Dawn Goodwin spent her 50th birthday among towering pines and yellow birches whose tree rings make her lifespan seem like a child’s in comparison. But on that cool, overcast Saturday in December, the growling of construction trucks and chainsaws drowned out the natural soundscape of gushing freshwater and wind whispering between pine needles on the banks of the Mississippi River.

Goodwin was at this river crossing near Palisade, Minnesota, to protest the construction of the energy company Enbridge’s Line 3 pipeline, a $9.3 billion project to carry tar-sands oil ― one of the dirtiest varieties of crude oil ― from Joliette, North Dakota, to a terminal facility in Clearbrook, Minnesota. From there, it’s distributed to refineries. Goodwin winced as workers felled a mighty spruce while clearing a 50-foot berth for the pipeline, its sappy rings laid bare as its crown thudded to the ground.

“At that moment, the tree just spoke to me, saying, ‘I’m being disrespected. I am medicine. And they’re just cutting me and throwing me aside with no care,’” said Goodwin, who lives on the White Earth Reservation and goes by the Ojibwe name Gaagigeyaashiik. “I just felt like I needed to go and pick it up, so I walked over.”