Calling time on New Zealand's oldest tree species

Abstract

New Zealand’s largest and oldest living tree species, the kauri (Agathis australis), is threatened with extinction by an invasive pathogen, Phytophthora agathidicida. These conifers live for more than 2,000 years, reaching heights in excess of 50 metres and girths of up to 14 metres. They are cultural icons, regarded as living ancestors by the indigenous Maori people. With no known treatment against kauri dieback, we stress that the only immediate option to halt the soil-borne pathogen’s spread is complete closure of kauri forests.

This drastic proposal has met with strong resistance because of the economic implications of losing a million or so visitors every year. The collective action from mandated government agencies has so far been inconsistent and ineffective, despite reasonable resources. Indigenous and community groups are being left to develop their own management plans in isolation.

As scientists, we know that the losses we face are too catastrophic to risk piecemeal measures. The government must push for urgent research into controlling the pathogen. Until that is better understood, all kauri forests should remain shut