Worldwide, researchers and urban planners are looking for innovative approaches to mitigate the increasing heat stress and thus the UHI effect in growing cities. Urban trees, with their various positive ecosystem services are an essential part of green infrastructure. Especially during the daytime, trees increase the thermal comfort on hot, sunny summer days by significantly reducing the perceived temperature, particularly due to their shading effect (Ziemann et al. 2024). Therefore, the planting of additional trees is considered a suitable measure to implement climate adaptation strategies in cities. However, during summer nights, cities in valley locations are mainly cooled by the nocturnal cold air drainage flows from the surrounding rural areas. Placing trees in unfavorable locations can prevent the cold air flows and thus hinder the urban cooling in city centers. Hence, the plantation of urban trees needs to be planned carefully. For this reason, model simulations with the cold air drainage model KLAM_21 developed by the German Weather Service, DWD (Sievers 2005) were performed for the city of Plauen, which is located in a low mountain range region in Germany. The objective of this work was to analyze the effects of additional urban trees distributed throughout the city (maximum scenario) on the cold air flows and thus on the nocturnal ventilation compared to the current situation. In addition, the results of the simulations are evaluated in terms of the advantages and disadvantages of planting trees in cold air corridors. In general, the results showed that the implementation of the maximum amount of urban trees throughout the city can lead to a moderate or locally intense negative change in the ventilation potential along the main cold air corridor. Therefore, it is recommended to keep the exposed cold air corridors open and to carefully manage the tree planting in such critical areas. On the positive side, the valley of Weisse Elster remains in a very high to extremely high climatic-ecological compensation potential even in the maximum scenario.