Carbon pools of biomass and dead organic matter in typical forest ecosystems of Tibet: A new estimation based on the first forestry carbon sequestration monitoring undertaken in China

Abstract

AbstractThe forest ecosystems of Tibet function as important carbon sinks. However, previous estimates of carbon budgets have included large uncertainties owing to the limitations of data acquisition and the method of estimation. In this study, IPCC and model estimation methods have been used to calculate all the sectors of carbon stocks in typical forest vegetation of Tibet and explore the biogeographical patterns and potential drivers of these pools. The results showed that the total carbon pools of biomass and dead organic matter in six typical forest ecosystems in Tibet was 457.67 Tg C, of which 10.52–164.85 Tg C (76.53%) was stored in aboveground biomass, 1.87–59.37 Tg C (22.07%) in belowground biomass, 0.01–2.75 Tg C (0.73%) in the forest understory, 0.02–1.57 Tg C (0.53%) in litter, and 0.01–0.27 Tg C (0.14%) in dead wood. These carbon reserves are primarily distributed in mature and over mature forests, comprising 48.89% and 31.58%, respectively. Geographical location and natural conditions affect the carbon sequestration capacity of the Tibetan forest ecosystems that decreases from southeast to northwest. An analysis also suggests that the canopy and tree densities have some effect on the carbon sequestration efficiency in different carbon pools. This is primarily because these two indicators have a greater impact on the growth of trees. In addition, it was found that the forests of Abies fabri and Platycladus orientalis had the highest and lowest degrees of carbon fixation, respectively.