FutMon Scientific Report : Further Development and Implementation of an EU-level Forest Monitoring System (FutMon) : Prepared by the partners of the EU-LIFE+ project FutMon : With co-financing under the LIFE+ Regulation (EC) No. 614/2007 of the European Parliament and of the Council

Braunschweig

2013

191 S.

Monographie

179313

Introduction; Improvement of the monitoring system; Revision of the monitoring grids; Large scale representative monitoring: test of methods for harmonis-ing information from national forest inventories (NFIs); Representativeness analysis for intensive forest monitoring plots – Evaluation and optimization based on representative information from small scaled maps; Implementation of a quality control system; Tree condition; Crown condition as an indicator for forest health; Damage cause assessment; Recommendations for future monitoring; Deposition of acidity and nitrogen; Temporal and spatial variation; Comparison of measured and modeled deposition; Status and development of forest soils; Exceedance of critical limits of nitrogen concentration in soil solution; Exceedance of critical loads under different emission scenarios; Climate change, air pollution and impact on biodiversity; Linking climate model results to Level II plots; Epiphytic lichen diversity in relationship to atmospheric deposition; Exceedance of critical limits and their impact on tree nutrition; Exceedances of critical loads and their impact on biodiversity; Climate change, carbon fluxes, water, and growth; Forest growth and its relation to deposition and climate; Water budgets; The carbon budget under current and future climate
The EU-LIFE project “Further Development and Implementation of an EU-level Forest Moni-toring System” (FutMon) established a pan-European forest monitoring system which can serve as a basis for the provision of policy relevant information on forests in the European Union. The project was implemented by a consortium of 38 ministries and research institutes in 22 EU-Member States. The new forest monitoring system constitutes a further development of a system (ICP Forests) established under UNECE in 1986. It comprises a large-scale forest monitoring grid with links to national forest inventories (NFIs) as well as a forest ecosystem monitoring grid. The large-scale grid comprises 5455 plots in 26 EU-Member States and 7503 plots together with the non-EU-countries. The forest ecosystem monitoring grid comprises 252 plots furnished with a particularly high monitoring intensity under FutMon in EU-Member States. Together with the remaining forest ecosystem monitoring plots (with lower monitoring intensity) there are more than 800 plots with about 30 of them situated in non-EU-countries. Harmonised methods and standards further developed under FutMon, taken over by ICP For-ests in its Manual, and respected across all EU-Member States guarantee long-term compara-bility of data. An innovative database permits on-line data submission, automated data valida-tion and an inter-active Web-GIS. The scientific analysis of forest ecosystem monitoring data in combination with large-scale forest monitoring data permits the holistic view of the interac-tions between climate change and other impacts on forests postulated in the Green Paper (KOM(2010)66). Such scientific analyses were started under FutMon, involving all available data including the small additional portion from non-EU-countries. The results refer to rela-tionships between climate change, carbon fluxes, air pollution, forest health, forest growth, and biodiversity. Results of FutMon reflect the successful reduction of sulphate emission under CLRTAP and EC policies, but show that nitrogen deposition decreased only little. Nitrogen and sulphur deposition was highest in Central Europe, with sulphur deposition showing an obvious de-crease. On about 160 plots mean sulphur throughfall decreased from 8.9 kg ha-1 yr-1 in 1998 to 5.1 kg ha-1 yr-1 in 2007. In contrast, throughfall of ammonium decreased only from 6.7 kg ha-1 yr-1 to 5.9 kg ha-1 yr-1 and throughfall of nitrate hardly showed a decrease at all in the same period. Atmospheric deposition, in particular that of nitrogen, still affects forest soils, forest trees as well as forest ground vegetation, and therefore biodiversity. In forest soils, N deposition was found to cause disturbed organic matter and nutrient cycling evidenced by a C/N index lower than 1 on 14% of the plots. These plots were particularly frequent in central-western Europe. In comparison to the soil surveys carried out between 1986 and 1996, pH and base saturation increased in the very acid forest soils but decreased in the other soils. A measure for the risks posed by deposition to a forest ecosystem is the exceedance of critical limits. Exceedances of critical limits for total nitrogen concentrations in soil solution were calculated based on samples from 171 Level II plots from the early 1990s to 2006. Mean con-centrations were compared to critical limits that were available from literature. Results show that N concentrations in soil solution regularly exceed two widely used critical limits on the majority of Level II plots in Europe. On 93% of the plots critical limits for nutrient imbalanc-es in the organic layer were exceeded in more than 50% of the measurements. On 67% of the plots critical limits for elevated N leaching in the organic layer were exceeded in more than 50% of the measurements. For the mineral topsoil and subsoil, the critical limits for elevated N leaching were exceeded on 38% and 37% of the plots, respectively, in more than 50% of the measurements. The respective share of plots where limits for reduced fine root biomass or enhanced sensitivity to frost and fungi were exceeded in organic layers were 32% and 16%. Exceedances in the mineral soil layers were lower. Data from 140 plots were available for the calculation of time trends of at least five years per plot. In most of the plots there was no tem-poral trend in the critical limit exceedance for nitrogen. In cases where trends could be docu-mented they were usually decreasing. Nutrient imbalances and N saturation and leaching to deeper soil layers are expected consequences of these findings in large parts of Europe. Ni-trate concentrations in the ground water violating the permissible values of Council Directive 91/676/EEC had been found already on a quarter of the Level II plots by an earlier study. A key question of clean air politics is if the prevailing deposition will sooner or later lead to the exceedance of critical limits. The answer to this question is the critical loads concept. The critical load is the deposition per unit of time which an ecosystem can tolerate without negative consequences for its functioning. Exceedances of critical loads for acidity and nutrient nitrogen therefore indicate a risk of acidification and eutrophication. Modeling results for the large-scale plots indicate high risks for acidification of forest soils especially in central Europe in 1980. The dynamic model VSD+ was used to estimate future critical loads exceedances assuming continued implementation of legally binding protocols of clean air politics. Results show that in 2020 forests will be protected against acidification on nearly all the plots. For nitrogen inputs, however, the share of plots with exceedances decreased by 10% only between 1980 and 2000. The scenarios for the future indicate a further increase in the number of sites protected against eutrophication, but no protection of all sites. The Level II plots provide the basis for the risk assessment and for evaluating potential recovery of forest ecosystems under reduced atmospheric deposition and climate change. These future tasks require adaptation of forest management and nature conservation practices as well as continued monitoring and modeling. The results of the dynamic modelling of soil chemistry obtained with VSD+ were coupled with the BERN model permitting an estimation of future regeneration abilities of plant communities. Tree species may not be adapted to changes in soil properties induced by deposition. Low adaptation poses a risk to the sustainable development of the affected stands. In such cases changes in tree species may be a suitable management target. Though the number of plots available for this pilot study was low and not representative for Europe, the methodology offers a wide range of estimating future effects as well as suitable management adaptations. The carbon budget of 28 selected Level II plots was simulated using the simulation model Biome-BGC (version ZALF). Level II data on meteorology, stem growth, litterfall, phenolo-gy, leaf area index, soil respiration, stand precipitation, soil water content, and soil tempera-ture were used for the initialisation and calibration of the model. As result of the model cali-bration 22 plots could be identified as carbon sinks and 6 plots as carbon sources between 1996 and 2009. For the period 2040 to 2059 and 2080 to 2099 the development of carbon budgets on the Level II plots was simulated based climate projections assuming IPCC scenar-ios. In general, the carbon sink function was found to increase under expected future climate conditions.