云南省中密度纤维板工业现状及其对策

近年来， 云南中密度纤维板工业发展迅速， 但同时暴露出一系列问题。在对云南中密度纤维板工业现状分析的基础上， 从人才、管理、产业开发应用领域以及利用研究等方面提出了云南中密度纤维板的发展对策。     

北京市场中密度纤维板质量堪忧

近年来，随着国家对森林保护力度的加强和木材加工业技术的发展，实木在各行业的应用日渐减少，人造板特别是中密度纤维板的用量与日俱增。据统计，在过去的１５年中，销售量每年以１３％的速度增长。中密度纤维板以较好的物理力学性能，板材厚度变化范围大等特点，被广泛用于家具、建筑、交通、家电、体育、乐器等行业。为规范市场、引导消费，北京市技术监督局对在北京销售的部分中密度纤维板产品质量进行了抽查。共抽查了１１家企业生产的１１种中密度纤维板。检验依据ＧＢ１１７８－８９《中密度纤维板》对甲醛释放量、静曲强度、吸水厚…     

我国中密度纤维板生产能力发展概况

对我国中密度纤维板生产能力的发展情况进行了简要回顾，提出其在发展过程中依靠科技进步，促进了我国中密度纤维板生产能力的发展。指出我国中密度纤维板生产起步于20世纪80年代初，20世纪90年代是我国中密度纤维板生产能力快速增长时期，进入21世纪我国已成为全球中密度纤维板生产量最大的国家。     

我国的中（高）密度纤维板产业正在重组

目前，我国的中(高)密度纤维板产业取得了较大的发展，许多大型的生产线或投产或在建设中。2004年6月，山东省东营Zhenghe木业公司的年产16万m^3的中密度纤维板生产线投产；7月，广东省亚洲创建(河源)集团的年产20万m^3中密度纤维板生产线开始生产；广西梧州三成木业公司的年产24万m^3中密度纤维板生产线正在建设中，同时，广西南宁高峰Rongzhou公司年产13．5万m^3的中密度纤维板生产工厂也在建设中。     

影响中密度纤维板热压质量的主要因素

中密度纤维板是我国目前发展最快的人造板品种，如何提高中密度纤维板的质量是促使其进一步发展的关键。作者着重剖析了影响中密度纤维板热压质量的几个主要因素。对中密度纤维板的生产厂家有一定的指导作用。     

中密度纤维板发展概况及环保性能分析

论述了中密度纤维板的发展概况、环保方面的现状及其必要性和紧迫性，介绍了降低中密度纤维板游离甲醛释放量的方法，并讨论了中密度纤维板的现存问题和发展趋势。     

用应力波非破损检测技术检测中密度纤维板弹性模量的研究

本研究探讨了采用现代电子技术精确测定波速的方法；研究被测物的弹性模量与其密度和应力波波速之间的关系；研究应力波非破损测定中密度纤维板的弹性模量与国家现行标准规定的破损法测定的弹性模量之间的相关性。研究结果表明：应力波非破损测试法测定的中密度纤维板弯曲弹性模量具有足够精确的保证，从面为实现中密度纤维板生产线产品质量以力学性能为标准的在线检测系统的正常运行和生产线的自动控制成为可能。     

采用喷幕热压技术提高中纤板和刨花板的热压效率

蒸汽喷蒸热压是近年来研究开发的一种热压新技术,它可以提高中密度纤维板和刨花板的生产效率,保证产品质量,减少能耗,降低成本,在中密度纤维板和刨花板生产中具有广阔的应用前景.     

复配防霉剂对中密度纤维板抗霉效力的研究

南方地区中密度纤维板容易霉变,影响了产品质量,限制了纤维板的应用范围,因此开发纤维板防霉性能尤为重要。本研究采用复配防霉剂处理中密度纤维板,并对防霉处理后的纤维板试材进行防治效力测试,结果表明:采用质量分数0.01%~0.1%甲基硫菌灵,0.1%~1.0%丙环唑,0.1%~1.0%戊唑醇,5%~25%二癸基二甲基氯化铵,添加有机溶剂10%~25%乙醇胺和10%~25%乙醇,余量为水复配防霉剂拮抗4种变色菌,MDF试材抗霉效力评价值达到0级或1级,效果明显,可用于中密度纤维板防霉处理,为开发防霉纤维板提供参考。     

中密度纤维板成套设备的开发

中密度纤维板成套设备的开发商定柱１国内外中密度纤维板生产概况自从１９６６年美国在世界上第一个建成中密度纤维板厂以来，中密度纤维板发展相当迅猛，现有１０７家工厂，年生产能力达８７０万ｍ３，消费量每年以１５％的速度递增。同１９８０年比较起来，工厂数增长了...     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions.     

CAD与建筑设计的关系

本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。     

Natural Regeneration in Clear-cuts: Effects of Scarification,Slash Removal and Clear-cut Age

The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided.     

Risk Perception Among Non-industrial Private Forest Owners

Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken.     

Interactions in decomposition and N mineralization between tropical legume residue components

In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts (stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea (Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea, largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols. Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its components are mixed.     

Pasture production and tree growth in a young pine plantation fertilized with inorganic fertilizers and milk sewage in northwestern Spain

The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization, (2) milk sewage sludge at 40 kg N ha⁻¹ target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha⁻¹. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹); (2) Lolium perenne L. var. Tove (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea (Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m², with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral systems. This revised version was published online in June 2006 with corrections to the Cover Date.