This work presents linear and nonlinear regression equations developed for estimating the stem (over bark and under bark), bark, living branch, dead branch, total branch, needle and aboveground biomass of 31-year-old Scots pine (Pinus sylvestris) trees in Bolu-Aladağ. Biomass conversion and expansion factors (BCEF) for converting stem volume over bark into tree components and biomass expansion factors (BEF)–for expanding stem biomass over bark into aboveground, branch and needle biomass – are also obtained. In this study, the average aboveground biomass of 13 trees with diameters ranging between 6.10 cm and 10.90 cm is found to be 22.4 kg tree-1. Significance level of all power functions developed for the biomass estimation is above p < 0.05. The most significant regression equations are those developed for calculating the aboveground biomass. Stem (over bark and under bark) and aboveground biomass equations are compatible with the equations developed for Scots pine trees in temperate regions. However needle and branch biomass equations show low levels of significance and are incompatible with other Scots pine biomass equations. The biomass conversion and expansion factor for the aboveground biomass (BCEFaboveground) is 0.535 t m-3. Biomass expansion factor for the aboveground biomass (BEFaboveground) is 1.263.