Green Wood

Green wood is freshly cut lumber that hasn't been dried -- still carrying close to the moisture content the living tree had, often well above 30%. It's noticeably softer and easier to cut, carve, and shape than dried wood of the same species, which is exactly why green woodworking (chairmaking, spoon carving, riven furniture parts) deliberately works wood in this state rather than waiting for it to dry.

The tradeoff is that green wood is actively shrinking and moving the entire time it's being worked and afterward, right up until it reaches equilibrium with its surroundings -- a green-wood project has to be designed around that ongoing movement (a wedged through-tenon that tightens as the parts shrink around it is a classic example) rather than treated as dimensionally stable the way dried, kiln-dried lumber is.