The temporal and spatial variability of phenological phases of the Norway spruce (Picea abies (L.) Karsten) in the Czech Republic
Abstract
The paper analyzes the main vegetative and generative phenological phases (the bud burst BBCH 07, the first leaves BBCH 15, the beginning of flowering BBCH 61, the end of flowering BBCH 69) of the Norway spruce (Picea abies (L.) Karsten) observed at Czech Hydrometeorological Institute (CHMI) phenological stations in the period from 1991–2010. There were analysed data from phenological stations located at elevations from 155 m (Doksany) to 860 m a.s.l. (Pernink).
The altitude determines the mean onset dates of the phenophases: bud burst was observed from 19th April to the 10th May, the first leaves from 11th May to 26th May, male flowering from the 3rd May to 18th May, and the end of flowering on average between the 20th May and 2nd June. The duration of flowering took on average between 15 and 17 days with the standard deviation from 1.9–2.1 days.
The earliest onset of the beginning of flowering was recorded on the 15th April 2009 (Lednice); the latest on the 24th May 2001 (Pernink). Vertical phenological gradients for the discissed phenological stages (BBCH 07, BBCH 15, BBCH 61 and BBCH 69) were 2 days/100 m of elevation.
For the study 20-year period, all the studied phenophases show an overall tendency for the earliest onset, the results underlying this observation, however, exhibit only a low significance level.