Revisiting the transition between juvenile and mature wood: a comparison of fibre length, microfibril angle and relative wood density in lodgepole pine

Abstract

In an attempt to examine the dynamic inter-relationship among wood density and fibre traits wtracheid length and microfibril angle (MFA)x in lodgepole pine (Pinus contorta), 60 trees were sampled in three age classes from four sites in central British Columbia. Breast height discs were taken and relative wood density was measured along two radii. Tracheid length was assessed on isolated 5-year increments from pith to bark at breast height for each tree. MFA was determined every 50 mm and the 5-mm composite intervals from pith to bark per disc at breast height were used in the analysis. Segmented regression was employed to identify the ''juvenile to mature wood'' transition point, which revealed transition ages of 31, 18 and 15 for wood density, fibre length and MFA, respectively. These traits were related to primary growth, expressed as area increment, ring width, percent earlywood and height increment during the juvenile wood phase. Comparisons of wood and fibre traits showed a higher congruence between the time of transitions for fibre length and MFA (Pearson correlation coefficient 0.52) than that between fibre length and wood density (0.07), and MFA and wood density (0.16). The cessation of early rapid radial increment growth terminated before wood and fibre transitions to mature wood occurred. Fibre length was significantly, but not strongly, related to ring width and percent earlywood (0.35 for both). The duration of juvenile fibre production was not significantly related to height growth.

Network-based integration of systems genetics data reveals pathways associated with lignocellulosic biomass accumulation and processing

“…TUA2 specifically is known to be a target of SND1, the master regulator of secondary cell wall deposition (45,46), and is one of two alpha-tubulins that is significantly up-regulated in Eucalyptus during tension wood formation, during which MFA is one of the main physical changes in the wood (47). Given that MFA is thought to affect wood ultrastructure and stiffness (48,49), it is interesting to find this tubulin associated with bioprocessing-related traits such as sugar release in this study. Several associations were identified (mainly with sugar release efficiency) for genes involved in cysteine and methionine metabolism, including ATCIMS/MS1.…”

Modelling variation in wood density within and among trees in stands of New Zealand-grown radiata pine

“…The results from the current study show that wood density is still increasing rapidly with cambial age at ten rings from the pith, suggesting that the arbitrary ten ring definition may be inadequate. However, other properties, such as microfibril angle, also need to be considered when determining the age of transition from corewood to outerwood (Mansfield et al 2009). The models developed in this study can be used to further investigate the extent of the corewood zone, particularly if defined based on a wood density threshold, and how this is affected by different factors, such as environment and silviculture.…”

Impact de trois interventions sylvicoles sur la croissance et la qualité du bois de l'épinette noire en forêt boréale /

“…Ces deux propriétés nuisent à l'utilisation du bois de construction en augmentant le niveau de distorsion des planches (Zobel et Sprague, 1998). De plus, le bois juvénile a moins de force de cohésion et une plus grande instabilité dimensionnelle lors du séchage (Zobel et van Buijtenen, 1989;Zobel et Sprague, 1998), provoquant ainsi une plus grande proportion de défauts que dans le bois mature (Mansfield et al, 2009).…”

“…Selon Zhang (1998) et Wang et al (2002), le pourcentage de bois final de l'épinette noire diminue avec l'augmentation de la largeur des cernes. De plus, les résultats sont en accord avec l'hypothèse de juvénilité, celui-ci étant caractérisé par une proportion de bois final moindre (Panshin et Zeeuw, 1980;Mansfield et al, 2009 (Pothier et al, 1989). De ce fait, l'aire du lumen des trachéides doit être plus importante afin de compenser cette perte de conductivité causée par la longueur réduite des trachéides (Schneider et al, 2008).…”