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Microscopic evidence in soil reveals forest garden's past
Through 天美mv天美 Indigenous Studies assistant professor Chelsey Geralda Armstrong and her research team examined soil phytoliths to understand the distant past of Lhemqw贸:tel, a forest garden in Sts鈥檃iles territory on the Harrison River. A collaborative effort among Sts'ailes community members and university researchers, Armstrong and her graduate student, 天美mv天美 alumnus Levi Cormier (MSc, 2024), led the project.
Phytoliths are microscopic silica structures found in plants. After plants decompose, these structures are preserved in the soil. As some phytoliths have unique shapes (morphotypes), researchers can analyze phytoliths found in soil samples to identify the plants that once grew in an area.
Armstrong鈥檚 team established that phytoliths are well-preserved in forest soils in Lhemqw贸:tel, challenging long-held assumptions that phytoliths don鈥檛 preserve in the Pacific Northwest. The researchers were also able to identify phytolith morphotypes for plants found in the region, demonstrating how phytoliths can be used as a reliable research tool.
By analyzing phytolith qualities in soil samples taken from deeper depths, the scientists found that Lhemqw贸:tel was larger 1,400 years ago than it is today.
鈥淐hanges in specific phytolith types across soil layers suggest that open, managed forest-garden, and open meadow conditions once extended beyond the current boundaries,鈥� explains Armstrong. 鈥淭oday鈥檚 dense conifer forest appears to be a relatively recent regrowth following the imposition of reserve systems and other colonial land-use policies.鈥�
The study shows how soil phytoliths can provide scientists with insight into an area鈥檚 past, even when archaeological features are not apparent on the surface. Soil phytoliths can help scientists understand how the land was stewarded by people in the past and to trace how land-use has changed over the course of time.
Our faculty specialize in a variety of research areas across the field of Indigenous Studies. Find out more about research at 天美mv天美 Indigenous Studies.