Abstract:
This study investigated how carbon can be sequestered in a planted native forest. The study location is Tiritiri Matangi Island which experienced the land degradation and deforestation since Maori occupation and European settlement for their purposes of cultivation and farming activities. A restoration plan began in 1983 with the main aims of replanting and translocation. This project is quite successful, and current Tiritiri Matangi Island is an open sanctuary that provides pest-free habitat for a number of rare and endangered species. Vegetation plots were used to measure key variables to enable the above-ground carbon estimation. A set of soil samples were also taken, including the vegetation plots, to enable estimation of soil carbon. Two different approaches were used to estimate the overall carbon accumulation of the planted forest. These averaged to a total of 10,736.3tC accumulated in the trees since the replanting started in 1984. The per hectare value of 131.4tCha-1 is consistent with other studies, as is the mean rate of carbon accumulation of of 5.3tCha-1yr-1. Under the planted forest there is an estimated soil carbon stock is 6424.7tC (78.6tCha-1). This is very similar to analyses from 1980, suggesting there has yet to be significant additional carbon accumulating in the soil under the planted forest. This study also suggested the best planting scheme for carbon sequestration on Tiritiri Matangi Island would be Pohutukawa ‘dominant’ forest. But due to the very low or no regeneration underneath the Pohutukawa and very low usage by birds compared to other species, it does not provide good habitat.
