Rimu

Botanical name: Dacrydium cupressinum
Synonyms: Thalamia cupressina
Common name(s): Rimu, Red Pine

About:
Rimu is a magnificent evergreen conifer endemic to New Zealand and one of the country’s most recognisable forest trees. It is distinguished by its graceful weeping branchlets, fine scale-like foliage, dark flaky bark and reddish timber. Young trees have a narrow pyramidal form, while mature specimens develop immense straight trunks and broad spreading crowns. Rimu is long-lived, commonly reaching 600–800 years old and occasionally surviving for more than 1,000 years.

Natural habitat:
Lowland to montane native forest, including mixed podocarp-broadleaf forest, temperate rainforest and forest margins. It occasionally extends into subalpine scrub.

Growing environment:
Prefers moist, fertile, humus-rich soils with reliable rainfall. Young plants establish best in partial shade or beneath a light forest canopy, while mature trees eventually rise into full sunlight. It tolerates a wide range of soil types but grows slowly in dry or exposed conditions.

Endemic distribution:
Endemic to New Zealand. Found from North Cape throughout the North Island, South Island and Stewart Island/Rakiura. It is uncommon or absent from large areas of the eastern South Island and is now nearly extinct naturally on Banks Peninsula.

Height:
35–60 m

Width:
10–20 m

Flowering:
December–March. Rimu produces cones rather than true flowers.

Fruiting:
February–May. Fruit takes more than a year to mature and may occur alongside young female cones.

Uses:
• Large-scale native forest restoration
• Specimen tree for parks and extensive properties
• Wildlife habitat and food source
• Mixed podocarp forest planting
• Traditional Māori medicine and tools
• Furniture, flooring and interior joinery historically
• Educational and conservation planting

Appearance:
Growth habit:
A large, upright evergreen conifer with a narrow pyramidal habit when young. Juvenile trees have numerous slender, strongly drooping branches. Mature trees develop a massive cylindrical trunk that may remain free of branches for most of its length, with a broad domed crown of spreading branches and hanging branchlets.

Trunk and bark:
The trunk is stout, straight and commonly 1.5–2 m in diameter. Bark is dark brown to grey-brown and sheds in large, thick elongated flakes. Newly exposed bark beneath often displays distinctive wavy parallel ridges resembling contour lines.

Leaves:
Foliage varies greatly with age. Juvenile leaves are narrow, sharp, slightly curved and spreading, measuring 4–10 mm long. They may be dark green, bronze-green, reddish-green or orange. Adult leaves are much smaller, 2–3 mm long, rigid, triangular and tightly overlapping against the branchlets.

Cones:
Male and female cones are produced on separate trees. Male cones are solitary or paired at the branch tips, oblong and 5–10 mm long, releasing pale yellow pollen. Female cones are borne singly on short upward-curving branchlets.

Fruit:
The seed is dark brown to black, oblong and slightly flattened. It sits above a small fleshy cup formed from bright red or deep orange reproductive structures. These colourful fruiting structures are highly attractive to native birds.

Ecology:
Rimu is an important canopy and emergent species in New Zealand’s mixed forests. Its fruit is eaten and dispersed by kererū, tūī, bellbirds, silvereyes and other birds. Heavy rimu fruiting is particularly important to kākāpō, whose breeding cycles are closely linked to mast fruiting years. Mature trees support rich communities of epiphytes, fungi, lichens and invertebrates.

Associated habitats:
Podocarp-broadleaf forest, kauri forest, temperate rainforest, beech forest margins, lowland forest, montane forest and subalpine scrub.

How to grow:
Plant in moist, fertile, well-drained soil with shelter from strong wind during establishment. Young plants benefit from partial shade and consistent moisture but should not remain permanently waterlogged. Growth is naturally slow, particularly beneath dense shade. Allow ample space for the tree’s eventual height and crown.

Propagation:
Easily propagated from fresh seed, although germination may be slow and uneven because seeds commonly remain dormant for at least several weeks. Hardwood cuttings can also be used but are usually slow and difficult to strike.

Cultural use:
Rimu is highly significant to Māori. Its resin was used to stop bleeding, bark preparations were applied to wounds and burns, and foliage was used medicinally. The timber was crafted into waka, weapons, hunting spears and long war spears. The fruit, known as huarangi, was gathered as a seasonal food. Captain James Cook also used young rimu branch tips to brew spruce beer at Tamatea/Dusky Sound in 1773.

Garden value:
Rimu is an exceptional specimen tree for large gardens, parks, reserves and native forest restoration projects. Its elegant weeping juvenile form, fine foliage and impressive mature stature provide outstanding landscape value. Although too large and slow-growing for many urban gardens, it is one of the finest trees for creating authentic New Zealand forest character and long-term ecological habitat.