Not long ago, the memory of chestnut trees was deeply rooted in the consciousness of rural communities around the Mediterranean. Known as sweet chestnut (Castanea sativa), the tree likely spread by hand from the Balkans and Asia Minor to other parts of Europe. It thrived in mountainous areas, where chestnuts were readily accepted as means to self-sufficiency by otherwise isolated communities. The American chestnut (Castanea dentata) served a similar function in the Appalachians, before it fell prey to an Asian fungus that put an end to the tree’s dominance in the forests of the Southeastern United States. In Corsica, the chestnut is firmly established in the island’s culinary traditions which impressively features chestnut beer. Likewise in Sardinia, as well as other parts of Italy, chestnuts have become an integral part of the country’s rich culinary tapestry.
Berlin is home to thousands of horse chestnuts (Aesculus hippocastanum) which casual observers may confuse with the lonely occurrences of sweet chestnut trees in parks and streets. Although the horse chestnuts do resemble the delicacy found in outdoor Christmas markets – roasted marroni – they are, in fact, mildly poisonous to both humans and horses. Take a look at the leaves and you will see that these trees have very different features. Once you’ve discovered the differences, you will never mistake horse chestnuts for the “real” chestnut again!
Despite its geographic adaptability and relative hardiness, the sweet chestnut is a paradoxically fragile creature. Once dormant, the tree can withstand temperatures of -20 degrees Celsius; on the other hand, a late spring or early fall frost can easily cause irreparable damage. Chestnuts prefer a moist, humid environment but well-drained soils. Prolonged periods of rain can stress the tree and, if drainage is not adequate, many specimens will drown. In Germany, as well as other parts of Northern Europe, sweet chestnuts were historically managed as coppice because their tall, straight suckers make perfect poles for growing hops. Unfortunately, Berlin lies slightly above the sweet chestnut’s northern limit of fruit production, which means that yields are low and erratic. Looking for and finding sweet chestnuts in Berlin is a reward all in itself, but is compounded by the rarity of such a find. Platforms like mundraub.org are quite helpful in indicating potential locations, as is our berlin plants map and your own happy wanderings around the city.
In a classic example of plant blindness, we kept missing a sweet chestnut tree on Schönfließer Straße next to Arnimplatz even though we frequently walk by there on our way to Con Calma – one of our favorite coffee shops in the area. This year the burrs looked promisingly full but once they fell to the ground, we were disappointed to see small and shriveled chestnuts inside. We did not fare better with an older duo of sweet chestnut trees in Volkspark Humboldhain despite their bountiful appearance. Refusing to give up our fat chestnut dreams, we pressed south toward Treptower Park where we spent a sunny afternoon wandering along the Spree River. Even there, despite a number of both young and old chestnut trees, the spiny burrs were full of disappointingly shriveled nuts. With some luck and tenacity we were able to find a single small but fat chestnut – the one featured in our photo. Perhaps some of our readers have had better luck?