Fig. 2

Observed (open circles) and predicted (red line) tree height against tree diameter at breast height (DBH) for birch (upper panel, r² = 0.85) and pine (lower panel, r² = 0.78), using Eq. (2) with the fitted value for the parameter s (see Table 1). Black circle: ORPHEE data; blue circles: ISLANDES data (only birch trees); green circles: GIS COOP - Castillonville data (only pine trees)