The chemical composition of newly shed needle litter of Scots pine and some other pine species in a climatic transect. X Long-term decomposition in a Scots pine forest

Significant differences in the chemical composition of falling needle litter were found among various pine species. A comparison between the needle litter of northern species (Scots pine and lodgepole pine) and that of 17 other, southern species combined showed that concentrations of N, P, Mg, K, and lignin were significantly lower in the northern group. In contrast, the Mn concentration was significantly higher in this northern group. Along a transect from the Barents Sea (69 degrees 45'N) to the Carpathian Mountains (49 degrees 53'N), concentrations of N, P, S, and K in Scots pine litter fall increased significantly. The best-fit regression models described asymptotic curves, suggesting that concentrations of these major nutrients approach their maximum values at sites with high values for actual evapotranspiration (AET). Low values were found in the north. By contrast, Mn concentrations, increased with latitude and decreased with increasing AET. High covariation among concentrations of the major nutrients (N, P, S, and K) can be attributed to their being major constituents of structural compounds. Analysis of various regression models relating the chemical composition of needle litter fall to latitude and AET, together with a factor analysis, suggested that concentrations of N, P, S, and K were related mainly to climatic conditions, whereas those of Mg and Mn were related more to site-specific properties such as soil fertility. A high level of predictability was found for concentrations of N, P, S, and K using multiple regression, with values for R(adj)(2) between 0.63 and 0.93