Pseudotsuga menziesii

Douglas fir

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Common name

Douglas fir.

Scientific name

Pseudotsuga menziesii (Mirbel) Franco

Conservation status and threats

NOT protected species in Bulgaria.

Description and identification

Pseudotsuga menziesii is medium-size to extremely large evergreen trees, 20–100 metres (70–330 feet) tall. The leaves are flat, soft, linear needles 2–4 centimetres (3⁄4–1+1⁄2 in) long, generally resembling those of the firs, occurring singly rather than in fascicles; they completely encircle the branches, which can be useful in recognizing the species. As the trees grow taller in denser forest, they lose their lower branches, such that the foliage may start as high as 34 m (110 ft) off the ground. Douglas-firs in environments with more light may have branches much closer to the ground. The bark on young trees is thin, smooth, grey, and contains numerous resin blisters. On mature trees, usually exceeding 80 years, it is very thick and corky, growing up to 36 cm (14 in) thick with distinctive, deep vertical fissures caused by growth. Layers of darker brown bark are interspersed with layers of lighter colored, corky material. This thickness makes the Douglas-fir perhaps the most fire-resistant tree native to the Pacific Northwest. The female cones are pendulous, with persistent scales, unlike those of true firs. They have distinctive long, trifid (three-pointed) bracts which protrude prominently above each scale and are said to resemble the back half of a mouse, with two feet and a tail. The cones are tan when mature, measuring 6–10 cm (2+1⁄2–4 in) long for coastal Douglas-firs and a couple of centimetres shorter inland¹.

Habitat

Douglas-fir is light-loving and does not tolerate prolonged shading. It is attached to high atmospheric humidity and a mild climate. She is sensitive to low temperatures and suffers from them at a young age. It grows best in fresh, deep and fertile soils. It does not tolerate a high content of carbonates in the soil².

Distribution in Bulgaria

Douglas fir in Bulgaria is cultivated in parks and forest crops. It originates from the Pacific coast of North America³.

References

1 Douglas fir - Wikipedia.

2 Юруков, Ст. 2003. Дендрология. Издателска къща при ЛТУ. София.

3 Юруков, Ст. 2003. Дендрология. Издателска къща при ЛТУ. София

Pseudotsuga menziesii на български