ECOLOGICAL AND BIOLOGICAL ROLE OF LIGHTING IN THE DEVELOPMENT AND SEASONAL DYNAMICS OF NORTHERN WHITE-CEDAR (Thuja occidentalis L.) NEEDLES AND ITS ORNAMENTAL FORMS IN LVIV

Abstract

For the research, we selected urban green spaces with a simple and complex planting rhythm, where we examined the effects of light on the results of competition between individuals, according to the nature of the light flow: from the top to the bottom of the crown and towards the open space. The differentiation of the columnar Thuja occidentalis L. in terms of tree thickness distribution was revealed, and a forecast was made for the further development of plants that have lagged behind in growth and should be removed from the row in a timely manner so as not to reduce the aesthetic compositional integrity of the green walls. In order to clarify the role of light in the competition individuals for its intensity, the relationship between the level of lighting of the crown of Thuja occidenatlis (Th.o.) “Fastigiata” in summer and autumn and their growth was examined. The role of lighting in changing the colour of coloured cultivars and the place of chlorophylls a and b, as well as carotenoids in this process were studied. In the shaded crowns of Th.o. “Aureaspicata” and Th.o. “Aureovarigiata”, the golden colour changed to light green due to a decrease in carotenoid content. At the same time, the winter brown-green colour was a consequence of an increase in the concentration of carotenoids in the cells. Understanding of the statics and dynamics of the colour of decorative forms of northern white-cedar makes it possible to select cultivars with the most decorative colour for various garden and park compositions.