Aesculus - quo vadis?

Aesculus hippocastanum, the horse chestnut, has characterized many cities in Central Europe for centuries. Hardly any other tree is so well suited to illustrate the effects of stress factors and negative site and environmental influences. Although this tree species is generally considered to be extremely robust, it is under increasing pressure from a variety of stress factors. The main factors include the chestnut leaf miner, plant pathoges like Pseudomonas syringae, soil sealing, drought stress and heat radiation. For many inner-city and historic green spaces planted with horse chestnut trees however, there are no proven strategies to preserve the tree population in the long term. The situation is even more critical due to increasing loss of habitat in the natural distribution areas of the horse chestnut in the south-eastern Balkans (Greece, Albania and North Macedonia). Because of the endangerment of the populations, ex-situ conservation culture is being considered. Using the example of the Hirschengraben in Bern, a late 19th century promenade with 25 horse chestnut trees, the challenges and possible solutions for the future of the horse chestnut in Europe will be presented. We would like to initiate a discussion about how to take care of Aesculus hippocastanum within the urban forest in order to preserve this culturally and historically valuable tree species.