NZ Journal of Forestry Science 39 (2009)

Publication: New Zealand Journal of Forestry, Volume N.Z.J.For. 2009, Issue N.Z.J.For. 54(2) 2009, pp 6-7, Aug 2009
Publisher: New Zealand Institute of Forestry

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Abstract: Effect of Green Density Values on Pinus radiata Stiffness Estimation using a Stress-wave Technique Use of acoustic tools for assessing stiffness of green wood in standing trees relies on the assumption of a constant value for wood density. Wielinga et al (pp. 71-79) examined the variability in the green density of the outerwood of 13-year-old Pinus radiata trees and determined the error introduced by using a constant value. Assuming a constant green density introduced a small (~3%) error in the calculated modulus of elasticity (i.e. density ‘as measured’ x acoustic velocity²). Acoustic velocity was the dominant term in the equation. Green density of the fresh core samples showed little variation and was more strongly determined by the sample’s moisture saturation than the amount of wood material (basic density). Modulus of elasticity was inversely related to diameter at 1.3 m. Basic density and fresh moisture content were inversely related. Basic density and fresh moisture content both influenced the acoustic velocity, but their effects were weak and opposite.

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