J.E. Jones Jr. doesn't blink when developers wave money for the rolling farmland and thick woods his family owns near Montpelier.

For years, he has tossed out their solicitation fliers with the rest of the junk mail.

But Jones, who runs the lumber company his father and uncle started around the Great Depression, knows development is creeping up Mountain Road from western Henrico County into rural western Hanover County.

"There are economic forces that look like they're coming this way."

Like many landowners across the state, Jones and his family have enrolled much of their property in a tax-relief program called land use.

Since the early 1970s, Virginia has given localities the authority to initiate such programs as a way to help farmers hold onto their land and to preserve open space. About 85 localities, including the counties around Richmond, now offer the relief.

Jones, the 67-year-old president of J.E. Jones Lumber Co., said the lower taxes help his family resist the overtures of developers and land speculators.

But two professors at Virginia Commonwealth University don't believe the program is meeting its goals. They've found it doesn't preserve open space or delay development.

"This is not the open-space panacea, for sure," said Dr. Jerry T. Ferguson, a VCU professor of real estate.

The loss of open space is a big concern of Richmond-area residents, according to a Times-Dispatch poll conducted this past summer.

Sixty-two percent of respondents considered the loss of fields, farms and forests to development a concern to some degree. Twenty-eight percent labeled it "very seri ous," while 34 percent called it "somewhat serious." Thirty-eight percent said the loss of open space was "not at all serious."

Land use allows taxes to be paid on a property's "use value," not its market value, which is the most probable selling price. The use value of land is determined by local assessors and is based on the money that could be earned if the predominant crop from that locality was grown.

In exchange for the tax benefits, owners may not develop or rezone their land without paying five years of roll-back taxes, plus interest, on the value that had been deferred.

In calendar 1998 and fiscal 1998-99, about $96.5 million in real estate taxes was deferred across Virginia because of programs taxing property by their use, rather than their market value, according to the state Department of Taxation. The total taxable value of property, excluding buildings, was 7 percent, or $9.2 billion, less than the fair market value.

Jones, who runs the lumber company in Montpelier, estimates his family owns 4,000 to 5,000 acres in Hanover, Caroline, Louisa and Spotsylvania counties, and nearly all of it is in land use. Without the program, the family would have to sell some of its property to pay taxes on the rest, he said.

Jones said farming businesses like his keep Hanover's growth pressures at bay because the businesses don't require many expensive services, such as schools and parks.

"It's like everything. You're either part of the problem or part of the solution," Jones said. "This, I believe, is part of the solution."

Ferguson, of VCU, agrees farmers should get tax breaks because they're often land-rich and cash-poor. But, he added, the public needs to recognize that land use isn't preserving open space.

Ferguson and Dr. Michael A. Spinelli, an associate professor of management science at VCU, tried to measure the effectiveness of land use by studying development in the counties of Fauquier, Loudoun and Prince William and the city of Virginia Beach.

The professors looked at the rate of farmland conversion before and after those localities adopted land-use programs in the early 1970s, just as they were beginning to develop.

The professors found no correlation between the start of land use and a lower rate of conversion. Actually, they found development was happening just as fast or faster. Their findings were published in a 1998 article in Assessment Journal, a trade publication for academics and professionals interested in property tax policy.

Spinelli said no one knows what would happen if land use were eliminated in Virginia because no locality has dropped its program. "It seems to be entrenched."

Ferguson said Virginia needs to look for other ways to preserve open space. So far, few localities have done much on their own. Two exceptions are Virginia Beach and Albemarle County, which have programs to buy development rights from landowners.

Richard L. Wood, Albemarle's deputy assessor, agreed with the professors' findings but said land use still has value. He suggested that state officials take a closer look.

"Any program you have that's getting on 30 years old probably should be revisited to see if it's doing what it's supposed to be doing."

The Virginia Farm Bureau believes land use deters development in growing areas because the roll-back penalties can be stiff, said Mandi Smith, a spokeswoman. She agreed that Virginia should pursue other, more permanent ways to preserve open space.

"Land-use assessment has to be one of the tools in the toolbox."

The future of the J.E. Jones Lumber Co. will be determined largely by Jones' 29-year-old son, John. One recent afternoon, he climbed from a loader truck and rested on a log, not far from the sawmill he oversees.

John Jones didn't want to make predictions but said he can envision a time when common sense would have the family sell some of its land, take a portion of the profits and buy even more property farther out.

That decision shouldn't be made lightly, he added, because development would end a tradition of growing and harvesting trees every 25 to 40 years.

"One or two trees lasts you about a minute at the mill."