Green infrastructure is a thematic alternative to scientific research, planning processes, social movements and implementation of activities in developed and strongly urbanised countries. This infrastructure alleviates accumulated environmental problems, especially in large urban agglomerations, and it requires both plant and water components. The most important of the many city ecosystem services is mitigation of climate extremes which create heat islands in the cities. Plants reduce the amount of pollutants and greenhouse gases in the air through photosynthetic and biomass-assimilation organelles, and thus enhance biodiversity and the cultural, aesthetic and residential value of a city. Here, tree vegetation in urban forests and culturally designed parks prove most effective in these endeavours. Appropriate standards in creating green spaces have been adopted in Slovak urban planning processes and these progressive methods depend on the following; increasing the percentage and quality of green areas in the city, creating vertical green walls and roof gardens, retaining rainfall in created water basins and ensuring water infiltration to the soil profile. An ecologically and environmentally balanced city should have at least 40% green areas.