The fire started at about 2:25 a.m. in the rear of a one-story home at 3847 Pinewood Terrace. Six persons escaped uninjured, but firefighters were unsuccessful in their attempts to revive three other persons found inside the home.
Claudio G. Melgar, 45, and his two children, Claudio A. Melgar, 25, and Beatriz Melgar, 14, were pronounced dead at the scene.
Fairfax County fire department spokesman Daniel Schmidt said the tree, which had a number of extension cords attached to it, had been in the home for six weeks and had not been watered for some time.
"The cause of the fire was accidental," Mr. Schmidt said. "The tree was the fuel. The electrical point was the ignitable source."
Mr. Schmidt said firefighters had been called to the home twice before in the past seven years - including two months ago for a candle fire. He said there was no working smoke detector in the house then, but a smoke detector did go off yesterday in the basement.
Regional authorities say an increase in the number of fires are typical in winter and especially during the holidays, but they say this year's fires have been particularly severe.
"It certainly seems that way," said Pete Piringer, a spokesman for the Montgomery County Fire and Rescue Service. "We've had larger fires, more-serious fires."
A spate of fires in the county this month have claimed three lives and caused more than $4 million in property damage.
On Dec. 21, an unattended candle in the dining room of a house on Calgary Avenue in Kensington resulted in a fire that killed Carol Parker, 57.
Separate kitchen fires claimed the other two lives.
Sally Spielman, 80, died after a Dec. 2 fire in her home at 8519 Freyman Drive in Chevy Chase. James Dunbar, 89, died after a Dec. 13 fire in his town house in the 18100 block of Rolling Meadow Way in Olney.
Through November, the county had recorded only two fire deaths, Mr. Piringer said.
Prince George's County fire department spokesman Mark Brady said fire activity has been "normal for the holiday season." He said there have been no fire deaths and no fires that caused more than $100,000 in damage associated with Christmas trees, decorations or candles. Officials in the District, Alexandria and Arlington County said the same.
Mr. Brady said winter months are particularly dangerous because of fires that start with heating systems or electrical components.
"Overall, our activity has been the same, if not a little bit slower due to the mild weather," he said.
Apartment fires in Lanham and Marlow Heights on Dec. 22 displaced 22 families just days before Christmas. Investigators said an electrical problem sparked the Lanham fire, and children playing with matches were responsible for the Marlow Heights fire. The two fires resulted in $150,000 in damage.
Mr. Brady said an unattended candle triggered a fire at the Adelphi home of Takoma Park Volunteer Deputy Chief Mark Prince. The fire resulted in $20,000 in damage and left the home uninhabitable.
According to the National Fire Protection Agency, Christmas Day has the highest number of reported candle fires of any day of the year. New Year's Day ranks second.
Fire officials warned people never to light candles near ignitable objects and never to leave unattended candles burning, especially if pets or small children are in the house.
Officials also said people should continue to water their Christmas trees so they don't become dry and brittle and promptly discard trees when they do.
