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Agathis australis
Credits
Article from New Trees by John Grimshaw & Ross Bayton
Recommended citation
'Agathis australis' from the website Trees and Shrubs Online (treesandshrubsonline.
Common Names
- Kauri
Synonyms
- Dammara australis D.Don
- Dammara purpurascens W.Bull.
- Podocarpus zamiifolius A.Rich.
- Salisburyodendron australis (D.Don) A.V.Bobrov & Melikyan
Other taxa in genus
Monoecious forest tree attaining heights of 30–60 m and diameters of 3–4 m, or up to 7 m in the largest specimens, with a bole typically cylindrical and scarcely tapered, often clear of branches for 10–20 m or more. Juvenile trees exhibit a narrowly columnar crown, while mature individuals develop massive spreading branches and crowns that become globular or flat-topped upon emergence above the canopy; with age, trunks frequently become hollow. Bark bluish to ash-grey, sometimes mottled purple, exfoliating in large, thick flakes with scalloped margins, the undersides rust-brown when freshly detached. Branches occur in whorls or irregularly horizontal arrangements; once the leaves on a branch die, the tree naturally sheds the whole branch from its base, leaving the bole bare; abscised branchlets are a conspicuous component of the forest litter. Branchlets smooth, glaucous; buds rounded, with imbricate scales. Leaves are alternate to subopposite, sessile, coriaceous, parallel veined. Juvenile leaves lanceolate, 5–10 × 5–1.2 cm, pinkish to glaucous-green, often black-spotted due to fungi. Adult leaves oblong to ovate-lanceolate, 2–3.5 × 1–1.5 cm, apex obtuse, slightly glaucous beneath near the petiole, with ~15 parallel nerves. Pollen cones stout, cylindrical, 20–50 mm long, borne on short peduncles, sporophylls imbricate with weakly erose margins. Seed cones subglobose, 5–8 cm in diameter, glaucous-green, borne on short peduncles, scales ~18 mm long, broad at first then narrowing toward the base, each bearing a single ovule and terminating in a short mucronate umbo. Seeds are compressed, ovoid, with winged margins. The reproductive cycle is extended, requiring 19–20 months from pollination in October to seed maturity in February–March of the following year (New Zealand). (Allan 1961; de Lange 2004; Earle (ed) 2026; Grimshaw & Bayton 2009)
Distribution New Zealand North Island (Northland Region and Coromandel Peninsula)
Habitat Warm temperate lowland forest with subtropical affinities. It grows primarily in mountains at 150–400 m elevation but is generally found at 0–600 m.
USDA Hardiness Zone 9-11
RHS Hardiness Rating H2
Conservation status Not evaluated (NE)
Agathis australis is one of those species that is grown in the mildest parts of our area, for its inherent interest as an important and magnificent tree in its native New Zealand, but has never reached its potential here. It first reached Europe in 1823, with a further importation to Kew in 1838 (Dallimore et al. 1966). Successive generations have tried to grow it, and there are sparse records of trees around the western fringes of the British Isles. The largest known to have grown in the northern hemisphere was a specimen at Tresco Abbey, Isles of Scilly, that attained 19.5 m, dbh 31 cm, while the current surviving champion is one of 16 m at Ilnacullin, Co. Cork, a garden where four specimens over 10 m were measured in 2002, by Aubrey Fennell (Johnson 2007). There are attractive, fruiting specimens of about 8 m at Mount Usher. A slow-growing specimen at Tregrehan recorded to be only 4 m after 40 years in 1931 (Dallimore et al. 1966) has disappeared and been replaced by a group of young trees that appear (so far) to be doing better than their predecessor. On these specimens the new growth is brownish bronze. Agathis australis will, it seems certain, remain a curiosity for those in our mildest areas.
