In the year 2017 the satellite images for the southwest Slovenian area, taken by Sentinel-2, were cloudless enough for research of the leaf-out phenology of local dominant tree species. In the area of northern Karst we were able to use vegetation index NDVI (Normalized Difference Vegetation Index) to determine the difference of leaf-out of dominant tree species. The start of leaf-out was mostly by 25th of March. The full leaf out was longest for downy oak (Quercus pubescens Willd.) by 13th of June and the earliest for the tree of heaven (Ailanthus altissima Mill.) by 21st of April. Examined grasslands that are a part of GERK showed significant differences with those not part of GERK. Grass fields part of GERK had a large drop of values of NDVI during June, which is due to grasslands mowing.
|