Change in the seasonal development phases of plants

Climate change in Germany can be clearly seen in changes in the temporal development of plants (phenology). Above all, the increase in temperature leads to earlier budding, flowering and fruit formation compared to previous decades. The consequences for biological diversity and the structures and functions of ecosystems have hardly been researched to date.

Plants as indicators of climate change

Today, the term "phenology" essentially refers to the observation of developmental processes of living beings in the open air. For example, stakeholders in a Germany-wide observation network record when, in the individual years, leaf sprouting, flowering or fruit formation of certain indicator plants began or when the leaves of deciduous trees turned colour or fell. These phenological phases depend essentially on the temperature development and water supply in the respective years. Phenological data are therefore very good indicators of the effect of climate change on vegetation. The existing time series now cover up to seven decades.

The length of the vegetation period is increasing

The vegetation period, i.e. the time of the year when plants grow, flower and bear fruit, has increased in Germany since 1961 by about two weeks on average. The vegetation period begins with early spring, the start of which is indicated by the beginning of flowering of coltsfoot. It ends with late autumn, which is indicated by the beginning leaf fall of the English oak. Despite weather-related fluctuations from year to year, the following data clearly prove the above-mentioned trends.