Trees are an indispensable part of our urban landscape. Due to detrimental conditions regarding the urban climate and location it is of key importance to optimise a tree's setting and its maintenance in order to sustain a vital and durable tree population. Traffic areas in particular show a constant negative impact on urban vegetation, which constitutes the primary source of this dilemma. This master thesis discusses the particular conditions of young trees along streets in the 13th and 14th district of Vienna. Based on a sample of 148 trees, they were ascerstained and evaluated according to the current knowledge of Vegetation technology, local and general conditions as well as specific parameters of trees' care. The results of these investigations indicate a predominantly satisfying situation concerning the general conditions, though there are some requirements of improvement concerning the trees' sites and their maintenance. The MA 42 (Wiener Stadtgärten) has already taken first steps for advancing the tree bindings, the tree trunk protection and the substrate composition by introducing a directive on plantation and care for street trees in the year 2008. But there is still urgent need for action regarding a professional accomplishment of cutting measures and tree trunk protection against mowing damages. Soil analysis revealed that all analysed street sites show excessive percentages of silt and clay as well as significant soil compactions in many cases. Also the investigated tree sites' dimensioning often undercuts recommended minimum face values. The comprehensive analysis leads to a number of concrete guidelines valuable for the optimisation of tree sites and young tree care within the Viennese urban region. In recent years, there was an obvious increase in pest infestations all over Europe and likewise within the Viennese tree population causing serious damages in the vegetation under review. Particularly because of their unfavourable location, street trees definitely show a higher risk of being affected by those attacks. Therefore, a whole section is exclusively dedicated to the subject of "New biotic injury symptoms at urban trees". It analyses in more detail four selected animal and fungal pathogens and provides suggestions to prevent and control them.