Log characteristics and basic density of four common Mongolian softwoods

ABSTRACT Log characteristics and basic density were evaluated in four common Mongolian softwoods, Pinus sylvestris L., Pinus sibirica Du Tour, Picea obovata Ledeb., and Larix sibirica Ledeb. by developing the linear or nonlinear mixed-effects models for longitudinal and radial variations of measured characteristics. Total of 19 trees from four species were used in this study. Log taper and juvenile wood percentage increased from base to treetop in all species, except for log taper in Pinus sylvestris. Dynamic young’s modulus of logs decreased from base to treetop, and the mean values were 7.81, 5.74, 7.12, and 8.78 GPa for Pinus sylvestris, Pinus sibirica, Picea obovata, and Larix sibirica, respectively. Basic density increased (Pinus sylvestris and Larix sibirica) or decreased (Pinus sibirica and Picea obovata) and then became stable values. The estimated whole tree values of basic density in juvenile wood significantly differed from those in mature wood for all species.