An Edgewater, Md., man, accused of felony murder in the death of a 22-year-old Navy medic after an attempted Christmas tree theft last year, pleaded guilty yesterday in Montgomery County Circuit Court to lesser charges, including manslaughter by automobile.

Under a plea bargain, John Alan Parater, 29, of 112 Brice Dr., will serve no more than three years and nine months for the death last Dec. 20 of James Joseph Phillips of Oregon City, Ore.

Parater pleaded guilty to manslaughter by automobile, theft, driving with a ficticious license while his own license was revoked -- charges that carry a combined maximum sentence of 8 1/2 years and a $500 fine -- and prosecutors dropped charges of felony murder and robbery.

"The problem is the tree was already loaded onto the truck before the confrontation occurred, and that technically makes it a theft [a misdemeanor] instead of a robbery," said Robert Dean, assistant state's attorney. To prove felony murder under Maryland law, a prosecutor must show that death occured as the result of commission of a felony such as robbery.

Phillips, assigned to Bethesda Naval Hospital and scheduled to be discharged from the Navy early this year, died instantly when a speeding pickup truck driven by Parater collided head-on with his Toyota.

Police said that at 1:10 a.m. on Dec. 20, Parater drove his pickup onto a Christmas tree lot at 16126 Columbia Pike in Burtonsville and began to load a tree onto the truck. Lot owner Fathollah Azari and Parater argued, police said, then Parater tried to hit Azari with his truck. The lot owner pulled a gun and fired several warning shots, police said.

They said Parater then fled north in a southbound lane of Rte. 29, colliding head-on with Phillips' car.