Me and momma had lunch once at the Milestones restaurant in Sudbury, Ontario. If I remember correctly it was them that had tables made from huge wooden timbers that had been used to regulate a dam. The water wore the soft grain of the wood more than the hard grains, and left incredibly deep grooves in the surface. Beautiful.
Anyway, just came across this video, which shows how fire can age the wood in the same fashion.
15:28 burning wood with mapp gas
16:10 brushing off char with brass brush
25:42 final wood finish.
Enjoy.