The Hasselbach is a small body of water - and yet of great importance in the valley.

This is because streams cool their surroundings, keep the soil moist for longer and make forests more resistant to periods of drought. Where water flows, trees can root deeper and the forest remains more stable overall.

At the same time, the stream allows us to observe how the climate is changing. Precipitation is less frequent, but often heavier. The soil cannot always absorb the water, it runs off superficially, floods occur - and yet groundwater levels are falling in some places. It is precisely then that the stream becomes an important buffer in the forest's water balance.

However, a stream is more than just a watercourse. It is a habitat and connecting path for species such as dragonflies, frogs, dippers and kingfishers. The more diverse the banks and bed are, the better both function: the stream as a buffer for the forest and as a home for animals and plants.

Stream check: Stop for a moment and read the stream. Where is the bank flat, where is it steep? Where is the water allowed to spread out, where is it constricted? This will tell you how well the stream is helping the forest - or where it is coming under pressure.