Estimating carbon stocks in stands of Podocarpus cunninghamii in the eastern South Island high country of New Zealand

The Land-Use, Land-Use Change and Forestry (LULUCF) sector of the Kyoto Protocol requires New Zealand to monitor changes in the country’s carbon stocks, including those within indigenous forests. Podocarpus cunninghamii Colenso was, in pre-human times, a dominant tree species within the forests of the South Island high country. Anthropogenic disturbance, primarily fire, has converted most of these forests to grassland. Despite this mass deforestation, remnant stands of Podocarpus cunninghamii still exist, and may represent important point sinks of carbon. This study provides first estimates of existing above- and below-ground carbon stocks in high country stands of Podocarpus cunninghamii and presents a preliminary model of Podocarpus cunninghamii carbon sequestration rate. Carbon stocks within high country stands of Podocarpus cunninghamii range from 7.3 t ha-1 in the drylands to 130.1 t ha-1 in the wetter areas. Estimates based on tree ring widths indicate a high country-wide Podocarpus cunninghamii carbon sequestration rate of 0.1 – 0.5 t ha-1 yr-1 for 250 – 1000 stems ha-1, respectively.