Walls tell time: Dendrochronology dates 1800s pioneer home

Matt Franz has learned that walls can talk. They just need someone to translate.

The senior who is majoring in forestry and fire ecology is working with Associate Professor Grant Harley, who runs a tree-ring laboratory in the Department of Geography and Geological Sciences. In Summer 2021, Harley’s team traveled to Chewelah, Washington, to age the Colville Indian Agency Cabin.

The cabin was the home of Maj. John A. Simms, an Indian agent of the United States who worked with the Coeur d’Alene, Spokane, Kalispel and Colville tribes. The Stevens County Historical Society believes the cabin was built in the mid-1800s and reached out to Harley for help pinpointing its exact year of construction.

The team used hollow drills to extract tree cores from the cabin’s walls and ceiling. Each core contains a record of the tree’s growth, or a ring for every year. The width of each ring varies depending on the climate each year.

The team will compare the growth pattern of the cabin’s tree cores with cores taken from local living trees. If the living trees are old enough that the tree-ring pattern from the cabin logs matches the early rings from the living trees, the team will know when the cabin logs were harvested for use and help the historical society piece together the history of the region.