Ranking very young Pinus radiata families for acoustic stiffness and validation by microfibril angle

Abstract

Abstract Key message Acoustic techniques can be utilised to rank a large population of young trees for stiffness and stability for breeding purposes. Introduction This study sought to validate new approaches to rapid, very early screening and selection of radiata pine families, using microfibril angle (MFA) as a reference for comparative purposes. Method A key feature was tilting the trees at an angle of ∼30° after the initial 12 months of growth in order to force production of opposite wood (OW) and compression wood (CW) and prevent the co-mingling of the two distinctive wood types as occurs ‘at random’ within vertical stems. After 34 months, OW and CW materials were characterised independently for acoustic velocity (V), dynamic modulus of elasticity (MOEdynamic), basic density and longitudinal shrinkage. Finally, MFA were determined with X-ray diffraction. Result No phenotypic correlation was observed between OW and CW wood properties. The Spearman ranking correlation between V2 and MFA values in OW was 0.81. Conclusion We show that families or individual trees with superior wood properties can be screened at this young age using acoustics. Further, the same outcomes can be achieved as with X-ray diffraction (MFA) but more cheaply and rapidly.