Mayor Mitch Landrieu has won another round in his legal battle with the heirs of wealthy philanthropist Edward Wisner, leaving a question mark over the future control of more than 50,000 acres of valuable coast land that Wisner donated to the city 100 years ago.

A five-judge panel of the 4th Circuit Court of Appeal voted unanimously Friday to uphold most of a lower court’s decision in Landrieu’s favor. Barring a successful appeal by the heirs to the state Supreme Court, that means the 100-year trust that has governed Wisner’s donation officially expired last month.

The big question is what happens next. For most of its history, proceeds from the land have been split among Wisner’s heirs, the city, The Salvation Army, Tulane University and Charity Hospital, now controlled by LSU.

In 2012, the land generated about $8 million in income, much of it rent from Port Fourchon, a hub for vessels serving offshore rigs.

Wisner’s heirs, joined by The Salvation Army and LSU, have been trying to get the courts to declare the trust perpetual, citing a 1920 state law that allowed any charitable trust to live on indefinitely unless it contains some express provision that would “dissolve, abolish or destroy” the arrangement.

The city argued that the 100-year term of the original Wisner trust qualified as such a provision, and the district court and the 4th Circuit agreed.

“The trust provisions set forth a 100-year term for its existence,” Judge Roland Belsome wrote for the appeals court. “Thus, the trust will end on August 4, 2014.”

So far, Landrieu has been silent about what he thinks should happen to the Wisner donation should the courts declare the trust dissolved. Presumably, more legal squabbling could be in store if the beneficiaries can’t agree on how to proceed.

The 4th Circuit did reverse one portion of Civil District Court Judge Melvin Zeno’s ruling, though it likely won’t have much of an effect if the trust has in fact expired.

The Wisner heirs have been furious at Landrieu for doling out grants from the city’s share of the Wisner proceeds without consulting the committee set up to govern the trust, as previous mayors have done. In their lawsuit, they even asked that Landrieu be removed from that committee altogether.

On that point, the 4th Circuit agreed, though it did not find grounds for tossing Landrieu from the committee.

“The testimony and documentation admitted at trial makes it clear that the mayor must obtain the advice and consent of the advisory committee, and may only act on trust matters with a majority vote,” Belsome wrote.

The committee last month approved 65 grants of city money totaling nearly $2 million, discounting complaints from a Wisner heir that the city was misspending the money.

The grants go to various nonprofit organizations and programs. They include about $630,000 for city programs, most of it for Landrieu’s NOLA for Life anti-violence initiative.

The Lens reported that the committee voted in favor of every grant that Landrieu’s office submitted for approval.

It did so over the objections of member Michael Peneguy, who represents Wisner’s heirs. He sought to reject nine grants, including most of the city programs, totaling about $1 million.