Outside and inside bark diameter at breast height for Platycladus orientalis and Pinus tabulaeformis in the Beijing area.

Linear models were used to determine the relationships between outside and inside bark diameter at breast height of 57 Platycladus orientalis and 60 Pinus tabulaeformis trees in the Beijing area.Results showed that mathematical models of outside bark(DOB) and inside bark(DIB) diameters at breast height in Platycladus orientalis(PO) and Pinus tabulaeformis(PT) were DIBPO = 0.918 DOBPO and DIBPT = 0.916 DOBPT.Two equations of bark thickness,such as BPO = 0.082 DOBPO and BPT = 0.084 DOBPT,as well as two ad-justed bark coefficients,KPO = 1.089 and KPT = 1.092,were obtained indirectly from the above two bark thickness models.These data also indicated that the models formed and the coefficients obtained were stable for diameter growth model optimization of both trees in the Beijing area.