SPATIAL VARIATION OF EUCALYPTUS FIBRES CONSIDERING THE STRUCTURE OF ANNUAL GROWTH RINGS

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Fabiola Magalhães Mendes
https://orcid.org/0000-0002-3029-4607
Jonas Massuque
https://orcid.org/0000-0001-6162-0287
Angélica de Cássia Oliveira Carneiro
https://orcid.org/0000-0002-5992-3059
Franciane Andrade de Pádua
https://orcid.org/0000-0002-3349-8648
Paulo Ricardo Gherardi Hein
https://orcid.org/0000-0002-9152-6803
Paulo Fernando Trugilho
https://orcid.org/0000-0002-6230-5462

Abstract

Background: The fibres dimensions vary along a tree trunk, and these variations are related to the apical
meristem and vascular cambium activities; understanding these variations would guide the best use of
wood. There have been studies on the pattern of fibres dimensions’ variation along the tree trunk in the
radial and longitudinal directions; however, the vast majority do not take into account the structure of
the annual growth rings. Hence, this study aimed to obtain the pattern of fibres dimensions’ variation
and their quality indexes along the tree trunk take into account the structure of the annual growth rings.
Two Eucalyptus urophylla x Eucalyptus grandis hybrid clones were used in the study. Ten-year-old trees
were selected and discs were removed from 13 longitudinal positions. The disks were prepared and the
growth rings were subsequently identified and the samples used for maceration were collected. Twenty
fibres were measured in the annual growth rings present in each longitudinal position.
Results: In the longitudinal direction, within the annual growth rings, the fibre dimensions and their
quality indices did not show a well-defined pattern of variation. In the radial direction, the length, cell
wall thickness, wall fraction, and Runkel ratio of the fibres tended to increase following the pith-bark
direction, while the lumen diameter and flexibility coefficient decreased.
Conclusion: Nevertheless, the fibre width and fibre slenderness index did not present a well-defined
pattern of variation in the radial direction.

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Author Biographies

Fabiola Magalhães Mendes, Department of Forest Sciences, Federal University of Lavras, Lavras, Brazil

Author contribution: Conceptualization, formal analysis, methodology, investigation, and writing—original draft.

Jonas Massuque, Faculty of Agrarian Sciences, Lúrio University, Unango, Mozambique

Author contribution: Formal analysis, writing—review and Editing.

Angélica de Cássia Oliveira Carneiro, Department of Forest Engineering, Federal University of Viçosa, Brazil.

Author contribution: writing—review and editing.

Franciane Andrade de Pádua, Department of Environmental Sciences, Federal University of São Carlos, São Carlos, Brazil

Author contribution: writing—review and editing.

Paulo Ricardo Gherardi Hein, Department of Forest Sciences, Federal University of Lavras, Lavras, Brazil

Author contribution: supervision and writing—review and editing.

Paulo Fernando Trugilho, Department of Forest Sciences, Federal University of Lavras, Lavras, Brazil

Author contribution: Conceptualization, methodology, supervision, writing—review and editing, funding.