The Loudoun County Board of Supervisors has voted to require that builders plant or replace trees in new developments but has delayed action on a proposal to protect special trees on established properties.

The builder law was approved 6 to 1 on June 19, less than two weeks before a new state law would have limited the county's ability to require tree cover in new residential, commercial and industrial projects. Supervisor Steve W. Stockman (R-Broad Run) cast the dissenting vote.

Under the measure, subdivisions of single-family homes would not be approved on wooded sites unless plans called for preservation or replacement of at least 20 percent of the existing trees. In addition, each building lot would be required to have tree coverage of 2.5 percent or 3,000 square feet, whichever is less. Industrial developments would have to have 10 percent tree coverage.

The standards for "tree canopy" coverage apply to expected tree sizes 10 years after the homes are occupied. If Loudoun had waited until July to pass its measure, the new state law would have taken effect and the Loudoun ordinance would have applied to tree coverage expected 20 years after occupancy. "The county has a choice; it can always lighten the standards in the future," said Milt Herd, Loudoun's planning director.

The Loudoun law, similar to one enacted in Fairfax County, goes into effect immediately. But county officials said last week that there will be a grace period while implementation details are worked out.

Subdivisions built on treeless fields will be required to plant only 2.5 percent tree coverage under the Loudoun measure. That provision prompted County Board Chairman Betty W. Tatum (D-Guilford) to question the "equity" of the law's proposals last week. Tatum concluded, "We'll have to see how it works."

Stockman said he saw "a lot of problems" with the way the measure was drafted, noting that a builder could dig up trees the day after an occupancy permit is issued and plant them elsewhere. Also, Stockman said he did not want to rush the measure.

The board voted unanimously to delay action on two related ordinances, one concerning landscaping and buffering, the other regulating tree conservation. The latter has drawn fire from county residents concerned that trees on their land could be subject to legal controls without their permission.

Among the trees that would be affected are "heritage," "specimen" and "memorial" trees. Heritage trees are defined as those individually designated by the county as having "notable historic or cultural interest." Specimen trees are those officially designated as having "outstanding size and quality" for their species. Memorial trees are defined as trees planted by groups of citizens and formally recognized by the Board of Supervisors.

In a letter to the supervisors, Lucketts area resident John Whitmore, president of the landowner coalition Loudoun 20/20, said last week that the law on planting and replacement of subdivision trees is "a very reasonable document." But he criticized the proposal to protect special trees on existing properties as being vague and a possible intrusion on residents' rights.

"We believe that the landowner must be part of any nomination process and we believe that no nomination should go forward without the landowner's written permission," wrote Whitmore. "We do not want our property rights tied up by other people."

The county staff has said that it does not know how much it would cost to implement this measure. It estimated that the number of trees that would be nominated for protection would be in the hundreds.

The proposal now goes to the supervisors' Policy Legislative Committee.