Differences in the phenological development of the prevailing tree species on the Pahernik\u27s Forest Estate, estimated using satellite images

Fenološke razlike prevladujočih drevesnih vrst na območju Pahernikove posesti smo ocenjevali na podlagi satelitskih posnetkov misije Sentinel-2. Analizirali smo normirane diferencialne vegetacijske indekse (NDVI) v obdobju od 29. marca do 15. oktobra 2017. Na podlagi razlik v vegetacijskem indeksu NDVI je mogoče ocenjevati fenološki razvoj prevladujočih drevesnih vrst bukve (Fagus sylvatica L.), smreke (Picea abies L. (Karsten)) in macesna (Larix decidua Mill.) v gozdnih sestojih. Na območju posesti ugotavljamo omejitve ocenjevanja fenološkega razvoja smreke v mešanih sestojih smreke in jelke (Abies alba Mill.), ki imajo podobne vrednosti NDVI. Pri bukvi pa smo ugotovili manjšanje vrednosti NDVI na posnetkih 21. aprila in 5. oktobra z višanjem nadmorske višine, kar povezujemo s poznejšim olistanjem in hitrejšim rumenenjem listov bukve na višjih nadmorskih višinah.Phenological differences of the prevailing tree species in the area of the Pahernik%s estate were estimated on the basis of satellite images by the Sentinel-2 mission. We analyzed the normalized difference vegetation indices (NDVI) in the time period from March 29 to October 15, 2017. It is possible to estimate phenological development of the prevailing tree species European beech (Fagus sylvatica L.), Norway spruce (Picea abies L. (Karsten)), and European larch (Larix decidua Mill.) in forest stands, on the basis of the differences in the vegetation index NDVI. We found limitations in assessing the phenological development of Norway spruce in the mixed Norway spruce and silver fir (Abies alba Mill.) stands, because of the similar NDVI values of Norway spruce and silver fir. We found the decrease of NDVI on the images of April 21 and October 5 with increasing elevation of the beech stands, which we associate with later start of leaf-out and faster start of autumn leaf colouring of the beech trees growing on higher elevations