The Development of Phenological Stages of European Beech (Fagus sylvatica L.) in Slovakia during the Period of 1996-2010

The paper presents results of 15 years lasting observations of European beech (Fagus sylvatica L.) in Slovakia within the altitude of 177-1265 m. During the years of 1996-2010 the start of vegetative phenological stages of first leaves, full leafing, beginning of leaf colouring, beginning of leaves fall at 40 phenological stations has been observed. The statistical analysis pointed out that the first leaves were created on the average from 20. 04. till 05. 05. The full leafing was approached on the average from 27. 04. till 10. 05. The spring phenological stages were shifted and started sooner by 5-6 days. The beginning of leaf colouring occurred on the average from 11. 09. till 24. 09. and its trend was also shifted and occurred later by 2 days. The beginning of leaves fall was recorded on the average from 01. 10. till 10. 10. and its trend approached the balanced state. The soonest autumn phenological stages started on the average in 2009 and the latest ones were recorded in 1997. The detailed analyses of 3 stations Zvolen (300 m), Observatory Modra (531 m) and Telgart (825 m) pointed out the sooner starts of spring phenological stages only in the lower and medium altitudinal areas of Slovakia. This trend has not been detected within mountainous areas. The dependence of leaf colouring on the influence of environmental factors as temperature and rainfall on its beginning has been confirmed at the all 3 phenological stations.