Red tulips, lunching office workers and springtime tourists all were out in Lafayette Park yesterday, but anybody who had a camera was photographing protest signs.

"I'm going to take a couple of pictures, because this may be history . . . we may never see this again," said Don Heilemann, a National Park Service spokesman, who trained his camera on the collection of large plywood signs and assorted protest messages that line the southern edge of the park directly across from the White House.

The billboard-type structures, most of which admonish the president and the rest of the world to dismantle nuclear weapons, are expected to be removed this morning under federal regulations that take effect today and restrict the size and number of protest signs allowed in the park.

The Park Service has given written notices of the protest guidelines to the handful of longtime park demonstrators, warning that they can be arrested if their signs do not conform to the new display limitations.

"The regulations are enforceable, and the regulations will be enforced," Park Service spokeswoman Sandra Alley said yesterday.

Violators risk fines of up to $500 or up to six months in jail or both.

Alley's enthusiasm for what officials have described as the impending "cleanup" of Lafayette Park was not shared by at least one perennial protester.

"Lafayette Park is going to be precisely the same as Red Square, because you can't demonstrate there either," said William Thomas, 39, who has spent the last five years in the park or in front of the White House campaigning against nuclear weapons.

Under the new guidelines, signs placed or set down in the park must be no larger than four feet in either dimension, no thicker than a quarter of an inch, and may not be raised more than six feet from the ground.

No protester may have more than two such signs in the park at any one time, and demonstrators must remain within three feet of their signs or the signs will be considered abandoned property and be removed.

Hand-carried signs are exempted from the restrictions and protest groups, depending upon their size, will be allowed to set up temporary speaker or "soapbox" platforms for rallies.

The removal of the large protest signs, however, is not expected to silence a controversy that has raged since the Park Service proposed the new regulations last August.

According to Park Service officials, the issue has generated more mail than any other Park Service matter in recent memory, pitting concerns about free speech against concerns about scenic beauty.

Opponents of the restrictions contend that the demonstrators are exercising their constitutional right of free speech and that the park, once an apple orchard and soldiers' encampment, is the best place to catch the attention of policy makers and the public.

Proponents of the regulations argue that the protesters have turned the picture-postcard beauty of the historic park into an eyesore that obstructs the view of the White House.

One office worker, stretched out on the grass yesterday with his tie loosened and white shirt risking green stains, seemed oblivious to the great park debate. But others enjoying an outdoor respite had no trouble taking sides.

"I come here every day, and I think they're an eyesore," Debbie Watson, who works for a law firm and takes lunch and the sun in the park regularly, said of the signs. Dressed in shorts and strapless top yesterday, she worked on her tan while facing away from the protest signs.

Not far away, a man and a woman who declined to give their names expressed guarded support for the protesters.

"I think the signs are sort of interesting to look at," the man said. His friend called them "ugly," but added: "If you want to get a message to the president, this is the best place for it."

There were more than 30 signs in the park yesterday that did not conform to the new regulations. Park Service officials said that if they are there today, trucks will haul them away for probable storage in the service's property facility, where their owners can claim them.

Alley said that fewer than five protest permits, which are granted on a week-to-week basis, are being exercised by demonstrators and that none will be revoked under the regulations.

Only the circumstances of the demonstrators' protests, "not their right to be here," have changed, Alley said.

Thomas complained that the new regulations are just the latest government restrictions on demonstrations that began when officials banned protesters from the sidewalk in front of the White House, citing security concerns. At that time, Thomas said, Lafayette Park was presented as an alternative site for protests.