Stockholmer Baumpflanzsystem im Versuch

The HBLFA-Schönbrunn is currently investigating the new Stockholm tree planting system (often referred to as the "sponge city"). Even though this system has proven successful in many places and is already being implemented in numerous Austrian cities, many questions remain. One of these questions is the selection of the right tree species. Six different tree species are being tested to see how they cope with the fluctuating water levels in this new stone substrate. The same trees are also being planted simultaneously in open topsoil to allow for this comparison. Furthermore, in this video, we show you a completely new channel and shaft system that uses a simple valve to direct salt-laden winter water directly into the sewer. This new system also features the option of first filtering the incoming water through a soil filter before it enters the sponge city and thus reaches the tree's root zone. This urban tree planting system is therefore becoming increasingly professional and easier to implement. This experiment is particularly exciting because the trees are to be dug up again in six years. At that point, we will have our first opportunity to observe the root system and assess which areas the roots prefer and which they tend to avoid. As mentioned, this system is already feasible now – an elm planted here four years ago demonstrates this very effectively. A key component of this system is our fine substrate, which is incorporated into the coarse gravel (or, in the case of dry installation, mixed with the stones). Our experience in Terra Preta research proves invaluable here, and we now know precisely how to condition the main component, biochar, to ensure the fine substrate functions so well. We are therefore happy to partner with you on such planting projects.