臺北市都市樹木重要效益評估之研究

Abstract

都市中的樹木為重要的綠色資源，可以帶來多樣的生態系服務效益提升都市的環境品質，為了維持效益的提供並改善可能產生的問題。都市樹木需要進行妥善的管理維護，而了解居民對於都市樹木之效益與問題的感受，以及如何提升居民支持及參與保護都市樹木，是都市樹木管理之重要參考資訊，此外，透過準確量化評估都市樹木之生態系服務效益，亦可提供科學化之管理依據，然而國內相關研究仍付之闕如。因此本研究以臺北市為案例，首先透過問卷調查發現居民最重視都市樹木帶來之「碳吸存」效益，而對都市樹木產生的問題除「病蟲害問題」外均認為不嚴重；而根據延伸計畫行為理論模型(Extend TPB)結果，居民對都市樹木之「知覺有用性(PU)」與「知覺樹木效益(PTB)」之認知，會正向影響保護都市樹木之「態度(ATT)」與「行為意向(BI)」，因此未來可透過教育與推廣樹木之有用性以及生態系服務效益，提升居民對保護都市樹木的態度，以及支持與參與保護都市樹木的行為意向。此外，本研究針對居民較重視之「碳儲存及吸存」及「空氣污染移除」效益，應用i-Tree Eco完成量化計算，結果顯示臺北市碳儲存量最高之前三名樹種為榕樹(Ficus macrocarpa)、白千層(Melaleuca leucadendra)與樟樹(Cinnamomum camphora)，碳吸存量最高的樹種則為榕樹、樟樹以及茄苳(Bischofia javanica)，空氣汙染移除量最高之前三名樹種為榕樹、樟樹及白千層，各項效益量化結果可作為不同區域與管理措施效果參考。最後，為瞭解i-Tree Eco是否適用於臺北市樹木效益量化分析，本研究建立茄苳、樟樹與楓香(Liquidambar formosana)之材積式與胸徑生長率式，完成碳儲存及吸存量本土化評估，結果發現以i-Tree Eco估算臺北市樹木之碳儲存及吸存量有高估的可能，建議i-Tree Eco之分析結果僅作為相對比較使用，為準確估算碳儲存及吸存量應建立各都市樹種之本土化模式。

Urban trees are significant green resources that enhance the environmental quality of cities and provide diverse benefits to residents. To maintain these benefits and address potential problems, urban trees require proper management and maintenance. Understanding residents' perceptions of the benefits and problems associated with urban trees, as well as how to increase their support and participation in urban tree protection, is crucial for urban tree management. Furthermore, accurately quantifying the ecosystem services provided by urban trees can offer scientific references for management. However, related research in Taiwan is still lacking. Thus, this study takes Taipei City as a case study. Through a questionnaire survey, it was found that residents prioritize the "carbon sequestration" benefits of urban trees and do not perceive most of the problems caused by urban trees, except for "pest and disease issues". Based on the Extended Theory of Planned Behavior (Extend TPB) model, residents' perceptions of the "perceived usefulness (PU)" and "perceived tree benefits (PTB)" of urban trees positively influence their "attitude (ATT)" and "behavioral intention (BI)" towards protecting urban trees. Therefore, future efforts could focus on education and promotion of the usefulness and ecosystem service benefits of trees to enhance residents' attitudes and behavioral intentions towards supporting and participating in urban tree protection. Additionally, this study applied the i-Tree Eco to quantify the benefits that residents value most, such as "carbon storage and sequestration" and "air pollution removal." The results indicate that the top three tree species in Taipei City for carbon storage are Ficus macrocarpa, Melaleuca leucadendra, and Cinnamomum camphora, while the top species for carbon sequestration are Ficus macrocarpa, Cinnamomum camphora, and Bischofia javanica. For air pollution removal, the top three species are Ficus macrocarpa, Cinnamomum camphora, and Melaleuca leucadendra. These quantified benefits can serve as references for different regions and management measures. Finally, to assess the applicability of i-Tree Eco for quantifying tree benefits in Taipei City, this study established volume equations and DBH relative growth rate equations for Bischofia javanica, Cinnamomum camphora, and Liquidambar formosana, completing a localized evaluation of carbon storage and sequestration. The results suggest that i-Tree Eco may overestimate the carbon storage and sequestration of trees in Taipei City. Therefore, it is recommended that the results from i-Tree Eco be used only for relative comparisons, and that localized models for various urban tree species be established for accurate carbon storage and sequestration estimates.