Dependence of Phenorhythms of North American Maples on the Meteorological Parameters in the Southern Urals (Ufa)

The phenological development of 13 taxa of North American maples for 2013–2020 has been analyzed on the basis of the collection of the South Ural Botanical Garden-Institute, Ufa Federal Research Center, Russian Academy of Sciences. The sum of positive, effective, and active temperatures and the sum of precipitation required for the onset of the main phenophases have been calculated. Most phenophases depend on weather conditions, except for the phases of the beginning and end of flowering and fruit ripening: they are genetically determined. This fact explains the large difference in the sum of temperatures and precipitation at the beginning of these phases in different species. The sum of positive temperatures at the beginning of flowering is 11–497°C; the amount of precipitation is 33–80 mm. At the end of flowering, the sum of positive temperatures at the beginning of flowering is 149–722°C; the amount of precipitation is 43–112 mm. The number of positive temperatures attributable to the phenophase of fruit ripening varies from 693 to 2662°C, and the amount of precipitation by this time varies from 47.5 to 315 mm. The duration of vegetation of North American maples in Ufa, depending on the species, ranges from 140 (A. tschonoskii) to 172 days (A. rubrum Summer Red).