The “Sponge City” principle, based on the Stockholm model, is the empirically proven infrastructure solution for climate-resilient cities. We provide the core component: the biochar-based fine substrate for urban trees—developed in collaboration with the City of Graz and proven effective after six years of open-root growth.

Planting trees is becoming increasingly important in cities, both to cool them and to better manage water flows. Especially where there is no separate sewer system, this innovative method of tree planting pays for itself within a few years through savings in sewer maintenance. In addition, the trees grow vigorously and healthily and are significantly better able to withstand increasingly severe weather events. There are virtually no more failures after pla ...