Наукові праці Лісівничої академії наук України (Nov 2023)
Ecological and biological features of Parrotia persica (DC.) C.A.Mey in the conditions of Seaside arid and North-western sufficiently humid climatic zones of Ukraine
Abstract
Parrotia persica (Persian parrotia, Persian ironwood) – a moisture-loving and heat-loving endemic of the Hyrkanian floristic region, which stretches along the southern and southwestern coast of the Caspian Sea, is rather a rare species in botanical gardens and arboretums of Ukraine. The biological and ecological features of the species were formed in the Tertiary period, and therefore the main characteristics of Persian ironwood are the absence of winter dormancy and the presence of summer dormancy (which in the natural range is not associated with a period of drought). Despite the significant difference between the climate of the Hyrkanian floristic region and the climate of Ukraine, the initial attempt to introduce Parrotia persica in the South of Ukraine in the 30s of the XX-th century was carried out by the director of the Odesa Botanical Garden, Volodymyr Lipsky, an outstanding botanist and researcher of the flora of the Caucasus. Unfortunately, Parrotia persica of this period has not survived because during World War II many trees of the arboretum were cut down to heat the greenhouse with a collection of valuable tropical plants. Due to the reintroduction of Parrotia persica since 1955, seven middle-aged Parotia trees are now growing in the arboretum of the Odesa Botanical Garden (Odesa, 87 Frantszuzsky Bulvar; 46°26´31″ N 30°46´08″E), which became the subject of these studies. The seeds for the initial introduction of all the trees were obtained from the Lenkaran forest division in Azerbaijan. The main problem of growing Parrotia persica in Odesa (Seaside arid climatic zone of Ukraine) is a significant deficit of moisture. This is a cause of florescence shortening, insufficient (scanty) seed ripening (only 1-2%) and lack of the secondary increasing of shoots. Due to a lack of moisture during the summer drought, the edges of the leaf blades dry out and the falling of leaves from the entire crown is completed already in November. Therefore, the success of Parrotia introduction in such environmental conditions is possible only due to high tending of seedlings, first of all abundant watering. It was due to the prolonged watering of one of the Parotia trees in 2014 that most of the seeds got fully ripe and, as a result, under the crown of this tree 145 seedlings were recorded the following year, which subsequently formed the young up-growth. The degree of introduction of Parrotia trees in the Odesa Botanical Garden is clearly demonstrated by climographs constructed by G. Taylor’s method. They reflect abrupt changes in climate - from humid subtropical (Cfa) in the natural range of Azerbaijan to climates in intermediate introduction points - humid subtropical with a tendency to Mediterranean in Tbilisi (Cfa→Csa), Mediterranean with a tendency to continental with dry summers and a predominance of winter precipitation in the form of snow in the city of Tashkent (Csa→Dsa), to a humid continental climate in the city of Kyiv (Dfb), and, finally, to a continental climate with hot summers and cold winters and a certain tendency to a steppe climate at the final point of introduction - the city of Odesa (Dfa→BSk). These climographs show that the most unfavorable factor for Parrotia persica in Odesa is the insufficient amount of precipitation. The success of survival of the young plants in such conditions is based on the experience of the researcher. Despite the fact that seedage of Parrotia in Seaside arid climatic zone of Ukraine is assessed as insufficient, the prospect of its use in this region as a valuable collection and ornamental plant species is undoubted. In Ukrainian Roztochia, which is the part of a region with relatively high climate humidity (the North-Western sufficiently humid climatic zone of Ukraine), the amount of precipitation is not a limiting factor for the growth of Parrotia persica, but in frosty winters its one-year-old shoots are damaged. In the arboretum of the Botanical garden of the Ukrainian National Forestry University (the village of Stradch, 20 km in the north-western direction from Lviv; 49°54´N 23°46´30″E), the oldest 20-year-old Parrotia tree has characteristic signs of development similar to those in the natural range - bright summer color of young leaves, re-growth of shoots in autumn, preservation of leaves throughout the winter. The general conclusion is that Parrotia persica is a perspective tree species for botanical collections and landscaping provided it receives the necessary tending in both study climatic zones of Ukraine – Seaside arid and North-western sufficiently humid one. The main causes of its limited distribution are insufficient popularization and lack of planting material in the local nurseries.
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