速生杨树全树材化学热磨机械浆(CTMP)的研究——Ⅱ废液特征及治理

在实验室条件下,系统研究了速生杨树全树木片碱性亚钠和烧碱蒽醌预浸渍废液及热磨挤浆废水的pH值、色度、波美度、总固形物含量、COD_(cr)、COD_(Mn)、BOD_5、固形物中有机物及无机物比例、分子量分配、无机微量元素及其含量,测定了废液部分循环回用上述指标的变化情况,探索了治理方法和途径。研究表明,(1)杨树CTMP废液及废水污染发生量约为化学浆的1/6—1/10;(2)在废液和废水总固物中,80—90％为有机物。经超滤分级,70—90％为分子量<10000的物质,10—30％为分子量>10000有机物质;(3)无机灰分中,有较高的Na、K、Fe、Zn、Co、Mg、Al、Sr等元素;(4)杨树全树木片CTMP废液、废水可部分循环回用,另一部分建议采用厌氧消化—好氧曝气—凝聚处理为宜。     

桉树CTMP法制浆性能的研究

应用正交试验设计方法分析预浸时间、预浸温度、NaOH用量、Na2SO3用量对尾巨桉CTMP制浆性能的影响并选取最优方案,在此基础上,对4年生和6年生尾巨桉分别进行制浆抄纸,并对纸张物理性能进行测定。研究表明,适当的预浸时间、预浸温度、NaOH用量、Na2SO3用量可制得质量较好的CTMP。     

家具用材马尾松碱液皂化脱脂技术

报道了利用碱液皂化法进行家具用马尾松板材的脱脂工艺试验.采用正交试验设计方法,探讨了板材厚度、NaOH浓度、压力、处理时间等工艺因素对马尾松板材含脂率、脱脂率、质量损失率和白度的影响.试验表明:利用碱液皂化法对马尾松板材进行脱脂,脱脂率高,板材材色均匀美观,符合制作中高档实木家具要求.最佳的脱脂工艺参数为:板材类型为生材厚度20 mm,NaOH浓度为0.8％,压力为-0.08 MPa(30 min)至0.6 MPa,处理时间为6h,脱脂率达67％.     

抽提预处理对木材的热重分析研究

为探究不同抽提方式对木材热解特性的影响,以云南松(边材和心材)为原材料,通过热水、丙酮、苯醇以及NaOH溶液抽提预处理,利用热重分析方法研究了不同预处理方式对木材热解失重特性的影响。结果表明:云南松心材与边材热解特性是不一致的;经NaOH溶液处理云南松及西南桦样品热解失重率较对照材较低了13%左右,可见经过低浓度NaOH溶液处理后木材增加了木材的残碳率,低浓度NaOH溶液处理使得木材生成一定量的酚类和酮类组分;经有机溶剂及热水处理虽加快了热解反应的进行,但对热解失重率影响不大。     

制浆废水水生植物净化处理的研究

在实验室条件下,系统研究了水葫芦(Eichhornia crassipes)、水花生(Alternanthera philoxeroides)、水浮莲(Pistia stratiotes)及浮萍(Lemna sp.)等水生植物对针叶材硫酸盐法、阔叶混合材半化学浆法、化学浆及半化学浆法混合废水及碱法草浆废水净化处理的效果。测定了废水COD_(Cr)、COD_(Mu)及色度去除情况。结果表明,水花生净化效果最佳。     

基于热舒适的湿热地区露营地树木种植配置模式

为探究夏季湿热地区不同树种及配置模式对城市露营地热舒适度的影响,在深入分析湿热地区露营地常见树木的基础上,利用ENVI-met建立10种不同场景、采用生理等效温度对5种不同树木布局空间的热舒适度进行分析。结果表明：1)不同空间热舒适度梯度为：群植全遮荫(B₃)>群植半遮荫(B₂)>孤植遮荫(B₁)>树木包围无遮荫(A₂)>开敞无遮荫(A₁)。2)叶面积指数高且大冠幅的树木能较好地改善B₁、B₂和B₃的热舒适度;同理,A₂应选择高树干和大冠幅的树木。3)高叶面积指数、大冠幅且种植方式为群植的树木,对热舒适的改善效果最明显。据此对湿热地区户外露营地的树木种植及优化提出相关建议。     

UNDP项目——《中国速生材及林区废材高得率浆技术开发》考察团赴北欧参观考察

由联合国开发计划署(UNDP)资助的项目——“中国速生材及林区废材高得率浆技术开发”考察团一行六人,在项目主任沈兆邦所长带领下,于1993年5月24日至6月12日赴芬兰、瑞典、挪威及奥地利参观考察。这次考察的目的,旨在结合项目实施,深刻了解北欧各国高得率浆,特别是化学热磨机械浆(CTMP)生产工艺技术、废液回收处理以及研究发展状     

国外全树削片机的使用和生产潜力

全树削片是把整棵树木(特别是对于低价林)加工成木片,用于生产纸浆及其它纤维制品,如人造板等,它是七十年代初期才开始出现的一种新的木材采运生产工艺。全树削片有以下几个优点:1、能够充分利用森林资源,提高单位面积出材量。过去纸浆和人造板工业使用的木片大多是木材加工工业的剩余物,而采伐剩余物的利用率很低。全树削片新工艺的出现,使低质材、小径材以及枝丫材等采伐     

阔叶材热压法干燥的研究

本文通过对几种典型的难干阔叶材,从原料制备、干燥特征、2克优化和质量上进行分析,研究了难干阔叶材的热压板干燥。研究结果表明,采用热压板干燥法可大大缩短干燥时间,减少干燥缺陷(如蜂窝裂)。所有板材在干燥1—4h内终含水率为6％—10％左右。温度和压力对板材的厚度收缩和干燥速率也有很大影响,适宜的工艺参数为:温度160℃,压力0.7MPa。     

全树木片的生产与利用

小径材的生物量利用,即小径木的全树木片生产在我国还未进行过探索和尝试,而在许多发达国家,无论是多林或少林的国家,从70年代末开始就相继进行了研究和实践,目前已形成了完整的生产模式.     

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。     

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.     

Key Habitats in the Norwegian Production Forest: A Case Study

This study investigated the forest history, structural characteristics, the presence of fungal species suggested to indicate ecological continuity in old-growth forest, and the species composition of saproxylic beetles in 30 old forest ''woodland key habitats'' (WKHs), and compared them with production forest in the same age-class in south-eastern Norway. No statistically significant differences in forest characteristics, community of saproxylic beetles or number of red-listed beetles were found between the WKHs and the production forest, probably owing to a combination of profound long-term logging and a lack of will to delineate sufficiently large WKHs in the one area with significantly less forestry impact. The study indicates the advantage of including forest history information in WKH selection where such data exist, and the importance of restoring habitats in heavily exploited forest landscapes.