The National Wildlife Federation threatened yesterday to move its $3 million conservation education center out of Fairfax County because county supervisors have refused to recommend to the state legislature that the organization be given tax exempt status.

It the center leaves Fairfax, federation officials said, the county will lose 300 jobs, an annual payroll of $2.3 million and a nature trail and exhibit hall that attracted more than 12,000 visitors last year.

Board Chairman John F. Herrity said he would hate to see the organization leave Fairfax County. However, he said he doesn't think the nonprofit educational and scientific organization "deserves a tax break. There's no reason why these people (the wildlife federation) shouldn't pay taxes."

The wildlife federation is exempt from taxation by the federal government and the state of Maryland because it is considered a charitable organization, according to federal and maryland tax officials. It is exempted from sales and personal property taxes in the District, but must pay real estate taxes, an official said.

Tax exempt organizations in Virginia are determined by the Virginia General Assembly usually after recommendations from local jurisdictions.

Wildlife federation officials are considering moving to Loudoun County or Montgomery County, Md., where they already own land or to several Southern states, where they hope to receive favorable tax consideration.

Herrity said the county doesn't receive any taxes from the $2.3 million payroll and since the organization is talking about moving to nearby Loudoun or Montgomery counties, no jobs would be lost.