Observation of climatic parameters and plant phenology in the International Phenological Garden of Klaipėda University Botanic Garden, Lithuania

The phenology of plants varies greatly over broad geographic gradients, according to climate zone and vegetation type. Phenological records were collected from 2007 to 2024 at Klaipėda University Botanic Garden (KUBG), which is one of the 89 gardens belonging to the International Phenological Gardens (IPG No. 151). The garden is located in Western Lithuania, close to the Baltic Sea coastline (about 3.5 km) (55°42′40″N 21°7′50″E). For the analysis were chosen 5 species only. The average annual air temperature in Klaipėda is 7.9°C. The coldest period is in January-February, where the average air temperature is -1.0°C. The warmest period occurs in July-August (aver. 18.2°C). The most influence had autumn temperature of the last season: the strong correlation were with leaf unfolding of all trees, as well strong or moderate correlation were with beginning and full flowering of S. viminalis and S. ×chinensis. Only precipitation of last autumn and precipitation of January-February had the statistically significant influence on spring phenological plant parameters. The longest vegetation period had S. viminalis (224 days) while the S. nigra had the shortest one − 187 days. Precipitation during the January-February had strong or moderate positive correlation with the leaf unfolding of all examined trees, as well as had moderate positive effect for beginning and full flowering of S. chinensis . The summer and autumn temperature had the negative relation for the both vegetation periods. The strongest correlation appeared between summer temperature and vegetation period of C. avellana and S. nigra .