| phytophenological trends in switzerland. | nation-wide phenological observations have been made in switzerland since 1951. in addition to these observation programmes, there are two very long phenological series in switzerland: leaf bud burst of horse-chestnut trees has been observed in geneva since 1808 and full flowering of cherry trees in liestal since 1894. in addition to the presentation of these two long phenological series, trends for 896 phenological time series have been calculated with national data from 1951 to 1998. the earli ... | 2001 | 11769321 |