Pseudotsuga menziesii is a cone-bearing or coniferous tree. There are two varieties or subspecies of Douglas fir in British Columbia — one is found on the coast, while the other is found in the interior (Pojar & MacKinnon 1994).
Description:
P. menziesii is one of the tallest tree species in our temperate forests, growing straight and reaching up to 100 m in height (MFLNRO n.d.(a)). Once established, the Douglas fir trees grow faster than most other trees in the area. Branches radiate from the top of the tree trunk, with older lower branches being longer and drooping down. Together with the flat needle-shaped leaves they create a canopy that shade plants in the understory all year round. Seed cones and the small male pollen cones grow in clusters at the tips of branches. The persistent female seed cones are larger, 5 to 10 cm long and have scales with distinctive three forked bracts (Klinkenberg 2017, Pojar & MacKinnon 1994). The trunks of mature trees have a thick rough bark that insulates the tree from ground fires. Douglas fir trees can live for a thousand years (Pojar & MacKinnon 1994).
Ecology:
Douglas fir is native to western North America and is distributed along the coast of British Columbia and south to California. It grows at all elevations from coastal lowlands to the treeline of coastal mountains. Within this range, the Douglas fir is able to tolerate a wide range of temperature and moisture conditions (MFLNRO n.d.(a)). The seedlings are intolerant of deep shade and do not survive in areas with a dense understory of other plant species. They typically establish in areas that have been disturbed either as a result of forest fires or logging.
Douglas fir branches provide perching and nesting sites for many birds and rodents. The cones provide an abundant source of seeds that also serve as food for many animals (MFLNRO n.d.(b)). For example, the Douglas squirrel will collect, eat and store some seeds in caches as a supply of food for the winter. The Douglas fir tree is of primary importance to the BC timber industry. The large, tall, fast growing trees yield quality lumber that is a renewable resource.
Douglas fir branches provide perching and nesting sites for many birds and rodents. The cones provide an abundant source of seeds that also serve as food for many animals (MFLNRO n.d.(b)). For example, the Douglas squirrel will collect, eat and store some seeds in caches as a supply of food for the winter. The Douglas fir tree is of primary importance to the BC timber industry. The large, tall, fast growing trees yield quality lumber that is a renewable resource.
Reproduction and Dispersal:
When the trees reach 20 to 30 years of age, they begin to produce seed cones in the spring. Initially the green female cones are receptive to pollen. Following pollination, the seeds develop inside and during the summer they dry out and turn brown. When the cone is dry, it opens to release winged seeds that are then carried away by the wind.
References cited:
Klinkenberg B, editor. 2017. E-Flora BC: Electronic Atlas of the plants of British Columbia [eflora.bc.ca]. Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver. [accessed 2018 Jan 22]. http://linnet.geog.ubc.ca/Atlas/Atlas.aspx?sciname=Pseudotsuga%20menziesii.
[MFLNRO] Ministry of Forests, Lands and Natural Resource Operations. n.d.(a). Tree species compendium — Douglas fir. [accessed 2017 Jan 31]. https://www.for.gov.bc.ca/hfp/silviculture/compendium/DouglasFir.htm.
[MFLNRO] Ministry of Forests, Lands and Natural Resource Operations. n.d.(b). Tree book, Learning to recognize trees of British Columbia. Douglas fir Pseudotsuga menziesii. [accessed 2017 Jan 31]. https://www.for.gov.bc.ca/hfd/library/documents/treebook/douglasfir.htm.
Pojar J, MacKinnon A. 1994. Plants of coastal British Columbia: including Washington, Oregon & Alaska. Vancouver: Lone Pine Publishing.
[MFLNRO] Ministry of Forests, Lands and Natural Resource Operations. n.d.(a). Tree species compendium — Douglas fir. [accessed 2017 Jan 31]. https://www.for.gov.bc.ca/hfp/silviculture/compendium/DouglasFir.htm.
[MFLNRO] Ministry of Forests, Lands and Natural Resource Operations. n.d.(b). Tree book, Learning to recognize trees of British Columbia. Douglas fir Pseudotsuga menziesii. [accessed 2017 Jan 31]. https://www.for.gov.bc.ca/hfd/library/documents/treebook/douglasfir.htm.
Pojar J, MacKinnon A. 1994. Plants of coastal British Columbia: including Washington, Oregon & Alaska. Vancouver: Lone Pine Publishing.