Chamaecyparis Obtusa) Trees in 5 Half-Sib Families in a Progeny Test Stand in Kyushu, Japan
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J Wood Sci (2012) 58:471–478 DOI 10.1007/s10086-012-1285-3 ORIGINAL ARTICLE Termite resistance and color of heartwood of hinoki (Chamaecyparis obtusa) trees in 5 half-sib families in a progeny test stand in Kyushu, Japan Yoshio Kijidani • Noriko Sakai • Keita Kimura • Yoshitake Fujisawa • Yuichiro Hiraoka • Junji Matsumura • Shinya Koga Received: 22 March 2012 / Accepted: 25 July 2012 / Published online: 10 August 2012 Ó The Japan Wood Research Society 2012 Abstract Hinoki (Chamaecyparis obtusa) wood has been of hinoki trees on termite resistance of hinoki families was used as a structural material in Japan because of its superior small. mechanical properties, its excellent durability and the beautiful color of its heartwood. Variations of termite Keywords Hinoki plus tree Á Termite resistance Á resistance and compositions of extractives among hinoki Color of heartwood Á Growth rate trees have been reported. However, genetic variation of termite resistance and the effect of heartwood color on termite resistance remain unknown. In this study, we report Introduction the characteristics of termite resistance and color indexes (L*, a* and b*) of heartwood of hinoki half-sib families in Hinoki (Chamaecyparis obtusa) is one of the important a progeny test stand. The survival days of termites and the plantation species in Japan. Hinoki wood has been used as mass loss of samples of hinoki heartwood differed signif- a structural material in Japan because of its superior icantly among hinoki families. Families with red-color mechanical properties, its excellent durability and the heartwood had larger termite resistance than families with beautiful color of its heartwood. The MAFF (Ministry of yellow-color heartwood. The termite resistances of indi- Agriculture, Forestry and Fisheries) of Japan aims to vidual samples from two families with yellow-color achieve C50 % wood self-sufficiency by developing a heartwood were as small as that of Pinus densiflora. Larger reliable domestic wood supply/use system [1]. Therefore, a* and smaller b* induced larger termite resistance of improvements are sought in the reliability and wood heartwood. The effect of DBH (diameter at breast height) qualities of hinoki wood. To obtain information about the genetic variation of the wood properties of hinoki, we examined the microfibril angle (MFA) and wood densities Part of this report was presented at the 57th Annual Meeting of the of hinoki families grown in a progeny test stand [2]. Hinoki Japan Wood Research Society, Hiroshima, August 2007 and the 59th heartwood is believed to have excellent durability; how- Annual Meeting of the Japan Wood Research Society, Matsumoto, ever, a house builder in Miyazaki prefecture shared with us March 2009. his experience that hinoki heartwood is not always con- Y. Kijidani (&) Á N. Sakai Á K. Kimura sistent on this excellent durability (private communica- Division of Forest Science, Faculty of Agriculture, tion). Therefore, it is also important to obtain information Miyazaki University, Miyazaki 889-2192, Japan about genetic variations in the durability of hinoki heart- e-mail: [email protected] wood. Although preservatives can raise the durability of Y. Fujisawa Á Y. Hiraoka wood, the current desire is for superior-durability lumber Forest Tree Breeding Center (FTBC), Forestry and Forest that does not add an extra impact to the environment. In Products Research Institute (FFPRI), Ibaraki 319-1301, Japan this study, we focused on the variation of the natural durability of hinoki heartwood. J. Matsumura Á S. Koga Department of Agro-environmental Sciences, Faculty Many studies have examined the chemical compo- of Agriculture, Kyushu University, Fukuoka 812-8581, Japan nents that provide fungal and termite resistance to hinoki 123 472 J Wood Sci (2012) 58:471–478 heartwood. The antifungal components in hinoki heart- been established as a brand (Keichiku Hinoki), and a wood extractives have been identified as sesquiterpene questionnaire survey established that the branded hinoki alcohols, mainly cadinols [3]. The termite resistance of was characterized by the red-tinged color of its heartwood hinoki heartwood is attributable to both stable components [21]. Therefore, heartwood color-based selection of hinoki with low activity and unstable components with high families is assumed to be effective at enticing end users to activity [4]. The stable components with small termite purchase hinoki wood. In hinoki trees from eight regions in resistance include non-volatile cadinols [5] and a-terpineol Japan and Tono hinoki (one of brand hinoki trees), it was [6]. A major unstable component with large termite resis- reported that four norlignans were colored extractives; tance was the volatile component a-terpineol acetate [6]. hinokiresinol, 3-methoxyhinokiresinol and cryptoresinol Variations of termite resistance and amounts of extrac- were pale pink and isocryptoresinol was pale yellow, and tives among hinoki trees have been reported. Decay and the content of hinokiresinol was reflected in the pink color termite resistance, and amounts of extractives of hinoki of the heartwood [22]. From these results, it was assumed heartwood from different area in Japan showed variations that heartwood color of hinoki trees came from heartwood with no apparent effect of density or ring width on decay extractives and varied from red to yellow. As previously and termite resistance [7]. Hinoki wood from a natural described, many researches reported that heartwood forest had higher termiticidal activity than that from a extractives contributed durability of heartwood. Therefore, plantation forest, and the higher termiticidal activity was we guess that there was some relationship between heart- explained by the larger volatile extractive contents and wood color and the durability of heartwood; although smaller average ring width [8]. Volatile monoterpenes in extractives contributed to durability might have no color. needle samples of 50 hinoki trees from five different Heartwood color-based selection of hinoki families may plantations had considerable compositional variation, affect the termite resistance of hinoki heartwood. However, especially in sabinene composition, and there was no the relationship between color and the termite resistance of relation between tree size and volatile monoterpene com- hinoki heartwood remains unknown. position [9]. From these studies, it was assumed that the The objective of this study was to examine: (1) the termite resistance of hinoki varied among trees, and that it differences between hinoki families in color indexes of was so difficult to predict the variations of termite resis- heartwood, (2) the differences between hinoki families in tance of hinoki heartwood, genetic backgrounds of which termite resistance, (3) the relation between color of heart- were unknown. In western red cedar (Thuja plicata) and wood and termite resistance of hinoki families and (4) the Alaska cedar (Chamaecyparis nootkatensis), methanol- relation between DBH (diameter at breast height) and ter- soluble heartwood extractives are an important factor for mite resistance in hinoki families. Differences among the natural durability of the heartwood and there was hinoki families in termite resistance are discussed based on considerable variability of natural durability among and data obtained at 1.2 m above ground. Therefore, the dif- even within trees [10]. ference between hinoki families at other heights in the In hinoki clones selected as cold and wind-resistant trunks remains unclear. trees, sabinene composition in needles is constitutively steady in most clones [11]. In the heartwood of sugi (Cryptomeria japonica), contents and composition of Materials and methods extractives differ among cultivars [12–14]. In the heart- wood of sugi plus tree (selected as trees with various Sample trees superior traits, e.g., fast growth and trunk straightness) families, the contents and composition of extractives were Hinoki half-sib families were planted in a progeny test shown to differ among families, and the effects of planta- stand in Oita prefecture, Japan in 1974 by Forest Tree tion area on the contents and composition of extractives Breeding Center (FTBC), Forestry and Forest Products were observed [15–19]. The termite resistance of sugi Research Institute (FFPRI). Hinoki trees (31 families 9 2 heartwood has been shown to differ among cultivars [20]. replicates 9 49 trees) were planted at 1.8-m spacing, and From these studies, also in hinoki, the genetic effect on the stands were not managed by silvicultural practice. termite resistance of heartwood may be significant. Hinoki Sample trees (31 families 9 2 replicates 9 3 trees) were plus trees could contribute to a reliable domestic wood harvested after 29 years of growth. Eighty hinoki trees (15 supply. However, the termite resistance of heartwood of half-sib families 9 5 or 6 trees) were selected as sample hinoki plus trees remains unknown. trees for this study from the harvested trees (Table 1). The color of hinoki heartwood is a very important factor These 15 half-sib families were the same families dis- for the end user purchasing hinoki wood in Japan. The local cussed in a previous study [2]. The local families in this cultivar of hinoki in northeastern Fukuoka prefecture has progeny test stand were the families that had been selected 123 J Wood Sci (2012) 58:471–478 473 Table 1 Sample trees from 15 half-sib families Family Family name Prefecture n DBH (cm) Ed (GPa) Color index of