• We offer an evaluation of technical experts' and community members’ knowledge and perception on the use of nature-based solutions for coastal protection across multiple European countries. • For technical experts, a good level of knowledge correlated with a higher level of consciousness regarding nature-based solutions employment. • Compared to technical experts, community members showed a more limited knowledge on nature-based solutions but overall support for their implementation with desire for sustainable and eco-friendly management practices. • Results offer initial insights for coastal planners, guide larger-scale studies, inform community-scale research, and highlight opportunities to improve knowledge exchange. The use of nature-based solutions (NBSs) in coastal management strategies is gaining popularity, with broad consensus on the critical role of public engagement in assessing the benefits of sustainable practices. However, the number of existing studies that tackle public knowledge and perception of NBSs in coastal management is still low and most studies only target specific communities. As a result, it is challenging to determine whether these findings reflect general trends or are influenced by unique circumstances in the studied communities. To clarify this, it is essential to assess the broader public perspective on the use of NBSs in coastal management. Here we assess the results of a pilot study conducted across Europe to evaluate technical experts’ and community members’ knowledge and perception on the use of NBSs for coastal protection. The evaluation was conducted by collecting responses provided to a survey distributed via social media. The study focuses on three countries: United Kingdom, Netherlands and Italy. The survey revealed common trends across the three countries. There is general support for the application of these solutions in coastal management amongst both groups, which correlates positively with concern for flooding and erosion. While technical experts have a solid understanding of the topic, which corresponds to a considerable degree of awareness and a higher level of consciousness regarding NBSs implementation, the community members’ support is accompanied by an overall more limited knowledge of what NBSs entail (higher amongst residents of coastal areas) but also a considerable desire for more sustainable and eco-friendly management practices. While offering an initial insight into public perceptions of NBSs for coastal planners, these results can also guide larger-scale perception studies, provide a framework for interpreting community-scale research, and highlight opportunities to improve knowledge exchange between technical experts and community members.

• First experimental field trial to measure the climatic benefits of urban tree irrigation. • Irrigation increases the benefits of trees as nature-based solutions. • Tree irrigation leads to air temperature reductions up to 0.67°C and humidity increase up to 5.98 %RH. • Diverse behaviour of soil water potential under urban trees due to different irrigation strategies. With regard to the rising temperatures due to climate change and the intensification of the urban heat island effect (UHIE), nature-based solutions (NbS) are becoming increasingly important. In particular trees can mitigate the effects of the UHIE by shading and through transpiration. As trees suffering from heat and drought decrease their cooling properties under stress, this study investigates the effects of supplementary irrigation to increase the cooling capacities. The research focus is on how different irrigation practices can directly support the cooling effects of young urban trees as a NbS. The novelty of our study is the direct field trial comparison of irrigation quantities in combination with the quantification of their microclimatic effects. From May to September 2024, we observed three groups of Tilia cordata (unirrigated, monthly irrigated, weekly irrigated) in the city of Hanover, Germany, and measured air temperature and relative humidity (RH) within the tree crowns. The results show, that an investment in tree irrigation results in an increase of cooling capability of up to -0.67°C and up to +5.98 %RH on hot days over 30°C. Urban tree care is more than just keeping trees alive by minimizing water use, trees are a valuable resource that we can benefit from by using water wisely. Future-oriented tree irrigation, which not only ensures the survival of the trees but also promotes their natural functions, optimises the urban climate in a natural way.