Sapwood and heartwood taper in Scots pine stems

The heartwood and sapwood of Pinus sylvestris L. were analysed using simultaneous taper models for stem without bark and for heartwood. Sapwood area tapered monotonically from the base to the top of the stem. Below crown base the stem tapered more slowly than in the crown. The proportion of heartwood in the tree stem was higher in dense sample plots than in sparse ones and also decreased significantly with increasing relative size of a tree in a plot. Height at crown base correlated significantly with the proportion of heartwood, stand density, and relative size. Height at crown base was the most effective additional independent variable for predicting sapwood basal area at crown base when diameter at breast height and tree height were measured. Connected with diameter at breast height and tree height measurements, width of the sapwood at breast height explained significantly better sapwood and heartwood volumes than height at crown base.