A Loudoun County planning commissioner announced yesterday that he would run as an independent for chairman of the Board of Supervisors on a "smart growth" platform -- as long as the incumbent bows out of the contest.

Alfred P. Van Huyck, a retiree with a background in urban planning, said at a news conference that he wants to challenge Republican nominee Scott K. York, a slow-growth advocate, as a way to spark detailed debate about how to limit development.

Van Huyck said he would not run if Chairman Dale Polen Myers (R-At Large) joins the race as an independent, which she said she would do after losing last Saturday's GOP primary to York, the county supervisor from Sterling. Van Huyck said that another four years of Myers would be bad for the county and that he did not want to risk splitting the slow-growth vote with York.

"Dale's entry into the race is a huge complicating factor," said Van Huyck, 66, a millionaire who ran an unsuccessful campaign for board chairman in 1991. "A three-way race gives her the chance to go back to the developers and get refunded. . . . I can't take the chance that she could actually split the vote."

Myers lost the nomination to York by a nearly 3-to-1 ratio, despite thousands of dollars in campaign donations from developers. The outcome was seen by political analysts as sending a clear message that county residents are furious with the frenetic growth that is bringing Loudoun 1,000 new residents a month. York's victory has prompted other candidates in Northern Virginia to address growth issues.

Myers was away yesterday and could not be reached. A Myers campaign adviser, Richard McCary, said she was unlikely to change her plans to run. Myers said on Tuesday that she would file papers to run by the deadline -- June 8 -- but left open the possibility that she would get out of the race before the November election if she failed to get enough support.

Tom Berezoski, the chairman of the Loudoun Republican Committee, and five previous chairmen issued a statement yesterday urging Myers to "accept the voters' decision" and drop plans to run as an independent.

Van Huyck expressed mixed opinions of York. Van Huyck donated money to York's campaign but said his slow-growth platform was shallow.

Van Huyck took issue with York's contention that luring big technology firms might spark too much growth. Van Huyck said revenue from those companies was needed to pay for a "smart growth" agenda. Van Huyck said his background in planning -- a master's degree and professional experience -- means he is better suited than York for the chairman's job.

York disputed Van Huyck's criticisms and said bringing in big technology business is not always a good thing. A rapid increase in the number of corporate employees with children could increase the demands on schools, he said.

York, a home improvement contractor, said that there was more to the job than planning and that it was "a little ludicrous" of Van Huyck to say his background was better suited to the office.

Also yesterday, Loudoun Democrats announced the cancellation of their June 3 caucus because they have no nomination contests in a county where Republicans hold the vast majority of elected offices.

CAPTION: Alfred P. Van Huyck talks to reporters at a news conference. Huyck wants to run as an independent for chairman of the Loudoun County Board of Supervisors. (Photo ran in an earlier edition)