Fig. 5From: Longitudinal height-diameter curves for Norway spruce, Scots pine and silver birch in Norway based on shape constraint additive regression modelsModel effects of stand age on the first order parameter A (left) and B (right) of a non-shape-constrained gamm, for Norway spruce where stand age instead of the quadratic mean diameter has been used as the longitudinal covariate (Eq. 7.1)Back to article page