灰綠基礎設施之間：臺北市行道樹的維護治理

本研究探討臺北市行道樹的維護治理，包括各種涉及行道樹的爭議事件及其應對方式，並藉此考察夾在道路等灰色基礎設施，以及日受重視的綠色基盤之間的樹木，如何體現了都市治理的複雜性。本文的材料取自既有研究、官方文獻，主管機構的相關人員、市民組織、專業技術者訪談，以及田野觀察，並且運用政治生態學取向、基礎設施研究及協力治理等觀點加以分析，提出都市自然治理、公私劃界之爭，以及都市僵固性與樹木生機的基本衝突等議題。本研究首先概述臺北市行道樹的發展，掌握行道樹從權力象徵與都市景觀，轉化為提供生態系統服務、體現市民記憶的功能疊加，分析行道樹部署的歷史過程。接著，作者以過往行道樹維護與爭議的案例，及新發展市區灰綠基礎設施之協調，作為分析策略，爬梳早期發展市區尚未發展成熟的樹木治理知識、密集配置的建築型態，冒現竄根事件，並令行道樹的部署緊挨民房，衍生活生生的樹木與灰色基礎設施之衝突。再者，晚近行道樹作為都市綠色基礎設施之功能，引發許多都市行道樹移植的護樹運動。這些案件顯示行道樹維護不僅是種植或栽植管理的技術，而是牽涉複雜的維護治理過程，隱含都市多重行動者的相互交纏。反觀新發展市區部分重劃區——信義計畫地區、大彎北段地區——以土地使用分區管制要點，及都市設計準則所規劃的大街廓型態、寬闊人行道、帶狀樹穴植栽方式，呼應了環境主義治理範型。此外，晚近環境主義興起，政府部門亦逐漸重視綠政政策的擬訂，如林蔭大道四年計劃、綠網成蔭十五年計畫等專案類型的樹木治理政策。新的管制措施師法早期市區的灰綠基礎設施衝突，一方面減緩了行道樹爭議，但是一方面亦成為市政府政治性的施政作為，仍是重視政績亮點大於實質作為，因而免不了忽視樹木治理過程最重要，也最耗費資源的維護作業。最後，本研究以都市政治生態學視角結合協力治理概念，指出都市發展過程行道樹成為都市治理場域。行道樹兼有灰色與綠色基礎設施的特質，成為跨界、多重、受擠壓的問題化過程，卻因此陷於灰色基盤的僵固性與綠色基盤的新陳代謝彈性之間，隱含灰色及綠色基礎設施之協調，與治理場域之轉化。行道樹中介於灰綠基礎設施之間，因而需要治理的介入，反映傳統公部門治理體制的轉變。這個轉變過程涉及了各種不同行動者之間的權力關係。公部門技術官僚、各種民間團體（專家學者、廠商、市民、護樹人士與環境團體等）的協力治理，構成行道樹維護治理的權力網絡，亦形構行道樹治理過程的維護政治。

關鍵字

環境治理；協力治理；都市治理；都市政治；政治生態學

並列摘要

This article discusses the maintenance and governance of street trees in Taipei City, including various controversial incidents involving street trees and how to deal with them. It also examines how the trees sandwiched between gray infrastructure such as roads and green bases that are increasingly valued, reflecting the complexity of urban governance.The material of this paper is taken from existing research, official documents, interviews with relevant personnel of competent institutions, civic organizations, professional experts, and field observations. Furthermore, this article use the perspectives of political ecology orientation, infrastructure research and collaborative governance to analyze, point out the issue such as natural governance, the debate over public-private demarcation, and the fundamental conflict between urban rigidity and the vitality of trees . The author firstly outline the development of street trees in Taipei City , grasps the transformation of street trees from a symbol of power and urban landscape to a functional superposition that provides ecosystem services and reflects citizens' memory, and analyzes the historical process of street trees deployment. Next, the author uses past cases of street trees maintenance and disputes, as well as the coordination of gray-green infrastructure of the newly developed urban as an analysis strategy, and organize the early development of urban areas has not yet developed mature knowledge of trees management and densely configured building types, which led to the occurrence of root-crossing incidents, and the deployment of street trees close to residential houses, resulting in the conflict between living trees and gray infrastructure. Furthermore, the recent function of street trees as urban green infrastructure has brought about many tree-protection campaigns for urban street trees transplants. These cases show that street trees maintenance is not only a technique of planting or planting management, but involves a complex maintenance governance process, implying the intertwining of multiple actors in the city. In contrary, the partial rezoning of newly developed urban areas—Xinyi Project Area, North Dawan Area—Based on the regulations of building and land use zoning and the urban design criteria , the super street block profile, wide sidewalks, and strip tree planting method, echoing the environmentalist governance paradigm. In addition, with the recent rise of environmentalism, Taipei government have gradually paid more attention to the formulation of green policy policies, such as the four-year plan for boulevards and the 15-year plan for green nets. The new regulations combat grey-green infrastructure conflict in early urban areas. On the one hand, it alleviates the street trees controversy, but on the other hand, it also becomes a political act of the municipal government. It still pays more attention to the highlights of the political achievements than the actual actions, so it is inevitable to ignore the tree governance process. The most important and most resource-intensive maintenance operation. Finally, this article combining the perspectives of urban political ecology and the concept of collaborative governance, and points out that street trees have become the field of urban governance in the process of urban development. Street trees have the characteristics of both grey and green infrastructures, and become a cross-border, multiple, but they are trapped between the rigidity of the grey base and the metabolic flexibility of the green base, implying the coordination of gray and green infrastructure and the transformation of the governance field. The street trees is between the gray and green infrastructure, which requires the intervention of governance, reflecting the transformation of the traditional public sector governance system. This transformation process involves power relations between various actors. The collaborative governance of public sector technocrats and various civil organizations (experts, scholars, manufacturers, citizens, groups of tree-protection, and environmental groups, etc.) constitutes a power network for the maintenance and governance of street trees, and also forms the maintenance politics of the street tree maintenance and governance process.