The Stadtgärtnerei Basel commissioned the Zurich University of Applied Sciences to accompany defined tree plantings with biochar-enriched substrate and to investigate its effect on vitality. The biochar is incorporated into compost and used as a substrate additive during planting. The trees are assessed and their vitality and growth behaviour are measured on the respective substrates. The substrates are analysed and evaluated for their nutrient dynamics, gas exchange and structural stability. The measurements and assessments are carried out annually according to a developed experimental design. The aim of the project is to determine which composition of the substrate produces the best results. For this purpose, trees with different substrate compositions and a control group are planted and analysed.