Vol. 124, No. 3 * Pages 311–426 * July - September 2020

The dependence of the influence of extreme climate conditions on the variability of forest fires in the Timočka Krajina region of northeastern Serbia was studied. The impact of extreme conditions was investigated with extreme climate indices using air temperature, relative humidity, and precipitation measured at three meteorological stations in northeastern Serbia. The De Martonne index was used to analyze climate conditions as a measure for aridity. The study analyzes trends in extreme climate indices with an emphasis on the two contrasting years, 2012 and 2014, and compares them to the baseline period 1961–1990. The year 2012 was very warm and dry, while 2014 was one of the wettest recorded in Serbia. There was an increase (decrease) in warm (cold) temperature indices. Non-significant increases in extreme precipitation indices were observed, while the number of precipitation events greater than 1 mm decreased, as did relative humidity.
Ångström index values were used as an index for assessing the risk of forest fires. These indices were analyzed and a correlation between them and forest fires in northeastern Serbia was established. The aridity index was low during the years 2012, 2011, and 2017, correlating with the large number of forest fires. High values of the Ångström index in 2013 and 2014 were associated with a minimum number of registered forest fires. As an improved indicator for the number of forest fires, the modified Ångström index using daily maximum temperature is proposed.