The effect of mistletoe presence on the content of essential oils in fir twigs

The aim of this study was to determine the effect of the effect of fir mistletoe Viscum album ssp. abietis presence on the content of essential oils in fir twigs Abies alba. The research material was collected in the Gorlice Forest District, Łużna Forest Range (Regional Directorate of the State Forests in Kraków, Poland). Two healthy trees (without mistletoe) and four mistletoe−infested trees, approximately 100 years old, were selected for the study. The trees were then felled, and their twigs were collected and grouped into three categories: I – twigs from trees without mistletoe; II – twigs from infested trees, taken from branches where mistletoe was not present; and III – twigs from infested trees, taken from branches where mistletoe was present (a fourth group, IV, was also distinguished in the analyses, which combined groups II and III). Ten samples, weighing 100 g each, were randomly collected from each twig. The amount of essential oils in the fir twigs was determined using a Deryng apparatus. The obtained results indicate variations in the essential oil content of the fir twigs depending on the analysed sample group. In the samples collected from trees not infected with mistletoe (type I twigs), the average essential oil content was 0.861%. Lower essential oil contents were obtained in samples from trees infested with mistletoe (type IV), with values more than twofold lower than those from healthy trees. In the group of samples collected from branches of infected trees on which mistletoe was not directly present, the average essential oil content was 0.306% (type II). For samples taken directly from branches with mistletoe, the average essential oil content was 0.452% (type III). The comparison of mean values between the individual types of fir twigs indicates that the highest essential oil content was recorded in samples from trees not infested by mistletoe, while the lowest values occurred in samples taken from infested trees without the direct presence of mistletoe on the examined branches. These results confirm that the phytosanitary condition of fir trees significantly affects the quality of fir twigs, as determined by their essential oil content, which may be important when assessing the suitability of this raw material for further use.