A land trust in Washtenaw County has concluded that maintaining agricultural and other open space lands substantially reduces long-term government expenses, and moderates property taxes.

Graduate students at the University of Michigan School of Natural Resources and Environment spent last summer conducting research in Washtenaw County's Scio Township, just west of Ann Arbor. Their report, published by the Potawatomi Land Trust, found that the cost of providing services to residential properties cost $1.40 for every dollar in tax revenues those properties contributed. In contrast, farm land cost just 62 cents for every dollar raised, and commercial land cost 26 cents.

The study's results are serving as a basis for citizens to call for the establishment and funding of a purchase of development rights program focusing on the area's most productive farmland. The program would be funded by a small property tax increase.

Under such a program, farmers receive payments equal to the difference between the land's value for agriculture and its value for residential development. In return, an easement is placed on the land to keep it from being developed.

Peninsula Township, north of Traverse City, established Michigan's first such program for the purchase of development rights in 1994.

"It's pay a little now or pay a lot later," said Barry Lonik, executive director of the Potawatomi Land Trust. "Purchasing development rights is a one-time tax increase. Building new roads, new schools, and new sewers results in much higher taxes that rise year after year."

For instance, Mr. Lonik said, citizens in the Dexter Community School District, which covers about half of the study area, spent more than $26 million just three years ago to build and outfit new schools, which already are at capacity for the year 2000. Taxpayers now are facing another bond measure to build more schools. Paying for development rights would have resulted in a short-term tax increase that would never have to be renewed, Mr. Lonik said.

The study was supported by a grant from the C.S. Mott Foundation and the Michigan Environmental Council.u

Potawatomi Land Trust, P.O. Box 130122, Ann Arbor, MI 48113-0122, Tel. 313-449-7229.