ALBERT

Description:    We analyzed the leaf phenology of European beech ( Fagus sylvatica ) and its variation due to spatial and temporal climatic variability, using a modified data set of the phenological network in Slovenia. We used first leaf unfolding (LU) and general leaf colouring (LC) time series of 47 sites (altitudes from 55 to 1,050 m a.s.l.) and corresponding climate series (52 of precipitation and 38 of temperature) for the period 1955–2007, collected by the Environmental Agency of the Republic of Slovenia. Across the network in average, LU occurred from 14 April until 13 May, and LC from 3 October until 29 October. LU was delayed by 2.6 days and LC was promoted by 1.9 days when the altitude increased by 100 m. Year-to-year variation of LU was significantly correlated with March and April temperatures. March temperatures had a greater effect at lower elevations and April ones at higher elevations. LC was related to August and September temperatures, and occurred later if the temperatures were higher. Recently, March and April temperatures showed an increasing trend and LU occurred 1.52 days earlier per decade at 1,000 m a.s.l. but no significant shifts were observed at lower altitudes. August temperatures were also increasing but the trends of LC were not significant and were not clearly related to altitude. Our detailed sub-regional data from a relatively small area with high geographic variability showed that changes in climate affect phenological response, mainly leaf unfolding, to a greater degree at higher altitudes than at lower ones. Content Type Journal Article Category Original Paper Pages 1-10 DOI 10.1007/s00468-012-0686-7 Authors Katarina Čufar, Department of Wood Science and Technology, Biotechnical Faculty, University of Ljubljana, Rožna Dolina, Cesta VIII/34, 1000 Ljubljana, Slovenia Martin De Luis, Department of Geography, University of Zaragoza, y O.T. C/Pedro Cerbuna 12, 50009 Zaragoza, Spain Miguel Angel Saz, Department of Geography, University of Zaragoza, y O.T. C/Pedro Cerbuna 12, 50009 Zaragoza, Spain Zalika Črepinšek, Agronomy Department, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000 Ljubljana, Slovenia Lučka Kajfež-Bogataj, Agronomy Department, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000 Ljubljana, Slovenia Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890