40mm厚杉木锯材高温干燥工艺研究

对40 mm厚杉木锯材制定两个高温干燥工艺并进行试验研究,检测和分析干燥周期、干燥速率、锯材干燥质量等指标。干燥工艺I采用高温湿空气进行干燥;干燥工艺II在干燥前期高含水率阶段采用过热蒸汽条件,干燥后期低含水率阶段采用高温湿空气进行干燥。结果显示:两个干燥工艺在各阶段的干燥速率差异明显,干燥前期工艺II的干燥速率为1.30%/h,较工艺I低约37.2%;但干燥后期工艺II的干燥速率为1.89%/h,较工艺I高约70.27%。干燥工艺II可以有效避免锯材内裂的发生,干燥质量满足GB/T 6491—2012《锯材干燥质量》二级材的指标要求,干燥效率提高。     

杉木短周期小径材培育模式的林分直径结构及经营要素预测

以6~14年生杉木短周期小径材人工林为研究对象,对其直径结构进行统计分布检验,采用Weibull生长方程对林分直径累积分布进行模拟,并通过动态预测分析立地、林分密度、主伐年龄对培育目标的影响。结果表明:88.3%的样地其林分直径分布为左偏,林分直径分布峭度为负值的样地占所有样地的81.7%,林分平均直径对应的植株数量累积分布率为55.1%,直径结构为Weibull分布的林分占86.7%;两参数Weibull生长方程对各林分直径分布具有较好的适合度(R2>0.99),参数b、c具有明显生物学意义,分别与林分平均直径和直径变异系数呈紧密线性关系(R2=0.986 7、0.885 7)。采用回归法建立直径曲线1-1/e和拐点处参数回收方程,关键点处直径与林分平均直径呈紧密幂函数关系(R2≥0.95),由此构建的林分直径预测系统K-S检验通过率为85%。通过建立林分平均直径与年龄、立地指数和林分密度的多元非线性关系,在对不同关键要素组合模式下林分不同径级立木植株数量动态预测的基础上,比较分析不同要素对培育目标的影响,提出了杉木短周期小径材培育模式关键技术的理论参数。     

油松建筑材密度管理图的编制及其应用

针对建筑材目的油松人工林经营措施,探讨不同生长发育阶段油松人工林密度调控下蓄积变化,为森林可持续经营提供科学依据。对河北平泉阳坡中土、阴坡中土和阴坡厚土3种主要立地类型的全生命周期油松人工林编制密度管理图,得出培育小、中、大径级建筑材措施。结果表明:河北油松建筑材林的培育,阳坡中土培育小径材、阴坡中土和阴坡厚土培育中大径材,期间经过2~3次间伐以达到高效培育的目的。阳坡中土林分,初植密度3 000~3 300株/hm2,10年生间伐强度12%,15年生强度20%,25年生强度25%,主伐时树高级为9~11 m,培育小径材。阴坡中土林分,初植密度2 700~3 000株/hm2,9年生间伐强度25%,19年生强度30%,主伐时树高级为9~11 m,培育中径材;初植密度2 200~2 500株/hm2,9年生间伐强度20%,17年生强度25%,27年生强度30%,主伐时树高级为11~13 m,培育大径材。阴坡厚土林分,初植密度2 000~2 300株/hm2,7年生间伐强度20%,15年生强度30%,主伐时树高级为11~13 m,培育中径材;初植密度1 000~1 200株/hm2,7年生间伐强度20%,13年生强度20%,23年生强度25%,主伐时树高级为13~15 m,培育大径材。     

木材检验技术在木材运输中的应用探讨

文章介绍了木材检验技术在木材运输中的作用与地位,分析了木材运输中常见的木材检验技术误区,阐述了由此引起的责任风险或者造成的危害,并依据现行木材检验标准规定,针对性地提出了规范的木材检验技术操作要领。     

正交胶合木应用及发展前景

介绍了一种新型的工程木产品-正交胶合木的定义、特点、国外发展现状及生产工艺,并指出了正交胶合木在国内的发展前景。     

勐腊县珍贵用材林发展可行性研究及树种规划概述

通过对珍贵用材林发展的概述、市场需求和产业发展趋势的分析,论述了勐腊县珍贵用材林产业发展的迫切性和可行性。在此基础上,针对勐腊县的实际情况,就发展珍贵用材林所用树种及种植技术进行设计规划。     

Supply consequences of subsidizing thinning activities in Sweden

This paper is an attempt to measure the supply consequences of the thinning subsidy which was in operation during the cutting season 1979/80. The econometric analyses are based on a questionnaire to a sample of 2500 private non‐industrial forest owners, which was produced by the official Swedish investigation SOU 1981:81. The analyses show that it is questionable whether the subsidy did affect the total cut. The estimates of the supply increase range from an average of zero to 122 m³/owner. As a by‐product we obtain estimates of the price elasticity of the private non‐industrial forest owners supply curve. These estimates range from 0.63 to 1.69.     

Multivariate product adapted grading of Scots Pine sawn timber for an industrial customer,part 2: Robustness to disturbances

ABSTRACT

Holistic-subjective automatic grading (HSAG) of sawn timber by an industrial customer's product outcome is possible through the use of multivariate partial least squares discriminant analysis (PLS-DA), shown by part one of this two-part study. This second part of the study aimed at testing the robustness to disturbances of such an HSAG system when grading Scots Pine sawn timber partially covered in dust. The set of 308 clean planks from part one of this study, and a set of 310 dusty planks, that by being stored inside a sawmill accumulated a layer of dust, were used. Cameras scanned each plank in a sawmill's automatic sorting system that detected selected feature variables. The planks were then split and processed at a planing mill, and the product grade was correlated to the measured feature variables by partial least squares regression. Prediction models were tested using 5-fold cross-validation in four tests and compared to the reference result of part one of this study. The tests showed that the product adapted HSAG could grade dusty planks with similar or lower grading accuracy compared to grading clean planks. In tests grading dusty planks, the disturbing effect of the dust was difficult to capture through training.     

STABILIZATION OF DUNE SAND AT BORGO BONSIGNORE IN SICILY / STABILISASIE VAN DUINSAND BY BORGO BONSIGNORE IN SICILIE

The methods employed and the results achieved in stabilizing an area of about 225 ha dune sand is described. The techniques employed in allowing tree species to become established are mentioned and are illustrated by various plates     

木材内部腐朽特征识别专家系统

简单介绍了专家系统在林业上的应用 ,详细阐述了木材内部腐朽特征识别专家系统的设计过程。该系统可以为合理造材 ,提高木材的经济价值提供依据。