WHITE MISTLETOE VISCUM ALBUM L. DISTRIBUTION AND IMPACT ON HOST TREE IN EASTERN PART OF LATVIA

Abstract

White mistletoe Viscum album L. is not a common species in the territory of Latvia, it is mostly distributed around the cities Preiļi (Eastern population) and Liepāja (Western population). The specific of the species is that it receives water and minerals from its host tree in a parasitic way, thus gradually destroying it. One of the factors in the prevalence of Viscum album is climate. During recent times the climate in the territory of Latvia is getting warmer every year. This is very noticeable in the winter. As a result Viscum album as a warm-loving species is slowly spreading.

The main goal of the research was to evaluate the population of Viscum album and the response reaction of host trees in Eastern population in Latvia.

Dendrometric indicators of host trees, meteorological data and wood samples of the host trees were needed for the development of the study, for which changes in annual tree-ring width and density of wood were further analyzed. Also in order to understand the significant differences between the tree-ring widths in exact seasons and the density of wood of affected and unaffected trees wood samples were collected from trees with no Viscum album on them.

Conclusions show that the climate is getting warmer and the number of specimens of Viscum album has increased compared to previous period. Changes in the tree-rings width and wood density of the host tree are negatively directed.