With a paint can in hand, a forester walks step by step through the dense Arizona ponderosa pine forest, marking trees with distinctive orange streaks. The forester is part of a timber-marking crew assessing if each tree should stay or go during harvest, per a prescription from the Forest Service silviculturist. Trees to remain receive the orange marking; the others will be harvested. Timber-marking crews cover thousands of acres of Forest Service lands each year, prepping critical thinning projects to reduce the number of trees and move forest lands toward a condition less vulnerable to catastrophic wildfire. With this laborious operation, many began to ask: Couldn’t there be a more efficient way of marking trees?