Street trees suffer from drought and temperatures

Saxony's street trees are suffering from rising temperatures and fluctuating water supplies. Climate change is placing particular demands on the drought and temperature tolerance of around 233,000 trees on federal and state roads in the state, the State Office for Road Construction and Transport announced in response to an inquiry. These requirements are taken into account in the 2367 replanting and new plantings each year. The current maximum temperatures are around seven degrees higher than in the 1970s. According to the information, the rising temperatures are creating a longer vegetation phase and the winter dormancy is shortening.

In addition, fluctuations in water supplies are causing problems for the trees. During the growing season in particular, there are times when soil water is hardly available, while waterlogging occurs repeatedly after extreme rainfall. In both cases, this jeopardizes the material cycle and the storage of reserve substances in the trees, as the state office explains. As a result, vitality can suffer and susceptibility to pathogens can increase.

The Office for Urban Greenery and Water in Leipzig refers in particular to the heat and drought years of 2018, 2019 and 2020, which were very hard on the trees. "Due to drought damage and consequential damage caused by disease or pest infestation, tree failures are still to be expected", the office announced. Due to the persistently dry summers, the city has been watering trees up to the age of ten since 2018. In addition to good site conditions, such as sufficient root space, the selection of species and varieties in terms of crown shape, foliage coloration and fruit shape as well as climate tolerance is of particular importance when planting trees. There are currently around 57,300 street trees in Leipzig and 1370 were planted last year.

The city of Chemnitz also wants to convert its stock of 36,000 street trees to be climate-resilient. Around 250 trees are planted every year. According to a spokesperson, the focus is on comparatively drought-tolerant tree species. These include the plane tree, the silver lime, the hazel tree, the sweet chestnut and the amber tree. When replanting individual trees, however, an attempt will be made to replant the tree species that already dominates the street.

In addition to heat and drought, the state capital also sees the dense and mostly cramped habitat as a challenge for its approximately 54,000 street trees. In the current planting season, 624 new street trees are to be planted there, and a further 643 in the coming spring of 2025, according to the city of Dresden. According to the announcement, tree species will be planted that can withstand heat and drought stress and are better able to cope with the climatic conditions expected in the future.