RELATIONSHIPS BETWEEN GROWING SEASONS DETERMI-NED BY TREES’ PHENOLOGY AND AIR TEMPERATURE:THE CASE OF THE TAUNUS MOUNTAIN AREA IN CENTRAL GERMANY

The true growing season is defined as the number of days in a year in which a crop can grow.However,the comm on measure of the growing season has been the number of days between the first date and the last date of the daily mean temperature above a threshold value such as 5℃or 10℃etc..In this paper the temporal relationships between growing seasons determined by trees'phenology (the period between the dates of leaf emergence and the date of leaf coloration by Fagus sylvatica,Quercus robur and Betula pendula) and air temperature (the period of the daily mean temperature above 5℃ and 10℃) has been analysed using the time series from 1951 to 1990 at Geisenheim,Koenigstein and Kleiner Feldberg in the Taunus Mountain area.