An aesthetic townscape is hardly imaginable without trees. Besides their effect on design they fulfill a lot of other functions, which have positive impacts on the climate in cities. Trees filter pollutants off the air and alleviate extreme temperatures. For this reasons and the climate change the urban trees become more and more important. This master thesis discusses the vitality and applicability of urban trees in the pannonian area considering the climate change. In the pannonian area there is a specific climate: summer are warm and dry, winter are cold and also dry. Drought tolerance and cold hardiness are the crucial factors for healthy urban trees. Nine tree species were selected for vitality determination, a total of 456 trees were probed in the cities Mödling, Baden and Wiener Neustadt. Basis for this ascertainment were the cadastral tree registers of the cities and the key of crown vitality according to ROLOFF. The researches took place in May, July and September of 2012 in order to determine tendencies in development during the growing season. On the evaluation of vitality in the growing season 2012 Acer campestre, Celtis australis, Gleditsia triacanthos and Koelreuteria paniculata showed the highest vitality. Therefore those tree species are classified as the “most suitable” urban tree species in the pannonian area. Carpinus betulus, Fraxinus ornus, Prunus serrulata and Sophora japonica are classified as “suitable”. Only Corylus colurna was of limited suitability as urban tree in the pannonian area. This tree species showed least vitality. It became apparent again, that a correct selection of tree species is essential for a healthy tree population in cities, particularly with regard to the climate change. Besides the appropriate selection of tree species, the correct planting, early educations by cutting measures, continuous tree care and a high biodiversity in city-tree population are important criteria for a vital urban green.