AbstractCombustion characteristics of leaves fallen off ornamental trees in city and forest parks were evaluated. The moisture content of the leaves at the time of falling was between Wr = 36.1 and 46.9%. The average contents of the individual elements in the combustible material were Cdaf = 48.1%, Hdaf = 6.1%, Ndaf = 1.2%, Sdaf = 0.1%, and Odaf = 44.6%. The resulting ash from the dry leaves varied between Ad = 4.8 and 13.1%. The heat of combustion of the dry leaves was between Qs = 16,046 and 20,247 kJ.kg-1, and the lower heating value was between Qn = 13,479 and 19,120 kJ.kg-1. The results were compared with dry firewood of hard deciduous trees. The higher heating value of the dry leaves was 11.7% lower and the lower heating value was also lower by 15.1%. The decline of these basic combustion characteristics is caused mostly by its high ash content and to a smaller extent by the increased nitrogen content.