PHENOLOGICAL PHASES OF THE ULMUS PUMILA L. DEVELOPMENT IN SPRING AND SUMMER PERIOD IN THE CHERNIHIV CITY

Abstract

Ulmus pumila L. is a potentially invasive species capable of rapid spread across the territory of Chernihiv Polesie. It is known that the invasion of U. pumila occurs due to seed and vegetative reproduction. Therefore, in order to develop measures to regulate the population of this invasive species, it is necessary to study its phenological features in the places of growth.

Phenological phenomena are the result of the adaptation of various types of plants to abiotic conditions (temperature, photoperiod duration, humidity, wind direction and strength, amount of precipitation) in a specific habitat and as a result of the onset of phenological phases (leaf formation, budding, flowering, fruiting, leaf fall) which are sensitive to climate change.

The purpose of the article is to establish the course of phenological phases of U. pumila, whose populations grow on the southwestern outskirts of Chernihiv city, along the railway track.
Research materials and methods. Phenological observation of U. pumila in spring and summer period of 2023 was carried out according to the methodology of I.N. Beideman. Phenological observations were carried out every 1/2 days during the spring period, 2 times a week during the summer period. All observation data were recorded in the journal. Meteorological phenomena were also recorded every day.

Scientific novelty. This article presents the results of a phenological study, namely, data on the course of the phenological phases of U. pumila (which is an invasive species) in the spring-summer period. The dependence of the onset of certain main phenological phases and subphases on the average daily temperature is presented.

Conclusions. During the phenological study, it was established that the course of phenological phases in U. pumila is closely related to changes in the average daily air temperature. According to the phenological study of U. pumila, which was carried out in the spring-summer period of 2023, the following can be stated: the vegetative phase in U. pumila takes place from 22.03 to 18.04; budding phase from 27.03 to 13.04; the flowering phenophase lasts from 19.04 to 3.05; the fruiting phenophase lasts from 11.05 to 22.05.

Since in the second decade of March, the air temperature was warmer than normal, the sub-phases of «budding» and «swelling of buds» passed faster, and the sub-phases «unfolding of the first leaves» and «unfolding of most of the leaves» are characterized by a slow course due to a sharp decrease in air temperature in the first decade April.

The prospect of further research and observations of the course of phenological phases and subphases of U. pumila is the development of ways to prevent the invasion of this species in the territory of Chernihiv Polesie.