Atmospheric depositions affect the growth patterns of Scots pines (Pinus sylvestris L.)—a long-term cause-effect monitoring study using biomarkers

Recording the causes, effects, and effect mechanisms of vegetation health is crucial to understand process-pattern interactions in ecosystem processes. NO_X and SO_X in the form of air pollution are both triggers and sources of vegetation health that can have an effect on the local or the global level and whose impacts need to be monitored. In this study, the growth patterns in Scots pines (Pinus sylvestris L.) were studied in the context of changing atmospheric depositions in the lowlands of north-eastern Germany. Under the influence of atmospheric sulfur (S) and nitrogen (N) depositions, pine stands showed temporal variations in their normal growth behavior. In such cases, the patterns of normal growth can be suppressed or accelerated. Pine stands which were influenced by high S deposition up until 1990 changed from suppressed growth to accelerated growth by decreasing S, but increasing N depositions between 1990 and 2003. The cause of these changes in pine growth patterns was imbalances in S and N nutrition, in particular, enrichments of sulfate, non-protein nitrogen or arginine, and finally, also imbalances and deficiencies in phosphorus, glucose, and adenosine triphosphate in the needles. Our long-term monitoring study shows that biochemical markers (traits) are crucial bioindicators for the qualitative and quantitative assessment of tree vitality and growth patterns in Scots pines. Furthermore, we were able to show that NO_X and SO_X depositions need to be monitored locally to be able to assess the local effects of biomolecular markers on the growth patterns in Scots pine stands.