Adirondack

From MartinGuitarWiki

The term Adirondack is used by Martin (and other guitar builders) to refer to Red Spruce (Picea rubens) that is used for guitar tops. So called Adirondack was used almost exclusively by Martin until 1945 when they switched to Sitka Spruce. The switch was probably made due to over-harvesting of Red Spruce, and because Sitka was available in larger trees, making it cheaper to source.

There are noticeable audible differences between Sitka and Adirondack topped guitars; see Top Woods.

It’s unclear why the name Adirondack was used in place of Red Spruce as Red Spruce is not limited to the Adirondacks, and other spruces come from that region (white and black.) On the other hand, Red Spruce may be confusing to buyers because it is not red in color (the name comes from the color of the cones and bark) and the name might be confused with Red Cedar.

See: Red Spruce