The role of environmental factors in ozone uptake of Pinus mugo Turra

Abstract Montane forests in the High Tatra Mountains are exposed to high ambient ozone (O 3 ) concentrations that may adversely affect the physiological processes and health of plants. This study presents the modelled results of the phytotoxic ozone dose (POD) for dwarf mountain pine ( P. mugo ) in 2016. POD metrics were calculated using the deposition model DO 3 SE, with O 3 concentration and meteorological data measured in three altitudinal zones. In addition, maximal stomatal conductance (G max ) derived from gasometric field measurement in local conditions was included in the model. Field measurements confirmed the robust performance of the DO 3 SE model for stomatal conductance (G sto ). The site-specific stomatal conductance response model was largely congruent with average values estimated by DO 3 SE, though differences in temporal G sto distribution were observed. We determined a moderate limitation of O 3 uptake due to environmental factors (f ENVI ) such as air temperature and relative humidity, solar radiation, and soil water availability. It appears that G max is more relevant for annual POD than f ENVI in the temperate mountain forest. The results indicate a high level of POD and O 3 uptake by P. mugo in the High Tatra Mountains, which corresponds with the O 3 -induced visible injury symptoms observed. We also identified visible O 3 injury in P. mugo needles, which was more prevalent among the two-year old needles than younger individuals.