A. Thonemann (2024)
The application of biochar as a substrate supplement on the vitality of four typical street tree species in Berlin,
Masterarbeit, FU-Berlin

Abstract

Trees in urban environments face significant challenges due to climate change-induced stressors, like extreme weather events and soil degradation. Biochar has emerged as a promising solution to enhance tree vitality and soil health in urban settings. This study investigates the impact of biochar as a substrate supplement on the growth, water supply and nutrient uptake of four street tree species: Ulmus “columella”, Prunus avium, Liquidambar styraciflua, and Tilia cordata. Different biochar treatments, including control, 30% (PK30), and 70% (PK70) biochar content, were applied to assess their effects on tree performance. Results reveal species-specific responses to biochar application, with varying effects on growth, nutrient uptake, and soil moisture-water uptake dynamics. While biochar shows potential for improving tree growth and water retention, its efficacy depends on factors such as species traits and biochar concentration. The findings suggest that tree species with higher metabolic rates may possess mechanisms for accessing the more tightly bound nutrients and water in biochar, whereas those with conservative strategies may lack the structures needed to efficiently utilize these resources. Moreover, negative consequences appear to outweigh the benefits of the 70% biochar amendment. This underscores the importance of considering species-specific responses and ecological context when implementing biochar as a soil amendment for urban tree management. Further research is needed to explore the complex interactions between biochar, tree species, and soil dynamics to optimize its use for sustainable urban forestry practices.