The European Modern Pollen Database (EMPD) project

Modern pollen samples provide an invaluable research tool for helping to interpret the quaternary fossil pollen record, allowing investigation of the relationship between pollen as the proxy and the environmental parameters such as vegetation, land-use, and climate that the pollen proxy represents. The European Modern Pollen Database (EMPD) is a new initiative within the European Pollen Database (EPD) to establish a publicly accessible repository of modern (surface sample) pollen data. This new database will complement the EPD, which at present holds only fossil sedimentary pollen data. The EMPD is freely available online to the scientific community and currently has information on almost 5,000 pollen samples from throughout the Euro-Siberian and Mediterranean regions, contributed by over 40 individuals and research groups. Here we describe how the EMPD was constructed, the various tables and their fields, problems and errors, quality controls, and continuing efforts to improve the available dat

Quantitative vegetation reconstruction from pollen analysis and historical inventory data around a Danish small forest hollow

Questions Can the model performance of the landscape reconstruction algorithm (LRA) for small forest hollows be validated through comparison to inventory-based vegetation reconstructions from the last 150yrs? Does the application of LRA and the comparison to historical data enhance interpretation of the pollen record? Location Denmark. The Gribskov-Ostrup small forest hollow (56 degrees N, 12 degrees 20E, 44m a.s.l.) in the forest of Gribskov, eastern Denmark. Methods Pollen analysis was carried out on a small forest hollow, and LRA used to derive pollen-based quantitative estimates of past vegetation. Historical forest inventory data and maps were used to reconstruct the vegetation within three different circles around the hollow (20, 50 and 200m ring widths) for five time periods during the last 150yrs. The results of the two approaches were compared in order to evaluate model performance, and the LRA-based reconstruction used to describe how the model changes interpretation of vegetation development during the last ca. 6500yrs compared to the use of pollen percentages alone. Results Distance-weighted inventory-based reconstructions within 200m of the hollow's edge provide the best match with the LRA-modelled vegetation. Precise validation of the model is not possible due to insufficient historical data, but the comparison indicates that the LRA reconstruction for Gribskov tends to (1) underestimate tree cover and overestimate open areas, (2) give a too high representation of on-site pollen types, (3) give an underestimation of Fagus and (4) a small overestimation of Quercus and Corylus. Despite these uncertainties, application of the LRA model shows a higher degree of openness than would be apparent from the uncorrected pollen diagram, and makes it possible to attempt to distinguish changes at the local scale from regional vegetation changes, thus giving a clearer picture of the vegetation changes at the site. Conclusions We demonstrate that the estimates of the LRA model applied to pollen data from small forest hollows can be compared with small-scale historical data to evaluate model performance

Long-term forest dynamics at Gribskov, eastern Denmark with early-Holocene evidence for thermophilous broadleaved tree species

We report on a full-Holocene pollen, charcoal and macrofossil record from a small forest hollow in Gribskov, eastern Denmark. The Fagus sylvatica pollen record suggests the establishment of a small Fagus population at Gribskov in the early Holocene together with early establishment of other thermophilous broadleaved trees, including Quercus sp., Tilia sp. and Ulmus sp. The macrofossils contribute to the vegetation reconstruction with evidence for local presence of species with low pollen productivity or easily degraded pollen types such as Populus. The charcoal record shows frequent burning during two periods of the early Holocene and from c. 3000 cal. BP to present. The early-Holocene part of the record indicates a highly disturbed forest ecosystem with frequent fires and abundant macrofossils of particularly Betula sp. and Populus sp. The sediment stratigraphy and age-depth relationships give no clear indication of post-depositional disturbance, although a possible short-lived hiatus occurs around 6500 cal. BP. The early pollen record from thermophilous trees could indicate that there may have been some downwash following sediment desiccation through wood peat layers deposited between c. 6500 and 10,000 cal. BP, but the overall biostratigraphy is consistent with other Danish small hollow records