On the second floor of the Nuclear Physics Lab on the University of Illinois campus, you’ll find Mary King, Kim Schaefer, and Mary Simon in a room full of boxes filled with thousands of years of botanical artifacts. King, Schaefer, and Simon are archaeobotanists for the Illinois State Archaeology Survey.
“I was interested in botany in college but I started working for an archaeobotanist in college, and the intersection of looking at botany but also looking at human behavior and human patterns was why I got interested in it,” said Schaefer. “Botany itself is very abstract in some ways, it’s a lot of taxonomy and genetics, but [in archaeobotany there is] a human tie – why are these important, why do we care about these things.”
Archaeobotany is the study of archaeological plant remains with the goal of understanding how humans used plants in the past. This can take the shape of analyzing how humans used plants for food, ceremonial purposes, early commerce, and even technology.
Mary Simon began working at ISAS in the early ’90s and over the course of her three-decade-long career, she has watched the archaeobotany field expand from subsistence studies to the technological uses of plants, adding a new layer to a more complete picture of how people were using plants in the past.
“Now we are looking at all sorts of other things that are plant-related – how plants were used for construction purposes, what types of wood were people using, was there evidence of environmental degradation, even sometimes we find early textile works, although plant fiber textiles don't preserve as well, so they are pretty rare,” said Simon.
However, archaeobotanists may never know the full extent of the technological uses of plants.
“Mainly, if it is not carbonized, then we have no evidence because it just degrades due to soil bacteria and moisture,” said Simon. Plant remains become carbonized after they have been charred.
Overall Simon says the field is heading in a more biology-driven direction, and advances in modern technologies offer specialized techniques to more accurately and efficiently identify and age botanical artifacts, including ancient DNA testing, isotopic analysis, and residue analysis.
“We use a process called water flotation, where we sift the soil into a screened bucket and then use water to float the botanical material that would not usually be recovered through a usual sized screen. It is then dried and that is called the light fraction,” said King.
Once Simon, Schaefer, and King collect the light fractions, they begin analyzing them by looking for different types of plant remains—seeds, stems, rinds, etc. Some things, like wood, are easy to pick out, but other botanical materials require microscopic analysis or more advanced methods.
Some artifacts are sent to the Illinois State Geological Survey, which, like ISAS, is part of the University of Illinois’ Prairie Research Institute, for radiocarbon dating to determine age. This process may take a couple of weeks, but according to King and Schaefer, it is a vast improvement from the past when carbon dating would take much longer.
The turnaround time from excavation to analysis is no swift process. An archaeobotanist can spend anywhere from a few months to multiple years to complete a project. For every archaeological investigation, Simon, King, and Schaefer collaborate with the entire ISAS team to finalize a hefty report that aims to better understand the culture, environments, and ecologies of prehistoric people.
But in the end, the curiosity and the passion that motivates these women comes down to the human tie.
“I like learning new things about how people lived in the past and what their lives were like,” said Schaefer. “It’s like being a detective: How can we figure those things out from the little things they have left behind?”