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-Common European tree species (oak, ash, beech, birch, lime and spruce) planted in adjacent stands on six sites were compared in terms of macronutrient concentrations in foliar and stem wood (including bark) biomass. The nutrient concentrations in both biomass compartments were much more dependent on species than on site although soil conditions differed between the sites. Differences between species regarding stem wood nutrient concentrations only partly corresponded to the differences in species foliage. The concentrations in spruce were considerably lower than in deciduous species, except P in foliage, and Ca in both stem wood and foliar biomass. Differences were also observed between the deciduous species both regarding foliar and stem wood nutrient concentrations. The differences should be considered when modelling nutrient circulation in forest stands and when evaluating the long-term sustainability of forest management. nutrient / hardwood / Norway spruce / stemwood / foliage Résumé -Éléments minéraux dans le tronc et le feuillage : une étude comparative de six essences tempérées plantées sur les mêmes sites. Les essences européennes communes (chêne, frêne, hêtre, bouleau, tilleul et épicéa commun) plantées dans des parcelles adjacentes sur six sites ont été comparées en termes de concentrations en macro-éléments minéraux dans la biomasse foliaire et dans le tronc (écorce y compris). Ces concentrations dépendaient plus de l'espèce que du site, bien que les conditions de sol étaient différentes entre les sites. Les différences entre les espèces observées dans le bois de tige ne correspondaient que partiellement à celles observées dans le feuillage. L'épicéa commun était plus pauvre en éléments minéraux que les feuillus excepté concernant le P dans le feuillage, et le Ca dans le tronc ainsi que dans la biomasse foliaire. Des différences de concentrations minérales ont également été observées entre les espèces de feuillus dans le bois ainsi que dans le feuillage. Ces différences devraient être considérées pour la modélisation de la circulation des éléments minéraux dans les peuplements forestiers et dans l'évaluation des aménagements forestiers dans le cadre d'une gestion durable. nutriment / feuillu / épicéa commun / bois de tige / feuillage e

Micronutrient concentrations in foliage and stemwood (including bark) of six European tree species (Betula pendula Roth., Quercus robur L., Fraxinus excelsior L., Fagus sylvatica L., Tilia cordata Mill. and Picea abies (L.) Karst.) planted on the same type of soil at six sites in three different countries were studied. Micronutrient concentrations in foliage were considerably higher than in stemwood for all elements and species studied, except for Fe in spruce. Interspecies comparisons revealed significant differences in concentrations both in foliar and stemwood biomass, as well as in stemwood:foliage nutrient ratios. Lime foliage showed a considerably higher concentration of B than all other species, while the stemwood concentration of this element was highest in ash. Mn concentration in both foliar and stemwood biomass of ash was extremely low compared with concentrations in other species. Birch stemwood showed nearly double the level of Zn in other species at all sites. Zn concentrations in the birch foliage were also higher than in other species, with the exception of the Lithuanian sites, which showed lower EDTA-extractable Zn concentrations in the soils. The concentration of Cu was lowest in spruce foliage, while Cu concentrations in stemwood were similar in all species. It was concluded that species-related differences in microelement nutrition must be taken into account when evaluating the nutrient status of common European forest tree species, and when using them as bio-indicators of the effects of environmental pollution.

The influence of canopy composition on litterfall and throughfall was investigated in a mixed spruce beech forest in central Germany. We hypothesised that different parts of the mixed canopy created distinct patterns of element inputs via litterfall and throughfall. The investigation was carried out in two plots, representing the most contrasting cases of mixed forests: a stand greatly dominated by spruce (SDP) and a stand greatly dominated by beech (BDP). The canopies of the two plots were classified in four categories: pure beech, pure spruce, mixed canopy and gap. Amounts of throughfall water were lower and major element fluxes were higher under spruce than under beech in both plots, indicating that the nutrient inputs under the canopies of individual trees are driven by speciesspecific properties of the canopies and are quite independent of the degree of admixture. With the exception of K ? , mixed canopies showed intermediate element inputs via throughfall, compared with pure canopy classes. The K ? input was significantly greater under mixed canopies, and these differences were more pronounced in the SDP than in the BDP. Results suggest that individual spruce trees in the BDP induce greater spatial heterogeneity of throughfall input than individual beech trees in the SDP. Nutrient inputs via foliar litterfall were similar among the different canopy classes, but the Mg input was lower under spruce canopy. This effect was balanced by higher Mg input via spruce throughfall. In our study, throughfall was the main source of heterogeneity in nutrient inputs, while foliar litterfall had a homogenising effect.

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