The requirement would not apply to homeowners, said Ken Silva, Honolulu Fire Department assistant chief in supportive services. The Maui and Kaua'i fire departments are not adopting the requirement, Silva said.

In the Uniform Fire Code, combustible decorations fall under a general category of concern and Christmas trees are not mentioned specifically, but the Honolulu Fire Department has decided to play it safe and adopt the new requirement, he said.

"We want to make sure we have a fire-safe holiday," Silva said.

The adoption was based on an opinion by the national Uniform Fire Code Association, which among other things interprets the fire code for fire departments across the country, he said.

"The general requirement was put into place mostly for curtains and that's a no-brainer for us," Silva said. "But when people put other things up we want to make sure that it's safe."

HFD adopted the 1997 fire code but didn't adopt appendices that came with it, including a section on Christmas trees, he said. This opinion covers the issue that has been under discussions with other fire departments that have also adopted the Christmas tree opinion.

Random calls to hotels, hospitals, stores and schools revealed that hotels such as the Halekulani that use real trees have them treated by the supplier, as does The Queen's Medical Center. Ala Moana Center and Castle Medical Center use artificial trees.

In schools, parents often donate trees to their children's classroom, but the Department of Education said it has not received an official letter outlining the requirement. The fire department called the DOE's safety section but Greg Knudsen, DOE spokesman, said he can't comment until he sees the official notice.

"Our schools are very aware of safety precautions and there's no record of negligence in those areas," Knudsen said.

Elton Hara, general manager of Koolau Farmers garden shop in Kane'ohe, said his trees are not pretreated and he won't be carrying any flame retardant this year. But Lowe's Home Improvement Warehouse said it will carry the flame retardants and have them available this week when its trees arrive.

Hara said he remembers another time when the city tried to get the public to treat their Christmas trees, many years ago. Retailers brought in products but no one purchased them, he said.

During the same period, Hara said, he also remembers watching a demonstration of a particular flame retardant product that failed.

"The tree just went up in flames," Hara said. "Maybe now they have better products."

Anyone caught violating the requirement will be issued a citation and required to correct the hazard, Silva said.