A decision by Pennsylvania's highest court on Tuesday was hailed as a victory by environmental advocates on the use of public natural resources and money from oil and gas drilling in state forests.

Brought originally as a challenge to the state government's unfettered use of money from drilling in publicly owned forests, the state Supreme Court went farther in its effort to strengthen the hand that environmental considerations play in government decisions.

John Dernbach, a professor of environmental law and sustainability at the Widener University Commonwealth Law School, called it a "landmark" decision. It the second major high court decision won by environmental advocacy groups in challenges that grew out of the Marcellus Shale natural gas boom in Pennsylvania.

The biggest victory in the decision is that it cites a 1971 constitutional amendment to require that the state act as a trustee, and not a proprietor, of public natural resources, said John Childe, a lawyer for the nonprofit Pennsylvania Environmental Defense Foundation. That effectively overturns four decades of case law that had weakened what is known as the environmental rights amendment, Childe and others said.

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A splintered state Supreme Court in 2013 had relied, in part, on the environmental rights amendment when it struck down a two-year-old law imposing new limits on the power of local governments to determine where the natural gas industry could operate. Just three justices had backed that rationale, leading to arguments that it was not settled law, Dernbach said.

With a five-justice majority now backing a stronger application of the amendment, the court is insisting that environmental rights are on par with other constitutional rights like property rights and free speech, said Jordan Yeager, a lawyer for the Delaware Riverkeeper Network and Pennsylvania Land Trust Association.

"And all branches of government and all levels of government can be held accountable if they take action that would injure our right to a healthy environment," Yeager said.

The 45-page decision could make it more difficult to lease state forests for oil and gas drilling, and it could force governments to be more careful about allowing development that would damage public lands, wildlife, groundwater, rivers and air quality.

Gov. Tom Wolf's office would only say it was reviewing the decision. Wolf has backed a moratorium on drilling in state forests.

The Pennsylvania Chamber of Business and Industry said it will check with its members on the real-world effect of the decision. The Marcellus Shale Coalition, a major natural gas drilling association, said it viewed the decision solely in the context of its effect on the use of state revenue from drilling in state forests.

The decision will certainly make it more difficult for the state to tap revenue from drilling in state forests. When the state began leasing state forestland anew to take advantage of the drilling boom, it diverted some of the revenue to prop up its recession-wracked finances.

That prompted the Pennsylvania Environmental Defense Foundation to sue in 2012 to stop the state government using the money for anything besides improving public lands.

Some $926 million in total oil and gas lease revenues accumulated from 2008 through 2015, according to figures cited in the decision. About half of it went to the Department of Conservation and Natural Resources, which manages the state's parks and forests.

To some extent, the court agreed with the foundation, reversing a lower court decision and saying that royalties must be used to maintain or conserve public natural resources.

However, the high court ordered the lower Commonwealth Court to sort out whether the same limits should apply to forest leases. Childe said it also remained unclear whether the state would have to repay the hundreds of millions it drew from oil and gas drilling that ultimately was not spent on improving public lands.