Embracing ambivalence as the key to promoting tree diversities as nature-based solutions in European cities

Abstract

Urban trees are recognised worldwide as one of the most sustainable and effective nature-based solutions to combat the effects of climate change and improve the quality of life for city dwellers by cooling the air, absorbing pollutants and damping noise. Along with protection from flooding and soil retention/restoration, trees also symbolise beauty, aesthetic quality, and orientation in urban spaces. Nevertheless, the relationship between street/park trees and urban society is highly ambivalent when it comes to pollen emissions and allergies, but also due to clearing space for new housing, road extensions, or parking places, which is accepted by large sections of urban society. In addition, climate change in itself is a major challenge to urban trees, as they suffer from drought and are increasingly attacked by pests. Urban planners and community partnerships have already developed a range of strategies (from more expert-led approaches to participatory co-design and actions) to maintain, increase, and diversify tree cover. They have also created new habitats and at the same time caused competition for space in the city, where every square centimetre is fought over. Using the case studies from Central and Eastern Europe and also considering the examples from Northern America and Asia, this commentary highlights the ambivalent relationship between humans and nature in regard to urban trees. It also demonstrates that the acceptance of this ambivalence can be a key to the conservation and maintenance of urban biodiversity through the involvement of different stakeholders including citizens.