The new boss of the state Department of Environmental Protection, Jon Steverson, wants to make the award-winning Florida State Park system pay for itself.

That means letting some things into the parks that until now have been kept out. Timber companies chopping down the state's trees. Cattle grazing on taxpayer-owned grass and leaving behind cow pies. Metal cell phone towers looming over the tallest pines, palms and oaks.

Legislators and other state officials have tried to change Florida's parks before by adding such things as golf courses, hotels, even a prison. But this goes beyond that, say park advocates.

"This is the biggest threat to the park system I've ever seen," said Jim Stevenson, a retired DEP employee who worked for the Florida park system for 24 years.

The change is the result of a concerted push by Gov. Rick Scott and the Legislature to convert the parks from pristine refuges that attract millions of visitors into a state land-management operation that benefits agriculture as much or more than the environment.

A pair of bills to make this experiment mandatory have been working their way through the House and Senate, even as the DEP is quietly testing the idea out with a proposed cattle lease at Myakka River State Park near Sarasota.

Former DEP employees say this effort to convert the parks into a moneymaking operation by adding agriculture or other uses goes against a policy that dates back to the start of the state park system in 1935.

"State parks in Florida have not been designed to make money," Florida's first state parks director, Lewis Scoggin, said in 1941. "They have been designed to give something to the people of Florida and to our guests that money cannot buy."

For decades, "Florida's lawmakers, governors and administrators understood that a state park was . . . for the perpetual preservation of unique portions of original, natural Florida," said Phillip A. Werndli, who recently retired as chief historian of the Florida Park Service. In fact, state law said the parks are supposed to "conserve these natural values for all time."

The parks do make money for Florida, though, because their natural beauty attracts so many visitors, both from within the state and around the globe. A DEP analysis last year found that about 27 million people visited the parks, generating an economic impact of $2.1 billion.

To Steverson, though, that's not enough. In March he told a Senate committee the parks cover only 77 percent of their expenses, and he wants to boost that to 100 percent.

Steverson told the senators he believes the park system can protect the environment "while still becoming self-sustaining. . . . We can do a lot to expand the utilization of this land to support other areas of the DEP mission."

Steverson said his goal is simple: "I want to maximize value for the taxpayers, but also for the environment."

That's also the goal of HB 7135 and SB 7086, bills that are rapidly nearing a final vote in the Legislature. Both call for state park management plans to include "preservation of low impact agriculture" among their mandated goals, and to find parks that could support low impact agriculture. The bills do not really define "low-impact agriculture" except to say it's the kind of farming or ranching that doesn't pollute too much or interfere with recreation in the park.

In some cases where ranching, timber or other forms of agriculture are adjacent to a park, the state should try to swap some public land with the owner in exchange for a promise not to develop the private land, the bills say.

The legislation is being driven by "a world view amongst folks involved in natural resources up here (in Tallahassee) for looking at how to maximize the use of the lands that we have," explained the House bill's sponsor, Rep. Matt Caldwell, R-Lehigh Acres. "You hear 'park' and you think about the 5 or 10 acres around the spaces that the park facilities are on. But we've got a lot of parks that are huge tracts of land."

Caldwell's House bill passed that chamber this week by 88 to 24 and was sent to the Senate for final action. Meanwhile the Senate bill, which includes some language limiting what agriculture can do in those state parks, has yet to pass its last committee.

DEP officials were not part of drafting the two bills and have taken no position on them, an agency spokeswoman said. She said that before making any changes to boost the parks' earning potential, the agency will invite public comment.

The test case for this new approach is one of the oldest and largest parks in the system, Myakka River State Park in Sarasota County.

The DEP has been putting together a request for cattle ranchers to bid on taking over 6,630 acres of the 37,000-acre park, which hasn't had any cattle in it since the state bought it in the 1930s. The proposed lease documents, which have not yet been released publicly, include a number of requirements to limit the impact from the cows' grazing and subsequent fecal output.

The taxpayers may not get any money for leasing all that public land to a rancher, though. The proposal calls for the rancher to build fences and do other chores for free in exchange for parking his or her herd on public property.

"The draft request for proposal has not finished an internal review, nor do we expect it to be issued anytime soon," DEP spokeswoman Lori Elliott said Friday. So that no-fee aspect may disappear, she said, just as the whole ranching lease might wind up being ditched as unworkable.

Jono Milller, a retired New College environmental studies teacher, is already rallying opposition to the Myakka lease. He pointed out that the state spent years at Myakka River turning what had been cattle pasture into a restored natural landscape — and now the state wants to undo that.

"It seems crazy to me," he said.

Contact Craig Pittman at craig@tampabay.com. Follow @craigtimes.