竹材制浆造纸述评

竹材纤维素含量一般在４０％～６０％，纤维长度平均在２ｍｍ左右，基本上属于长纤维范畴，是制造中高级纸张的适宜原料。在造纸工业中实现以竹代木，将解决我国造纸优质原料紧缺的燃眉之急，对发展我国造纸工业具有重大意义。发展我国的竹材制浆造纸，要纠正各种模糊观念；要建设好纸浆竹林基地，把原料基地建设作为竹浆纸厂的第一车间；要在竹浆纸厂周围地区积极发展更适宜制浆造纸用的优良丛生竹纸浆林，对毛竹纸浆林要因地制宜，实行集约栽培，提高其经济效益；要加强对竹浆造纸的科学研究，以促进我国竹浆造纸业迅速发展。     

印度竹材制浆造纸

印度：印度竹材造纸发展较早,1951年就有了第一家竹浆厂,50年代中期,竹浆产量曾达到全国纸浆总产量的73．6％。随着竹产业的变革发展,目前印度是世界上使用竹材造纸最多的国家,全国近百个造纸厂中有1／2以上以竹材为原料。估计竹材在造纸原料中的比例为45％-60％,其中牡竹是造纸的主要原料。     

求购竹浆造纸机械设备

在纸浆工业中实现以竹代木,建立林纸一体化的竹浆生产基地,成为节约木材资源,减少纸浆的进口,使制浆造纸工业能持续发展的有利途径。据调查,中国80％的纸浆靠进口,中国又是竹材生产大国,如果利用竹材作为“第二木材”,在造纸工业中实现以竹代木,是中国急待解决的问题。近年来,经常有业内人士寻求关于能生产竹浆造纸的成套设备,年产在2万t左右。欢迎生产竹浆设备的企业和个人随时与本编辑部联系。     

培育竹林资源基地——发展造纸业

竹浆是一种优良的中长纤维纸浆。世界上较多利用竹子制浆造纸的国家有印度、阿根迁、孟加拉国、斯里兰卡、泰国、中国和日本。印度年产竹浆136万t,印支半岛(包括泰国、缅甸、柬埔     

印度竹材制浆造纸

印度竹材造纸发展较早，于1951年建立了第一座竹浆厂，至19世纪50年代中叶．竹浆产量曾达到全国纸浆总产量的73．6％。虽然之后一段时间处于下降趋势，随着竹产业的变革发展，目前印度是世界上使用竹材造纸最多的国家。在该国牡竹是造纸的主要原料。全国近百个造纸厂中1／2以上是以竹子为原料。估计竹材在造纸原料中的比例为45％-60％。20世纪80年代中期竹浆产量为310万t。     

竹浆市场前景广阔

在日前召开的“竹浆产业发展规划”研讨会上,竹子制浆造纸得到了国内制浆造纸界专家的充分肯定。这次由中国造纸协会组织召开的“竹浆产业发展规划”研讨会就竹浆产业发展规划展开了广泛、深入、细致、客观的研究和讨论。 长期以来,我国纸浆产业基本上只有木浆和草浆(芦苇、麦草、庶渣等非木原料)两种分类,对于竹子这种优于草浆、介于阔叶木浆和针叶木浆之间的纤维原料,一直没有予以其应有的地位。但随着制浆造纸业的发展,这种纤维原料有利于资源利用、有利于环境、可替代部分木浆的优点越来越受到人们的关注。     

发展竹浆造纸 节约木材资源

随着社会经济水平的发展,中国纸及纸板的现有产品结构已不适应纸张消费市场的变化与发展,加剧了国内市场对进口纸及纸板的依赖性。竹材纤维细长,是制浆造纸的优质原料。竹浆纸的开发有利于节约木材资源,有利于环境保护。中国竹资源丰富,发展竹浆造纸的市场前景非常广阔。因此,在造纸工业中实现以竹代木,建立林纸一体化的竹浆生产基地,将成为节约木材资源,减少纸及纸浆的进口,使制浆造纸工业得以持续发展的有利途径。     

我国竹浆生产现状及发展前景

近年来,以竹子为原料的制浆造纸技术取得了重大突破。2018年,我国年产竹浆近200万吨,成为世界上竹浆产量和使用量最大的国家,竹浆已成为我国竹产业新的重要经济生长点。利用竹浆生产的纸张(板)多达近百个品种,一批高档竹浆生活用纸产品深受消费者的喜爱,并成功打入国际市场。而竹浆在生活用纸的使用量占生活用纸总量的比例,也由2016年的9.5%提升到15%。因此,随着竹浆生产规模的不断扩大,我国迫切需要创新纸浆用竹林的培育技术,以不断满足对竹材原料日益增长的需求。     

日本落叶松纸浆材造纸性能及工艺成熟期的研究

通过日本落叶松８、１５、２０、２５年生４种年龄木材物理性能和形态，化学分析及纸浆造纸性能的研究，并与美国，加拿大进口的纸浆比较，认为该树种木材纤维素含量高，纤维长、粗浆得率高达４７．３％，而且制浆容易，成本低，纸浆造纸性能较好，是良好的造纸用材树种。分析确定，日本落叶松纸浆材工艺成熟期为１５￣２０年生。     

中国竹浆造纸的潜力与发展

中国竹子资源丰富，分布广泛，发展竹材制浆造纸产业，对于缓解木浆原料短缺现状具有重要意义。根据对竹浆的理化性能分析，竹材是较好的造纸原料，竹材的纤维形态及化学组成表现出较好的制浆性能，仅次于针叶木，接近于阔叶木。从竹材应用于竹浆造纸的角度，综述了竹材的物理化学性能、现行的竹浆造纸工艺、竹浆造纸设备，并就竹浆造纸的发展潜力与发展方向提出了个性化观点，以期为探索绿色、低碳、环保的竹资源利用新途径，为开发高技术含量和高附加值竹产品提供借鉴，从而促进中国竹产业可持续发展。     

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.