Three-dimensional reconstruction of an in-situ Miocene peat forest from the Lower Rhine Embayment, northwestern Germany—new methods in palaeovegetation analysis

Palaeovegetation reconstructions, particularly of fossil forests, are generally restricted to scant information on the taxonomic composition, relative abundance of individual taxa, or on tree density. We have developed new techniques for the analysis of stump horizons that result in a relatively detailed three-dimensional reconstruction of ancient forests. In addition, a rough estimate of their above-ground standing biomass can be calculated. These techniques are applied to an in-situ Miocene peat forest preserved in the Lower Rhine Embayment, northwestern Germany. In a study area of 2500 m², 476 stumps were mapped and used in the forest reconstruction. Additionally, pollen samples and leaf remains have been analysed. The peat forest consists primarily of conifers (in particular Taxodiaceae and Pinaceae) with Sciadopitys being the most common genus. The only angiosperms in the wood flora were palms, but in the pollen flora, evidence for the Myricaceae, Mastixiaceae, Ericaceae and a few other angiosperms is also present. The forest was relatively dense with 1904 trees/ha and a basal area of 164 m². Mean trunk diameter was 28 cm, while mean tree height is calculated to have been 9.9 m. Height, diameter and density distribution are illustrated using contour and three-dimensional surface plots. Estimated above ground biomass is 750 t/ha, but this value also includes dead or partly dead trees. This peat forest does not closely compare with previous reconstructions of Miocene peat forests. Its three dimensional structure and biomass differ from those of modern bald cypress swamps.