Sitka Spruce is the preferred spruce used for aircraft though that is primarily because a lot of testing for aircraft use was done back before WWII when it was cheap and plentiful. Those beams may well be sitka spruce and quite possibly a Luthier (wooden bodied sringed instrument maker) would be interested as spruce is used for the front (srigned) face of violins and such, as well as in guitars.
The "Spruce Goose" was mostly made of birch plywood, BTW.