Inter-tree variability of autumn leaf phenology of European beech (Fagus sylvatica) on a site in Ljubljana, Slovenia: Variabilnost jesenske listne fenologije med drevesi navadne bukve (Fagus sylvatica) na rastišču v Ljubljani | Variabilnost jesenske listne fenologije med drevesi navadne bukve (Fagus sylvatica) na rastišču v Ljubljani: Inter-tree variability of autumn leaf phenology of European beech (Fagus sylvatica) on a site in Ljubljana, Slovenia

English. Temporal variability of leaf senescence (autumn phenology) was observed in 2020 in 11 European beech (Fagus sylvatica) trees in Tivoli, Rožnik and Šišenski hrib Landscape Park in Ljubljana, Slovenia, and also observed for spring phenology in the same year. General leaf colouring, BBCH94, occurred between 19 and 24 October 2020, with lower inter-individual variability than that of leaf unfolding, BBCH11. The trees had active leaves (time between leaf unfolding and leaf colouring) between 177 and 199 days. In only three trees total leaf fall, BBCH97, occurred before 19 November 2020. Leaf colouring of the tree included in the long-term monitoring program of the Slovenian Environment Agency ARSO occurred on 24 October 2020. This is 7 days later than the 65-year average of the same tree/location and is ascribed to weather conditions. Investigation of tree tissues showed that the width of the last formed tree-ring in the wood varied between 0.39 and 9.61 mm and in the phloem between 0.09 and 0.26 mm, and that the tissues reflect the health condition of the trees.

Slovenian. V letu 2020 smo spremljali jesensko fenologijo listov 11 dreves navadne bukve (Fagus sylvatica) v Krajinskem parku Tivoli, Rožnik in Šišenski hrib v Ljubljani, Slovenija. Na teh drevesih smo spomladi 2020 spremljali proces olistanja. Splošno obarvanje listov, BBCH94, je nastopilo med 19. in 24. oktobrom 2020, v ožjem časovnem intervalu kot spomladansko olistanje, BBCH11. Drevesa so imela aktivne liste (čas med olistanjem in obarvanjem listov) od 177 do 199 dni. Samo s treh dreves je do 19. novembra 2020 odpadlo vse listje, BBCH97. Pri drevesu, ki je vključeno v dolgoletni program spremljanja fenologije listov Agencije Republike Slovenije za okolje ARSO, je obarvanje listov nastopilo 24. oktobra 2020, kar je za 7 dni kasneje od 65-letnega povprečja za isto drevo / lokacijo. Raziskave drevesnih tkiv so pokazale, da je znašala širina zadnje branike v lesu med 0,39 in 9,61 mm in v floemu med 0,09 in 0,26 mm in da tkiva nakazujejo zdravstveno stanje dreves.