修枝对人工林生态系统影响研究进展

修枝是培育优质人工林无节材的主要营林措施。为了满足人们对高品质木材的需求,众多学者开展了修枝对人工林生态系统影响的系列研究。文中在总结国内外人工林修枝研究成果的基础上,分别从修枝对人工林生长、林下植被发育、土壤肥力、木材材性的影响等方面,综述了修枝对人工林生态系统影响的研究进展;指出目前人工林修枝研究中存在的问题,提出今后应加强人工林修枝的理论基础研究、制订不同树种人工林的修枝技术规范和标准、加强修枝对人工林生态系统长期影响的定位研究、研发适应山地作业的修枝机器人等建议,为人工林修枝及无节材培育提供科学依据。     

桉树无节材修枝技术

指出了桉树是全球速生丰产的主要树种之一,对幼林桉树进行合理的修枝有助于林木的生长和木材无节子的形成,并且深加工无节子的木材有着特殊的意义。综述了无节材修枝的技术要点、发展前景和存在困境,探讨了今后培育、推广无节材工作中的主要研究方向。     

杉木人工林无节材培育技术研究

采用目标树培育技术,通过人工修枝的方法来培育杉木人工林无节木材,以提高南方杉木木材的市场价值。为了形成一套较为完整的杉木无节材培育技术,按照不同的保留密度和修枝强度等因素进行试验设计。根据1999—2003年连续4 a的观测数据,分析结果表明,杉木8年生前林分的保留密度对杉木生长无显著影响,在1 800株.hm-2范围内可以采用较大的保留密度;不同的修枝强度对杉木生长造成显著影响,随着修枝强度的增大,杉木的树高、胸径和冠幅生长都显著下降,考虑到修枝效果和杉木生长两方面因素,以10 cm的修枝强度(修枝的基础粗度)最好。     

树木怎样修枝才合理

树木怎样修枝才合理李承水，董金伟树木修枝，能消除死节（枯枝残桩被树干包被形成的节子）．增加树干的圆满度，提高木材质量；同时减少了树冠中阴生叶和消耗叶的数量，可调整树势，促进树木生长和开花结实。若树木修枝不合理，一次修枝强度过大，伤口多，叶量减少比例大...     

杉木人工林无节材培育技术分析

从杉木生长特性入手,参考相关研究资料,在阐述了保留密度与修剪强度直接影响杉木人工林无节材培育的基础上,重点从人工修枝的角度出发,对杉木人工林无节材培育中的技术要点进行了简要分析,提出了合理选择林分、控制修剪强度、规范人工修枝等方法,以助于优化杉木人工林无节材培育成效。     

树木修枝的适宜期

为了使树木集中使用养分,培育无节、少节的通直干材,新栽的幼树需要及时修枝。根据我们的经验,树木修枝一定要掌握适宜的季节树木在生长季节里,其生理活动最为活跃,这个时候修枝,由于树液不断流动,修枝后伤口不能很快愈合,往往在修枝处造成细菌感染和虫害的寄生,引     

项东云:扩大无节材培育应用

<正>2012年初春,广西林科院研究人员在高峰林场六里分场对一年生桉树人工林实施不同强度人工修枝试验,标志着桉树无节材培育正式进入广西用材林培育技术体系。2014年,七坡林场新桥分场建成900余亩的桉树无节材示范林,为全区乃至全国无节材培育技术应用的首创。目前,该林场已对3万亩     

关于桉树生长应力的研究现状

前言本研究是澳大利亚 ACIAR、CSIRO 林业及林产品研究所及昆士兰林业研究所及中国合作的课题之一。本项目是特别针对桉树利用和原木的生长应力的测定技术,最终目的是通过遗传育种和营林措施减小生长应力对桉树人工林的影响,达到桉树人工林的高效利用。限制桉树人工林幼龄材的高价值使用的一个关键因子是桉树锯材的高生长应力。生长应力是在木材成熟期新的木材结构形成时自生的应力。在树木生长期持续     

中龄林修枝对杉木林生长和材种结构的影响

为培育杉木大径级无节柱材,探讨修枝对杉木人工林生长和材种结构的影响,选择17年生中龄林,设置修枝与不修枝处理试验,20 a后调查中龄林修枝处理对杉木人工林生长和材种结构影响。结果表明:修枝后的前两年,修枝处理显著提高了杉木人工林的胸径年生长量(P<0.05),对树高、林分蓄积量年生长量没有显著影响,随后修枝处理对杉木人工林生长的影响逐渐减弱。中龄林修枝处理20 a对杉木人工林的胸径、树高、林分蓄积量和总生物量均没有显著影响,但显著提高了杉木人工林干生物量分配比例(P<0.05),显著降低了叶生物量分配比例(P<0.05)。中龄林修枝处理20 a显著提高了杉木人工林大径材出材率(P<0.05),有利于杉木人工林大径无节柱材培育。     

桉树无节材修枝技术的实施及效益分析

指出了桉树是广西地区主要的经济性树种,桉树种植为满足市场对木材的需求发挥了重要作用,同时也是国家重要的战略储备。深入阐述了桉树无节枝修枝技术,分析了无节枝修枝技术对桉树种植产生的经济效益,以期不断提高桉树木材的品质,增加广西地区桉树种植的经济收入。     

云杉属木材纵向和径向声振动特性参数关系的研究

采集7种我国具有代表性的云杉属木材及1种作对比用的美国产西加云杉试件,通过纵、横向木材试件在高次振动模式下的试验,测量木材各项声振动参数.研究发现:纵向材与径向材振动参数比之间存在着一定的相关性,据此可以选择各向异性适中,韧性好,纵向、径向振动受剪切影响小的木材制作乐器的音板.     

轻型木结构锯材用原木标准的制订

通过对我国原木生产实际状况的调研及参考国内外相关标准和技术资料,阐述了木材缺陷对规格材力学性能的影响,并据此对轻型木结构锯材用原木缺陷的技术指标进行了规定,同时介绍了该标准的制定方法。     

我国木材标准体系

初步提出我国木材标准体系的框架结构:底层为原条原木和锯材、木材处理技术、木质半成品和木结构等4类标准,顶层为木材专业的基础标准。通过分析我国木材标准体系的现状,指出现有体系的不足,为我国木材标准体系的建设和完善提供参考。     

Relationships between longitudinal and radial Picea genera sound vibration parameters

Longitudinal sawn wood are usually selected as samples in the study of sound properties of a musical instrument board. But in real production, radial sawn timber are cut and are also widely used as vibration component. Therefore, it is very important to evaluate the vibration properties of the board in the round, especially for the sound radiation characteristic of radial sawn timber and its relationship to longitudinal sawn timber. However, for the national and international experts, researches on radial sawn timber and its role and function in sound emission have not yet been developed. This paper describes a study of seven important spruces that grow up in the Sichuan and Heilongjiang provinces of China, and one Picea sitchensis specimen from North America. Under the high bending vibration mode, resonance frequency and other parameters of longitudinal and radial wood were tested. Analysis result disclosed the relationship between longitudinal and radial wood vibration property. An important conclusion of wood for musical instruments with proper anisotropy, fine toughness, and weak shear of longitudinal and radial vibration was inducted. __________ Translated from Scientia Silvae Sinicae, 2006, 42(3): 21–24 [译自: 林业科学, 2006, 42(3): 21–24]     

Estimation of rubberwood production in Cambodia

We estimated the production of rubberwood from 1996 to 2011 in Cambodia. We employed data from interview surveys with three rubberwood processing companies and statistics from estate rubber plantations and wood retailing companies. The result was that the end use of rubberwood in Cambodia was the sawntimber products, being exported to Vietnam and China. The yield rate from rubberwood stumpage into sawn timber was between 11.6 and 14.9%, closely matching the rates of Malaysia and Thailand. The average production of rubberwood roundwood from 1996 to 2011 was 254,697 m³/year, of which sawn timber as well as residuals in secondary processing was 84,559 and 170,138 m³/year, respectively. Although the timber production of Cambodia has declined sharply due to the strict restriction of natural forest logging, rubberwood could explain more than 60% of the domestic industrial roundwood production from 2000. We suggest the necessity of monitoring the expansion of rubber plantations in new rubber producing countries and linking the rubberwood production with the regional wood resource management.     

Potential of Phytophthora pinifolia to spread via sawn green lumber: a preliminary investigation

Phytophthora pinifolia causes the needle and shoot disease of Pinus radiata in Chile known as Daño Foliar del Pino. Although P. pinifolia is primarily a needle pathogen, there are concerns that it might be spread to new environments via the export of contaminated timber. In order to determine whether P. pinifolia can enter or persist in green sawn lumber, its presence in lumber produced from trees exposed to the pathogen for at least four years was examined. Green lumber produced from the infected trees, and green wood samples artificially exposed to P. pinifolia inoculum, were analysed by making extensive isolations on Phytophthora selective media. In addition, PCR was conducted using species-specific primers developed for P. pinifolia. Results of the study showed that the green sawn lumber taken from trees infected by P. pinifolia, or green lumber exposed in infected pine plantations, displayed no evidence of the pathogen surviving in this material.     

Simulated yield and quality distribution of sawn timber from final felling in a Norway spruce [Picea abies (L.) Karst.] stand with varying thinning regimes: A case study

Abstract

An integrated simulation tool, formed by integrating the InnoSIM sawing simulation system with the RetroSTEM simulator, was used to convert available wood raw materials from final felling into sawn timber, allowing for calculation of the three-dimensional wood properties of individual stems (stem geometry, heartwood formation, knottiness) as well as the volume, quality and value of sawn timber in a Norway spruce stand with different thinning regimes (unthinned, normal and intensively thinned). Based on the input data of sawing patterns, the simulations indicate that there are relatively small differences (<8%) in the volume yield (m³ha^?1) of sawn goods resulting from sawlogs available from final felling with different thinning practices. However, intensive thinning yielded the largest stem diameters and the greatest volumes (m³ha^?1) of large-sized centre goods (thickness: 50, 63, 75 mm) of rather poor quality. Normal thinning yielded the largest volume of A-grade side boards and centre goods (m³ha^?1), as well as the best total value ([euro]ha^?1) of sawn timber. Differences observed in sawn timber quality distribution can contribute to even more significant variation in value yields, if pricing mechanisms of timber products change to favour higher grade timber products.     

基于数字图像处理的樟子松锯材分级研究

为了解决传统锯材检测方法效率低、劳动强度高和人为因素影响大的问题,笔者运用数字图像处理的方法对樟子松锯材等级进行检测,实现樟子松锯材等级检测的标准化和程序化。根据樟子松锯材缺陷与天然木纹颜色存在显著差距的特点,利用Otsu's方法的最佳全局阈值处理锯材图像得到最佳分割阈值,获得锯材的二值图像,得到缺陷位置像素坐标,将缺陷坐标与锯材实际尺寸对应,计算出相应锯材的净划材尺寸和出材率,完成对锯材等级的划分。利用该方法对75片试件进行表面质量检测和等级划分的准确率为94.67%,分级程序的运行时间约为1.793 s。该方法在保证检测准确率的情况下不仅可以减少检测时间、降低人工劳动强度、提高检测准确率,而且解决了人工检测主观性强的问题。     

双钩异翅长蠹生物学特性及用防腐剂TWP防治试验

双钩异翅长蠹是橡胶树锯材及其制品的严重害虫。在海南岛1年完成二至三代,约有16种阔叶材被害。用新的水溶性木材防腐剂TWP进行防治试验的结果:①TWP在木材中保持量1.0kg/m~3,初龄幼虫死亡率100％;②新鲜橡胶树锯材用2％TWP真空加压或振荡加压法处理,药剂保持量不少于3.7kg/m~3,可获得长久的保护效力;③TWP不含氯化酚化合物,对人畜和环境十分安全。     

日本林产品供需现状与林业政策走向

日本是世界上林业发达国家之一, 面对林业生产衰退和地震灾害, 通过林业政策调整实现了木材供需改善和林业产业体系改造, 因此研究日本林业生产现状和政策走向对我国林业现代化建设具有重要的借鉴意义。文中介绍了日本林业产业总体发展态势, 重点分析了原木生产情况以及锯材、胶合板、人造板等木材加工企业情况, 概述了日本木材供给需求变化和木材进出口变化以及应对这些变化的最新林业政策和发展规划, 特别是林业需求促进政策的新变化和新内容, 并借鉴日本经验提出了促进中国林业现代化发展的几点政策建议。