How gum forms
New Zealand’s giant kauri trees (Agathis australis) ooze resin from their bark, leaves and cones. This protects the tree by filling holes and damaged areas. It builds up in the forks of the tree, around the roots and on the ground underneath. Kauri can live for more than 1,000 years, over which time they produce a large amount of resin. Occasionally branches oozing resin drop to the ground, and eventually the tree dies and falls. Over time, the ground where kauri trees grew becomes a litter of wood and gum, which is often gradually buried by soil or drowned in swamps.
Names for gum
Kauri gum is sometimes called copal or – mistakenly – amber. Copal is a general term for resins used to make varnish. Amber is a hard, fossilised resin used to make jewellery, and much of it found in the northern hemisphere is millions of years old. There has been little carbon dating of kauri gum, but most is probably only thousands or tens of thousands of years old. It can accurately be called copal or resin, but in New Zealand it is usually called kauri gum.
Who took the forest?
Kauri forest once covered most of Northland, but when people arrived in New Zealand much of it had gone. Some believe this could have been due to climate change, volcanic activity, tsunamis or fires. Some Māori traditions tell of the trees being destroyed by the forest god Tāne as he struggled with his parents. Another – more fanciful – theory speculates that the culprits were giant aliens wielding chainsaws.
Where is it found?
Kauri gum is found naturally only in New Zealand, because kauri trees are endemic to the country.
Large amounts of gum have only ever been found in the northern North Island, although in the past, when the climate was warmer, kauri grew as far south as Southland. At one time much of Northland was a vast kauri forest, which stretched from coast to coast in places. By the time Polynesians arrived in New Zealand (1250–1300 AD), kauri forests only grew in pockets. The kauri’s current natural range is northwards from around the base of the Coromandel Peninsula.
Māori called kauri gum kāpia, and had many uses for it. They chewed fresh gum from trees, and softened older gum for chewing by soaking it in water and mixing it with the milk of pūwhā (common sow-thistle, Sonchus oleraceus). As gum burns readily, it was used to start fires or bound in flax to make a torch for night-time fishing. Gum was also used for moko (facial tattoos): the black soot from burnt gum was ground into a fine powder, mixed with oil or fat and applied to cuts in the skin.
One historian writes that ‘in the very early days the gum would be hanging down like huge bubbles all over the trees and that they could be knocked down easily. The ground too was covered with gum but its only use was for lighting fires.’ 1
Early European uses
In November 1769, the British explorer James Cook found kauri gum at Mercury Bay in the Coromandel, and mistakenly thought it came from mangroves. In October 1819 the missionary Samuel Marsden noted its correct source as the kauri tree, and in 1842 the explorer Charles Heaphy remarked that he had seen good quality varnish made from kauri gum.
An early consignment of gum was reportedly sent to London in the early 1840s to make fire-kindlers and marine glue. But its real value would be as an ingredient in varnish, which in the 1800s was made from the resins of various trees. Kauri gum was found to be superior to other resins, and by the mid-1840s was exported to manufacturers in London and America. An industry was born. Māori and European settlers set about digging gum from the ground.