” Architecture preservationists are busy protecting Brutalist monuments from the wrecking ball. Environmental activists have their hands full with deforestation, oil spills, and the like. Urban designs like Tacha’s that fit seamlessly into the cityscape “are, if you will, invisible works,” according to Birnbaum.