Karaka

Corynocarpus laevigatus (karaka) is a medium-sized evergreen leafy canopy tree with erect spreading branches. It is endemic to New Zealand. It grows to heights of up to 15–20 metres (49–66 feet) and has a stout trunk usually up to 60 centimetres (24 inches) in diameter, but can be up to 1 metre (3 feet 3 inches) in diameter. The largest trunk of a C. laevigatus specimen diameter ever measured was 3 m (10 ft) in diameter. The bark is typically a grey colour, although on young trees it can be a lighter brown-colour. C. laevigatus is predominantly a coastal tree, although in the North Island, it can also be found in lowland inland forests. C. laevigatus is suggested to have a maximum lifespan of 500 years in mainland New Zealand, and potentially 600 years from a specimen found on Lady Alice Island. Mature trees have dark-brown corrugated bark with corrugations that are broken up into pieces that are roughly 1 cm × 3 cm (0.4 in × 1.2 in) and 0.5 cm (0.2 in) thick. Younger trees have light brown bark that frequently has short, horizontal bands that resemble sewing stitches. C. laevigatus has alternating elliptic oval-shaped leaves that are up to 8 cm (3 in) wide, with petioles less than 2 cm (0.8 in) long. From August to November, C. laevigatus produces large, stout, erect panicles of tiny greenish-yellow flowers, each less than 0.5 cm (0.2 in) in diameter. …

Corynocarpus laevigatus is found 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. It is also found on the Chatham Islands, Kermadec Islands, and the Three Kings Islands. It is possible that before Polynesian arrival in New Zealand, C. laevigatus was likely restricted to the far north of the North Island, despite its current range across offshore islands and the northern half of the South Island, which likely spread from Māori plantings. Populations are often found in association with former pā (Māori village) sites. The species was not naturally present in the Otago and Southland Regions of New Zealand prior to human settlement. All individuals south of the Banks Peninsula are likely to be recent introductions. The distribution in Otago and Southland is naturally uncommon and scattered along the coastline. C. laevigatus's South Island population is exclusively located near coastal areas and most of the population is centred in the Banks Peninsula (including Christchurch's coastal areas) and the Marlborough Sounds. C. laevigatus has been introduced to the United States, it is naturalised and considered an invasive species in Hawaii, where it is naturalised in wet soils and considered a threat to endangered or rare species. C. …

The fruits that C. laevigatus produces are a valuable food source for native New Zealand birds. The kererū (Hemiphaga novaeseelandiae) and the Chatham Islands pigeon (Hemiphaga chathamensis) are the only native bird species with a gape large enough to consume the fruits of C. laevigatus. Duvaucel's geckos (Hoplodactylus duvaucelii) have been reported eating the fruits of C. laevigatus. The New Zealand bellbirds (Anthornis melanura) have been seen feeding on the sap from the bark of C. laevigatus. Other smaller native birds, such as the North Island robin (Petroica longipes), silvereye (Zosterops lateralis) and whiteheads (Mohoua albicilla) are known to search around C. laevigatus for insects. The endocarps of C. laevigatus are sometimes nibbled by Polynesian rat (Rattus exulans), while the larger brown rats (Rattus norvegicus) sometimes chew through the endocarps. Both species consume the flesh of C. laevigatus. Possums, an invasive species in New Zealand, consume the flesh of C. laevigatus fruits. The extinct moa and other large birds likely consumed the fruits of C. laevigatus centuries ago. C. laevigatus plays host to the endemic New Zealand beetle species Oemona hirta. C. laevigatus is one of New Zealand's least flammable tree species with the highest moisture contents and lowest flammability rates, as examined in a 2016 study.

Corynocarpus laevigatus is common in cultivation and widely available for sale both in New Zealand and elsewhere in the world. It was one of the most grown food crops by pre-European Māori (alongside kūmara and aruhe); they ate the drupe and seed after a long detoxification process. C. laevigatus's seeds contain highly toxic glucosides of 3-nitropropionic acid, such as karakin. Some initial symptoms of poisoning include diarrhoea, nausea and restlessness which develop to more severe gastrointestinal and neurological problems. Every autumn, pre-colonisation Māori could collect the seeds dropped from C. laevigatus trees. The seeds could be placed in open-weaved traditional baskets (kete), washed in water to remove the outer pulp and baked and sun dried, a process that would remove toxicity from the seeds.

The etymology (word origin) of the genus name Corynocarpus derives from the Greek koryne, meaning 'club', and carpus, meaning 'fruit', translating in English to 'club fruit'. The specific epithet (second part of the scientific name) originates from the Latin laevigatus meaning 'smooth', in reference either to the fruit, the leaves or the skin. The species is commonly known as karaka or the New Zealand laurel. In the Māori language, karaka can either refer to the fruit of the tree or the tree itself. The word has origins in Proto-Polynesian languages. Cognates of karaka are used in Polynesian languages for members of the Planchonella genus, which share a similar appearance with Corynocarpus laevigatus. Karaka is also the Māori word for the colour orange, and has likely only been in use since the 19th century, as no word meaning orange appears in early Māori language dictionaries. In the Moriori language and on the Chatham Islands, both the tree and the fruit are known as kōpi. This name may share an etymology with Polynesian names used to describe members of the true ginger genus, Zingiber. In English, C. laevigatus is also commonly known as the "New Zealand laurel".