Classification of Functional Elements of Green Infrastructure as Key Indicators of Sustainable Development in Residential Areas of Green Cities: Evidence from Olsztyn in Northeast Poland.

Residential green spaces are one of the key factors determining the quality of life for urban inhabitants, as well as an important element of the functional and spatial structure of cities. Their presence within the system of urban green and blue infrastructure contributes to improving microclimatic conditions, increasing water retention, and enhancing biodiversity, making them a vital aspect of sustainable urban development. Unfortunately, there is a lack of studies classifying green infrastructure elements in green cities, which motivated the authors to undertake this particular research topic. This study analyzes the types and forms of residential greenery from a functional and spatial perspective and assesses the degree of green space development based on three residential districts of Olsztyn: Jaroty, Pojezierze, and Kormoran. The specific objective of the research was to identify areas with development potential for green infrastructure within the studied residential neighborhoods and to provide corresponding recommendations. The research involved classifying greenery according to its functions, evaluating its accessibility, and assessing its integration with the built environment. Methods employed included spatial analysis, field surveys, observation, and both qualitative and quantitative evaluations of residential greenery. The results indicate a varied level of functional diversity and accessibility of green spaces across the studied neighborhoods. Based on the findings, recommendations were made to improve the management of green spaces, including the introduction of new green areas, supplementation of existing ones, and modification of their functions.