Nenad Potočić

Tree mineral nutrition is deteriorating in Europe

The response of forest ecosystems to increased atmospheric CO2 is constrained by nutrient availability. It is thus crucial to account for nutrient limitation when studying the forest response to climate change. The objectives of this study were to describe the nutritional status of the main European tree species, to identify growth-limiting nutrients and to assess changes in tree nutrition during the past two decades. We analysed the foliar nutrition data collected during 1992-2009 on the intensive forest monitoring plots of the ICP Forests programme. Of the 22 significant temporal trends that were observed in foliar nutrient concentrations, 20 were decreasing and two were increasing. Some of these trends were alarming, among which the foliar P concentration in F. sylvatica, Q. Petraea and P. sylvestris that significantly deteriorated during 1992-2009. In Q. Petraea and P. sylvestris, the decrease in foliar P concentration was more pronounced on plots with low foliar P status, meaning that trees with latent P deficiency could become deficient in the near future. Increased tree productivity, possibly resulting from high N deposition and from the global increase in atmospheric CO2, has led to higher nutrient demand by trees. As the soil nutrient supply was not always sufficient to meet the demands of faster growing trees, this could partly explain the deterioration of tree mineral nutrition. The results suggest that when evaluating forest carbon storage capacity and when planning to reduce CO2 emissions by increasing use of wood biomass for bioenergy, it is crucial that nutrient limitations for forest growth are considered.

Exceedance of critical loads and of critical limits impacts tree nutrition across Europe

Key messageExceedance 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.ContextForests 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.AimsWe 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.MethodsWe 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.ResultsCritical 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.ConclusionThe findings support the hypothesis that elevated nitrogen and sulphur deposition can lead to imbalances in tree nutrition.

How to Support Forest Management in a World of Change: Results of Some Regional Studies

This article presents results of several studies in Middle, Eastern and Southeastern Europe on needs and application areas, desirable attributes and marketing potentials of forest management support tools. By comparing present and future application areas, a trend from sectoral planning towards landscape planning and integration of multiple stakeholder needs is emerging. In terms of conflicts, where management support tools might provide benefit, no clear tendencies were found, neither on local nor on regional level. In contrast, on national and European levels, support of the implementation of laws, directives, and regulations was found to be of highest importance. Following the user-requirements analysis, electronic tools supporting communication are preferred against paper-based instruments. The users identified most important attributes of optimized management support tools: (i) a broad accessibility for all users at any time should be guaranteed, (ii) the possibility to integrate iteratively experiences from case studies and from regional experts into the knowledge base (learning system) should be given, and (iii) a self-explanatory user interface is demanded, which is also suitable for users rather inexperienced with electronic tools. However, a market potential analysis revealed that the willingness to pay for management tools is very limited, although the participants specified realistic ranges of maximal amounts of money, which would be invested if the products were suitable and payment inevitable. To bridge the discrepancy between unwillingness to pay and the need to use management support tools, optimized financing or cooperation models between practice and science must be found.

GIS-based probability assessment of natural hazards in forested landscapes of Central and South-Eastern Europe.

We assessed the probability of three major natural hazards—windthrow, drought, and forest fire—for Central and South-Eastern European forests which are major threats for the provision of forest goods and ecosystem services. In addition, we analyzed spatial distribution and implications for a future oriented management of forested landscapes. For estimating the probability of windthrow, we used rooting depth and average wind speed. Probabilities of drought and fire were calculated from climatic and total water balance during growing season. As an approximation to climate change scenarios, we used a simplified approach with a general increase of pET by 20%. Monitoring data from the pan-European forests crown condition program and observed burnt areas and hot spots from the European Forest Fire Information System were used to test the plausibility of probability maps. Regions with high probabilities of natural hazard are identified and management strategies to minimize probability of natural hazards are discussed. We suggest future research should focus on (i) estimating probabilities using process based models (including sensitivity analysis), (ii) defining probability in terms of economic loss, (iii) including biotic hazards, (iv) using more detailed data sets on natural hazards, forest inventories and climate change scenarios, and (v) developing a framework of adaptive risk management.

How Socio-Economic Conditions Influence Forest Policy Development in Central and South-East Europe

In this article, several findings on socio-economic conditions derived from national reports and a web-based questionnaire are discussed and related to the changing role of forestry and the future forest policy development. A number of Central and South-eastern European countries taking part in a SEE-ERA-NET project ReForMan project (www.reforman.de) participated in data acquisition: Austria, Bosnia and Herzegovina, Croatia, Germany, Serbia and Slovenia. The aim of the research was to illustrate the present structure of forestry sector, as well as investigate newly emerging topics in forestry of Central and South-eastern Europe. The results indicated certain patterns in attitudes and perceptions among stakeholders that can be related to socio-economic conditions defined for each country. Clear differences between member and non-member countries exist only in level of implementation of EU legislation. Results showed consensus on main threats to the forests among all countries, but also some country specifics in perceptions of factors influencing forestry, their importance and professional competencies. These results could be additionally explained by influence of historical conditions which shaped development of forest sector in SEE region especially in its organizational dimension as well as in perceived role of forestry expressed through recognition of main forest functions. The influence of European forest policy processes in the region is evident through adaptation of EU legislation and perceived implications of international processes on national levels. Based on this observation, two possible options for future development of the forestry sector can be foreseen: (i) focusing on the productive function of forests and fostering its’ sustainable use; or (ii) putting an emphasis on environmental and social issues. In both cases supporting public participation in decision-making processes is recommendable. Another conclusion based on perceived medium to low professional competencies to cope with new topics, that there is lack of confidence and need for professional support in decisionmaking processes.

Erratum to: Variables related to nitrogen deposition improve defoliation models for European forests

In the original paper two errors were spotted after online publication.