Fulfilling a campaign promise, Gov. Wolf on Thursday reinstated a moratorium on natural gas drilling on state parklands. It came less than a year after his predecessor lifted the ban.

The executive order protects about a million acres - or 60 percent - of Pennsylvania state parks and forests that sit atop the natural gas-rich Marcellus Shale formation.

Fracking companies that already have leases on public lands can continue to operate. And new leases may be signed to drill under land for which the state lacks "subsurface" rights.

The decision, which Wolf announced at a news conference in Benjamin Rush State Park in Northeast Philadelphia, marked the latest turn in the state's attempt to accommodate its burgeoning natural gas industry while addressing concerns about the environmental impact of widespread drilling.

Gov. Ed Rendell imposed the ban in 2010, and his Republican successor, Tom Corbett, lifted it last year. Corbett had projected up to $95 million in revenue from leases that would have been signed.

At the news conference, Wolf cast doubt on Corbett's revenue figure and said it would not be in the proposed budget he will release in March.

The Democrat reiterated his general support for natural gas drilling as well as a new severance tax for operations, a sentiment held by a majority of Pennsylvanians, according to recent polls.

"I absolutely want to do natural gas," Wolf said. "I think, if we do it right, we can create really good jobs and create industry, and sustain our strong economy in Pennsylvania."

Wolf's moratorium is in stark contrast with the New York governor's decision last month to bar fracking statewide. Andrew Cuomo, a Democrat, instituted his ban after a state report cited health concerns over contaminated drinking water and air pollution.

Wolf has taken a much more moderate stance, pushing for a new fracking tax to help offset shortfalls in education funding. Pennsylvania remains the only major natural gas-producing state without such a tax, although energy companies have paid more than $600 million since 2011 in impact fees to municipalities that host drilling operations.

Corbett lifted the moratorium in May with certain conditions. Companies could extract natural gas under untouched public lands by using horizontal drilling techniques from properties with existing leases.

But no new drilling took place because of a legal challenge over the generated revenue. The Pennsylvania Environmental Defense Foundation claimed that the Republican-led legislature could not take the royalties from a special conservation fund to help balance the budget.

Commonwealth Court sided with the Assembly this month, two months after Wolf defeated Corbett in the governor's race.

Some Democratic lawmakers and environmental groups applauded Wolf's restoration of the ban.

"We are pleased to see Gov. Wolf move quickly to protect our state parks and forests from natural gas drilling," said John Norbeck, acting president and CEO of PennFuture, an environmental advocacy group.

"The governor has wisely chosen to protect the people of Pennsylvania over the profits of drillers," he said.

Another group, Pennsylvanians Against Fracking, asked the governor to ban fracking, despite his explicit support for it.

Pro-industry groups lamented the moratorium's return and called it a blow to taxpayers.

Dave Spigelmyer, president of the Marcellus Shale Coalition, said Wolf's decision ignored input from drillers and "flies in the face of common sense."

Drilling under additional acres of public land boosts the economy and is an "enormous current and potential source of revenue for the commonwealth at a time when revenues are sorely needed," Spigelmyer said.

Louis D. D'Amico, president of the Pennsylvania Independent Oil and Gas Association, said the additional drilling would not have affected the land "in any way."

"The irony of this administration preventing drilling for a resource that they are also seeking to tax cannot be overlooked," he added. "This is a lose-lose for Pennsylvania's taxpayers and energy consumers."