Wood species

Douglas fir - tree that rivals redwood and wood with unbeatable strength-to-weight ratio

Douglas fir is said to rival redwood in height and has the best strength-to-weight ratio of all wood species used for flooring. It is often called red fir or red pine, but it is neither fir nor pine. Although it is an exotic species, native to North America, it has been in Europe for almost 200 years and in Romania for over 100 years. It has a different colour from fir and pine, the smell is a bit lemony, but in specialist shops, the one from our forests is rarely sold as a different species, being another resinous alongside molid, brad or pin. As properties and appearance it seems to be more than that, that's why it will be presented at length below.

Douglas fir

Although native to America, it is now found throughout Europe

Douglas (Pseudotzuga mensiensii) is a resinous tree native to western North America. Although it is also known as Douglas fir, Douglas spruce, Oregon pine or Columbian pine, is not of the genera Abies (fir), Picea (spruce) or Pinus (pine). Name Pseudotzuga (douglas' kind) means false hemlock, often confused with this species. In our country it is also called duglas greento distinguish it from Pseudotzuga mensiensii Glauca, also called blue or misty Douglas-fir.

Both the common name and the scientific name are tributes to those who discovered, studied and promoted it. The scientific name comes from the Scottish naturalist Archibald Menzies who discovered and described it in 1791. Douglas is named after the Scottish botanist David Douglas who first brought it to Europe in 1827. Unlike in other countries, we spell the words as they sound, so the tree is recorded in the DEX as Douglas fir.

In Europe, the dugong first arrived in the UK. From there it spread quite quickly to Italy, France, Germany, Belgium, the Netherlands and Denmark. Today it can be found from the mountains of Portugal to the Carpathians and from Poland to Sicily. In France, thanks to forestry policies, it has even become the second species used for reforestation. Here we find it in the forests around Brasov, in Marghita, but especially in western Transylvania and Banat due to the mild winters it enjoys.

Douglas fir

A tree that can reach over 80 m high, up to 5 m in diameter and over 1000 years old

In North America, specimens growing on the western coasts can reach over 80 m in height and 4-5 m in diameter, as the humid, mountainous oceanic climate favours the growth and development of the species. In Europe, douglas rarely exceed 60 m in height and 2.5 m in diameter. The stem grows straight, cylindrical, with smooth, greyish, light-coloured bark at first, which thickens, darkens and cracks strongly in length as it matures.

The crown is conical, with branches pointing upwards. The needles are persistent, glossy green on the front and with a whitish stripe on the back. They are 2-3 cm long and 1-1.5 mm wide, soft, pointed and arranged around the branch. When squeezed between the fingers, they give off a very pleasant, distinctive smell, a combination of resin and lemon. The cones hang on the branches, are conical, 5-10 cm long and have rounded scales. The seeds are 7 mm long, winged, brown and resin-free.

The douglas mature early, around 8 years old. At over 30 years old it bears much fruit annually. It is a fast-growing species, after 8 years growth is sustained and vigorous. It typically lives to 600-700 years, but there are specimens that have exceeded 1000 years.

Douglas fir

Douglas fir wood: characteristics, properties

In cross-section you can see the difference between albumen and heartwood. The sapwood is thin, yellowish-white, and the heartwood is light brown with orange-red hues. The colour is darker the more mature the tree. Annual rings are clearly visible due to the difference in colour between late and early wood and the abrupt transition between them. This difference in colour makes the wood appear striped in radial cuts and spectacular in tangential cuts.

The fibre is straight, sometimes slightly wavy. The texture is medium to coarse, with moderate natural lustre. Resiniferous channels are small to medium, unevenly distributed, solitary or in groups. The tracheids are medium to large in diameter. As in all softwoods, there are no pores. Wood from European Douglas fir has a lower resin content than American Douglas fir.

Douglas fir density is between 510 and 540 kg/m³, depending on origin. It dries well, without large dimensional variations and without significant cracking. It is very resistant to compression, tensile and bending and is considered the strongest conifer. It has medium resistance to decay but low resistance to insect attack. It works well, but it shreds tools faster than other species and can sometimes load them with resin. It glues fairly well, stains, oils and varnishes/paints without problems.

When processed, it gives off a specific, resinous, slightly citric smell.

Douglas fir

Douglas fir
source: wood-database.com
Versatile wood with various uses

Because of its very good strength-to-weight ratio, Douglas fir is used primarily in construction as a structural material. It is used in the manufacture of timber frameas a roofing material (asphalt) and to obtain laminated beams. Due to its good resistance to abrasion it is used for flooring. It is recommended for making window frames and doors.

It is used to make furniture, veneer and plywood. It is used in the construction of ships and small aircraft. It can be impregnated under pressure making it much more resistant to the outside. Thus treated it is often used for exterior cladding of houses.

It is used for reforestation, as an ornamental tree, even adapting to lowland areas. Its pleasing shape, needles arranged around the branch and characteristic scent make Douglas fir a very popular Christmas tree.

Douglas fir

A volatile oil is extracted from the needles and used in massage oils or products to treat colds and nose and throat ailments.

I hope you find the information useful. As usual, additions are welcome. And if you have any questions or queries, please leave them in the space below. I'm sure I'll reply.

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About the author

Mihaela Radu

Mihaela Radu is a chemical engineer but has a great passion for wood. She has been working in the field for more than 20 years, wood finishing being what defined her during this period. She gained experience working in a research institute, in her own company, as well as in a multinational. She wants to continuously share her experience with those who have the same passion - and more.

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