Distribution of Within-Ring Internal Checking in Pinus radiata Grown in Southern Chile

A Aguilera,L Inzunza

doi:10.4067/s0718-221x2009000200001

Abstract

The increase of Pinus radiata plantations in Chile has brought larger annual volumes to the industry and the opportunity to process them into value-added products. Within-ring checks constitute an important problem that may affect the appearance quality of lumber. This problem occurs in the early wood portion of sapwood growth rings in dry lumber and can only be seen when the board is cross cut. The purpose of this study was to analyze the frequency of within-ring internal checking in kilndried Pinus radiata lumber from different logs grown in southern Chile. Centre boards were more affected by the internal checking. Checks were located more frequently between rings 4 to 6. Key words: Internal checking, radiata pine, sawmill, kiln-dried.

Highlights

IntroductionWithin-ring internal checking appears with higher frequency in fast growth conifers species such as Pinus radiata (Cown and McConchie 2000, Ball et al 2001)
Within-ring checking is one type of internal checking, where the checks are internal to the wood, and generally do not break the surface or become visible without processing, as distinct from surface checking (Miller and Simpson 1992a, Booker 1994).Within-ring internal checking appears with higher frequency in fast growth conifers species such as Pinus radiata (Cown and McConchie 2000, Ball et al 2001)
Three log sections showed a higher frequency of internal checking, at 1.3, 3.0 and 4.5 meters of log length but with a critical section at 1.3 m, where more internal checks were found

Summary

Introduction

Within-ring internal checking appears with higher frequency in fast growth conifers species such as Pinus radiata (Cown and McConchie 2000, Ball et al 2001). It is after the kiln drying process that these checks become visible. Cown and McConchie (2000), Simpson et al (2002), Ball et al (2005a, b) note that some factors that determine the appearance of within-ring internal checking are the site, genetic factors, the board position on the log and kiln-drying intensity. The authors indicate that little can be done to prevent within-ring checking by, for instance, reducing the thickness of the board or the drying temperature

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