Universal History Annotation << Back WOODY PLANTS AND CLIMATE OF SAINT-PETERSBURG IN THE XX CENTURY G.A. Firsov, A.V. Volchanskaya The experience of arboriculture at Saint-Petersburg shows that abnormally cold winters are especially dangerous for trees and shrubs. In fact, they are the main factor of selection. There were 31 cold winters at Saint-Petersburg in the 20-th century. The majority of them happened to occur at the beginning of that century. There were 21 of such cold winters in the fi rst half of the 20-th century, and only 10 – in the second half of it. The winter 1941/42 with sum of temperatures during the cold period of the year ... -1800 о was in fact the record one not only in the 20-th century, but during the whole period of instrumental meteorological observations since 1752. The absolute minimum temperature at Saint-Petersburg (–35,6 о оn 17 January 1940) was registered in winter 1939/40 (–1310 о). The last severe winter of strong influence on introduced woody flora was the winter 1986/87. In general the winters at the end of the 20-th century were mostly warm and normal ones. In modern conditions of the warming of the climate the levels of adaptation of woody plants have been changing. The earlier published data on winter hardiness of woody exotic species at the North-West of Russia need to be revised. In the 20-th century the investigation of winter hardiness and of reaction of woody plants on hard winters were of first grade interest. But nowadays the united complex research of different levels of adaptation, of steadiness and longevity are required. This is of importance to develop groups of plants which have different reaction on the warming of the climate. Keywords: arboriculture, winter hardiness, warming of climate, Saint-Petersburg. DOI: 10.25791/vseist.01.2021.1126 Pp. 42-51.