植生工程中所使用的樹木材料,除了有水土資源保育功能外,也能吸存大氣中的溫室氣體CO_2,減緩溫室效應。本研究透過文獻資料蒐集與實際測量,建置一個包含了480種水土保持樹種之木材密度和碳含量資料庫。此資料庫內種階層的木材密度平均值為0.55 ± 0.13(g cm^(-3)),碳含量平均值為46.3 ± 2.2 %(g g^(-1))。比對六個生物量的估算公式後,本研究發現Chave et al.(2014)的公式能提供平均的樹木生物量估計值。資料庫使用者於野外植生工程施工地區內,測得胸高直徑≥ 5 cm樹木的胸高直徑、紀錄物種種類與樹高後,可應用本資料庫查詢木材密度及碳含量,套入生物量與胸高直徑的迴歸公式,估算樹木的碳存量。本研究成果可協助量化植生工程在碳吸存之貢獻,凸顯植生工程所能提供的生態系服務功能。
Trees used in vegetation engineering can conserve soil and water, sequestrer CO_2 from the atmosphere, and in turn reduce greenhouse effects. Through literature review and direct measurement, we established a database of wood density and carbon fraction for 480 tree species that can be used for soil and water conservation. In the database, the average species-level wood density was 0.55 ± 0.13 (g cm^(-3)), and the average carbon fraction was 46.3 ± 2.2 %. Comparing six biomass estimating equations, the equation in Chave et al. (2014) provided relatively moderate estimates. After identifying tree individual's species, measuring its diameter at breast height (DBH) and height in the field, database users need only query its wood density and carbon fraction in the database, and apply these variables to biomass allometric equations to estimate the carbon stored in the tree (minimum DBH is 5 cm). This process can be used to quantify the amount of carbon captured by vegetation engineering, and highlights the valuable contribution of soil and water conservation plants to ecosystem carbon sequestration services.