Prolific in the Past
Kauri are among the world's mightiest trees, growing to more than 50 metres tall, with trunk girths of up to 16 metres. They covered much of the top half of the North Island when the first people arrived around 1000 years ago.
Forests Exploited
The arrival of European settlers last century saw the decimation of these magnificent forests. Sailors quickly realised the trunks of young kauri were ideal for ships' masts and spars and settlers who followed discovered the mature trees yielded sawn timber of unsurpassed quality for building.
Maori used their timber for boat building, carving and housing and their gum for starting fires and chewing (after it had been soaked in water and mixed with the milk of the puha plant).
The gum, too, became essential in the manufacture of varnishes. Gum was obtained through digging, fossicking in treetops, or, more drastically, by bleeding live trees. The exploitation of forests increased with the demand for more and more cleared farmland. Kauri forests once covered 1.2 million hectares; now they have been reduced to 80,000 hectares.
Pressure to Protect
There are calls for a national park comprising all the substantial scattered remnants of kauri forest. Adolescent trees have straight pole trunks and a distinctive narrow conical crown. As the trees mature the trunk thickens and the lower branches are shed, resulting in the clean, straight trunk of the adult kauri.
Kauri forests are home to many other trees and plants including large trees like taraire, kohekohe, towai and rata, with diverse understory and shrub layers beneath the canopy.
A New Threat
Commonly known as PTA, Phytophthora taxon Agathis is a microscopic fungus-like plant pathogen (a disease causing agent) that only affects kauri. Recent research has identified PTA as a distinct and previously undescribed species of Phytophthora.
Symptoms include yellowing of foliage, loss of leaves, canopy thinning and dead branches. Affected trees can also develop lesions that bleed resin, extending to the major roots and sometimes girdling the trunk as a ‘collar rot'. PTA can kill trees and seedlings of all ages.
You can help prevent spreading of the disease by ensuring your shoes and other gear are clean before you enter, and after you leave, the park. When placing the cache, there was disinfectant provided at the trail head for this purpose. Additionally dogs should be kept on the leash at all times and kept away from any kauri trees.
kiwicouple & kiwifeet
