Lessons from Travels: Peat Soils

by Carl Strang

With November’s arrival, this blog shifts to its winter mode. I will be bringing in posts that share comments on the year’s scientific literature that are relevant to local natural history. There also will be more species dossiers. Of course, ongoing observations from the present season will continue to appear. Finally, there will be weekly episodes in the winter series. Past winter series have focused on science and spirituality (the Winter Campfire) and prehistoric life. This winter I will continue, and perhaps conclude, the Lessons from Travels series I began last year. The idea is to draw upon comparisons between northeastern Illinois and other parts of the world which cast a light on our local ecology and natural history.

A few years ago the Forest Preserve District of DuPage County collaborated with Chicago’s Field Museum of Natural History to conduct a paleontological dig at Pratts Wayne Woods Forest Preserve. Some mastodon molar teeth and bone fragments had been found at the site, and we brought in high school teachers and students to excavate parts of the site.

Here the digging began, 2007. Note the marsh in the background.

The dig went for two seasons. We mainly found fragments of the mastodon’s tusks. During the second year we uncovered some buried black spruce trees.

The stem of one of the trees runs the length of this trench.

The spruces were there when the mastodon died. That tree species no longer occurs in Illinois, though it is common in the North, where it retreated in the wake of the melting glacier. As we dug, we encountered buried soils that were familiar to me.

Buried peat soil.

This was exactly like soils we found when we dug into the permafrost in western Alaska, where I lived for several summers conducting my thesis research on glaucous gulls. Today there is much concern about the amount of carbon dioxide, and perhaps methane as well, that will be added to the atmosphere as climate change melts the permafrost. It seems that tundra fires will be major news in the future. At least then, maybe people will be able to bury their dead.

This scene, fitting with Halloween just past, is from an abandoned village site in western Alaska. The powerful churning of the surface soil as it thaws and freezes each year prevents burials.

We were not able to complete the mastodon dig. We suspect that the major bones remain beneath that marsh. The Field Museum withdrew from the project, and keeping even a small portion of the marsh pumped out for digging is more difficult and expensive than anyone wishes to pursue (though who knows, if we continue to have droughts like this past summer, it may become a practical possibility). For now the buried peat soils, the tree stems we left in place and covered, and the remainder of the mastodon, wait patiently as they have done for thousands of years.

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