Comparative Study Using Three Estimation Methods for Carbon Sequestration in the Plain Area

• Main Authors: Chung-I Chen, 陳忠義
• Other Authors: Ya-nan Wang
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/xqv23h

博士 === 國立臺灣大學 === 森林環境暨資源學研究所 === 105 === In this study, we used tree growth, photosynthesis measurement, and eddy covariance methods to estimate carbon sequestration in 12 plantation species in the Wan-Long farm. The tree growth method was based on complete enumeration of sample trees; the photosynthesis measurement method was based on construction of the light-response curve and measurement of leaf area index to estimate carbon assimilation; and the eddy-covariance method was based on measurement of CO2 exchange using instruments on a flux tower. In 2010, the woody tissue in this site fixed 23.36 Mg CO2 ha-1. The average CO2 sequestration was 22.8 Mg ha-1 yr-1, with large variation among years. The average woody net primary production was 4.13 Mg C ha-1 yr-1 as estimated by the tree growth method, and 4.34 Mg C ha-1 yr-1 as estimated by the photosynthesis measurement method (2011–2014). Thus, the significant positive correlation between the two methods provides confidence in the results. The eddy covariance-based net ecosystem production showed a similar pattern to, and a significant correlation with, photosynthetic-based carbon sequestration. According to the regression model, Melia azedarach might be the largest carbon sink among the 12 species. On the stand scale, carbon sequestration ranged from -0.88 to 4.25 Mg C ha-1 yr-1 during 2010–2014, and was 1.80 Mg C ha-1 yr-1 on average. The relative humidity, soil water content, and wind speed were the main factors affecting carbon sequestration. Therefore, the plantations were the main contributors to carbon sequestration in the stand, and the entire stand in the Wan-Long farm sequestered 522 Mg C yr-1. Therefore, we recommend Melia azedarach as the plantation species for the purpose of carbon sequestration in this site, but not Fraxinus formosana, Cinnamomum burmannii, Terminalia catappa, Pongamia pinnata, and Sapindus mukorossi. The flux tower is used for continuous long-term monitoring of the carbon–water budget and microclimate data; however, other estimating methods are required to understand the contribution of each species in the forest ecosystem. The use of a combination of these methods can aid in accurate estimation of carbon sequestration at different temporal and spatial scales. Additionally, this estimation can provide plantation species information for forest management.