Douglas fir

The Douglas fir is a giant tree, that can reach a height of 100 metres in its country of origin, the United States, and heights of up to 50 metres in Europe.

Pseudotsuga menziesii. © Calypso Orchid, Flickr by nc-nd 3.0

Names

This tree (Pseudotsuga menziesii), from the Pinaceae family, is also called the "Oregon pine" or "Douglas spruce" depending on the region.

Botanical description

The Douglas fir has a characteristic structure, with staggered branches at the base that are often raised at their ends. Its bark is smooth, pustular and cracks with age. Its evergreen needles measure 2 to 3 centimetres in length and have two white stripes on their lower side. Flexible, they are fixed to the branches by an oval cushion. These leaves have a lifespan of about five years and produce a lemon grass smell when bruised. This is a monoecious tree, with round and yellowish male flowers and more elongated female flowers that are greenish and purplish. Its cones are 8 centimetres long and mature in October. They hang down and measure between 6 and 10 centimetres, with the particular characteristic of 3-pointed, prominent bracts applied on the scales.

Forest of Douglas fir. © Guillermo S., Flickr by nc-nd 3.0

Origins

This species grows all along the Pacific coast of North America, from Canada to Mexico. In the Rocky Mountains of the United States, a botanist named Archibald Menzies discovered this species in 1792 during a scientific expedition. It was introduced into Europe a few years later by a British scholar, David Douglas.

Growing conditions

The Douglas fir is a tree species that tolerates summer droughts and very cold winter weather. It does well in acidic, deep and light soil and requires well-drained and quite cool soil.

Use

First introduced as an ornamental tree, this species above all is a source of heavy and durable wood, used in construction and joinery, especially for transformation into plywood.

Author: Michel Caron