Kauri gum (kāpia)

Kauris (Agathis australis) are one of the largest trees found in New Zealand’s North Island. They live for hundreds of years.

Over the tree’s lifetime it oozes sticky sap. Exposed to the air, the sap hardens and eventually falls to the ground where it becomes buried in leaf litter and soil. Gradually it forms a solid and stable polymer. The colour and clarity depends on how it formed and how long it’s been buried.

Kauri gum was used commercially as a varnish. It was one of Auckland’s main exports in the 19th century. The Māori call it kāpia and use it as chewing gum, to start fires and for beautiful carvings. When burnt and mixed with animal fat it is a key ingredient for making facial tattoos (moko).

Some sap loss is normal during the tree’s growth. When the bark is damaged the gum forms a protective seal, just like a scab on a grazed human knee. Yet some trees are showing excessive oozing. A disease known as ‘kauri dieback’ caused by a microscopic fungus-like organism (Phytophthora agathidicida) is killing kauri forests.

Is it the same as amber?

Like amber, kauri gum can be a mesmerising golden orange colour. True amber can be millions of years old, radiocarbon dating suggests kauri gum is maybe a few thousand years old. Like amber, kauri gum can also contain trapped plant fragments and insects from times long passed.

Visual description: A roughly curved rectangular piece of kauri gum, a hard tree resin. It has smooth sides and tapers to a point at one end. It is amber coloured and semi-translucent. Lighter coloured marks on the surface show where it has been scratched or worn.