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Temporal and spatial distribution of ozone symptoms across Europe from 2002 to 2014
No full textOne of the aims of ICP Forest is to estimate the potential risk of ozone on European forest
ecosystems. In this respect, ozone-induced, visible foliar injury is one of the most considered
response indicator to assess ozone impact on vegetation. In the present study, we analyze
visible injury data from the Light Exposed Sampling Sites (LESS) installed close to the Level
II monitoring plots, and where ozone concentration and meteorological parameters are also
measured.
Over the period of 2002-2014, nineteen European countries participated in the field
assessment of ozone visible injury according to the ICP Forests standardized methodology
(Schaub et al., 2010). Overall, 295 woody species were recorded, of which 28% are being
reported as symptomatic*. In 2009, the year with the highest number of countries
participating in the field campaign, 60% of the countries reported the presence of ozone
symptoms in some plants. In the same year, 12.4% (24 out of 194) of the woody species
were symptomatic.
Preliminary results for temporal trends reveal that four out of five countries with at least eight
years of data show a decreasing trend in frequency of symptomatic woody species,
statistically significant for two countries. Enhanced data quality control is being carried out to
perform further analyses to better quantify the spatial and temporal distribution of ozone
symptoms across European forests, also in relation to ozone exposure (cf. Schaub et al.,
2015)
Ozone risk assessment for European forests: a ten-year study on permanent monitoring plots
No full textGround level ozone still poses a serious threat to forest ecosystems across Europe and represents a priority for the UNECE Convention on Long-range Transboundary Air Pollution. The ICP Forests Expert Panel on Ambient Air Quality has coordinated the monitoring of ozone concentration and effects (i.e. foliar injury on native vegetation) since 2000 on an annual basis on intensive long-term forest monitoring sites across Europe (Level II). Methodologies, including quality assurance such as data harmonization, completeness and plausibility tests have been applied according to the ICP Forests Manual, parts X and XV (Schaub et al. 2010a & 2010b). Here, the authors evaluate the available data on ozone concentration, exposure, and foliar injury that have been collected at the very forest sites across Europe from approx. 80 – 150 plots and over 1’000 native species. Emphasis will be put on European scale analyses for i) spatial and temporal trends for ozone concentration; ii) different AOT40 assessment methodologies; iii) comparison between measured concentrations with passive samplers, respective AOT40 estimates and modeled EMEP outputs; and iv) foliar injury occurrence in relation to ozone concentration and ozone exposures respectively. Considering stress factors such as drought and physiological response indicators, these analyses will favor a comprehensive evaluation of ozone risk for European forests based on data from the very forest sites. Furthermore, these harmonized data sets will serve as a valuable basis for further integrated analyses and validation of models, such as from EMEP
2000-2013 ozone trends across Europe
No full textTropospheric ozone (O3) has been recognized as an important factor within global change, that has the capacity of reducing carbon sink strength of forest ecosystems and thus represents a priority for the UNECE Convention on Long-range Transboundary Air Pollution.
The ICP Forests Expert Panel on Ambient Air Quality has coordinated the monitoring of ozone concentration and effects (i.e. foliar injury on native vegetation) since 2000 on an annual basis on intensive long-term forest monitoring sites across Europe (Level II). Methodologies, including quality assurance such as data harmonization, completeness and plausibility tests have been applied according to the ICP Forests Manual, parts X and XV (Schaub et al. 2010a & 2010b). Here, the authors evaluate ozone concentration, exposure, and foliar injury data that have been collected at the very forest sites across Europe from approx. 200 plots and 20 countries. Emphasis will be put on European scale analyses for spatial and temporal trends for ozone concentration and AOT40 exposure. These harmonized and aggregated data sets will serve as a valuable basis for further integrated analyses and validation of models, such as from EME
Ground level ozone and its impact on European forests
No full textTropospheric ozone (O3) is a gaseous air pollutant
that can impact forest vegetation, causing effects
ranging from visible injury to reduced carbon sink
strength of forest trees, and it is thus a priority for
the UNECE Convention on Long-range Transboundary
Air Pollution. Emissions associated with the
burning of fossil fuel and biomass have approximately
doubled the mean global tropospheric ozone
concentrations, and further increases are expected
over the course of the twenty-first century
Assessing the potential impact of ozone on native vegetation: findings from the long-term pan-European monitoring program of ICP Forests
No full textThe assessment of air pollution levels and effects on European forest ecosystems is the main goal of the UNECE ICP Forests program. Currently, ground level ozone is of primary interest due to its phytotoxicity and the exceedance of critical levels over large parts of Europe.
Within ICP Forests, monitoring of ozone concentrations and effects on vegetation have been carried out since 2000 according to standardized and quality assured methods on a number of intensive monitoring (Level II) sites purposively selected throughout Europe.
Ground-level ozone concentrations have been measured from April to September by passive sampling, a method proved to be particularly useful at remote sites. Effects on vegetation have been evaluated once a year through the assessment of ozone-like visible foliar symptoms, considered one of the most specific and easily detectable indicator for ozone impact.
Overall, data collected on 170 intensive monitoring Level II sites in 20 countries for 12 years reveal a downward temporal trend for both, ozone concentrations and frequency of ozone-symptomatic species. While a decreasing south-north gradient across Europe is obvious for ozone levels, a clear spatial pattern seems to be lacking for visible symptoms.
There is a great potential of the ICP Forests long-term dataset for understanding ecosystem status and trends in response to ozone. Further analyses are being undertaken to better clarify temporal and spatial patterns and to better identify relationships among ozone, other important environmental drivers, and the response of forest ecosystems
Ozone concentrations are decreasing but exposure remains high in European forests
Full text linkOzone is a gaseous air pollutant present in remote areas at levels causing visible symptoms in plants. Despite a significant reduction, ozone levels at ICP Forests sites still exceed the threshold value fo r adverse effects. Ozone-induced foliar symptoms have been observed on woody plant species all across Europe. Further observational and long-term monitoring studies are needed to better quantify dose-response relationships and a potential impact on forest growth
Ground level ozone concentrations and exposures from 2000 to 2013
No full textTropospheric ozone (O3) concentrations from passive samplers have been monitored according to harmonized methodologies on ICP Forests intensive monitoring (Level II) sites since the year 2000 with the aim to (i) quantify ozone concentrations during the vegetation period (April-September), (ii) estimate the related ozone exposures of forest ecosystems, and (iii) detect temporal and spatial trends across Europe. Season mean ozone concentrations ranged from 19 to 64 ppb with similar deviations from the median among the countries. A decreasing south-north gradient across Europe is apparent with the highest concentrations having been measured in Italy, southern Switzerland, the Czech Republic, Slovakia, and Greece. Mean AOT40 for 2000-2013 ranged from 2 to 67 ppm h. The AOT40 threshold of 5 ppm h set to protect forests from adverse ozone effects was exceeded in 18 out of 20 countries. An overall trend analyses, including all April–September data from 20 countries, revealed a significant decrease of 0.35 ppb ozone per year (n = 29 356; p = 0.000) from 2000 to 2013. When considering only sites with a data coverage of at least 4 years and 120 days (66%) between 1 April and 30 September, site-specific trend analyses did not reveal any uniform patterns across Europe
Spatial and temporal distribution of ozone symptoms across Europe from 2002 to 2014
No full textOzone-induced visible foliar injury has been assessed during 2002-2014 according to ICP Forests
standardized methods. This activity provided 29,809 records from 285 woody plant species, 169 plots
and 19 countries. Data were evaluated for the entire period 2002-2014 as well as for 2009 only, when
spatial coverage was the greatest. First results reveal that 55.0% of the assessed plots were
symptomatic, and 26.0% of species developed ozone visible injury. Beech (Fagus sylvatica) was the
species with the highest frequency of symptomatic observations (plot and years) in both 2002-2014
(40.1%) and 2009 (42.9%). The frequency of symptom reports occurred without a clear spatial pattern.
In case, higher frequency of symptom occurrence seemed more common from northern Italy to NorthWest
Germany, and towards East Europe. At country level, temporal trend analysis indicates a
downward trend of mean frequency of symptomatic species for five out of six countries. Overall (all
plots together), there is a slightly decreasing trend, which is consistent with the decreasing trend
observed for ambient ozone concentrations. These first results demonstrate the potential of the survey
on visible foliar injury to detect the potential impact of ozone on European vegetation. Further,
enhanced quality control procedures are underway to aggregate the datasets and promote a more indepth
exploitation of cause-effect relationships, considering ozone symptoms, ozone concentration and
measurements on forest health, growth, nutrition, biodiversity and climate undertaken at the ICP
Forests plots
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