Using of long-term phenological observations of SHMI and NFC for validation of Regional Phenology Model for European beech

This study describes the methods and results of the validation of Regional Phenology Model based on NDVI (Normalized Difference Vegetation Index) from MODIS (Moderate Resolution Imaging Spectroradiometer) satellite images for European beech (Fagus sylvatica L.). The time series of phenological observation of regional phenological observation sites of SHMI (Slovak Hydrometeorological Institute) for years from 2000 to 2009 and permanent monitoring plots of NFC (National Forest Centre) for 2002 – 2009 was used to validate the date of start of five main spring and autumn phenological events. The most accurately were derived the phenological events the first leaves, full leafing and the beginning of colouring of leaves. The resulting duration of full foliage was derived with an average error of ± 4.2 days (r = 0.84). Date of onset of phenophases bud break and full colouring of leaves, determining the duration of the entire growing season, were derived with a systematic negative (budbreak), respectively. positive error (full colouring) which increases with increasing altitude. It resulted in an overestimate of the duration of the growing season by an average of 26 days. Possible causes of the differences in the timing of the individual phenophases and their duration are discussed in this paper.