Karaka – Killer berry

Photograph Rob Tipa.

Karaka is one of few native New Zealand trees cultivated by Māori for its fruit. But there is a significant catch. Ripe berries exude a powerful mix of volatile chemical compounds and the kernels contain a lethal alkaloid poison called karakin.

Its bright orange berries were known to Māori who harvested them as kopi, or kopia, in some references.

The kernels of this forest fruit stored well and, in the days before fast food outlets, were a nutritious and important food supplement to the diet, second only to kūmara in some regions.

The fruit had to be meticulously prepared to remove the poison before the kernels were eaten or victims suffered violent convulsions and severe muscle spasms that could leave limbs permanently disfigured and often ended in death.

Most sources suggest the ripe berries were baked in an umu (earth oven) and then placed in harakeke baskets, trampled to remove the flesh and soaked in a freshwater stream or pool to leach out the toxins over a period of days or even weeks, according to some experts.

The kernels, or nuts, were then sun-dried and stored for future use – usually ground into a flour to make nut-flavoured bread. Due to the work involved in preparing it, this bread was usually reserved for chiefs and other important people.

Some sources say the raw flesh of the ripe berry is edible but is bitter and unpalatable in its fresh state.

One reference suggested it tasted like an over-ripe powdery apricot.

Andrew Crowe, author of A Field Guide to the Native Edible Plants of New Zealand, says no two authorities agree on how long karaka kernels should be steamed and soaked to remove the toxins. Some recommended days for each process and others suggested the process took weeks.

Crowe strongly warns against experimenting with this fruit. He said the few kernels of karaka he had eaten tasted rather like acidic chestnuts. They were certainly palatable and did him no harm. But the consequences of poor preparation were horrific, according to Murdoch Riley's ethnobotanical reference book, Māori Healing and Herbal. Small children were the most common victims of poisoning, attracted by the bright orange berries.

Victims were forced to vomit, often hung upside down over a smoky fire or held under water until they almost drowned. Less drastic remedies were to drink the juice of boiled pūhā leaves or to chew on the leaves of kohekohe.

Riley said it was important to stop the patient going into convulsions. The poison relaxes the joints so bones may bend the wrong way, permanently disfiguring the victim. Unless the head was kept straight, the person could dislocate their neck.
An old technique to keep the victim's limbs straight was to bury them in sand up to the chin and gag them to stop them biting their lips or tongue. Water was then forced down the throat to make the person perspire, sweating out the toxin.

Another extreme method to save a life was to trample the limbs to prevent permanent atrophy of the flexor muscles of the arms and legs.

It sounds brutal but survivors probably eventually forgave their torturers if it meant saving their lives.

If and when the convulsions stopped, the patient was given a steam bath and fed porridge made from dried kūmara, a meal of hākekakeha or harore (both edible fungi), or the roots of pōhue (a creeping plant like convovulus) or tātaraheke (a type of bramble known as bush lawyer).

Considering the lethal alkaloid poison karakin in fresh kernels and the drastic repercussions of not preparing karaka berries properly, it is hardly surprising that no part of the plant or fruit is commonly eaten today.

However, scientists are currently exploring karaka as an alternative nut crop. They are intrigued by its chemical compounds and why the plant appears to be disease and pest free. They are also interested in kohekohe, the traditional Māori plant antidote for karakin poisoning.

In other traditional medicinal uses, Riley notes the leaves were used to help heal wounds and draw the poison out of boils, but users were careful only to place the shiny side of the leaf on the wound.

A decoction of ngaio and karaka leaves was used as a wash to relieve pain and karaka oil was used to bathe small burns. The glossy leaves were also used to make head wreaths when visiting graves of tīpu na or to attend a tangi.

The timber is white, very brittle and makes good firewood when properly dry. Some reports suggest it was once used to build canoes in Rekohu (the Chatham Islands).

In Māori legend, karaka was thought to have been brought to New Zealand by early Māori from Hawaiki, but the distribution of Corynocarpus laevigatus tends to contradict this. It is not found anywhere in eastern Polynesia, although similar plants are.

In Ngāi Tahu tradition, the tree was brought south from Te Ika a Māui (North Island) to Kaikōura, where groves of karaka are still visi ble from the road along the Kaikōura coast.

Scientists believe Māori selected high performing karaka cultivars and propagat ed them at chosen sites throughout New Zealand. Remnant karaka groves have been found scattered from Northland to Otago, in the Kermadec and Chatham Islands.

Apart from isolated groves of trees that have survived on old marae and pā sites, this tree is not naturally found south of Akaroa in the east and Ōkārito in the west of Te Waipounamu.

In Traditional Lifeways of the Southern Māori, James Herries Beattie recorded Rāpaki and Tuahiwi contacts he inter viewed in the 1920s were familiar with the repercussions of poorly prepared karaka berries, but they did not like the bitter taste of the fruit anyway.

For gardeners, karaka is a handsome specimen tree up to about 15 metres that would grace any garden with its shapely form and its evergreen glossy leaves. It is easy to cultivate, with seedlings commonly sprouting under its parent, but is slow growing. Early settlers christened it the New Zealand laurel because its large glossy leaves reminded them of the English laurel.

For all its benign looks, karaka's bright orange berries are well worth leaving alone. There are plenty of tasty traditional foods to try without dicing with death.

For more information try the following sources used to research this article:
Māori Healing and Herbal, Murdoch Riley; A Field Guide to the Native Edible Plants of New Zealand, Andrew Crowe; Traditional Lifeways of the Southern Māori, James Herries Beattie; The Native Trees of New Zealand, J.T Salmon; The Cultivation of New Zealand Trees and Shrubs, L. J. Metcalf.