The Christmas tree that lights up Washington, D.C., can’t be just any Charlie Brown tangle of sparse needles and frail limbs. Every year since 1964, a commanding tree has lit up the west lawn of the U.S. Capitol. This year, it’s Colorado’s turn to send one of its prized Engelmann spruces east to be the People’s Tree. A team from White River National Forest narrowed down the choices to 12 before the superintendent of Capitol grounds handpicked the winner. We break down the tradition.