Wood ash treatment affects seasonal N fluctuations in needles of adult Picea abies trees: a 15N-tracer study

A 15N-tracer experiment was carried out in a stand of adult spruce trees [Picea abies (L.) Karst.] located on the Swiss Plateau in order to investigate the effects of wood ash treatment on seasonal nitrogen fluctuations in fine roots and needles. Treatments included irrigation (W), liquid fertilization (LF) and wood ash (A) application. 15N fluctuation in fine roots and current to 3-year-old needles was studied after one 15N pulse for 2consecutive years (1999, 2000). 15N tracer was rapidly incorporated into the fine roots of adult trees, and δ15N values reached similar levels in all treatments 2months after the pulse. In the needles, the largest increase in δ15N was observed in those of the current year. Following the initial peak during spring growth, δ15N values in needles of control trees showed an oscillating pattern through the season. This oscillation is attributed to the increased use of internal N sources, as soon as the roots can no longer meet the increased N demand during the sprouting phase. However, W-, LF- and A-treated trees no longer showed the oscillation in δ15N. Additional water (W and LF) as well as fertilizer (A and LF) may have induced shifts in the microbial flora, thus increasing the unlabelled N release from the soil. The strongest dampening was observed for the A treatment, indicating sufficient N availability from the soil, and making intensive use of the internal N sources unnecessary. Treatment with wood ash thus resulted in a similar fertilizer response to liquid fertilizatio

Effekte von Holzasche- und Flüssigdüngung auf die Nährstoffsituation und das Wachstum von Fichten ( Picea abies (L.) Karst.)

Summary: : We examined the effects of wood ash and liquid fertilizer on the nutritional status and growth of Norway spruce (Picea abies (L.) Karst.) in a 70-year-old, managed forest in the Swiss Central Plateau. Four treatments with four replications were applied over three years during the vegetation period: treatment I - irrigation with liquid fertilizer (mean: N 87, P 16, K 77 kg yr-1 ha-1, with 1.5 mm/d water) with the 'steady state fertilization' approach; treatment II - wood ash (4000 kg yr-1 ha-1); treatment III - irrigation only (1.5 mm/d); treatment IV - control. Growth was determined by analyses of tree rings, shoot length, needle weight and needle area. For the nutritional status, thirteen chemical elements were analyzed on 136 trees. The investigations showed increased growth of Norway spruce due to liquid-fertilization and wood ash input, but indicated no major shifts of nutrient contents and ratios in needle

Fine root growth and element concentrations of Norway spruce as affected by wood ash and liquid fertilisation

A field experiment to test various management practices of sustainable forestry was conducted in a Swiss spruce forest for two growing seasons. Treatments were a control (C), yearly application of 4000 kg ha−1 wood ash (A), daily irrigation with a steady state fertilisation as 'soptimal nutrition's (F) and irrigation with a water control (W). Samples were taken on a 5 × 5 m grid once a year with a soil corer to determine fine root biomass (≤ 2 mm) and soil pH of the topsoil. A subset of the fine root samples was further analysed for its nutrient composition by CN and ICP-AES analyses. The dynamics of root growth were observed with the aid of ingrowth-cores after 1, 1.5, and 2 years of treatment and the growth pattern was analysed in terms of biomass, tips, forks, length and root diameter of the samples. The A, F and also the W treatment resulted in a significant increase of soil pH in the topsoil. The fine root density increased over the two growing seasons, irrespective of the treatment. The root growth was only slightly different between the treatments with a initially faster growth under the A treatment. The W treatment reduced the number of root tips and forks, and the root length, while the A treatment increased the number of root tips, forks and the root length, but reduced the diameter. The differences between the three harvesting times (March 1999, October 1999, March 2000) of the ingrowth-cores stressed seasonal differences in root growth and the development of quasi 'ssteady state' root dynamics. The root turnover was not changed by the treatments. The elements in the fine roots were strongly affected by the treatments A and F and sometimes by W. Fine root N increased with the F treatment, while C concentrations decreased under the A, F and W treatments. The Ca and Mg concentrations were strongly enhanced by A but also by the F treatment. The K and P concentrations in the fine roots were improved by all three applications. Due to the pH increase Al, Fe and Mn concentrations in the fine roots were decreased by the A and F treatments. S and Zn concentrations showed inconsistent changes over the growing seasons. The results of this study were comparable with those of other studies in Europe and confirm the abilities of the fine roots as indicators of forest nutrition, to some extent more sensitive than the commonly used foliar analysi

Forest storm damage is more frequent on acidic soils

Abstract - We assessed the effect of chemical soil properties and acidifying depositions (sulphur and nitrogen) on the occurrence of storm damage during the storms "Lothar" and "Martin" (December 1999). Data from 969 sites in France, southern Germany and Switzerland was analysed with multiple logistic regression models. Variables found to be significantly related to storm damage, which was mainly scattered damage in our study, were "country", "soil pH", "proportion of coniferous trees", "slope", "humus type", "stand height", and "altitude". Wind speed was not significantly related to storm damage in the global model, but only in the model for France. Soil pH was one of the most significant factors with a lower pH on damaged plots. Atmospheric deposition rates were significantly associated with soil pH, but not directly with storm damage. Even though the mechanisms involved in the relationship between soil acidity and storm damage are still poorly understood, soil acidity should be considered a significant risk factor. Moreover, this large-scale study confirms that increasing the proportion of deciduous trees would reduce the susceptibility of forests to storm damage. deposition / logistic regression / soil pH / wind damage / wind speed Résumé -Les forêts au sol acide sont plus souvent endommagées par les tempêtes. Nous avons étudié l'effet des propriétés chimiques des sols et des dépôts acidifiants (soufre et azote) sur les dommages dus aux tempêtes durant les passages de « Lothar » et de « Martin » en décembre 1999. Les données de 969 sites en France, au sud de l'Allemagne et en Suisse ont été analysées à l'aide de modèles de régression logistique multiple. Les variables liées de manière significative aux dommages dus aux tempêtes étaient les suivantes : le pays, le pH du sol, la proportion de conifères, la déclivité du terrain, le type d'humus, la hauteur des arbres et l'altitude. Dans la plupart des sites, les dommages n'étaient que partiels. La vitesse du vent n'était pas liée de manière significative aux dommages dans le modèle global, mais dans un modèle utilisant uniquement les données de France. Le pH du sol, qui s'avère être l'un des principaux facteurs, était plus bas dans les forêts endommagées. Les taux de dépôts atmosphériques étaient étroitement liés à l'acidité des sols, mais pas directement aux dommages dus à la tempête. Même si les mécanismes provoquant l'interdépendance de l'acidité du sol et des dommages dus aux tempêtes ne sont pas clairement élucidés, l'acidité du sol devrait être considérée comme un facteur risque de grande importance. En outre, cette étude réalisée à large échelle confirme qu'une plus grande proportion d'arbres à feuilles caduques réduirait la sensibilité des forêts aux dommages dus aux tempêtes. dépôts atmosphériques / régression logistique / pH du sol / dommages dus aux tempêtes / vitesse du ven

Key sustainability issues and the spatial classification of sensitive regions in Europe

Cross-cutting environmental, social and economic changes may have harsh impacts on sensitive regions. To address sustainability issues by governmental policy measures properly, the geographical delineation of sensitive regions is essential. With reference to the European impact assessment guidelines from 2005, sensitive regions were identified by using environmental, social and economic data and by applying cluster analysis, United Nation Environmental Policy priorities and expert knowledge. On a regionalised ‘Nomenclature of Territorial Units for Statistics’ (NUTS) level and for pre-defined sensitive region types (post-industrial zones, mountains, coasts and islands) 31 % of the European area was identified as sensitive. However, the delineation mainly referred to social and economic issues since the regional data bases on environmental indicators are limited and do not allow the separation of medium-term vital classes of sensitive regions. Overall, the sensitive regions showed indicator values differing from the EU- 25 average.peer-reviewe

Key sustainability issues and the spatial classification of sensitive regions in Europe

Severe and cross-cutting environmental, social and economic changes have particular impact in sensitive regions and the geographical delineation of sensitive regions is essential to address sustainability issues by policy measures. Based on the European impact assessment guidelines from 2005, sensitive regions were identified using cluster analysis, UNEP priorities and expert knowledge. On a regionalised NUTS level and for pre-defined sensitive region types (post-industrial zones, mountains, coasts and islands) 31 % of Europe’s area was identified as sensitive. However, the delineation mainly referred mainly to social and economic issues since the regionalised data base on environmental indicators and including issues on soil quality is limited and does not allow the separation of medium-term vital clusters. Some visions on short-term and long-term perspectives will be discussed to ensure sustainable development in sensitive regions.peer-reviewe