Spontaneous natural redevelopment of urban voids in small cities: planning challenges from transient woodlands

Biodiversity in urban areas is significantly connected to anthropogenic actions. For example, novel woodlands are growing on urban voids previously intensively used by humans. These voids with spontaneously developing vegetation generally are not the result of urban planning and zoning, but rather the consequences of temporary or permanent economic and social changes. Here we focus on the implications of transient woodland patches for nature conservation, ecosystem services provision and urban planning, showing the examples of Padova and Bibione, two northern Italian small cities. Alien tree species are an important component of these woodlands and can influence understory species composition. However, also typical species of native communities are forming these forest patches. These woodlands are heterogeneous and different urban features can play a role in shaping their biological communities. Therefore, these green infrastructures provide further variability to green urban spaces, even in small cities. Multiple ecosystem services may derive from these woodlands highlighting their important role to ensure sustainability in cities. Novel planning and management solutions are needed to adequately recognize and promote the benefits deriving from the dynamic maintenance of these transient forests.