The Role of Deciduous Tree Species in Adapting Urban Spaces to Changing Climate Conditions

Urban greening has the potential to cool surrounding areas through shading and evaporation from vegetation. The silver lime (Tilia tomentosa) is becoming increasingly important as it turns the silvery underside of its leaves upwards in intense sunlight, which could help to reduce heat. This research project aims to investigate leaf-rotating tree species as an adaptation strategy for urban areas in the face of climate change. The focus is on analysing how this behaviour influences the albedo and reduces surface temperatures under the tree canopy.

The study is conducted in Kaiserslautern, Germany, using thermal imaging and temperature measurements to assess air temperature reduction under the canopy and around the trunk. In addtion, surface temperature changes in the canopy due to leaf albedo will be quantified. Thermal images of nearby buildings help to assess how radiation reflected from the leaves affects the façades. Close-up images of the leaves track the duration of the leaf-turning process and its temporal variations. The stage of development of the trees is taken into account as different strategies can be used at different stages of life.

The measurements are taken on summer days with temperatures above 25°C, low wind and clear skies. If silver lime trees are shown to have a local cooling effect, this research could provide recommendations for urban planning, particularly regarding integrating appropriate green infrastructure in urban regeneration projects. These findings could help to reduce the urban heat island effect and influence design strategies for urban spaces.