Fossil pollen is an important kind of data for reconstructing past plant communities. Because plants are sensitive to climate, specifically temperature and precipitation, the pollen preserved in lake sediments is a powerful kind of proxy data for reconstructing past climates. 

Using a microscope, scientists identify and count the pollen types in different layers of sediment. They calculate the percentages of each pollen type (spruce, for example) relative to the total number of pollen grains found in that layer. This information is displayed in a pollen diagram (such as the Nelson Lake diagram in the Ancient Forests section), which shows how the plant communities changed through time. 

Because scientists know the relationship between vegetation and climate and what climates different plant communities require today, they are able to reconstruct past climates based on the pollen data.

Learn more about palynology and pollen in the tour of the Illinois State Museum Research and Collections Center online

The North American Pollen Database is based at the museum, too.

For more information about the study of pollen, follow the links below

Prairies in the Prairie State - Palynology

MuseumLink Behind the Scenes - Pollen