Summary Report No. 78



Phenology in Germany in the 20th Century: Methods, Analyses and Models
J. Schaber (November 2002)

The strong advancement of spring phases especially in the decade before 1999 is not a singular event in the course of the 20th century. Similar trends were also observed in earlier decades.

An observed different trend behavior of early and late spring phases is explained by the differing behavior of mean March and April temperatures.

The advancement of spring phenology in recent decades is part of multi-decadal fluctuations over the 20th century that vary with the species and the relevant seasonal temperatures. Because of these fluctuations no significant correlation with an observed Global Warming signal could be found.

On average all investigated spring phases advanced between 5 and 20 days between 1951 and 1999 for all Natural Regions in Germany. Leaf coloring (LC) was delayed between 1951 and 1984 for all tree species. However, after 1984 LC was advanced. Length of the vegetation period increased between 1951 and 1999 for all considered tree species by an average of ten days throughout Germany.


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