This simulation is an interactive introduction to palynology — the study of fossil pollen preserved in lake and bog sediments. It builds a synthetic pollen diagram spanning the last 12,000 years (the Holocene), letting you see how regional vegetation shifted from tundra to boreal forest to the mixed woodlands of today, and how taphonomy (differential preservation of pollen grains) can distort the record before it ever reaches a microscope slide.
A stacked pollen diagram for six taxa — oak, pine, birch, grass, herb and shrub — interpolated between six named vegetation zones from "Tundra/Late Glacial" (12 ka) through "Boreal", "Atlantic optimum" and "Mixed Forest" to "Modern Forest" (0 ka). Each column's width at a given age represents that taxon's relative abundance in the sediment core at that depth.
Drag the Time window start/end sliders to zoom into a slice of the last 12,000 years, and adjust the Oak, Grass and Pine taphonomy sliders to see how differential pollen preservation and production changes the proportions in the diagram — resistant, heavily produced grains like pine routinely over-represent their source plant. Toggle vegetation zone bands and ¹⁴C radiocarbon date markers, then press Redraw to refresh the plot; live stats report the current vegetation type, forest and grass cover, and the key transition age.
Pollen grains have tough, chemically resistant outer walls (sporopollenin) that survive for thousands of years in waterlogged, low-oxygen sediment, which is exactly why lake and peat cores are one of the best archives of past vegetation. Pine and grass pollen are notoriously over-produced and wind-dispersed over long distances, so palynologists apply correction factors — like the taphonomy sliders here — before turning raw pollen counts into a vegetation reconstruction.
Palynology is the study of pollen and spores, especially as preserved in sediment to reconstruct past environments. Pollen grains are coated in sporopollenin, one of the most chemically resistant biological materials known, which lets them survive largely intact for thousands to millions of years once buried in anoxic, waterlogged sediments such as lake beds and peat bogs.
Each of the six coloured columns represents one plant taxon — oak, pine, birch, grass, herb or shrub — and the width of its shaded band at a given depth (age, shown on the vertical axis in thousands of years before present) shows its relative percentage in that sediment sample. Widening oak and narrowing grass bands moving toward the present, for example, illustrate the shift from open tundra to closed forest across the Holocene.
They apply a preservation/production weighting factor to each taxon before the proportions are renormalised to 100%. Lowering the Pine slider, for instance, down-weights pine's naturally over-represented, wind-blown pollen relative to less resistant or less abundant taxa, mimicking how real palynologists correct raw counts for known biases in pollen production, dispersal and preservation.
The simulation's six named zones track the real broad pattern of Holocene climate warming after the last glacial period: cold, open tundra and shrub-grassland dominated around 12 ka, giving way to expanding boreal pine-birch forest by around 8 ka, a warm "Atlantic optimum" with peak deciduous forest cover roughly 5-8 ka, and a gradual shift toward the mixed and managed forests of the modern era closer to the present.
The dashed lines labelled "¹⁴C" mark radiocarbon-dated horizons within the sediment core — points where organic material (such as plant macrofossils or peat) was directly dated using carbon-14 decay to anchor the age-depth relationship. Radiocarbon control points like these let palynologists convert sediment depth into a calendar age scale, which is essential for comparing pollen records between different lakes and regions.