[Show abstract][Hide abstract] ABSTRACT: Key message: Exceedance of critical limits in soil solution samples was more frequent in intensively monitored forest plots across Europe with critical loads for acidity and eutrophication exceeded compared to other plots from the same network. Elevated inorganic nitrogen concentrations in soil solution tended to be related to less favourable nutritional status. Context: Forests have been exposed to elevated atmospheric deposition of acidifying and eutrophying sulphur and nitrogen compounds for decades. Critical loads have been identified, below which damage due to acidification and eutrophication are not expected to occur. Aims: We explored the relationship between the exceedance of critical loads and inorganic nitrogen concentration, the base cation to aluminium ratio in soil solutions, as well as the nutritional status of trees. Methods: We used recent data describing deposition, elemental concentrations in soil solution and foliage, as well as the level of damage to foliage recorded at forest plots of the ICP Forests intensive monitoring network across Europe. Results: Critical loads for inorganic nitrogen deposition were exceeded on about a third to half of the forest plots. Elevated inorganic nitrogen concentrations in soil solution occurred more frequently among these plots. Indications of nutrient imbalances, such as low magnesium concentration in foliage or discolouration of needles and leaves, were seldom but appeared more frequently on plots where the critical limits for soil solution were exceeded. Conclusion: The findings support the hypothesis that elevated nitrogen and sulphur deposition can lead to imbalances in tree nutrition.
Annals of Forest Science 06/2015; DOI:10.1007/s13595-015-0489-2 · 1.98 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Transboundary Air Pollution (LRTAP). However, outcomes vary widely depending on the approach. Weathering rates and the gibbsite equilibrium greatly influence the endurable rates for sulphur and nitrogen deposition obtained, likely due to individual buffering capacities in the soils. The authors use different approaches to calculate CL for acidity and eutrophying nitrogen and compare them with the development of base cation leaching, the base cations–aluminium ratio, and acid neutralising
capacity. Furthermore change in pH as well as potential changes in foliar magnesium, calcium, and potassium content are looked at to detect effects on or even shifts within ecosystem functioning. Data derived from the ICP Forests database provide a timeseries on deposition, soil and foliar chemistry, growth, and tree condition. Initial results confi rm signifi cant variation in CL values due to methodological issues. Calculated CL exceedances are not necessarily manifested in a growth decline; on other sites a
decline in tree health is observed even though no exceedances have occurred. The aim of this ongoing work is to modify CL calculations depending on forest ecosystem responses.
IUFRO World Congress, Salt Lake City, USA; 10/2014
[Show abstract][Hide abstract] ABSTRACT: Atmospheric deposition to forests has been monitored within the International Cooperative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests) with sampling and analyses of bulk precipitation and throughfall at several hundred forested plots for more than 15 years. The current deposition of inorganic nitrogen (nitrate and ammonium) and sulphate is highest in central Europe as well as in some southern regions. We compared linear regression and Mann-Kendall trend analysis techniques often used to detect temporal trends in atmospheric deposition. The choice of method influenced the number of significant trends. Detection of trends was more powerful using monthly data compared to annual data. The slope of a trend needed to exceed a certain minimum in order to be detected despite the short-term variability of deposition. This variability could to a large extent be explained by meteorological processes, and the minimum slope of detectable trends was thus similar across sites and many ions. The overall decreasing trends for inorganic nitrogen and sulphate in the decade to 2010 were about 2% and 6%, respectively. Time series of about 10 and 6 years were required to detect significant trends in inorganic nitrogen and sulphate on a single plot. The strongest decreasing trends were observed in western central Europe in regions with relatively high deposition fluxes, whereas stable or slightly increasing deposition during the last 5 years was found east of the Alpine region as well as in northern Europe. Past reductions in anthropogenic emissions of both acidifying and eutrophying compounds can be confirmed due to the availability of long-term data series but further reductions are required to reduce deposition to European forests to levels below which significant harmful effects do not occur according to present knowledge.
[Show abstract][Hide abstract] ABSTRACT: Of the 42 countries that have participated in ICP Forests since 1986, 27 countries reported large-scale monitoring data from Level I plots and more detailed forest ecosystem related monitoring data from Level II plots for the year 2012. In total, the participating countries provided information on more than 15,000 plots and more than 220,000 trees. Data analyses for this 2013 Technical Report focused on the impact of air pollution on tree crown condition and on sulphate and nitrogen deposition to forests. In addition, the impact on individual trees of factors other than air pollution, e.g., biotic agents, was assessed.
[Show abstract][Hide abstract] ABSTRACT: Forest assessments aim at meeting a variety of information needs, such as forest health, forest volume and growth, carbon sequestration, biodiversity, as well as relationships between forests, climate change, and air pollution. Respective forest assessments have been implemented in Europe on different scales with different intensities. The ICP Forests has been established in 1985. With its currently more than 6800 large-scale and more than 760 intensive monitoring plots in Europe and with 40 countries of Europe as well as with Canada and the United States of America also participating, ICP Forests constitutes one of the largest forest monitoring programs in the world. It contributes cooperates with numerous scientific and political institutions and programs. In this context, an overview on current forest information needs and on monitoring approaches and initiatives is provided. Examples of main results are provided.
Forest Condition in Europe, 2012 Technical Report of ICP Forests., Edited by Lorenz M., Becher G., 01/2012: chapter 5. Exceedance of critical limits and their impact on tree nutrition.: pages 77-91; Thünen Institute for World Forestry.
[Show abstract][Hide abstract] ABSTRACT: This paper presents the variation of sulphur and nitrogen deposition and the exceedance of their critical loads on Level II ICP Forests plots. The fact that critical loads are still exceeded at many forest sites in Europe indicates a continuing need for further implementation of air pollution abatement strategies. Such results contribute to the scientific basis for the development and reviews of the effectiveness of clean air politics by the Convention on Long-range Transboundary Air Pollution.
[Show abstract][Hide abstract] ABSTRACT: Forest condition in Europe has been monitored for 20 years jointly by the United Nations Economic Commission for Europe (UNECE) and the European Union (EU). Large‐scale variations of forest condition over space and time in relation to natural and anthropogenic factors are assessed on about 6000 plots systematically spread across Europe. Causal relationships are studied in detail on about 860 intensive monitoring plots covering the most important forest ecosystems in Europe. This paper describes results of the large‐scale defoliation survey, relationships between large‐scale defoliation and modelled large‐scale deposition, as well as of changes in concentrations of air pollutants in bulk deposition measured on intensive monitoring plots. There is an increase in defoliation of the most abundant species, with high spatial and temporal variation. Bulk deposition measurements indicate that sulphate and nitrate concentrations decreased from 1996 to 2001, whereas ammonium concentrations fluctuated during the same measuring period.
International Journal of Environmental Studies 06/2008; 65(3):299-309. DOI:10.1080/00207230701862637
[Show abstract][Hide abstract] ABSTRACT: Intensive forest monitoring by means of harmonised methods has been conducted in Europe for more than a decade. Risks of atmospheric nitrogen and sulphur deposition are assessed by means of calculations of critical loads and their exceedances. In the present study throughfall and bulk deposition of nitrate (N-NO(3)), ammonium (N-NH(4)) and sulphate (S-SO(4)) show marked spatial patterns and temporal trends. In the period of observation (1999-2004), sulphate deposition on intensive monitoring plots decreased by about one quarter. This is in line with the reduction of S deposition by 70% since 1981 in Europe as a result of successful air pollution control politics under the Convention on Long-range Transboundary Air Pollution (CLRTAP). However, sulphate and especially nitrate and ammonium deposition were found to still exceed critical loads at many forest sites, indicating a continued need for further implementation of air pollution abatement strategies.
[Show abstract][Hide abstract] ABSTRACT: Forest conditions in Europe have been monitored over 20 years jointly by the International Cooperative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests) and the European Union (EU). Maps for mean bulk SO4, NO3 and NH4 deposition at around 400 intensive monitoring plots in the years 1999–2001, as well as time trends for the period 1996–2001, are presented. Mean bulk SO4 deposition at 169 plots mostly located in central Europe decreased from 7.4 to 5.8 kgS ha−1 a−1. Mean NH4 bulk deposition decreased from 6.2 to 5.3 kgN ha−1 a−1. Nitrate bulk deposition fluctuated around 5 kgN ha−1 a−1. On average, throughfall deposition was considerably higher than bulk deposition. Time trends for mean tree crown defoliation as an overall indicator for forest condition show a peak in the mid 1990s for most of the monitored main tree species and a recent increase for the years 2003 and 2004. Multivariate linear regression analyses show some significant relations between deposition and defoliation. These relations depend on the tree species and site characteristics. Effects of deposition are moderated by the influence of biotic stress factors such as insects and fungi and by abiotic stress factors, such as weather.