Cupressus gigantea
Credits
Article from New Trees by John Grimshaw & Ross Bayton
Recommended citation
'Cupressus gigantea' from the website Trees and Shrubs Online (treesandshrubsonline.
Genus
Common Names
- Tsangpo Cypress
Tree to 45 m, 3(–6) m dbh. Bark greyish or purplish brown, with slight longitudinal fissures. Crown narrow, conical to columnar. Branchlets typically decussate, densely arranged. Juvenile leaves needle-like; mature leaves scale-like, glaucous, abaxial surface ridged or grooved, decussate, appressed, densely crowded; the lateral and facial pairs are similar, 0.1–0.2 cm long, apex obtuse or acute, but expanded; leaf resin glands abaxial, partially active, rounded. Male strobili solitary and terminal, borne on short, lateral branches. Female cones axillary, usually solitary, globose to oblong, valvate, 1.5–2 × 1.3–1.6 cm, shiny dark brown. Seed scales in six decussate pairs, valvate; umbo large and prominent. Seeds shiny chestnut-brown, slightly warty, oblong; seed wings thin and to 0.1 cm wide. Fu et al. 1999e, Farjon 2005c. Distribution CHINA: southern Xizang, Tsangpo River valley. Habitat River valleys and plateaus between 3000 and 3400 m asl. USDA Hardiness Zone 7. Conservation status Vulnerable. Illustration Fu et al. 1999e; NT297. Taxonomic note Cupressus gigantea is closely related to C. torulosa. It differs from that species in that its ultimate branchlets are thicker (1.5–2 mm vs. 1–1.4 mm) and not pendulous and the leaves are glaucous (Fu et al. 1999e).
This potentially huge cypress is endemic to the Tsangpo valley in southeastern Tibet, where it is a conspicuous tree, with young plants lining the riverbank in places after a mass germination along a high-water line (see photograph in Kingdon-Ward & Cox 2001). Curiously, Kingdon-Ward makes no mention of it, leaving its introduction to Ludlow, Sherriff and Elliot (LUSE 13345) in 1947. Trees from this collection are widely dispersed, and much propagated-from: as an example of the value of careful record-keeping and the importance of maintaining the collection number with each generation of vegetatively propagated individuals, there is a specimen at Quarryhill propagated from a tree at Berkeley that was itself a cutting from the original LUSE 13345 tree at Washington Park Arboretum. The resulting Quarryhill tree is now a good size, c.8 m in 2004. Two originals at Kew are shapely straight columns of 10 and 15 m, showing no sign of broadening out. These trees are a greyish sage-green, but Keith Rushforth’s collection KR 5787 from 1997 has given rise to much more glaucous individuals, at least as seen at Quarryhill. Further collections have been made by Rushforth and others, and plants derived from KR 3353 (from 1995) are available from UK nurseries. Cupressus gigantea is clearly a reliable, hardy tree and is well worth planting where a very stately columnar cypress is desired.
