Growth drivers of monumental wild service tree (Sorbus torminalis) out of its natural range in Kyiv, Ukraine

Wild service tree (Sorbus torminalis) is a rare, endangered, relict species, that is protected by law in many European countries. Outside the species distribution range, the trees are usually planted in botanical gardens, parks, arboretums, and at the roadside. Such old introduced trees are an important source of knowledge about species’ acclimation process and current growth-limiting factors in the new environment. In Kyiv, the oldest live S. torminalis trees have been planted in botanical gardens and arboretums after the 1950s. In addition, some trees of this species are preserved in front of the historical building Liberman’s mansion, but the year of their planting remains unknown. Regarding dendroclimatological investigations of this species are scarce and have been provided only in Central European forests, a detailed analysis of the species growth-to-climate relationships should be performed not only the species’ natural range but also in its secondary ranges. In this article, we studied three S. torminalis trees in a historical place in Kyiv to determine their age and evaluate environmental conditions driving the growth of this rare species out of its natural range in Kyiv. To reach our goal we used the dendrochronological approaches, i.e. tree-ring dating, partial correlation analysis using stationary and moving time windows. Our results showed that S. torminalis trees were planted after the last building owner S. Liberman’s death (1917). The studied trees are the oldest of known alive S. torminalis trees in Kyiv. Dendroclimatological results revealed S. torminalis is sensitive to higher air temperature and moisture excess in the period of wood formation in Kyiv. S. torminalis trees at 2 Bankova Street are the oldest species examples in Kyiv and have important historical, cultural, and scientific values. S. torminalis species could be widely used in urban forestry, particularly in regions with projected soil moisture shortening.