First description and conservation implications of a unique stand of the Caucasian wingnut in Lapankuri (Georgia)

Many north-temperate tree species survived glacial periods in small, low-density populations in refugia. These refugia are located in eastern and western North America, South Europe, East Asia, and western Asia. As a part of western Asia, Georgia harbors two main refugia: the Colchis in western Georgia and the eastern Great Caucasus, where many Cenozoic relict plants still exist. In this article, we report a new population of Pterocarya fraxinifolia (the Caucasian wingnut) which was discovered in the eastern Great Caucasus, near the village Lapankuri. The Lapankuri P. fraxinifolia stand is unique because the species grows not only in a narrow strip of riparian vegetation, but is also occurring in a broad band up to 100 m away from the river. Pterocarya fraxinifolia is dominant in the stand and is represented by large and old trees. Many other relict trees such as Diospyros lotus and Juglans regia are also present in the Lapankuri stand. Although some Cenozoic relict species are widely cultivated and naturalized in Central and Western Europe, natural stands of these plants provide the only evidence of their past growing conditions; therefore, conservation of this place is strongly advocated.