Joint research project

Tropospheric ozone effects on forestgrowth and diversity (TROZGRODIV)

Project leaders
Elena Paoletti, Ovidiu Badea
ROMANIA - RA - The Romanian Academy
CNR/RA 2014-2016
Biology, agriculture and food sciences
Thematic area
Biology, agriculture and food sciences
Status of the project

Research proposal

Human and natural disturbances have a large impact on forest structure and diversity, and thus functionality. Air quality, and particularly ozone (O3), play a key role on forest physiological disturbances, by producing injuries, losses in growth and higher vulnerability to secondary stressors. Ozone is an important air quality issue, causes serious health problems and damage to materials and ecosystems, and drives climate change (Paoletti 2007; Kampa&Castanas 2008; De Marco &Screpanti 2009). Ground-level background O3 concentrations have doubled since pre-industrial times and continued to increase during the 1990s (Vingarzan 2004). IPCC (2007) pointed out that 11 out of 12 recent years (1995-2006) ranked among the warmest years in the instrumental record of global surface temperature (since 1850). O3 formation is strongly dependent on temperature (The Royal Society 2008).
Current European standards use the O3 exposure index AOT40 to protect vegetation, although it does not give information about physiological O3 uptake (Paoletti& Manning 2007) because it does not take into account the environmental constraints to ozone uptake into leaves, such as water stress. As a consequence, AOT40 is inadequate to quantify the impacts of O3 on vegetation. Astomatal flux-based approach was suggested for providing better assessments of ozone damage to plants in Europe (Embersonet al 2000). The stomatal flux-based approach estimates the critical amount of O3 that is absorbed into the leaf through stomatal openings and integrates the effects of multiple climatic factors, vegetation characteristics and local and phonological inputson O3 injury (Paoletti& Manning 2007). At the moment there are insufficient available evidences in order to validate the stomatal flux thresholds and critical levels for forests (UNECE 2010). This is mostly due to the fact that the parameters needed for stomatal flux calculation (e.g. air temperature and relative humidity, soil water content, ozone concentrations) and plant response indicators (e.g.relative growth) are usually not available at the same sites. Therefore, the dose-response relationships have been mostly derived from chamber experiments both for exposure and flux indices (LRTAP 2004; Manning 2005; Hayes et al 2007; Mills et al 2007; Pleijelet al 2007). Due to differences in the microclimates inside and outside a chamber, such a broad-scale field application is questionable (Paoletti 2007). This is why the effects of ambient ozone on forest growth and diversity under real-world conditions have not yet been quantified.
Romania and Italy possess extensive and invaluable in-field data-bases (see below) that can be cross-compared to answer the fundamental question about ozone impacts on adult forest species-specific growth responses.Romania and Italy possess also complementary expertise. IPP is one of the world-leader in the investigation of ozone impacts on forests (see the responsible's CV and collaborators). Center for Studies and Researches on Agricultural and Silvicultural Biodiversity (CSCBA), in collaboration with Forest Research and Management Institute (ICAS), which plays an initiating role in long-term monitoring of air pollutants effects on Romanian forests, offers fundamental information on permanent forest plots in the framework of Long-Term Ecological Research Network (LTER) and ICP-Forests level II network, and will become, along with ICAS, a key player in the development and consolidation of this domain in Romania .
Together, Romania and Italy representative institutions (CSCBA and IPP-CNR) have a mutual interest and willingness to develop their cooperation on continuously evaluating the impact of air pollution on forests, based on state-of-the-art methods, and to interchange and integrate their experience in future research projects proposals.
De Marco A, Screpanti A, Paoletti E 2009 Geostatistics as a validation tool for setting ozone standards for durum wheat. Environ Pollut30, 1-7.
Emberson L, Ashmore MR., Cambridge HM, Simpson D, Tuovinen JP 2000 Modelling stomatal ozone flux across Europe. Environ Pollut109, 403-413.
Hayes F, Jones MLM, Mills G, Ashmore M 2007 Meta-analysis of the relative sensitivity of semi-natural vegetation species to ozone. Environ Pollut146, 754-762.
IPCC WGI Climate Change 2007: The Physical Science Basis: Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change.
Kampa M, Castanas E 2008 Human health effects of air pollution. Environ Pollut151, 362-367.
Long-Range Transboundary Air Pollution -LRTAP- (2004) Mapping Manual, UNECE.
Manning WJ 2005 Establishing a cause and effect relationship for ambient ozone exposure and tree growth in the forest: progress and an experimental approach. Environ Pollut137, 443-453.
Mills G, Busea A, Gimeno B, Bermejo V, Holland M, Emberson L, Pleijel H (2007) A synthesis of AOT40-based response functions and critical levels of ozone for agricultural and horticultural crops. Atm Environ 41, 2630-2643.
Paoletti E 2007 Ozone impacts on forests. CAB Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources, 2 (No. 68), 13.
Paoletti E, Manning WJ 2007Toward a biologically significant and usable standard for ozone that will also protect plants. Environ Pollut150, 85-95.
Pleijel H, Danielsson H, Emberson L, Ashmore MR, Mills G 2007 Ozone risk assessment for agricultural crops in Europe: Further development of stomatal flux and flux-response relationships for European wheat and potato. Atm Environ 41, 3022-3040.
UNECE (2010) Mapping Critical Levels for Vegetation. International Cooperative Programme on Effects of Air Pollution on Natural Vegetation and Crops, Bangor, UK.
Vingarzan R 2004 A review of surface ozone background levels and trends. Atm Environ 38, 3431-3442.

Research goals

The scope of this project is to develop the cooperation between Romania and Italy in the area of quantifying ozone effects on forest growth and diversity. The main objective is harmonizing methodologies for assessing concentration of ozone, stomatal ozone uptake and their effects on forest growth and diversity, by means of a multidisciplinary collaboration. The expected results are novel and of great significance in the international context, and will provide both countries with innovative findings about the responses of their forests to ozone pollution in terms of carbon sequestration and biodiversity. This bilateral agreement is an unique opportunity of collaboration for those research teams.

In parallel, secondary objectives are to:
- Establish the best standards and thresholds for protecting Italian and Romanian forests from ozone
- Investigate the spatial and temporal variability of stomatal ozone fluxes over a range of forest ecosystems,
- Estimate which environmental variables among ozone pollution, soil water availability, light, air temperature, and humidity affect stomatal ozone fluxes of forests most severely
The involved teams aim also to develop research proposals with EU funding perspective and further consolidate the scientific cooperation between the participating countries.

Last update: 07/10/2022