FOOTNOTE
[87] Professor Frank Soulé, University of California. Trans. Am. Inst. M. E., p. 552, Vol. XXIX.
FIR. (Abies.)
Several of the fir-trees of the western United States attain to very great size. The silver fir (Abies grandis) and the white fir (Abies concolor) supply much wood in the section in which they grow. The balsam fir (Abies balsamea) of the Eastern States is of some commercial importance.
Balsam Fir (Abies balsamea).
Fir wood resembles spruce in appearance and in structural qualities. It may be told from spruce as well as from pine and larch by the fact that fir has no resin-ducts. The balsam fir is distinguishable by clear liquid resin which appears in blisters in the bark. The coarse, weak wood is cleaner than the bark would indicate. Spruce and fir woods are often confused in the United States, while pine, spruce, and fir are similarly confounded in Europe.
Fir trees have flat, scattered, evergreen leaves, and cones that stand erect (see footnote under spruce). [p157]