Properties of parallel strand lumber from Calcutta bamboo (<Emphasis Type="Italic">Dendrocalamus strictus)</Emphasis>

The objectives of this work were to analyze the physical and mechanical properties of parallel strand lumber (PSL) made from Calcutta bamboo. Based on the surface characteristics (Ahmad and Kamke 2003) and physical and mechanical properties (Ahmad and Kamke 2005) observed in previous work, a prototype PSL from Calcutta bamboo was manufactured and tested in the laboratory. Physical properties determined were dimensional stability and water absorption. The mechanical tests carried out were in compression and bending. Ultimate stress, stress at proportional limit, and modulus of elasticity were determined and compared to structural composite lumber (SCL) from several timber species produced by other researchers and manufacturers in the United States. The PSL produced was also exposed to accelerated aging process in order to assess its durability under extreme condition. PSL produced in the laboratory was stable in dimension. The mechanical characteristics compare favorably to SCL produced in other studies and SCL products available in the United States. The accelerated aging process was found to reduce the bending strength but no significant difference was detected in bending stiffness, and compression strength and stiffness. This is a promising indication of the suitability of Calcutta bamboo as raw material for structural composite products.     

Effects of clump spacing on nutrient distribution and root activity of Dendrocalamus strictus in the humid region of Kerala,peninsular India

The humid agroclimatic conditions of Kerala,India permit the cultivation of an array of bamboo species of which Dendrocalamus strictus Roxb.(Nees.) is an important one on account of its high growth rate and multiple uses. Stand density, a potential tool in controlling the productivity of woody ecosystems, its effect on growth and root distribution patterns may provide a better understanding of productivity optimization especially when bamboo-based intercropping options are considered.Growth attributes of 7-year-old bamboo(D. strictus) stands managed at variable spacing(4×4 m, 6×6 m, 8×8 m,10×10 m, 12×12 m) were studied. Functional root activity among bamboo clumps were also studied using a radio tracer soil injection method in which the radio isotope ~(32)P was applied to soil at varying depths and lateral distances from the clump. Results indicate that spacing exerts a profound influence on growth of bamboo. Widely spaced bamboo exhibited higher clump diameters and crown widths while clump heights were better under closer spacing. Clump height was 30% lower and DBH 52%higher at the widest spacing(12×12 m) compared to the closest spacing(4×4 m). With increasing soil depth and lateral distance, root activity decreased significantly. Root activity near the clump base was highest(809 counts per minute, cpm; 50 cm depth and 50 cm lateral distance) at 4×4 m. Tracer study further showed wider distribution of root activity with increase in clump spacing. It may be concluded that the intensive foraging zone of bamboo is within a 50-cm radius around the clump irrespective of spacing. N, P and K content in the upper 20 cm was 2197,21, and 203 kg/ha respectively for the closely spaced bamboo(4×4 m) which were significantly higher than corresponding nutrient content at wider spacings. About 50% of N, P and K were present within the 0–20 cm soil layer, which decreased drastically beyond the 20 cm depth.The results suggest that stand management practices through planting density regulation can modify the resource acquisition patterns of D. strictus which in turn can change growth and productivity considerably. Such information on root activities, spatial and temporal strategies of resource sharing will be helpful in deciding the effective nutrition zone for D. strictus. Further, the study throws light on the spatial distribution of non-competitive zones for productivity optimization yields, especially when intercropping practices are considered.     

毛竹笋材两用林定向培育技术

建设高效林业,提高竹林经济效益,增加林农收入,就必须科学地经营管理竹林。株洲县通过对3 600 hm2的毛竹林实施笋材两用林定向培育,实施后,给全县林业和竹农带来了可观的经济效益。     

风电叶片用毛竹和麻竹竹青片层积材性能评价

利用动态热机械分析仪（DMA）检测3～4年竹龄的毛竹与麻竹竹青试件的常温存储模量值,再按竹龄分别将毛竹与麻竹竹青制成竹青层积材,利用INSTRON5582万能力学试验机对毛竹与麻竹竹青层积材分别进行检测。实验证明：随着毛竹与麻竹竹龄的增加,毛竹与麻竹竹青试件的常温存储模量值也相应的增加。也就是说,在常温条件下毛竹与麻竹竹青的刚性随竹龄的增加而增加。3年生以上的成熟麻竹竹青部分的常温存储模量位于10 GPa数量级以上,一般能满足作为风力发电叶片复合材料中增强相材料的使用。而4年生以下毛竹的存储模量值有可能低于10 GPa,达不到风力发电机叶片复合材料对毛竹增强相的最低要求,一般不作为风力发电机叶片复合材料毛竹增强相使用。     

Effects of hydrogen peroxide treatment on the surface properties and adhesion of ma bamboo (Dendrocalamus latiflorus)

The poor adhesion of bamboo coatings is a serious issue in the bamboo industry. To develop a pretreatment method that improves the adhesion of films and increases the economic value of bamboo products, a study of hydrogen peroxide treatment with solutions of various pH (pH 4–9) on bamboo surfaces was conducted. Five-year-old ma bamboo (Dendrocalamus latiflorus Munro), and nitrocellulose lacquer were used in the study. Surface properties of the bamboo such as contact angle and color were evaluated, and 180° peel strength and shear strength tests for measuring adhesion of films were conducted. The results showed that the wettability of water droplets and the carbonyl group concentration on the bamboo surface were increased significantly by alkaline (pH 8 and 9) hydrogen peroxide treatments. There was only minor color variation and the outer wax layer of bamboo was etched to form additional recesses after hydrogen peroxide treatment. It was also found that all hydrogen peroxide treatments improved the adhesion of bamboo coating; bamboo treated with hydrogen peroxide at pH 7 showed the greatest improvement. The enhanced adhesion was attributed to the mechanical interlocking of the film on the treated bamboo rather than to surface activation.     

Characterization and acetylation behavior of bamboo pulp

In the present study, the chemical–physical properties of bamboo pulp prepared with a sequential totally chlorine-free procedure were analyzed and compared with that of commercial wood pulp by SEM, FTIR, TGA, and X-ray. α-Cellulose content was determined to be 95%, a little less than that of commercial wood pulp. But the crystallinity of bamboo pulp is lower than wood pulp. Acetylation activity of bamboo pulp was determined to be higher than that of wood pulp, which was carried out in heterogeneous media with sulfuric acid as catalyst. The cellulose acetate prepared with bamboo pulp can be quickly dissolved in acetone without distinct difference with that of cellulose acetate prepared with wood pulp. The results indicate the potential utility of bamboo as an alternative to wood pulp for cellulose derivate fiber material.     

竹林经营中绿肥种植与绿肥品种筛选试验

通过竹林绿肥种植试验表明：绿肥在散生竹林较高的郁闭度（郁闭度0.8-0.9）条件下生长较差,但豆科耐阴性好的印度豇豆、野豌豆在散生竹林中生长盖度达80%以上,生物量达2.65 kg/m^2和2.35kg/m^2;在郁闭度较低（郁闭度0.6-0.7）的丛生竹林中各绿肥生长发育正常,优以豆科绿肥表现最好,全部能够完成生活史,且结实率也较高;从竹林中绿肥生长观察发现,加强绿肥前期水、肥等生长管理非常重要,能够有效促进绿肥在高郁闭度的竹林中正常生长发育.     

眉山东坡区慈竹、麻竹、杂交竹等竹种栽植试验初报

通过多点较大规模栽植慈竹、麻竹、杂交竹林试验,表明3种竹种适宜于2月中旬至3月中旬栽植,黄壤好于紫色土,慈竹有较强的抗病虫害能力.在较好经营条件下,竹龄为6 a的成林竹,杂交竹每公顷产竹量可达58.5 t,麻竹可达81.0 t,慈竹可达31.5 t.考虑较好的适应性和抗病虫能力,建议加强乡土竹种一慈竹的良种选育工作.     

楠竹小母竹苗繁育及造林技术

在对"楠竹快繁和造林技术推广"项目实施4年的基础上,总结了:①楠竹小母竹繁育技术,包括母竹与园地选择、整地、栽植和苗期管理等;②小母竹造林技术,包括造林地与造林时间选择、苗木选择与处理、整地、栽植等;③小母竹造林后抚育管理技术。实践证明,该技术推广应用效果良好。     

A morphological study on the behavior of bamboo pulp fibers in the beating process

Summary Bamboo pulp fibers respond to beating more rapidly than do wood fibers. This is probably due to the difference in secondary wall structure between the fibers. In the present paper, the behavior on beating of pulp fibers from Bambusa polymorpha Munro was investigated from a morphological point of view. The secondary wall of bamboo fibers consists of alternately arranged broad and narrow layers. During the beating process, a number of transverse and concentric cracks are generated in the broad layers, which causes an internal fibrillation. The outer broad layers with their numerous cracks separate from the inner layers and swell highly toward the outside. The outer secondary wall layer of bamboo fibers has a microfibril angle of about 20° with respect to the fiber axis which is much smaller than that of the S1 layer of wood fibers. As a result this layer appears to offer little resistance to prevent the external swelling of the broad layers.Part of this work was financially supported by a Grand-in Aid for Scientific Research, Ministry of Education, Japan, 57470095Currently with the Japan Pulp and Paper Research Institute, Inc., Tsukaba, Japan     

吊丝竹林土壤肥力调查与分析

土壤肥力是土壤各方面性质的综合反映,是衡量林地生产力高低的重要技术指标。为了指导竹林的合理平衡施肥及管理,提高竹林经营水平,并为促进广西竹产业可持续发展提供科学依据和技术支撑,通过对广西不同栽培区的吊丝竹林土壤中N、P、K等主要养分含量和土壤主要物理性状等指标的测定分析,掌握广西石山区吊丝竹林土壤养分状况及其与吊丝竹生长状况之间的关系。     

锈蚀诱导处理下竹钉和钢钉的抗剪性能

以钢钉、普通竹钉和压缩竹钉连接SPF(云杉-松木-冷杉类)规格材试件,用质量分数为5%的盐水对试件作锈蚀诱导处理,进行短梁剪切和抗剪试验,探讨锈蚀诱导处理对钉抗剪性能的影响。结果表明,竹钉和木材连接部位呈犬牙交错状,能有效约束木构件,维持其抗剪性能;锈蚀诱导处理对钉连接的水平剪切承载力和极限抗弯承载力的影响不显著,不同钉连接的水平剪切承载力和极限抗弯承载力无显著差异,水平剪切承载力范围为6.08~6.90 k N,极限抗弯承载力范围为6.19~7.01 k N;锈蚀诱导处理使钢钉剪切破坏提前,而对竹钉的极限荷载影响并不显著;锈蚀诱导处理使普通竹钉的极限荷载对应位移显著增大,而对钢钉和压缩竹钉影响不显著。     

世界竹乐奇观

介绍了竹管风琴、独弦琴、竹箫和竹钢琴等传统竹乐器的制作,历史、发音特点和演奏风格等。并阐述了竹乐器的高雅、柔美和独特的音色,以及它给人民生活带来无限的快乐。     

云南(竹思)(竹劳)竹属一新种及其它

本文发表了■竹属1新种。它产于中国云南省南部。还报道了竹亚科的一些新组合和方竹属的新分布。     

株洲市花卉产业发展的方向及对策

1　世界花卉产业的现状及发展趋势自 2 0世纪 90年代以来 ,全球花卉生产和销售 ,始终保持旺盛发展势头。 1991年世界花卉消费额已达到10 0 0亿美元 ,预计到本世纪末将达到 2 0 0 0亿美元。我国花卉产业发展迅速 ,近 4年来生产总值从 30亿人民币增加到了 4 8亿人民币 ,出口创汇从 1993年 50 0 0万美元增加到了 1997年 1.3亿美元。据统计 ,全球排名前 10位的花卉出口国是荷兰、哥伦比亚、意大利、丹麦、美国、比利时、卢森堡、以色列、哥斯达黎加、德国和加拿大。1.1　世界花卉产业的发展趋势在一定时期内仍将以多种形式并存第一种依靠现代化…     

红壳竹笋用林竹鞭的生长结构及其分布

通过对红壳竹不同年龄竹鞭长度、重量、鞭段长度、鞭径、侧芽 (笋芽、壮芽、弱芽、空芽节 )数量及其在不同土层中的分布状况、竹鞭的分岔和延伸方向等进行分析。认为壮龄鞭所占比例最大 ,其次为幼龄鞭 ;壮龄鞭在 10～ 2 0cm土层分布最多 ,幼龄鞭在 0～ 10cm土层分布最多。竹鞭大多数为平行生长。为红壳竹笋用林的土壤管理提供科学依据     

中国传统插花的赏析与发展

论述中国传统插花的主要特征是精与雅,并分析其产生的根源,通过对传统插花作品的赏析,对今后插花发展提出了讨论的意见。     

辐射育种及其在林木育种中的应用前景

辐射育种既是常规育种的重要补充,又是常规育种难以取代的手段。本文就辐射源的种类、辐射材料和辐射剂量的选择以及辐射的方法手段等进行了综述,并分析了辐射育种在林木育种中的应用前景。