Karaka (tree)

Karaka
An illustration by John Frederick Miller
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Rosids
Order:	Cucurbitales
Family:	Corynocarpaceae
Genus:	Corynocarpus
Species:	C. laevigatus
Binomial name
Corynocarpus laevigatus J.R.Forst. & G.Forst., 1776

Karaka or New Zealand laurel (Corynocarpus laevigatus) is an evergreen tree of the family Corynocarpaceae endemic to New Zealand. It is common throughout the North and South Islands to Banks Peninsula and Ōkārito, on the Three Kings Islands, on Raoul Island in the Kermadecs, and on the Chatham Islands.^[1] It is widespread in coastal habitats, often forming a major component of coastal forest, though it rarely dominates.^[2]

Most botanists consider it to be native only to the northern half of the North Island, having been planted elsewhere by Māori near former village sites, and subsequently spread by birds. The common name karaka comes from the Māori language, and is also the Māori term for the colour orange, from the colour of the fruit. In the Chatham Islands, it is called kōpi, its name in the Moriori language. It is naturalised and considered invasive in Hawaii.

Considered a taonga (cultural treasure) amongst the Māori and Moriori peoples. Karaka was a significant source of food for the Māori. On the Chatham Islands, rākau momori are carved on to karaka trees, which are internationally significant and unique to the Moriori culture.^[3]

Karaka is a leafy canopy tree with erect or spreading branches. It grows to heights up to 15–20 m (49–66 ft) and has a stout trunk up to 1 m (3 ft 3 in) in diameter. Its leaves are 15–30 cm (5.9–11.8 in) long.^[4]

In winter and spring (August to November), large clusters of karaka produces stout, erect panicles of tiny flowers (less than 0.5 cm (0.20 in) in diameter). Individual flowers are 4–5 mm (0.16–0.20 in) in diameter and greenish-cream to off-white or pale yellow. The fruit is an ellipsoid to ovoid drupe 3–3 mm (0.12–0.12 in) long, with pale yellow–orange flesh,^[2] containing a single seed. The fruit ripens between January and April and the seeds are mostly dispersed by columbiform birds (such as the kererū) which feeds on its fruit.^[1][4]

• 
  A mature tree
• 
  Its orange fruit
• 
  Foliage

The etymology of Corynocarpus translates in English to "club fruit", and the Latin specific epithet laevigatus translates to "smooth", in reference either to the fruit of the leaf or the skin. In the Māori language, Karaka can either refer to the fruit of the tree or the tree itself. Karaka is also the Māori word for the colour orange.^[5][2] In the Moriori language and on the Chatham Islands, the tree is known as kōpi.^[6] The species is also known in English as the New Zealand laurel.^[7]

Karaka is in large numbers throughout the North Island and South Island as far south as the Banks Peninsula on the east coast of the South Island and Greymouth (on the West Coast). Karaka is predominantly a coastal tree, though in the North Island, it can also be found lowland inland forrests.^[8] Karaka is also found on the Chatham Islands, Kermadec Islands, and the Three Kings Islands.^[9] It is generally acceptedamong sources that prior to Polynesian arrival of New Zealand, karaka was possibly limited to the northern North Island, even though it is now found on many offshore islands and the northern half of the South Island (usually above the 38°S latitude line).^[3]

Karaka is a valuable food source for birds.^[10] Notably the kererū (Hemiphaga novaeseelandiae) and the Chatham Islands pigeon (Hemiphaga chathamensis) which are the only are the only extant bird species with a gape large enough to consume the fruits of karaka.^[11] Centuries ago the fruits would have been dispersed by the extinct moa and possibly other large birds.^[12] Possums (an invasive species in New Zealand) are also known to consume the ripe flesh of karaka berries. Its nectar from the flowers is also toxic to bees.^[13]

Kererū feeds on its ripe fruits in late summer and disperse the seeds. Other smaller New Zealand birds such as the North Island robin (Petroica longipes), silvereye (Zosterops lateralis) and whiteheads (Mohoua albicilla) search and around karaka for insects.^[14]

Karaka may be easily grown from fresh seed, but cuttings are very difficult to strike. Young plants are frost-tender and sensitive to cold. The tree often naturalises in suitable habitats. It is common in cultivation and widely available for sale both in New Zealand and in suitable climates elsewhere.^[1] It was one of the most grown food crops by pre-European Māori (alongside kūmara and aruhe (bracken fern root),^[8] who ate the drupe and seed after a long detoxification process.^[15][16]

Every autumn (March to May), pre-European Māori would collect the seeds dropped from the coastal karaka trees. The seeds would be placed in open-weave kete, washed in rivers to remove the outer pulp, afterwards baked and sun dried, a process that would remove toxicity from the seeds. Properly prepared kernels would keep for 2–3 years.^[16]

Māori primarily used karaka as a food source. In pre-European times, karaka was not known for its traditional healing (rongoā) value other than in its nutrition, though karaka did have other certain uses, with its underside of the leaf was used to extract an infection and its upper side was applied fresh to heal injured or infected skin.^[17] The seeds of karaka were of great value to Māori. The seeds needed to be prepared before they could be safely consumed, while the flesh of the berry was consumed uncooked. The seeds are bitter in taste and are very poisonous and had to be steamed properly in earth ovens (umu).^[8] It is also known that karaka wood was used in constructing canoes (waka).^[18]

On the Chatham Islands, karaka has played a distinguished role in the history of Moriori people, the soft bark of these trees has been used for making dendroglyphs. A 2000 report by the Department of Conservation indicated the existence of 147 kōpi trees with dendroglyphs on the Chatham Islands, though some may not have been authentically Moriori.^[19] Considered a taonga (cultural treasure) amongst the Māori and Moriori peoples. The carvings in the Moriori language are known as rākau momori, which are considered internationally significant and unique to their culture.^[20]

An exoplanet originally named HD 137388 was renamed in 2019 in honour of the tree.^[21] A small community 20 km (12 mi) west of Whanganui called Pākaraka is also named in honour of the "ambundance of karaka trees" that previously were situated here.^[22] Karaka has also been recognised on New Zealand Post stamps with its penny postage stamps in 1967 depicting an image of karaka in the centre of the image.^[23]

Theses

Books

Journals

• Media related to Corynocarpus laevigatus at Wikimedia Commons
• Karaka leaves used for scientific research