美國i-Tree系統應用於台灣都市林生態服務效益評估可行性研究

為全面了解整體都市林都結構的調查方法與樹冠層結構調查項目，如何精確地應用都市林生態系服務功能及效益評估上。本研究以美國林務署長期持續發展的i-Tree-Eco及i-Tree-Hydro系統模組為基礎，透過相關研究文獻，分析模組中都市林的結構的調查方法與調查項目的內涵。了解都市林冠層的調查項目如何應用於都市樹木碳儲存與淨吸存的推估方法、空氣乾沉降汙染物的移除及林冠與灌木層對降雨之逕流量控與水質改善的估算方法；也探究了他們的相關推估法則與計算公式。本研究特別強調都市林逢機取樣的樣區設置方法、都市樹木冠層的葉面積指數、生物量的調查與推算方法，以及如何引入土地覆蓋類型與數值地形、及土壤等因子，進行都市林區水平衡模式的計算。若能仔細參考本研究成果，將有利於發展本土都市林結構的調查方法，乾沉降空氣汙染物移除、都市林對雨水截流與水質改善等生態系服務功能的量化推算與金錢價值的效益評估的科學依據。

To comprehensively understand the survey methods for overall urban forest structure and the survey items of the canopy layer, and how to accurately apply these methods and items to the evaluation of urban forest ecosystem service functions and their benefits. This study is based on the i-Tree-Eco and i-Tree-Hydro modules long-developed by the U.S. Forest Service, and analyzes the connotations of survey methods and survey items for urban forest structure within these modules via relevant research literature. It clarifies how urban forest canopy survey items are applied to the estimation of urban tree carbon storage and net sequestration, the removal of atmospheric dry deposition pollutants, and the estimation of rainfall runoff control and water quality improvement by canopy and shrub layers; it also explores their corresponding estimation rules and calculation formulas. This study particularly highlights the sample plot setup method for random sampling of urban forests, the survey and extrapolation methods of leaf area index (LAI) and biomass of urban tree canopies, as well as how to incorporate factors such as land cover types, digital terrain data, and soil to calculate the regional water balance model of urban forest areas. If carefully referenced, the findings of this study will provide a scientific basis for developing indigenous urban forest structure survey methods, the quantitative estimation of ecosystem service functions including dry deposition air pollutant removal, rainwater interception and water quality improvement by urban forests, and the economic benefit assessment of such services.