Spatial variation of wood density, stiffness and microfibril angle along Eucalyptus trunks grown under contrasting growth conditions

Abstract

International audienceFew studies have investigated the influence of environmental conditions on the within-treevariation in Eucalyptus wood traits. The genotype and environment effects and their interactionsinfluence the wood properties. Their evaluations are crucial to estimate the genotype values andto select with efficiency. Thus, the aim of this study was to better understand the effect ofground slope and wind speed on the spatial variation of basic density (ρ), stiffness (MOE) andmicrofibril angle (MFA) of Eucalyptus wood. Wood discs cut along the trunk were sampledfrom 150 six-year-old Eucalyptus grandis x E. urophylla hybrids growing in 3 contrastinggrowing conditions influenced by ground slope and wind regime. Near Infrared (NIR)calibrations previously developed for ρ, MOE and MFA were used to predict in our discs. 2-Dplots presenting the spatial variation of predicted wood traits were compared. The higher theground slope, the greater the magnitude of radial variation in ρ, principally in the medium zoneof the trunk. The spatial variation of wood stiffness seems to be sensitive to two environmentalconditions. The MFA radial decreases were more pronounced where the wind speed was higher.At the base and top of the trees, however, there was no significant effect of growing conditionson the radial variation of the wood properties considered here

Prediction of microfibril angle for Eucalyptus microcorys wood by fiber length and basic density

“…Donaldson (2008) reiterates, however, that unlike conifers, in Eucalyptus wood, the MFA is smaller near the pith, with a typical range from 15° to 20°. The high coefficient of variation observed for MFA shows that the variation pattern found corroborates patterns in previous research, such as those described for Eucalyptus grandis (Ramos et al 2011, Lima et al 2014, E. nitens (Medhurst 2012) and hybrids of E. grandis × E. urophylla (Hein et al 2015).…”

“…The increase in FL and BD, followed by subsequent stabilization of values close to the bark, for both or just one of the properties, is a pattern commonly described for woody species, and results mainly from the juvenile wood formation in the early years of plant growth, which over time tends toward stabilization as the wood reaches maturity (Tomazello-Filho 1987, Bhat et al 1990. A similar variation pattern for FL was also recently described by Palermo et al (2015) to determine the limits between adult and juvenile wood of Eucalyptus grandis wood, and for increasing behavior of BD by Hein et al (2015) who studied the effect of terrain slope and wind velocity on the BD and other Eucalyptus grandis hybrids × E.urophylla wood properties. Melo et al (2016) also observed a significant radial increase in fiber length and basic density in Eucalyptus spp.…”

Do the Growing Conditions of Trees Influence the Wood Properties?

“…They found a positive relationship between fiber length and fiber wall thickness with radial position and a negative relation between vessel diameter and ray frequency with the radial position. Hein et al (2016), testing a 6-year-old Eucalyptus grandis x E. urophylla hybrids growing in three contrasting growing conditions influenced by ground slope and wind regime, found that pith-to-bark variations in wood density, MFA and MOE is more consistent than those along the trunk. Wood density, MFA and MOE have lower tree top variation because these woods were recently produced, few months before harvesting.…”

Variação radial e longitudinal da massa específica básica da madeira de Araucaria angustifolia com diferentes idades

“…O incremento da massa específica no sentido radial é comumente verificado para diferentes espécies, com destaque para as de rápido crescimento (Mattos et al, 2011;Melo et al, 2013;Machado et al, 2014;Melo, 2015;Hein et al, 2016).…”