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The main objectives of the present grant application are to study the impact of nitrogen deposition on growth, needle longevity and needle morphology of Scots pine in peatlands. The additional influx of nutrients to poor ecosystems offers several opportunities for solving fundamental questions. So far, the question of intra-specific variation in nutrient preservation and effective use has been little studied, though several researchers have made inter-specific comparisons. As the relationships between leaf structure, longevity and stress resistance have been found mainly in inter-specific comparisons, the same relations need not to be valid within a single species. Whether the nutrient residence time increases or decreases; how does the nutrient use efficiency change; whether the nutrient resorption efficiency decreases or increases? All this questions need to be answered for better understanding of nutrient cycling in bogs under anthropogenic influence. Considering that the development of leaf traces is strongly connected with the development of leaves, it is reasonable to presume that leaf traces reveal, besides to leaf longevity, also some aspects of leaf morphology. This would tell us how the trees had responded to variation in environmental conditions (including anthropogenic influences) because both leaf longevity and leaf structure are part of stress resistance syndrome. The expected relationship between the diameter of leaf traces and the dimensions of pine needles enables us to get information retrospectively about needle morphology and nitrogen content and to compare the present situation with that in the past. The use of leaf traces for retrospective estimation of needle size is a new approach at an international level. It is a development of the needle trace method and it gives additional information about the changes in the health of pine forests. |