Psuedostuga menziesii (Mayr.)

by Cara Meeker, Native Plants Class 2002
Common Names: Douglas fir (also referred to as Oregon Pine, Douglas Spruce, red fir, yellow fir, false spruce)
Family: Pinaceae
Synonomy: Was once called Psuedostuga taxifolia (4).
Etymology: "Psuedo" = false, "tsuga" = hemlock, but this species is neither a true fir nor a hemlock. The epithet menziesii refers to the man Menzies, the first to taxonomically identify the species (1,3).

Identification
Growth Form: Douglas fir is a tall, conical, evergreen tree, growing up to 300 feet in the Northwestern area of its range, but averages 100-130 feet in the southwest (1,2).
Roots:
Stem: The gray bark is thick and deeply furrowed, increasingly so as the tree ages. The bark can also appear dark and reddish, but is predominantly gray in color (2,3).
Leaves: Douglas fir bear single narrow needles, not bound in fassicles. They are bluish-green in color, flat and soft in texture. They are approximately 1 1/8 inch long and protrude from all directions of the branch (2,3).
Inflorescences/flowers: None.
Fruit: Reddish-brown in color, the cones are approximately 3 inches long and fairly papery. The bracts extend past the scales of the cones and have a characteristic shape. The bracts are often called "mouse tails" or "squirrel tails" because of their distinctive three-pointed shape, which is unique to this species (1).
Similar Species: There are two variations of this species: Psuedotsuga menziesii var. glauca (Rocky Mountain Douglas fir), and Psuedotsuga menziesii var. menziesii (coastal Douglas fir) (5).

Ecology
Life History: This species is a long-lived perennial
Native/Introduced: Native.
Photosynthetic Pathway: C3.
Phenology: This tree pollinates in the spring, as well as produces winged seeds, both of which are wind-dispersed. The pollen cones are developed every year, though seed batches are produced only every 2-11 years. Reproductive age is reached at around 12-15 years (5).
Distribution: Douglas fir is found from 5000-10000 ft in elevation, from British Columbia to western Texas, Arizona, California, and Northern Mexico (4).

Uses
Commercial: Douglas fir is used as lumber and as Christmas trees (1).
Wildlife: Douglas fir is associated with dwarf mistletoe, which creates habitat for animals, including the endangered spotted owl (3). The bracts and seeds are also a food source for wildlife.

References
1. Elmore, F.H. 1976. Shrubs and Trees of the Southwest Uplands. Southwest Parks and Monuments Association. Tucson, Arizona, USA.

2. Epple, A.O.1995. A Field Guide to the Plants of Arizona. The Globe Pequot Press. Connecticut, USA.

3. Hogan, P., Huisinga, K. 1999. An Annotated Catalog of the Native and Naturalized Flora of Arizona. Arizona Ethnobotanical Research Association. AZ, USA.

4. Kearney, T.H., Peebles, R.H. 1960. Arizona Flora. University of California Press, Berkeley. California, USA.

5. USDA Forest Service. Web-based plant database. www.fs.fed.us/database/feis/plants/tree/junsco