Variables related to nitrogen deposition improve defoliation models for European forests
Résumé
Key messageAtmospheric deposition of nitrogen compounds and soil and foliar variables related to N deposition resulted important factors accounting for the variability of defoliation in European forest plots.ContextNitrogen (N) deposition has increased in the northern hemisphere because of anthropogenic-related emission of N compounds. Increased N availability may have an adverse impact on forest sustainability.AimsThis study aims to test the importance of throughfall N (Nthr) deposition in explaining the variability of the frequency of trees with defoliation >25 % (F25), an indicator of forest condition.MethodsA pan-European data set (71 plots) with enhanced quality control was considered. The additive effect of Nthr-related predictors (identified conceptually and by rank correlation) in explaining F25 was investigated by partial least square regression in comparison with a reference model based on site, stand, management and climate data. Reported damage to foliage, Nthr deposition, foliar N ratios and mineral top-soil variables were added stepwise to the reference model.ResultsN-related variables improved defoliation models. Higher Nthr deposition led to higher F25 for beech and Norway spruce, while the effect was opposite for Scots pine. Higher foliar N ratios led to higher F25 for all species.ConclusionNthr deposition, damage to foliage, foliar N/P, N/Ca, N/Mg, N/K, top-soil pH, C/N and exchangeable base cation resulted important factors (although with possible diverse effect) in explaining the variability of F25 among plots.
Domaines
Sciences du Vivant [q-bio]
Origine : Publication financée par une institution
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