PROBLEM TO BE SOLVED: To provide a method for estimating the ratio of carbon dioxide emission amount through dividing the carbon dioxide emission amount of soil respiration and above-ground plant part respiration as component and carbon dioxide emission source of ecosystem respiration in a forest.SOLUTION: This method for estimating the ratio of carbon dioxide emission amount comprises setting a relational expression between carbon dioxide amount cE of ecosystem respiration, carbon dioxide amount csoil of soil respiration and carbon dioxide amount cav of above-ground plant part respiration, and stable carbon isotope &delta13CE of carbon dioxide of ecosystem respiration, stable carbon isotope &delta13Csoil of carbon dioxide of soil respiration, and stable carbon isotope &delta13Cav of carbon dioxide of above-ground plant part respiration, as [(&delta13CE×cE) equals (&delta13Csoil×csoil+&delta13Cav×cav)], and calculating the ratio of the carbon dioxide amount of soil respiration and the carbon dioxide amount of above-ground plant part respiration from the values of &delta13CE, &delta13Csoil and &delta13Cav.COPYRIGHT: (C)2007,JPO&INPIT【課題】森林内の生態系呼吸の構成要素であり二酸化炭素排出源である土壌呼吸と植物の地上部の呼吸の二酸化炭素放出量を分離して評価することを可能とする。【解決手段】生態系呼吸の二酸化炭素の量cE、土壌呼吸の二酸化炭素の量csoil及び植物の地上部の呼吸の二酸化炭素の量cav、並びに、生態系呼吸の二酸化炭素の炭素安定同位体比δ13CE、土壌呼吸の二酸化炭素の炭素安定同位体比δ13Csoil及び植物の地上部の呼吸の二酸化炭素の炭素安定同位体比δ13Cavの間の関係式をδ13CE×cE=δ13Csoil×csoil+δ13Cav×cavとし、δ13CE、δ13Csoil及びδ13Cavの値から土壌呼吸の二酸化炭素の量と植物の地上部の呼吸の二酸化炭素の量の比率を算出するようにした。【選択図】図1
