Effect of altitude on biomass production and essential oil composition of selected medicinal plants

This study provides new insights into biomass quality and quantity variability, including essential oil (EO) content, in selected Allium , Lavandula , Mentha , Origanum , and Thymus species cultivated at three altitudes. The first harvest date was primarily influenced by accumulated active temperature and sunlight intensity, while rainfall effects varied. Specific temperature and sunlight thresholds for each species were identified from three-year observations. Allium schoenoprasum yielded 50 % more biomass than its cultivar ‘Album’, though the warmest site was suboptimal. Lavandula x intermedia outperformed L. angustifolia in biomass and EO yield, with linalool as the dominant EO component. Mentha x piperita exhibited superior biomass and EO yield with menthol as the major compound, while M. wirtgeniana had lower biomass and a neodolenone-rich profile. Origanum vulgare had higher biomass and EO yields than O. laevigatum , with caryophyllene oxide as a dominant compound. In Thymus vulgaris , the cultivar ‘Compactus’ yielded less biomass but more EO than ‘White’, with p-thymol, (-)-β-cadinene, and linalool as key constituents. This study highlights the role of altitude in determining biomass productivity and EO composition, emphasizing the importance of selecting optimal species and cultivars for sustainable, high-quality production in pharmaceutical, cosmetic, and food industries. Understanding altitude-driven metabolic shifts can support adaptive strategies for medicinal plant cultivation amid global climate variability.