Successional processes ultimately determine and define carbon accumulations in forested ecosystems. Although primary succession on wholly new substrate occurs across the globe, secondary succession, often following storm events or anthropogenic disturbance, is more common and is capable of globally significant accumulations of carbon (C) at a time when offsets to anthropogenic carbon dioxide (CO ) emissions are critically needed. In Hawai'i, prior studies have investigated ecosystem development during primary succession on lava flows, including estimates of C mass accumulation.