Kauri dieback threatens more than trees—it could change how much carbon forests store

Kauri trees, some of New Zealand's tallest and longest-lived, hold significant cultural value and tremendous carbon storage capacity. However, these giants face a growing threat from kauri dieback, a disease caused by the water mould Phytophthora agathidicida. As the disease spreads, kauri lose foliage, branches, and eventually die, leading to the loss of stored carbon in their living biomass.

Our research reveals that areas with severe dieback lose more carbon annually compared to healthy stands, with the difference averaging 1.8 tonnes of carbon per hectare per year. The largest carbon losses occur in mature forests containing the most carbon, as the biggest trees are more likely to succumb to the disease. While our study focused on living vegetation, it highlights the importance of protecting mature kauri forests to maintain the carbon stored in these ecosystems.

Preventing disease spread is crucial, as measures such as phosphite treatments aim to slow dieback progression. Visitors can contribute by staying on marked tracks and cleaning footwear before entering and leaving kauri forests.