Structure and development of old-growth, unmanaged second-growth, and extended rotation Pinus resinosa forests in Minnesota, USA

► We examined structure and development of old-growth, second-growth, and extended rotation stands. ► We use datasets from Pinus resinosa studies that span 61 and 87 years. ► Old-growth stands were more structurally complex than second-growth and extended rotation stands. ► Extended rotation treatments created diameter distributions similar to the old-growth stands. ► Extended rotation forestry can accelerate development of old-growth structure if coarse wood is retained.