Abstrakt
The Czech Hydrometeorological Institute operates phenological network with 45 wild plants' observing programme (the programme includes among other species also the Common Hazel (Corylus avellana L.), the Common Alder (Alnus glutinosa (L.) Gaert.), the Silver Birch (Betula pendula Roth.), the Meadow Foxtail (Alopecurus pratensis L.) and the Cocks Foot (Dactylis glomerata L.). We have statistically evaluated the phenological stages closely connected with the pollen release into the air (the beginning of flowering - BBCH 61 and the end of flowering - BBCH 69) including maps creation.
The processed period was within last twenty years 1991 - 2010. The maps were processed with using geographic information systems (Application Clidata-GIS, method Clidata - DEM).
As the input data were used the mean dates of phenophase entrance from the twenty year period 1991 - 2010 The mean onset date of the beginning of flowering was from 24th February till the 24th March (the Common Hazel), from 6th March till 2nd April (the Common Alder), from 13th April till 7th May (the Silver Birch), from 5th May till 23rd May (the Meadow Foxtail) and from 16th May till 12th June (the Cocks Foot). The mean onset date of the end of flowering was from 18th March till the 15th April (the Common Hazel), from 27th March till 19th April (the Common Alder), from 28th April till 21st May (the Silver Birch), from 25th May till 6th June (the Meadow Foxtail) and from 7th May till 23th June (the Cocks Foot).
The duration of flowering lasts on average with selected allergens as follows: 22 - 23 days with standard deviation 2,3 - 5,3 days (the Common Hazel), 14 - 15 days with standard deviation 2,1 - 2,7 days (the Common Alder), 17 - 21 days with standard deviation 1,8 - 4,2 days (the Silver Birch), 20 days with standard deviation 1,0 - 2,7 days (the Meadow Foxtail) and 20 - 22 days with standard deviation 1,3 - 4,0 days (the Cocks Foot).