Hedycarya arborea

Hedycarya arborea, commonly known as pigeonwood and porokaiwhiri, is a species of shrub or small tree in the family Monimiaceae. It is endemic to New Zealand; its range covers the North and South Islands. It is also found on the Manawatāwhi / Three Kings Islands. The species is highly shade-tolerant, and is commonly found in wet environments. It reaches a height of up to 12 metres (40 feet), and produces bright orange to red fruits.

Hedycarya arborea was first described in 1776 by the German naturalists Georg and Johann Reinhold Forster. H. arborea is primarily wind-pollinated. The fruits are dispersed by fruit-eating animals (frugivores), such as birds. The fruits are not edible, and may be poisonous. The indigenous Māori people did not traditionally eat the fruits, although they did use the tree as a source of timber, and the leaves had some medicinal uses. H. arborea's 2023 conservation status in the New Zealand Threat Classification System was "Not Threatened".

Hedycarya arborea (pigeonwood) is a dioecious species of shrub or small tree that reaches heights of up to 12 metres (40 feet) tall, with a trunk up to 0.5 m (1 ft 8 in) in diameter. Its bark is firm and dark grey to brown-grey in colour.^[1] The wood is white and straight-grained.^[2] Leaves are dark green in colour and arranged oppositely. They are mostly coriaceous (leather-like) or glabrous (smooth). The underside of the leaves are similar, but they are a paler colour. Its petioles are usually 10–20 mm long. Its laminae (leaf blades) are usually 40–120 × 25–30 mm long, broadly oval to egg-shaped, narrowing to the base, and the margins are partly serrated or toothed.^[1][3]

Plants from northernmost populations have larger leaves.^[1] The inflorescences (flower clusters) are branched racemes. The peduncles and pedicels are slender. The male perianths are tiny, at about 10 mm in diameter. The female perianths are about 6 mm in diameter. De Lange (2026) states fruiting occurs from March to June; however, Crowe (2009) gives the period as spring to summer.^[4] The fruits produce drupes. Each ovoid fruit contains one seed, and they are 10–15 mm long. They are red or orange-red in colour. Endocarps are 9–14 mm long, usually oval to egg-shaped, rarely round, and brown to grey-brown in colour.^[1]

• Clusters of fruit
• Dark green foliage
• Flowering specimen
• A mature specimen

Hedycarya arborea was first described in 1776 by the German naturalists Georg and Johann Reinhold Forster.^[5] The lineage consisting of the genus Hedycarya, according to Conran et al. (2016), possibly dates to the early Eocene.^[6] There are three synonyms of H. arborea: H. dentata, H. scabra, and Zanthoxylum novae-zelandiae, described by Georg Forster, Allan Cunningham, and Achille Richard, respectively.^[1] There are sixteen species of this genus currently accepted by the Plants of the World Online taxonomic database. These species are native to Oceania: Australia, New Zealand, Fiji, Tonga, New Caledonia, Samoa and Vanuatu.^[7]

The etymology (word origin) of H. arborea's genus name, Hedycarya, derives from the Greek ηδυ-καρπον, simply translating to 'sweet-nut'.^[8] It is a combination of hedys, meaning 'sweet', and krayon meaning 'nut'.^[9] The specific epithet (second part of the scientific name), arborea, means 'tree-like'. It derives from the Latin arbor meaning 'tree'.^[9] The species is commonly known as pigeonwood and porokaiwhiri.^[1] There are many recorded Māori language names for the plant, such as pōporokaiwhiria and kōporokaiwhiri.^[10]

Hedycarya arborea's seeds are dispersed by fruit-eating animals (frugivores), such as birds.^[11] Several birds have been recorded as seed dispersers, such as blackbirds (Turdus merula), kererū (Hemiphaga novaeseelandiae), kōkako (Callaeas), tūī (Prosthemadera novaeseelandiae), song thrushes (Turdus philomelos), and weka (Gallirallus australis). The extinct huia (Heteralocha acutirostris) ate them too.^[4][12] H. arborea is primarily wind-pollinated.^[4][13] Leaves are eaten by introduced deer and goats, while possums instead prefer eating the buds and flowers.^[4] Rats also eat the fruits of the tree.^[14] H. arborea plays host to the endemic insects Lasiorhynchus barbicornis and Calliprason sinclairi.^[4]

Hedycarya arborea is endemic to New Zealand; its range primarily covers the North and South Islands. It also occurs on the Manawatāwhi / Three Kings Islands.^[1] It appears to be sparse on the eastern side of the South Island and grows south to the Banks Peninsula or Port Chalmers inside the Otago Harbour.^[15][16] H. arborea is more common on the western side of the island the botanist Thomas Kirk stated in The Forest Flora of New Zealand, that the species' southern limit was Jackson Bay.^[16] However, more recent revisions of New Zealand flora suggest that the species is found throughout the western coast of the island, or that the southern limit is Milford Sound.^[2][15] H. arborea does not naturally occur on the Chatham and Stewart Islands.^[2]

The conservation status of H. arborea was assessed by the IUCN Red List in 2024 as "Least Concern", and its population trend was evaluated as "Unknown".^[17] H. arborea's assessment in the New Zealand Threat Classification System was evaluated in 2023 as "Not Threatened".^[1]

Hedycarya arborea is typically found in lowland and montane ecosystems, reaching 800 m (2,600 ft) in maximum elevation above sea level.^[1][2] H. arborea is a fast-growing, highly shade-tolerant species.^[2][15] It is commonly found in wet environments.^[15] H. arborea commonly associates with akeake (Dodonaea viscosa), māhoe (Melicytus ramiflorus), ngaio (Myoporum laetum), and tītoki (Alectryon excelsus).^[2]

The wood is soft and not very durable. The indigenous Māori people used the timber to make various musical instruments and digging sticks.^[2] H. arborea had some medicinal uses for Māori; it is known they used the leaves in vapour baths.^[4][10] They did not traditionally eat the fruits, and Wardle (2011) notes that The Poisonous Plants in New Zealand classifies the plant as poisonous.^[18]

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• Media related to Hedycarya arborea at Wikimedia Commons