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

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 DO3SE, 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 DO3SE model for stomatal conductance (G(sto)). The site-specific stomatal conductance response model was largely congruent with average values estimated by DO3SE, 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.