Phenology of the Beech

The date of entry of certain phases in plant development (phenology) shifts over the years, inter alia, depending on temperature changes. From many years of observations, the influence of altered climatic conditions on the development of plants and ecosystems can be determined. Unlike direct temperature measurements, phenology thus reflects a reaction of nature to its environment. It is therefore an important and particularly sensitive bioindicator for climate change. As an indicator, the leaf output as well as the length of the vegetation phase of the beech is used. The vegetation phase is defined as the time span between leaf output and leaf discoloration. It is calculated as follows: Calendar day leaf discoloration minus calendar day leaf output. Leaf shoots are depicted as day in the year and the vegetation phase as number of days per year. The data is collected on six permanent observation areas or areas of intensive forest environmental monitoring in North Rhine-Westphalia (ForUm NRW) annually since 2001. Data is collected on 20 to 50 forest trees per survey. The beech is observed on the Lower Rhine, in the Ruhr area, in the Eggegebirge, in Sauerland and in the Nordeifel. The data of the surfaces are averaged.