Site-Specific Determinants and Remains of Medieval City Fortifications as the Potential for Creating Urban Greenery Systems Based on the Example of Historical Towns of the Opole Voivodeship

The article discusses the natural and historic heritage of medieval towns in the Opole Silesia region in the context of their ability to take advantage of their potential for sustainable development, especially in tourism. The chosen environmental, urban, architectural, and landscape factors were compared through this aspect and subjected to a multidimensional comparative analysis. The research studies applied mostly archival materials, contemporary topographic maps, statistical data, and both landscape as well as urban field studies. As a result, the studies indicated that the natural conditions of the locations, the preservation level of the urban system along with its development trends, and the areas of the old fortifications with their accompanying greenery constitute these towns' very value and identity. As they combine elements of nature and culture, they may serve as the basis for development of tourism, which is likely to contribute to the social and economic revitalization of the region itself. What may play a major role in the quest for sustainable development are the urban greenery systems to be designed based on former fortification areas, city greenery, and natural environmental resources, which have been integral elements of these towns over many past centuries.