WHY ARE KAURI SO IMPORTANT?
The largest kauri alive today is Tane Mahuta with a diameter of 4.6m and height of 52m. It is estimated to be between 1200 and 2000 years old. One of the largest kauri trees ever recorded was 'Kairaru of Tutamoe' with an estimated diameter of 6.4m and a height of 65m. Unfortunately, Kairaru was destroyed in a fire before 1900.
Kauri are naturally found throughout the upper North Island, in the Northland, Auckland and Waikato regions, and in parts of the Bay of Plenty. If you’re in natural bush and you’re in the upper North Island, it’s likely you’ll be near a kauri. Kauri have existed as a species for around 20 million years.
Kauri are a cornerstone of the indigenous forests of the upper North Island. They are also one of the longest-living tree species in the world (reaching ages of 1000 years-plus), as well as the largest.
Mature trees have an average diameter of two metres. These giants can live for more than 1000 years, The biggest can reach heights of over 50 metres, with girths of more than 13 metres.
The site, soil and temperature determine the type of forest that naturally contains kauri. There is no 'typical kauri forest': kauri can exist as solitary trees in broad leaf dominant bush or as dense stands.
When in a forest environment, mature kauri emerge above the canopy of other native trees. The lower forest can contain a variety of tree species including tōtara, tānekaha, taraire, tawa, miro and rewarewa, alongside juvenile kauri. At the shrub level a range of plant species can be found including tree ferns, nikau palms, lancewood, hangehange and mingimingi. Kauri grass is commonly found covering the ground beneath kauri. A range of orchids and epiphytic plants are also often found perching amongst the branches of mature trees.
Kauri growth requires high light levels but can tolerate low soil nutrient levels. Consequently, kauri seedlings are often suppressed under dense canopies of faster growing species in fertile soils. As a result kauri are often restricted to less fertile soils on ridges or establish en masse after a large disturbance such as a fire.
The plants, animals and ecosystems that kauri create and support are indirectly under threat from kauri dieback disease, as without kauri they cannot live and develop the way they do now.
Early European Settlers
Kauri were prized by the early European settlers, who felled many of the great kauri giants for profit. The timber was valued for its strength and ability to withstand sea-water conditions (ideal for ship masts and hulls).
Gum was largely collected from the ground, however, some was gathered by deliberately injuring or 'bleeding' trees.
By 1900, loggers had cleared most kauri forests. Kauri gum was also used, in varnishes, paint, linoleum and to create ornaments.
Estimates of the extent of kauri forest before European settlement in New Zealand are between 1 million and 1.5 million hectares. This was reduced to an estimated 7000 hectares (0.5% of original extent) by exploitation for timber or destruction by fire and clearance in the late 19th and early 20th century.
Kauri logging gang 1840s, NZ Native Riverwood
"Today there are only around 7,500 hectares of mature kauri left."