Fig. 2

Visual representation of parameter effects in the nonlinear models of cumulative annual ring width (upper column) and basic density (lower column). CRW, cumulative annual ring width; BD, basic density; β₀, β₁, and β₂ are the fixed-effect parameters. The parameter effects were calculated by the nonlinear models: Chapman-Richards formula [CRW = β₀ (1–e^–β1RN)^β2] and quadratic formula [BD = β₀RN² + β₁RN + β₂], where RN is the annual ring number from pith