To derive more realistic ozone critical levels and to improve our assessment of ozone effects on forest ecosystems, we advocate the need (i) for further experimental and long-term monitoring studies to better quantify species-specific ozone uptake by forests and its impacts on their growth under real forest conditions, and (ii) to develop physiological and demographic modelling tools that can upscale these impacts at longer temporal and larger spatial scales.

Despite increasing knowledge on the effects of ozone on plant physiological functions, its impacts at a higher organization level, i.e. on individual tree diameter increment and forest growth are highly uncertain and vary among studies. The contrasting dose-response relationships reported may arise from the different data used as input in terms of sample size and characteristics, and/or from differing methodological choices. The proposed study aims to make use of over 200 long-term monitoring plots across Europe where ozone concentrations have been measured since 2000, in parallel to forest and vegetation variables. Ozone related effects and critical levels on selected endpoints such as tree growth will be derived by quantifying ozone fluxes and applying multiple and various statistical techniques that consider for confounding abiotic and biotic environmental factors. Data sources from various networks will be combined for calibration and validation purposes.

See blog in Journal of Ecology "Toward an Integrative Approach to Assess Ozone Impacts on Forest Growth"