Douglas fir (Pseudotsuga menziesii)

Pseudotsuga menziesii is a species of tree in the Pinaceae family, native to the west coast of North America. It is called "Oregon pine" (in North America), "Douglas fir" or simply "Douglas fir".

In the wild, this tree can reach a large size: specimens “90 m high and 4.50 m in diameter” were rarely found and collected in the early 20th century, but individuals “75 m high and 2 to 3 m in diameter” were common in Canada. Native to North America (on the coast of the Pacific Ocean, from California to British Columbia, in Canada), it was introduced to Europe in 1827 and in France in 1842. Douglas is a tree with rapid growth hence its important use in reforestation. It also has good technical qualities (transformation of wood for the framework, exterior construction because it is rot-proof at heart).

The adult tree reaches an average size of between 50 and 80 meters with a diameter of 2 meters in its regions of origin, and between 40 and 60 m elsewhere. Douglas fir grows quickly and can live between 400 and 500 years. It likes moist and light soils but does not like heavily clayey or too dry soils.

Douglas fir is a species that needs at least 700 mm of water per year. It tolerates average summer droughts thanks to a well-developed root system and thanks to the maintenance of physiological functions down to a very low water potential. On the other hand, it is very sensitive to exceptional droughts. It tolerates extreme winter cold. It thrives in acidic, deep and light soils. It needs well-drained and fairly cool soil. It is sensitive to hydromorphy.

The leaves are needles, 1.5 to 3 cm long, thin, soft, flexible, arched, pointed, and narrowed at the base, without marked white bands on the back. They are inserted on a pad all around the branches of the lower branches or in two rows, in a brush, on the fertile branches. The needles are dark green on top and covered by two light green bands of stomata on the underside. The leaves have a lifespan of 5 to 6 years. They give off a lemongrass smell when you crush them. Hardy up to zone 4b.