Assessment of vegetative phenological phases of European beech(Fagus sylvatica L.) in relation to effective temperature during periodof 1992-2008 in Czechia

Abstract

The paper presents the results of long-term phenological observations of European beech (Fagus sylvatica L.) running in years 1992-2008 across the phenological network of the Czech Hydro-meteorological Institute, abbr. CHMI, in original language Český hydrometeorologický ústav. The data assembled over this period were used for identification of timing of the following vegetative phenophases: bud burst (BBCH 07), first leaves 100% (BBCH 15), leaf colouring 10% (BBCH 92), leaf fall 100% (BBCH 97). The stations are situated at altidudes from 165m (Lednice) to 1,102 m (Modrava). The mean date obtained for onset of bud burst is from April 12th to May 7t (on average April 22n4), the mean date for onset of the first leaves 100% is from April 29h to May 17th (on average May 7th), the mean date for onset of leaf colouring is from September 12a to October 14th (on average September 24th ), and the mean date for onset of leaf fall 100% is from October 9 to December 8 (on average November 7th). The trend analysis of bud burst stage showed a declining trend - that means a shift of phenological phases towards earlier date (5.7 days). On the other side, the phenophase of leaf fall 100% manifested an increasing trend - that means a shift of phenological phase to later date (6.1 days). The vegetation season is getting longer. The totals of effective temperatures were used as a bio-climatological criterion for assessment of dependence of phenological phases on meteorological variables. The above mentioned totals were obtained as subtotals of average daily temperatures higher than 0 °C, 5 °C, 8 °C and 10 °C (TS0, TS5, TS8, TS10). The average temperature total for bud burst TSO was found from 286.2 ℃ (Lednice, 165m a.s.l.) to TS0 = 144.2 °C (Modrava, 1,102m a.s.l.). The other effective temperature totals for the average day of bud burst are: TS5 = 71.5 °C; TS8 = 21.4 °C; TS10 = 7.2 °C (Lednice); TS5 = 20.0 °C; TS8 = 4.4 °C; TS10= 1.6 °C (Modrava). The highest temperature total for leaf fall was from TS0 = 3,822.4 °C (Lednice); the lowest TS0 = 1845.9 °C (Modrava).