Canopy leaf temperatures of selected tree species growing in forests and agricultural ecosystems using aerial thermal infrared (3.6-4.9 µm) data

Studies conducted in recent years have demonstrated high application potential of thermal remote sensing data in environmental analyses. This study aimed to determine the canopy leaf temperatures of selected tree species: Alnus glutinosa, Pinus sylvestris, Quercus petraea, Juglans regia, Quercus rubra and Robinia pseudoacacia. The studies were conducted in the forest and agricultural ecosystems. Thermal data were acquired on June 9, 2019, between 8:10 and 14:00 (CET). The temperature was recorded by the ImageIR 9400 sensor with a spectral range of 3.6-4.9 μm. The results indicate that the canopy leaf temperatures of species under study differ statistically significantly irrespective of data acquisition time. Between 8:10 and 14:00 the temperature of the tree canopies increased on average for the individual species by 4.86oC. The smallest increase in temperature of 4.10oC was recorded for Alnus glutinosa, and the highest increase of 5.76oC was noted for Juglans regia. The studies showed that the smallest variation in the canopy leaf temperature occurs at about noon between 12:00 and 13:00. Comparison of the temperatures of trees growing in and outside the forest also showed the forest’s significant impact in decreasing the average temperature of a tree canopy by about 1oC.