Tree to 60 m, 2.5 m dbh. Bark smooth, grey, breaking into large plates in older trees. Crown broad or columnar, becoming flat-topped in mature trees. Branchlets yellowish brown, becoming grey with age; conspicuously grooved, leaf scars circular; vegetative buds slightly resinous. Leaves spirally arranged, mostly on two planes, (1.5–)2–4(–5) × 0.2–0.25 cm, straight or slightly curved, margins revolute, apex emarginate. Male strobili arranged radially around the shoot, 2–4.5 cm long, yellow with purple microsporophylls. Cones erect, sessile or short-pedunculate, cylindrical, apex obtuse, 8–12 × 4–5.5 cm, purple-blue when immature, darkening later. Seed scales flabellate to cuneate, 1.5–2 × 2–2.5 cm. Bract scales ligulate to spathulate, 2–2.5 cm long, usually not exserted. Seeds brown, cuneate, with cuneate wings, 1 × 0.5 cm. Farjon 1990, Fu et al. 1999c. Distribution BHUTAN; CHINA: southeast Xizang; INDIA: Arunachal Pradesh, Assam, Sikkim; NEPAL. Habitat High mountain cloud forest between 2450 and 4000 m asl. Pronounced seasonality, with hot, wet summers and very cold winters; annual precipitation over 2000 mm. USDA Hardiness Zone 7. Conservation status Lower Risk. Illustration Farjon 1990; NT50.
Abies densa has never been a common tree in arboreta, but its presence has probably been masked by misidentifications and confusion with other Himalayan firs. This is discussed by Clarke (1988) under his entry for A. spectabilis; he concluded that A. densa was probably first introduced by Joseph Hooker from his famous Sikkim expedition of 1849–1850. With the confusion surrounding the identification of these taxa it is perhaps wisest to disregard old records and concentrate on more recent introductions, of which there have been several from Nepal and Bhutan in recent decades. The finest specimen known (said to have been collected by Ludlow & Sherriff, though of unknown origin) is at Benmore, and was 26 m tall (69 cm dbh) when measured in 1991 by Alan Mitchell (TROBI). It will be succeeded there by numerous young trees planted in the Bhutanese Glade, derived from collections made by expeditions from the Royal Botanic Garden Edinburgh during the 1980s and 1990s. In Charles Howick’s experience (pers. comm. 2005) A. densa is prone to die young, which may explain its general scarcity, but at Howick he has several young specimens of about 8 m. They are slightly untidy-looking trees, with mid-green needles (flushing bright green), but their abundantly produced young cones are a spectacular deep Prussian blue (with some resin on the top). As for most Himalayan firs, a cool wet site would seem to be the most appropriate for successful cultivation.