BETULACEAE 



Red Alder 

 Alnus rubra Bong. 



HABIT. A medium-sized tree 80-100 feet high and 1-3 feet 

 in diameter (max. 130 by 5 feet); clear trunk; crown narrow 

 and rounded with pendulous branches. 



LEAVES. Ovate to elliptic; 3-6 inches long and \V2-3 inches 

 wide; obtuse or rounded at base; apex acute; margins slightly 

 crenately lobed with doubly dentate gland-tipped teeth; thick 

 and firm; dark green and glabrate above, paler and rusty- 

 pubescent below; petiole orange, round, grooved, 34-% inch 

 long. 



FLOWERS. Preformed; the staminate aments 1^4 inches 

 long, becoming 4-6 inches long, orange; opening in early spring, 

 J/^-V^ inch long with dark red scales and bright red style. 



FRUIT. Strobiles Vz-^Va inches long; woody; persistent; 

 ovoid to oblong; on orange peduncles or rarely sessile; truncate 

 scales with much thickened, rugose tips;; nutlet nearly circular 

 with encircling membranous wing or 2 lateral wings. 



TWIGS. Slender to rather stout; light green and tomcntose 

 at first, becoming bright red and lustrous during second year. 

 Winter buds: lateral ^3-% inch long, stalked, dark red, with 

 pale, scurfy pubescence. 



BARK. Thin; smooth; nearly white to blue-gray outer bark 

 and bright red-brown inner bark; sometimes roughened by 

 small, warty excrescences; breaking into large, flat plates on 

 old trees. 



WOOD. Important (probably the most important hard- 

 wood on the Pacific Coast); light; soft; with prominent rays; 

 used for furniture, veneer, and novelties. 



SILVICAL CHARACTERS. Intermediate in tolerance; 

 rapid growth; short-lived, maturity being reached in 60-90 

 years; lateral roots; aggressive reproduction, often taking over 

 burned or logged areas; on varied sites, but typical of stream 

 banks; in pure or mixed stands. 



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