Influence of Dowel Center Spacing on Chamfered-Joint Components Made byCupressus funebris Wood

The traditional tenon and mortise joint has low processing efficiency and a weak theoretical basis,making the structure easy to deform and damage,reducing the safety,and increasing waste of resources.This study aims to determine the optimum dowel center spacing parameter for chamfered-joint components and the maximum value of the strength of joints loaded into bending strength and tensile strength.In this study,an integrated opti-mization method combining the single-factor test and one-way ANOVA analysis was proposed to study the influ-ence of the dowel center spacing on the bending strength and the tensile strength of chamfered-joint components made by Cupressus funebris wood.The results revealed that the bending strength of chamfered-joint components decreases linearly with the increase of the dowel center spacing.In addition,the tensile strength of chamfered-joint components increases first and then decreases with the increase of the dowel center spacing,showing para-bola change.The relational expression between dowel center spacing,the bending strength,dowel center spacing and the tensile strength were obtained.

Nursery Testing of Superior Tree Progeny of Cupressus funebris

[Objective] Breeding and genetic improvement for Cupressus funebris was performed based on the extensive genetic variation among provenances and fami- lies. [Method] The two-year-old Cupressus funebris, from 4 provenances and 34 superior Cupressus funebris families introduced from Chongqing and Qiandao Lake of Zhejiang Province, was used as test material, and the differences in growth traits among provenances and families at the seedling stage of Cupressus funebris were investigated. [Result] The height and ground diameter of seedlings differed signifi- cantly among provenances and families. Their variation coefficients among families were 11.37% and 18.89%, and among provenances were 7.25% and 12.58% re- spectively. [Conclusion] There was relatively rich genetic variation in height and ground diameter among provenances and families of Cupressus funebris. It has a certain breeding potential.

Study on the Variation in Growth Traits of Cupressus funebris

[Objective] This study aimed to investigate the variation in growth traits of Cupressus funebris in Chongqing Municipality, thus laying the foundation for further breeding and improvement of fine varieties. [Method] Growth traits of three fine stands of C. funebris in Qijiang, Pengshui and Youyang of Chongqing Municipality were investigated. [Result] The results showed that C. funebris stand in Pengshui exhibited the best growth performance, followed by C. funebris stand in Qijiang; C. funebris stand in Youyang exhibited the poorest growth performance. The average volume growth of C. funebris in Pengshui, Qijiang and Youyang was 0.14, 0.11 and 0.06 m^3, respectively. Among different stands, variation coefficients of major growth traits were above 11.31%, and the maximum variation coefficient of the volume was 39.11%; within the stands, variation coefficients of plant height were basically the same （about 20%）. The variation coefficient of diameter at breast height in Qijiang reached the maximum of 42.42%, followed by that in Youyang. The variation coeffi- cients of volume and diameter at breast height were consistent; seed bearing coefficient （SBC） of C. funebris stand in Pengshui exhibited the maximum variation, which indicated that C. funebris stand in Pengshui was conducive to establishing seed stands and constructing seed orchard by using the selected stands. [Conclusion] It is necessary to conduct provenance selection.