Acoustic-Based Non-Destructive Estimation of Wood Quality Attributes within Standing Red Pine Trees

Peter Newton

doi:10.3390/f8100380

Abstract

The relationship between acoustic velocity (vd) and the dynamic modulus of elasticity (me), wood density (wd), microfibril angle, tracheid wall thickness (wt,), radial and tangential diameters, fibre coarseness (co) and specific surface area (sa), within standing red pine (Pinus resinosa Ait.) trees, was investigated. The data acquisition phase involved 3 basic steps: (1) random selection of 54 sample trees from 2 intensively-managed 80-year-old plantations in central Canada; (2) attainment of cardinal-based vd measurements transecting the breast-height position on each sample tree; and (3) felling, sectioning and obtaining cross-sectional samples from the first 5.3 m sawlog from which Silviscan-based area-weighted mean attribute estimates were determined. The data analysis phase consisted of applying graphical and correlation analyses to specify regression models for each of the 8 attribute-acoustic velocity relationships. Results indicated that viable relationships were obtained for me, wd, wt, co and sa based on a set of statistical measures: goodness-of-fit (42%, 14%, 45%, 27% and 43% of the variability explained, respectively), lack-of-fit (unbiasedness) and predictive precision (±12%, ±8%, ±7%, ±8% and ±6% error tolerance intervals, respectively). Non-destructive approaches for estimating the prerequisite wd value when deploying the analytical framework were also empirically evaluated. Collectively, the proposed approach and associated results provide the foundation for the development of a comprehensive and precise end-product segregation strategy for use in red pine management.

Highlights

The future prosperity of the Canadian forest sector is increasingly dependent on its ability to embrace value-based management given that the economic viability of the traditional volumetric yield maximization proposition is becoming more challenging
The underlying field and laboratory records pertaining to this suspect observation were reviewed for the possible occurrence of procedural errors. No such errors were obvious, it was concluded that this observational pair should be removed based on the results of the statistical assessment
Red pine produces a wide array of economically-important end-products which includes appearance-based boards used for interior flooring, exterior decking and wall panelling, dimensional lumber for residential home construction, utility poles used in building electrical transmission grids, veneer logs used in furniture manufacturing, and raw fibre for pulp for paper production and engineered wood composites [37]

Summary

Introduction

The future prosperity of the Canadian forest sector is increasingly dependent on its ability to embrace value-based management given that the economic viability of the traditional volumetric yield maximization proposition is becoming more challenging This is due to a combination of factors which include increasing global competitiveness, accessibility of economically-viable fibre sources, and evolving market demands for increased end-product diversity and value (e.g., [1,2,3]). This transitional shift has generated a renewed focus on deploying intensive silvicultural-based crop plans that can result in improvements in wood quality and the production of a more diverse stream of end-products throughout the rotation [4]. Such a representative crop plan would consist of species, genotype and initial spacing control via plantation establishment of genetically-improved stock on well-prepared (scarified) sites followed by early vegetation management treatments and subsequent maintenance of optimal site occupancy levels through density management treatments (e.g., precommercial and commercial thinning; [5]).

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