Silent extinctions: how neglecting the ecological value of habitat trees threatens urban biodiversity and ecosystem services

Abstract Urban biodiversity is critically undermined by the loss and mismanagement of habitat trees—living or dead trees providing essential microhabitats for specialized organisms. Despite large-scale tree planting initiatives, mature and senescent trees remain largely neglected in urban planning and tree management practices. This paper highlights the irreplaceable ecological role of habitat trees in urban landscapes and analyse how current tree management practices often prioritize perceived risk and aesthetics over ecological integrity. We identify the lack of practical recognition of their ecological value—as well as the absence of standardized evaluation methods—as major obstacles to effective conservation. Building on recent evidence, we propose management approaches that combine ecological criteria with arboricultural practice, promoting uneven-aged urban forests and the recruitment and mapping of habitat trees as key strategies for long-term resilience. We also frame concepts such as ecological non-substitutability , the net-benefit balance in tree management, and the 4R rule (Respect, Retain, Reassess, Reduce) as tools for integrating biodiversity goals into routine care operations. We argue that the loss of habitat trees should be regarded as equivalent to the loss of threatened species, as they represent key functional elements in the urban landscape and their loss cannot be replaced in the short to medium term. Finally, we argue that fostering public and professional education on the cultural and ecological value of habitat trees is essential to advancing a conservation-oriented culture of urban tree management.