Evrim Yazgin
Cosmos science journalist
Native Americans in northern Michigan were prolific farmers according to archaeological research published today in the journal Science. The findings show the high-level societal organisation that the ancestors of the indigenous people of the region possessed.
The Sixty Islands archaeological site along the Menominee River is the most complete ancient agricultural site in the eastern US. The site was in use between the years 1000 and 1600 CE. Much of the ancient crop fields remain intact.
Today, the Menominee Indian Tribe of Wisconsin lives on the lands that their ancestors once cultivated.
“The scale of this agricultural system by ancestral Menominee communities is 10 times larger than what was previously estimated,” says lead author Madeleine McLeester, an assistant professor of anthropology at Dartmouth College in the US. “That forces us to reconsider a number of preconceived ideas we have about agriculture not only in the region, but globally.”
McLeester’s team found crop fields covering a 330-acre area using drone-based lidar technology. Lidar uses laser pulses to map objects on the Earth’s surface.
Only 40% of the total Sixty Islands site has been surveyed using this technique.
The researchers found raised fields of clustered, ridged garden beds ranging in height from 10 to 30cm. These would have been used to grow corn, beans, squash and other plants. Radiocarbon dating charcoal samples obtained from excavations show the ridges were constructed starting around the year 1000 and continuing for about 600 years.
Digs revealed charcoal and broken pieces of ceramics which suggests remains from fires and household refuse were used as compost in the fields. Wetland soils were also used to enrich the ground.
The region is in Michigan’s Upper Peninsula just 200km from the Canadian border. The area is known for being a difficult place for farming even today due to its cold climate, short growing season and dense forests.
“Our work shows that the ancestral Menominee communities were modifying the soil to completely rework the topography in order to plant and harvest corn at the near northern extent of where this crop can grow,” says McLeester. “This farming system was a massive undertaking requiring a lot of organisation, labour and know-how to maximise agricultural productivity.”
“When you look at the scale of farming, this would require the kind of labour organisation that is typically associated with a much larger, state-level hierarchical society,” says McLeester. “Yet, everything we know about this area suggests smaller egalitarian societies lived in this region but in fact, this may have been a rather large settlement.”
The site is part of a cluster of significant ancestral Menominee sites referred to as Anaem Omot – “Dog’s Belly” in Menominee. Burial mounds and a village were excavated between the 1950s and 1970s and the area was mapped in the 1990s.
McLeester’s team was requested by Menominee tribal leaders to survey and document the area using new technologies.
“Lidar is a really powerful tool in any kind of forested or heavily vegetated region where the archaeology is hidden below trees – where no kind of optical imagery can see what’s underneath the tree canopy,” says senior author Jesse Casana, a professor of anthropology also at Dartmouth.
“Forests are really confounding to archaeology in a lot of ways, so a lot of archaeologists rely on publicly available lidar that has often been obtained from a plane that flies really high,” Cassana adds. “But the resolution of the data is usually too low to see many archaeological features. Drone lidar enables us to collect the same kind of data but at a much higher resolution.”
Lidar scans revealed a quilt-like pattern of parallel ridges across the landscape. The ridges travelled in different directions, suggesting their locations might have been determined by individual farmers rather than the direction of the Sun or other environmental factors.
The survey also uncovered a circular dance ring, a rectangular building foundation that may have been a colonial trading post, two 19th-century logging camps and burial mounds.
“Through this research, we get this little window of preservation into pre-Colonial farming in the Upper Peninsula of Michigan,” says Casana.
