Science of Seasons

Phenology - a Definition

The science of seasons is called phenology in specialist circles. Phenology deals with the periodically recurring phenomena of the animal and plant world over the course of the year. These include the cycles of plants from the flowering and foliage development in spring to leaf shedding in autumn or the migration of migratory birds and other seasonally influenced animal behaviour.

Squirrel
Squirrel (Image: Dellex (Wikimedia Commons))
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Squirrel
Squirrel (Image: Dellex (Wikimedia Commons))

An Old Science

The first serie of phenological observations was compiled in the year 812 when experts of the Imperial Court in Japan examined the entry dates of the annual cherry blossom in Kyoto. In Switzerland, long series of measurements exist, for example for the leaf sprouting of chestnut trees in Geneva (measured since 1808) and for the full flowering of the cherry in Liestal (measured since 1894).

Since phenologists can fall back on large amounts of comparative data from earlier periods, it is possible to predict changes and trends. By analyzing the changes in the growth behavior of plants it is possible to predict climatic changes and trends for the future.

Find out more about the long series of data...


What Influences the Growth of Plants?

There are a number of environmental factors that influence the phenological development of plants.

The atmosphere, especially the temperature of the air, plays a key role. The spring phases, such as leaf development or sprouting, are influenced by the temperatures of the previous months. The fact that spring begins earlier and earlier, as observed in long series of data, is therefore a reflection of climatic changes.

Einflussfaktoren der Pflanzenphänologie nach Defila, C. (1991). Pflanzenphänologie der Schweiz. Veröffentlichungen der Schweizerischen Meteorologischen Anstalt 1, 235.
Einflussfaktoren der Pflanzenphänologie nach Defila, C. (1991). Pflanzenphänologie der Schweiz. Veröffentlichungen der Schweizerischen Meteorologischen Anstalt 1, 235. (Image: Sarah Arnold (adaptiert von promet Heft 1/2 2007))
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Einflussfaktoren der Pflanzenphänologie nach Defila, C. (1991). Pflanzenphänologie der Schweiz. Veröffentlichungen der Schweizerischen Meteorologischen Anstalt 1, 235.
Einflussfaktoren der Pflanzenphänologie nach Defila, C. (1991). Pflanzenphänologie der Schweiz. Veröffentlichungen der Schweizerischen Meteorologischen Anstalt 1, 235. (Image: Sarah Arnold (adaptiert von promet Heft 1/2 2007))
Cherry blossoms Seebodenalp KPS
Cherry blossoms Seebodenalp KPS (Image: Marcel Küttel)
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Cherry blossoms Seebodenalp KPS
Cherry blossoms Seebodenalp KPS (Image: Marcel Küttel)

For Weather and Climate Researchers

Phenological observations show that the vegetation period in spring starts earlier and earlier due to climatic changes.

Long series of measurements are particularly valuable for climate research.

For Agriculture

In agriculture phenology is used as a planning tool. It devides the country into cultivation areas and helps make the right crop choice or to be able to orientate oneself in time when carrying out various tasks. Hay harvest, for example, should start during the main flowering period of meadow grasses.

There have always been so-called country sayings, which are partly based on phenological observaions.

More on country sayings:

For Health

The pollen release is recorded in time series in order to detect its effect on the frequency of allergies or the spread of new allergenic plant species at an early stage.

For Tourism

Seasonal phenomena are also interesting for tourism. For example, when a cherry blossom hike in the Baselbiet is advertised as a natural spectacle.

For Ecology

Ecologists deal with phenological data in order to investigate, for example, the dispersal potential of a plant.

  • Publications

From "Periodical Observations" to "Anthochronology" and "Phenology" - the scientific debate between Adolphe Quetelet and Charles Morren on the origin of the word "Phenology"
  • 2011

From "Periodical Observations" to "Anthochronology" and "Phenology" - the scientific debate between Adolphe Quetelet and Charles Morren on the origin of the word "Phenology"

Mankind has observed and documented life cycle stages of plants and animals for a long time. However, it was comparatively recently that the newly emerging science was given its name. The name of Charles Morren and the year 1853 are being cited, although not frequently. Exact information is hardly known among present-day phenologists, yet new evidence shows that the term “phenology” was already in use in 1849.