Біолого-екологічні особливості поширення омели білої (Viscum album) в умовах міста Вінниця

Abstract

Within the settlements located in Vinnytsia, European mistletoe has gained intense influence. Tree damage by Viscum album leads to both the deterioration of the trees, their further drying and the reduction of aesthetic evaluation of the plantations. Despite the intensive damage of tree plantations in Vinnytsya caused by Viscum album, the trees of most coniferous species including pine, spruce and douglasia, appeared to be quite stable. Oak, hornbeam and beech are distinguished from deciduous species by high resistance. Chestnut, red oak, walnut and other deciduous species are found to be less damaged. At the same time, most of the alley cropping, in particular poplar and linden trees are largely damaged by this hemiparasite plant. This is due not only to the peculiarity of the tree species, but also their age. In particular, most of older trees with existing damage to the trunk and branches are more severely affected by mistletoe. As a result of our research we have found that the age of the trees mostly affected by Viscum album is 50-60\xa0years and with age the degree of damage increases, as well as the proportion of damage to trees aged 70-80\xa0years is 25-29\xa0%. The degree of damage to trees with European mistletoe is determined by a 5-point scale, according to which the highest score of damage is found in black poplar and eastern cottonwood stands (5\xa0points), the lowest score is found in European spruce and small-leaved linden stands (1-2\xa0points). Populus species are considered to have low and high level of damage by Viscum album (26\xa0% of trees), average (28\xa0% of trees), and a very high (30\xa0% of trees) respectively. P. nigra and\xa0P. deltoids account for the highest proportion of trees with high and very high levels of damage, 22\xa0%\xa0and 32\xa0%, respectively. The intactness of\xa0P.\xa0pyramidalis trees is apparently caused by the fact that the mistletoe birds find it uncomfortable to sit on vertically arranged branches. The same applies to\xa0P. bolleana. In\xa0P. alba, P. tremula, P. balsamifera, and\xa0P. laurifolia, the low population density of trees by hemiparasite plant is consistent with the findings of some other researchers, due to the fact that these poplar trees secrete volatiles that deter birds. Black poplar and eastern cottonwood trees with a spreading crown and a spreading branch system of different orders are most attractive to birds, and therefore to the appearance of mistletoe on their trees.