My sisters son-in-law just torn down an old barn near Anacortes Washington and found that it was made of black walnut...apparently not unusual for that region...
Barn wood and stock yard railings bring big bucks, especially with interior descrators...
Rail boards that have been cribbed (chewed) or constantly rubbed by cows and/or horses have a character thats hard to duplicate
Wouldn't be suprised if the structural timbers were made of solid white oak...
Old barns are a gold mine...seen some that have been taken apart, each piece numbered, then transported hundreds if not thousands of miles, then rebuilt...