Genetic variation of microfibril angle and its relationship with solid wood and pulpwood traits in two progeny trials of Eucalyptus nitens in Tasmania

Abstract

Microfibril angle (MFA) is a key biological trait contributing to wood stiffness, which is a common breeding objective for solid wood products in many tree species. To explore its genetic architecture, area-weighted MFA was measured in two Eucalyptus nitens progeny trials in Tasmania, Australia, with common open-pollinated families. Radial strips were extracted from 823 trees in 131 families and MFA assessed using SilviScan-2®. Heritability, genotype-by-environment interaction and inter-trait genetic correlations were evaluated to examine the genetic variability and stability of MFA and its relationships with other solid wood and pulpwood selection traits. Significant family variation was found for MFA in both trials. There was no significant genotype-by-environment interaction and the across-site narrow-sense heritability was 0.27. MFA was genetically independent of basic density, growth, and tree form. However, MFA was strongly and favourable genetically correlated to acoustic wave velocity in standing trees, modulus of elasticity and kraft pulp yield (KPY). The present study has shown that genetic improvement of E. nitens for pulpwood selection traits is unlikely to have adversely affected MFA, and thus timber stiffness. Rather these results suggest the possibility that selection for increased KPY may have indirectly improved MFA favourably for solid wood products.

Shifts in internal stem damage along a tropical precipitation gradient and implications for forest biomass estimation

“…abrupt loss of resistance) are used to infer changes in the material, in our case the presence of voids in the wood. Among other applications, resistance drilling has been used to assess termite damage in wood (Hickman & Forschler, 2012), radial changes in wood density in pedunculate oak stands (Tomczak et al ., 2022) and climate‐associated variation in wood in Eucalyptus nitens M. plantations (Rocha Sepúlveda, 2023). Trees across all sites were drilled at breast height (at 130 cm above ground) across the longest diameter from end to end (Fig.…”