Abstract

This study presents a method for predicting the local fiber orientation of veneers made from peeled Douglas-fir logs based on the knowledge of the tree branch characteristics (location, radius, insertion angle, azimuth angle, and living branch ratio). This model is based on the Rankine oval theory approach and focuses on the local deviation of the fiber orientation in the vicinity of knots. The local fiber orientation was measured online during the peeling process with an in-house-developed scanner based on the tracheid effect. Two logs from the same tree were peeled, and their ribbons were scanned. The knot locations and fiber orientation were deduced from the scanner data. The first objective was to compare the fiber orientation model with measurements to enhance and validate the model for French Douglas-fir. The second objective was to link data measurable on logs to veneer quality.

Highlights

  • The majority of French Douglas-fir forests were planted in the period between the 1950s and the1970s [1]

  • The fiber direction with the Rankine oval model was compared to the local fiber orientation, and modeled knot radii was near 0%

  • The fiber direction with the Rankine oval model was compared to the local fiber orientation, which was measured with localonline onlineorientation orientationfiber fiber analyzer analyzer (LOOBAR)

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Summary

Introduction

The majority of French Douglas-fir forests were planted in the period between the 1950s and the. According to Thivolle-Cazat et al [2], in the near future, a fraction of these forests will contain logs with diameters larger than 50 cm, which are rejected by industrial sawmills with the standard chipper canter. A method proposed by Bleron et al [12] based on the local density can predict the mechanical properties of Douglas-fir products. This approach, despite promising results, requires an. The description of the fiber directions in the vicinity of the knots is computed from a mathematical formulation based on the Rankine oval [14] This so-called flow-grain analogy was first described by Goodman and Bodig [15] and afterward by References [14,16,17]. Fibers 2020, 8, x FOR PEER REVIEW called flow-grain analogy was first described by Goodman and Bodig [15] and afterward by Fibers 2020, 8, 54

Log Sampling and Description
Peeling
Veneer
Picture
Modeling
Fiber the
Schematic
Discussion
Fiber in the Vicinity ofcenters
Fiber Orientation in the Vicinity of Knots
Thisarea methodology fiber orientation
Conclusions
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