Distribution of Betula pendula during late quaternary to present and characteristics of its lowest habitat in Turkey

Abstract

Betula pendula L. is a forest tree species having local distribution areas in Turkey. When it had a wide distribution area during Late Glacial time of Turkey, its distribution decreased at the end of Late Quaternary. The purpose of the paper is to discuss its past and present distribution in Turkey, climate features in growing areas by focusing on the lowest distribution area in Turkey. This species has local distribution areas in mainly east of Turkey together with Kayseri-Erciyes Mountain. Though, the elevation of common distribution area of this species ranges between 1300-2850 m in Turkey, we focused on the lowest distribution areas in Munzur Valley 1333-1206 m a.s.l. The species grows with riparian trees (such as Salix caprea, S.alba, Alnus glutinosa etc.) on valley bottom having high level of ground water like wetland forest. In Marho Bridge and Joining Point of Mercan River, distribution of Tamarix gracilis ends and birch trees start to grow. In this altitude it is represented with small stands and individuals on the river banks. The study area located at bottom land with high level of ground water table and deep alluvial soil, and semi-dry climate. The reason of its presence here may be these optimum soil and water conditions. The distribution of the species ceases immediately with the disappearance of bottom land relief. Thus, that unique and special ecosystem should be protected as a whole