The population of Common yew is endangered throughout Germany. This assessment is based on the regionally limited distribution of yew and its occurrence in small to moderate population share in beech forest communities.
The majority of the 60,000 trees documented were found within Thuringia and Bavaria, with the Mitteldeutsche Trias-Berg- und HÃ¼gelland, the OstthÃ¼ringische Trias-HÃ¼gelland, the Franconian Jura and the Upper Palatinate Jura representing the centres of distribution.
The portal GDI-BMEL (Spatial Data Infrastructure of the Ministry of Food and Agriculture) presents selected results (occurrence, number of trees, natural regeneration, vitality, conservation ability and gene centres) for yew as geoinformation based on a 5x5km grid
A total of 342 yew populations with a total of 60,000 trees were documented. The map shows the location of the populations in Germany. The number of occurrences in the Federal states is very differentiated.
Number of trees
With about 33,200 yews, Thuringia is the state with the highest number of yews, followed by Bavaria with about 14,700 and Baden-WÃ¼rttemberg (about 2,500). In Mecklenburg-West Pomerania, Hesse, Lower Saxony and Brandenburg there are between 3,000 and 1,000 individuals each. In general, the yew populations are very small.
The data underline the low regeneration potential of yew. Most populations with regeneration were found in the Alps, in the Swabian Alb and in Thuringia.
The vitality of an occurrence is one of the decisive parameters for describing the adaptation of a tree to its location and the surrounding environment. With the exception of Saxony-Anhalt, Saxony and Rhineland-Palatinate, most of the other Federal states have vital populations. Vitality is therefore of great importance for assessing if a population is designated as worthy of preservation.
To assess the conservation potential of populations, the parameters abundance, average vitality and age structure quality were analysed. The proportion of populations evaluated as very good or good is very low (4.1%). 11.5 % of the populations were assessed as weakened. The majority of the populations (83.8%) were classified as threatened and 0.6% of the populations were assessed as dying. These figures demonstrate the need for measures to preserve yew in situ or the establishment of ex situ conservation measures.
The aim of generic conservation measures is to preserve or create large, reproductive populations. The federal states or the forestry research institutes commissioned by them are responsible for the designation of gene conservation forests. Therefore, the results for the regions or occurrences in north-eastern Germany, western Germany, central Germany and southern Germany proposed from the federal point of view as gene centres are only recommendations.