The content of the chapter: 1) The history of phenological observations in the 18th and 19th century 2) The first phenological observations in the Czech Republic in the 20th century (the first phenological calendar, the first phenocartography results, zoophenological methods of observations) 3) Phenological observation - present status (the structure of the CHMI phenological network, brief methodology description) 4) The Czech phenology and Europe (the international phenological gardens in the Czech Republic, international cooperation and activities - COST action 725, COST action ES0603, PEP 725) 5) The example of phenological results: Specie: Hazel (Corylus avellana L.) Period: 1991 - 2010 Phenological phases: the bud burst, the first leaves (100 %), the leaves colouring, the leaves fall, the inflorescence emergence, the beginning of flowering, the end of flowering, the fully ripe Methods: statistical evalution of phenological results (charts and tables), GIS processing by method Clidata - DEM (maps) Text: the botanical description, spread of the specie, the pollen grain description