With development bearing down on its fertile farms and verdant woods, Evesham Township began to aggressively amass open space seven years ago.

Since then, the Burlington County community has snapped up 3,300 acres for preservation, costing taxpayers more than $13 million.

Buying, it turns out, was the easy part.

That protected ground now must be maintained. The grass has to be cut, the weeds tamed. On 1,000 acres of ecologically sensitive Pinelands, police specially trained on all-terrain vehicles pursue young joyriders and trash dumpers.

All told, annual upkeep of the parcels is a painful $400,000 bite out of Evesham's $30 million budget.

"It's a big undertaking for local governments to go into the land business," said Township Manager Ed Sasdelli, griping that mowing just one 76-acre tract is a 10-hour task.

In town halls across the suburbs, conservation euphoria is giving way to the sober realization that open space can be a money pit.

"What did we get ourselves into?" is the increasingly common refrain among municipal officials, said John Granger, manager of Solebury Township in Bucks County.

The shopping spree leading up to that lament has been going on for 20 years. In that time, with their voters' blessings, communities in the region have issued upwards of $300 million in bonds and raised more than $109 million in new taxes for land preservation. They've bought at least 52,000 acres in Bucks, Burlington, Camden, Chester, Delaware, Gloucester and Montgomery Counties.

In their "race" against developers to acquire land, "the thought was, 'Let's get it and figure out what to do with it later,' " said Jeffrey Marshall, a vice president of the Heritage Conservancy, a nonprofit land trust based in Doylestown. "It's later."

It certainly is in Lower Makefield, Bucks County. The township bought the 235-acre Patterson farm a decade ago for $7.25 million - a deal in which "there was never a lot of thought given to what we [saw] as the future of this place," said Steve Santarsiero, a township supervisor.

On the farm are 16 structures, some dating to the 1700s and declared eligible for the National Register of Historic Places.

They're also falling apart, said Terry Fedorchak, the township manager. One farmhouse alone needs $400,000 worth of work - new roof, new windows, reinforcement of sagging floors and beams - to bring it up to code.

Meanwhile, even without a clear source of funding for renovations, a committee of preservationists and Lower Makefield residents is looking into ways the buildings could be used by the public.

Taxpayers in many communities are demanding utility from the land they've bought. They clamor for bike trails and dog parks. Soccer and baseball fields are big, too. In Evesham, recreation groups are pushing for a synthetic-turf playing field, estimated at $1 million, to be installed on a yet-to-be-picked parcel.

Of the open space it scooped up in the last 10 years, Warrington Township in Bucks County put almost 120 acres to a crowd-pleasing use by beefing up its park system to 302 acres. But the parks millage had to be tripled this year to pay for maintenance and five new staffers, including a parks director.

Typically, the costs of upkeep come from municipalities' general funds, as well as preservation grants from county and state programs. But as stewardship responsibilities build, future open-space bond issues might focus not on buying land but on caring for the acreage already accumulated.

That is how Evesham residents say they want to spend at least a portion of the $3 million remaining from a $10 million bond issue in the late 1990s, according to Sasdelli, the township manager.

For local governments counting on the state to chip in for "the care and feeding" of protected open space, the timing isn't great, said Judy Jengo, director of the GreenSpace Alliance in Philadelphia. As an arm of the nonprofit Pennsylvania Environmental Council, it tracks the amount of land protected in the Pennsylvania suburbs.

The demand for open-space grants "is always greater than the supply," Jengo said. But she warned that the situation could worsen due to the uncertain funding of major preservation programs in Pennsylvania and New Jersey.

In Harrisburg, debate is expected to resume next month over a Senate-backed plan to divert $40 million a year from the Keystone Recreation, Parks and Conservation Fund to a hazardous-sites cleanup program. The 14-year-old Keystone fund is the source of $86 million in grants each year to Pennsylvania land trusts and towns, largely for open-space projects.

In New Jersey, the Garden State Preservation Trust, which has supported open-space and farmland preservation for nearly 10 years, is virtually out of money. Voters will be asked in November to approve an emergency infusion of $200 million until a longer-term funding source can be found.

Some municipalities have found a way to ease the financial burden by forging partnerships. In Lower Makefield, for instance, a soccer league will pick up the bill to retrofit some open space with $800,000 worth of artificial turf, said supervisor Santarsiero, who also wants to tap local businesses for donations for other improvements.

But the most important step for any community is to think before buying, said Dulcie Flaharty, executive director of the Montgomery County Lands Trust. Just last year, the Lower Salford-based nonprofit instituted an annual workshop to offer advice.

"What type of open space you offer to your community," Flaharty said, "greatly affects . . . maintenance costs."

In Solebury Township, officials have managed to minimize those headaches by primarily purchasing only the development rights to land, rather than the ground itself. Under such so-called easements, maintenance remains the responsibility of the property owner. So while the township has protected 3,000 acres, only 100 acres have been bought outright, said Granger, the Solebury manager.

"If we did own [all that] land," he said, "I'm not sure how we'd maintain it."

In London Grove, a Chester County community just beginning to venture into open-space preservation, Township Manager Steven Brown said one thing is certain: "Mostly easements is the way we are going to go."

Though they fret over the added cost of open space, most local officials say it's cheaper than the alternative.

Homes generate taxes, said Sasdelli, but they also are a source of trash, traffic and schoolchildren, whose "impact on the municipal budget would be tenfold."

To view a new Web site on open-space priorities by the Delaware Valley Regional Planning Commission and the GreenSpace Alliance, go to http://go.philly.com/greenspaceEndText