As a consequence of rising temperatures, spring and summer development of vegetation is occurring significantly earlier nowadays than several decades ago. Therefore, plants are excellent indicators for the effects of the global rise in temperature. The meteorological service MeteoSwiss is collecting a variety of data to illustrate these changes.
Vegetation development
Phenology
Phenology is the study of cyclic growth and development phenomena occurring over the course of a year in relation to flora and fauna. In the case of plant phenology, the onset dates of the so-called pheno phases such as new leaf formation, flowering, ripening of fruit, leaf colour change and fall are observed and recorded.
Reporting on current vegetation patterns
Did vegetation start to grow especially early in a particular year due to temperatures being much higher than average? The observations of the phenological observation network form the basis of the climatological evaluation of current vegetation patterns. Current analyses can be found in the monthly and annual retrospective reports.
The spring index
The spring index shows the point of time of vegetation development in spring compared to the long-time average from 1991-2020. The annually determined index summarises the phenological spring phases, from the blooming of the hazel bush to the new leaf formation of the beech tree.
Additional phenological observation series
Aside from the observation network, two long-term and hence very valuable phenological series of observations exist in Switzerland, which have been used to observe two types of plants since 1808 and 1894 at the same location: a horse chestnut tree in Geneva and the blossoms of a particular cherry tree in Liestal.