Sawing patterns for large-diameter sugi (Cryptomeria japonica D. Don) sawlogs: Current status and future outlook

Abstract

A survey was conducted at nine sawmills in Japan to evaluate and compare the sawing of sugi (Cryptomeria japonica D. Don) logs of 30 cm and more in diameter. The purpose was fourfold: (1) to document sawing patterns appropriate to the large-diameter logs; (2) to examine the composition of wood components (structural, nonstructural, and fixtures) produced from those patterns; (3) to investigate log and product prices; and (4) to ascertain distances to the log supplier and product markets. Impetus for the study arose from a forecasted shift in the diameter distribution of plantation trees in Japan; from small and medium-sized logs to large-diameter logs. With an overabundance of large-diameter domestic logs forecasted within the next decade, the need to understand how to best utilize and effectively process the large-diameter resource is of utmost importance.     

SEM-EDXA法测定分析柠檬桉木材中的晶体

采用扫描电子显微镜-X射线能量散射分析（SEM—EDXA）法对柠檬桉Eucalyptus citriodora木材中晶体的轴向分布、径向分布、形态和含量以及硅石的纳米结构进行了分析。结果表明：①柠檬桉木材中晶体主要分布在木射线细胞,形态多为菱形晶体;②柠檬桉木材钙元素含量高的可达所有元素含量的22％以上;③柠檬桉木材中晶体的纳米尺寸在350～400nm,晶体尺寸大小从树基向树梢呈递减趋势。图4表1参9     

Effect of high temperature heat treatment on pH value of Masson Pine wood

Heat-treated wood has good dimensional stability,corrosion resistance and visual quality,but it is prone to mold,which limits its application.Based on the pH value of heat-treated wood,this study examines the factors affecting the pathogenesis causing heat-treated wood mold.Normally,the pH value of the heat-treated wood is between 4.38 and 5.10,which is suitable for the growth of mold.However,the pH of the heat-treated copper-containing material is between 6.63 and 7.12,which deviates the treated wood from the comfortable growth conditions for the mold,thereby reducing the occurrence of mold.     

速生杨木改性研究进展

论述了近年来杨木改性优化的研究进展。对速生杨木材进行优化处理可使其在性能上接近或超过天然林木材,这对充分利用速生杨木资源、缓解木材供应紧张局面、促进林业经济良性发展等具有重要意义。目前对杨木改性研究主要集中在依靠物质填充处理和非填充处理两方面,主要包括浸注有机物、无机物的改性处理,压密化处理,高温热处理以及多种方法联合改性处理等。     

改性豆粕胶黏剂压制稻草板的研究

利用改性豆粕胶黏剂压制稻草板,可以有效缓解木材资源紧张的情况;采用正交实验方法考察了施胶量、热压时间、热压温度对不同配方改性的豆粕胶黏剂压制的稻草板的主要物理力学性能的影响,检测了稻草板的静曲强度和内结合强度;应用旋转粘度计,测定醋丙乳液改性豆粕胶黏剂的黏度。结果表明：改性豆粕胶黏剂的黏度均处于3000～8000 mPa·s范围内。在施胶量为30%时,利用稻草粒径在1.0～20 mm范围内的稻草刨花所压制出的稻草刨花板的静曲强度为14.23 MPa,内结合强度为0.43 MPa,其强度符合GB/T 21723—2008的要求。可见,施胶后的草片接触角明显减小,施加改性豆粕胶的稻草疏水性减弱;施胶后稻草的浸润性显著增强,稻草刨花彼此之间能形成良好的胶接效果。     

速生杉木为基材的水曲柳薄木贴面初步研究

以速生杉木为基材，水曲柳薄木为贴面材料，用脲醛树脂粘剂（UF）和聚醋酸乙烯醋乳液胶（PVAc）按一定比例混合后作为胶粘剂，热压贴面胶合，对温度和时间与巾面效果的关系进行了研究。结果表明：①用UF与PVAC比例混合的胶粘剂，在生杉木上进行水曲柳薄木贴面是可行的；②热压温度和时间对贴面效果的影响都是极显著的，并得到了一种较理想的薄木贴面热压工艺。     

Fungicidal activity of beta-thujaplicin analogues

The fungicidal activity of analogues of beta-thujaplicin, a natural product responsible for the durability of heartwood of several cupressaceous trees, was investigated in vitro on the growth of different white and brown rot fungi involved in wood biodegradation, Coriolus versicolor, Phanerochaete chrysosporium, Poria placenta and Gloephyllum trabeum. The study shows that 2-hydroxycyclohepta-2,4,6-trienone (tropolone), easily prepared according to a literature procedure, possesses interesting fungicidal activity when compared to beta-thujaplicin, azaconazole, tebuconazole and copper oxine, which suggests this compound should be examined further as a potential biocide for wood preservation.     

三种速生杨木材物理力学性质的比较研究

测试、分析比较了不同树龄3种速生杨木材的物理力学性质,结果表明:①树种对物理力学性能有较大的影响,三倍体圆叶毛白杨的物理力学性能最好,三倍体裂叶毛白杨次之,中林-46最差;方差分析表明,3种杨树的主要物理力学性质均达到显著和极显著差异。②树龄对物理力学性质的影响不大,随着树龄的增长,不同杨树木材的密度已趋于稳定,但力学性能有上升的趋势;方差分析表明,抗截切强度和抗弯强度受树龄影响较大,差异达到显著水平,其他性质无显著差异。     

预热处理对改善尾巨桉木材干缩性和材色的研究

为探讨预热处理对尾巨桉木材干缩性和材色的影响,分别在100℃饱和蒸汽和120℃过热蒸汽条件下对尾巨桉木材进行预热处理。对预热处理前后的尾巨桉木材进行干缩率及色度指数的测定,应用扫描电镜对预热处理后尾巨桉木材的微观构造进行分析。结果表明:1）100℃饱和蒸汽可以使尾巨桉的干缩性降低,材色无明显变化;120℃过热蒸汽处理使尾巨桉在干燥过程中出现较多缺陷,如皱缩、内裂等,但可以有效促使桉木颜色向珍贵树种颜色转变。2）经120℃过热蒸汽处理,尾巨桉木材导管中纹孔的内含物被部分排出,细胞被压扁,宏观尺寸发生变形,是导致尾巨桉出现干燥缺陷的主要原因。