Pseudotsuga menziesii (Douglas-fir, Red-fir, Coast Douglas-fir) [sometimes P. brevifloia]

Contrary to the name ‘Douglas-fir’, Pseudotsuga menziesii is a pine tree. It also happens to be one of the tallest trees in North America, with one giant at a recorded 329 feet tall. The cones appear unique, with many bracts covering up “mice tails”, as the wind-dispersed section of the seeds are called. Pseudotsuga menziesii was the first scientific name I ever remembered. I showed a cone to one of my first botany mentors, which I found particularly strange due to its structure. I have always had a fascination with these, as their common name implies it to be a fir, its scientific name a hemlock, its foliage a spruce, yet it is considered a pine.

Pseudotsuga menziesii (Douglas-fir, Red-fir, Oregon-pine, Douglas-spruce, Coast Douglas-fir (var. ‘menziesii’) [occasionally Pseudtsuga brevifolia]
Deciduous: no
Hardiness Zones: 4-6
Height: The douglas-fir grows 12.2-24.2 meters (40-80 feet) in cultivation, but one tree was recorded at 100.2 meters (329 feet), making it North America’s second tallest tree species. Trees may have once possibly topped 122 meters (400 feet) tall.
Diameter: 3.6-6.1 meters (12-20 feet) in cultivation at maturity, occasionally spreads further with older trees
Growth Rate: moderate to fast
Age: Commonly exceeds 500 years in proper care, sometimes lasts longer than a milennium.
Root System: Roots do not lift up nearby ground.
Family: Pinaceae
Subspecies: ‘menziesii’, ‘glauca’ (blue foliage, ‘Anguina’, ‘Brevifolia’ (shorter needles), ‘Compact’ (more conical growth), ‘Fastigiata’ (more pyramidal growth), ‘Fretsii’ (dense, short leaves and grows as a bush), ‘Nana’ (dwarf), ‘Pendula’ (drooping branches close to the ground), ‘Revoluta’ (curly leaves), ‘Stairii’ (variegated needles)

Tolerates: In a proper growing environment, P. menziesii has very few insect or disease problems. Strong winds are of little concern to Douglas-firs.
Problems (major): Droughts are especially dangerous to younger trees as the soil must remain at least moderately moist.
Problems (minor): Scale and bark beetles can harm trees under stress. Aphids may attack young trees. Root rot can affect trees with poor drainage.
Poisonous: presumably no

Soil requirements: Sandy, loamy, and clay soils are fine. No specific pH is required.
Air Requirements: not sufficiently researched
Watering requirement:medium or wet
Sun requirement: full sun

Needles: yellowish-green in ‘menziesii’, blue (Picea pungens blue) in ‘glauca’
Cones (male): pollination runs from March to May usually
Cones (female): up to 10 centimeters (4.5 inches) (seed begin ripening until around November)
Leaves: none
Flowers: none
Fruits: none
Seeds require stratification: yes
Monoecious or Dioecious: monoecious (Male and female cones grow on seperate trees.)

Notable characteristics:
These can grow at an elevation of of 5500 feet (var ‘glauca’ has been reported to grow at 9500 feet). The cones have unique bracts (small trident-shaped structures) that make their unique-looking cones easily identifiable. The oldest douglas-fir is estimated to be 1300-1400 years old.
These trees are narrow and pryamidal-shaped with branches hanging to the ground. Older trees are more cylindrical and only have needles on the upper third of the tree. The douglas-fir is also the state tree of Oregon.

Uses:
Especially in the Pacific northwestern region of the United States, this is one of the most valuable timber trees in North America. Douglas-firs grow well as shade trees and sometimes as ornamentals.

Sources used:

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var. menziesii

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A mature cone slightly closed post rain

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Foliage of var. glauca

 

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Multiple cones and foliage

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A fairly thinly branched var. glauca

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A mature, opening cone

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A cone, with the bracts and “mice tails” very visible

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A larger var. glauca Douglas-fir next to a young var. menziesii (to the right)

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The bark post rain

All of the images provided were taken by me. They may be used for educational/informational purposes only, provided that this article/online journal is appropriately cited first.

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