Fir wood

 Balsam fir is a popular Christmas tree species, and it’s closely related to the perennial favorite Fraser fir (Abies fraseri)—a smaller tree not used commercially for timber. Resin from the tree is used to make Canada balsam. Once purified, the resin has very good optical qualities, and was used as an adhesive in bonding optical elements and lenses up until the 1940s, when it was replaced by synthetic resins.

Commercial fir lumber is divided into eastern and western groupings, with six primary species in the western United States, leaving balsam fir as the sole commercial species in eastern North America.

Many species of fir have excellent stiffness-to-weight ratios, rivaling other softwood species such as Sitka spruce (Picea sitchensis)—another softwood species known to luthiers for its combination of low density and relatively high modulus of elasticity).