Stand age, structure, composition, and disturbance.

Stand structure and composition (stems/ha) based on inventory of trees ≥ 10 cm dbh. A pulse of establishment was defined as the earliest episode during which at least 30% of trees established within a 40 year period during the 18th century, at least 40% of trees established within a 40 year period during the 19th century, or at least 50% of trees established within a 40 year period during the 20th century. Stands were categorized as having been affected by the 1940s spruce beetle outbreak (SB) if at least 33.3% of trees showed releases in 1940–1959.