PHYSICAL QUALITIES: Weight, light (47th in this list); 28 lbs. per cu. ft.; sp. gr., 0.4584; medium strong (41st in this list); elastic (21st in this list); soft (54th in this list); shrinkage, 3 per cent.; warps little; not durable; easy to plane, tolerably easy to saw, hard to chisel neatly; splits easily in nailing. COMMON USES: Sounding boards, construction, paper pulp, ladders. REMARKS: The exudations from this species are used as chewing gum. Bark of twigs is used in the domestic manufacture of beer. The use of the wood for sounding boards is due to its resonance, and for ladders to its strength and lightness. [Illustration: Radial Section, life size.] [Illustration: Cross-section, magnified 37-1/2 diameters.] [Illustration: Tangential Section, life size.] [Footnote A: Not distinguished in the Jesup collection from _Picea nigra_.] 14 BLACK SPRUCE.[A] _Picea mariana_ (Miller) B. S. P. _Picea nigra_ Link. _Picea_, the classical Latin name for the pitch pine; _mariana_ named for Queen Mary; black and _nigra_ refer to dark foliage. [Illustration: Habitat.] HABITAT: (See map); best in Canada. [Illustration: Leaf.] CHARACTERISTICS OF THE TREE: Height, 50'-80' and even 100'; diameter, 6"-1' even 2'; branches, whorled, pendulous with upward curve; bark, gray, loosely attached flakes; leaves, pale blue-green, spirally set, pointing in all directions; cones, small, ovate-oblong, persistent for many years. APPEARANCE OF WOOD: Color, pale, reddish, sap-wood, thin, white, not very distinct; non-porous; rings, summer wood, small thin cells; grain, straight; rays, few, conspicuous; resin ducts, few and minute. PHYSICAL QUALITIES: Weight, light (47th in this list); 33 lbs. per cu. ft.; sp. gr., 0.4584; medium strong (41st in this list); elastic (21st in this list); soft (54th in this list); shrinkage, 3 per cent.; warps little; not durable; easy to work; splits easily in nailing. COMMON USES: Sounding boards, lumber in Manitoba. REMARKS: Not distinguished from Red Spruce commercially. [Illustration: Radial Section, life size.] [Illustration: Cross-section, magnified 37-1/2 diameters.] [Illustration: Tangential Section, life size.] [Footnote A: Not distinguished in Jesup Collection from _Picea rubens_.] 15 WHITE SPRUCE. ENGELMANN'S SPRUCE. _Picea engelmanni_ (Parry) Engelmann. Named for George Engelmann, an American botanist. [Illustration: Habitat.] HABITAT: (See map); grows at very high elevations, forming forest at 8,000'-10,000'; best in British Columbia. [Illustration: Leaf.] CHARACTERISTICS OF THE TREE: Height, 75'-100', even 150'; diameter, 2'-3', even 5'; branches whorled, spreading; bark, deeply furrowed, red-brown to purplish brown, thin, large, loose scales; leaves, blue-green, point in all directions; cones, 2" long, oblong, cylindrical.