. 2011 Evidence of widespread effects of ozone on crops and (semi-)natural vegetation in Europe (1990Europe ( -2006 in relation to AOT40-and flux-based risk maps. Global Change Biology, 17. 592-613. 10.1111Biology, 17. 592-613. 10. /j.1365Biology, 17. 592-613. 10. -2486Biology, 17. 592-613. 10. .2010 Contact CEH NORA team at noraceh@ceh.ac.ukThe NERC and CEH trademarks and logos ('the Trademarks') are registered trademarks of NERC in the UK and other countries, and may not be used without the prior written consent of the Trademark owner. and an international biomonitoring experiment coordinated by the ICP Vegetation. 5The latter involved ozone-sensitive (NC-S) and ozone-resistant (NC-R) biotypes of 6 white clover (Trifolium repens L.) grown according to a common protocol and 7 monitored for ozone injury and biomass differences in 17 European countries, from 8 1998 to 2006. Effects were separated into visible injury or growth/yield reduction. 9Of the 644 records of visible injury, 39% were for crops (27 species), 38.1 % were for 10 (semi-)natural vegetation (95 species) and 22.9% were for shrubs (49 species). Due 11 to inconsistencies in reporting effort from year to year it was not possible to determine 12 geographical or temporal trends in the data. Nevertheless, this study has shown 13 effects in ambient air in 18 European countries from Sweden in the north to Greece in 14 the south. These effects data were superimposed on AOT40 (accumulated ozone 15 concentrations over 40 ppb) and POD3 gen (modelled accumulated stomatal flux over a 16 threshold of 3 nmol m -2 s -1 ) maps generated by the EMEP Eulerian model (50 km x 50 17 km grid) that were parameterised for a generic crop based on wheat and NC-S/NC-R 18 white clover. Many effects were found in areas where the AOT40 (crops) was below 19 the critical level of 3 ppm h. In contrast, the majority of effects were detected in grid 20 squares where POD3 gen (crops) were in the mid-high range (> 12 mmol m -2 ). Overall, 21 maps based on POD3 gen provided better fit to the effects data than those based on 22 AOT40, with the POD3 gen model for clover fitting the clover effects data better than 23 that for a generic crop. 24 25

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a b s t r a c tTo derive O 3 doseeresponse relationships (DRR) for five European forest trees species and broadleaf deciduous and needleleaf tree plant functional types (PFTs), phytotoxic O 3 doses (PODy) were related to biomass reductions. PODy was calculated using a stomatal flux model with a range of cut-off thresholds (y) indicative of varying detoxification capacities. Linear regression analysis showed that DRR for PFT and individual tree species differed in their robustness. A simplified parameterisation of the flux model was tested and showed that for most non-Mediterranean tree species, this simplified model led to similarly robust DRR as compared to a species-and climate region-specific parameterisation. Experimentally induced soil water stress was not found to substantially reduce PODy, mainly due to the short duration of soil water stress periods. This study validates the stomatal O 3 flux concept and represents a step forward in predicting O 3 damage to forests in a spatially and temporally varying climate.Crown