灰綠基礎設施之間：臺北市行道樹維護治理

Between Gray and Green Infrastructures: The Governance of Street Trees Maintenance in Taipei

本文探討臺北市行道樹維護的治理，包括治理體制的形成、爭議及其應對，藉此考察夾在道路等灰色基礎設施與日益受重視的綠色基盤之間的樹木，如何體現都市治理場域的複雜性。筆者結合協力治理與基礎設施研究等觀點，探討基礎設施僵固性、樹木生機、維護權責劃分，以及市民多重利益之間的衝突，如何在都市生活中展開。筆者首先探討臺北市行道樹協力治理體制的構成，以及隨著社會變遷和爭議而展開的試驗和調整。接著，筆者討論舊市區行道樹的維護難題，關注竄根、落果、落葉、蟲害等，生物力量與人造環境的衝突，以及行道樹維護權責劃分的爭議。筆者在結論中強調，行道樹兼有灰色與綠色基礎設施的雙重特性，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。於是，都市治理必須考慮非人行動者的作用力，方能協調基礎設施穩固性與生態靈活性的難題。據此，本文也在「不止於人」的都市研究中，凸顯了治理體制在中介及塑造人與非人之間關係上的重要地位。

This paper explores the governance of street trees maintenance in Taipei City, focusing on the formation of governance structures, the controversies that have arisen, and the responses to those controversies. It examines how trees—positioned between grey infrastructure such as roads and an increasingly valued green infrastructure—embody the complexities of urban governance. Drawing on perspectives from collaborative governance and infrastructure studies, the paper investigates how the rigidity of infrastructure, the vitality of trees, the division of maintenance responsibilities, and the conflicting interests of citizens unfold within urban life. The paper first examines the composition of Taipei’s collaborative governance system for street trees, as well as the experiments and adjustments that have emerged in response to social change and public disputes. It then turns to the challenges of maintaining street trees in older urban areas, focusing on issues such as invasive roots, falling fruit and leaves, and pest infestations—biological forces that conflict with the built environment—and the controversies surrounding the division of responsibility for tree maintenance. In conclusion, the paper argues that street trees embody the dual characteristics of both grey and green infrastructure, caught between the rigidity of the former and the metabolic flexibility of the latter. Thus, urban governance must take into account the agency of non-human actors in order to navigate the tension between infrastructural stability and ecological adaptability. Accordingly, this paper also highlights the crucial role of governance regimes in mediating and shaping the relations between humans and nonhumans within the field of“more-than-human”urban studies.