ANALYSIS OF THE DENDROFLORISTIC COMPOSITION OF URBAN STREET TREE PLANTINGS IN SOFIA

Street landscaping is that part of the urban green infrastructure that is crucial for urban heat island mitigation, climate change adaptation and biodiversity protection. Moreover, it provides city dwellers with various ecosystem services and daily accessible public greenspace. The aim of this research is to assess the street tree diversity of the city of Sofia. A total of 10,011 street tree specimens were inventoried. The field studies were conducted from 2021 to 2022, according to the route method. The selection of the sample streets for the survey was made based on the following criteria: street tree plantings covered all street classes of the primary and secondary street network and the variety of possible orienta-tions and street canyon geometries; street tree plantings were located in different administrative territorial units of Sofia Municipality and the survey covered the entire length of the streets. In order to make an approximate assessment of the age of the specimens along the surveyed streets, DBH of each street tree stem was also collected and classified into categories. The established species composition in the surveyed streets consists of 55 taxa (species and cultivars). The most commonly used tree species in the new street plantings of the whole city street network was Platanus x aceri-folia (15.09%), while the most prevalent genera was Fraxinus (19.58%). One of the important findings in the analysis of the dendrofloristic composition was the low species diversity at street level. In most of the streets the number of spe-cies participating with more than 10% is 2-3. The analysis of the ratio of native to non-native (incl. cultivated varieties) street tree species showed that the non-native species and infraspecific taxa accounted for 57.32% of the total number of specimens. The results of the study can provide general guidelines for sustainable street plantings planning and de-sign incl. selection of dendrofloristic composition for diverse street tree populations.