According to New Hampshire State Police, Terry Pickard, 34, was a passenger in a 2009 Toyota Corolla being driven by Lynn Pickard, 30, also of Winchester.
Police said Lynn Pickard was driving south on Fullam Pond Road, lost control of the car just after 10 p.m., and crashed into the tree.
Terry Pickard died as a result of injuries sustained in the collision. Lynn Pickard was seriously injured and taken to Dartmouth-Hitchcock Medical Center in Lebanon for treatment.
State and Winchester police were assisted at the scene by members of the state police Technical Accident Reconstruction Unit and the Winchester Fire Department.
The investigation into the crash is ongoing. Anyone who witnessed it or has information about it is asked to call Trooper Thomas Byrne of Troop C in Keene at 358-3333.