Wednesday, October 6, 2010

Pseudotsuga menziesii - Douglas Fir

Pseudotsuga menziesii: Pseudotsuga, meaning false hemlock -- 'tsuga' is the Japanese name for hemlock; menziesii, named for Archibald Menzies, a Scottish surgeon and naturalist.

Native to the northwestern U.S. from northern California to Alaska east to the Rocky Mountains at 2,000-4,000' elevation.

Broadly pyramidal in youth, with lower branches horizontal or slightly drooping an dhigher branches ascending openly, older trees becoming more rounded with an irregular loose form. Growth rate fast to 80-160' tall and 20-30' wide in cultivation and up to 250' tall in habitat.

Needles are soft, dark green, new growth light green, 3/4 to 1 1/2" long, flattish, densely set, with a slightly grooved upperside, blunt to dull pointed ends and a distinctive fragrance, persisting 6-8 years. Twigs are orange to brown with shiny, brown, long-pointed buds.

Cones are thin, reddish brown, 2-4" long by 1 to 1/2" wide, narrowly ovate with tri-tipped, pointed bracts extending among and beyond the broad, thin scales, hanging from branch ends, ripening and opening in teh fall of the first season. Seeds are dull brown, 1/4" long with a 5/8" long wing.

P. menziesii cones are about half the size of P. macrocarpa (top), but the bracts are about the same length.

Bark is thin, smooth, grayish brown, becoming thicker, dark brown and roughly furrowed wtih heavy ridges interconnected by narrow cross-ridges.

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