The Hartheim Forest Research Site (ICOS code DE-Har) is a forest stand located in the land of Baden-Wurttemberg, Germany. The stand consists mainly of Scots pine (Pinus sylvestris L.) with scattered European black pines (Pinus nigra J.F.Arnold). The forest is characterized by a homogeneous structure. A particular characteristic of the Hartheim Forest Meteorology Site are regularly reoccurring summer dry periods. More info available at: https://www.meteo.uni-freiburg.de/en/infrastructure/hartheim-forest-research-site?set_language=en#section-3