荆树栲胶性能的初步观察

世界各国栲胶工业目前的主要发展趋势,是选择适当的鞣料植物,大力建立原料基地,使原料供应尽可能单纯、稳定,从根本上提高栲胶的产量和质量,降低生产成本。荆树生长快,树皮单宁含量高,栲胶鞣革性能好,木材坚实,在热带和亚热带地区,栲胶原料基地树种的选择,普遍趋向于发展荆树为主。     

黑荆树枝桠材及树叶栽培香菇试验初报

<正> 黑荆树(Acacia mearnsii)是含羞草科金合欢属,常绿乔木,原产澳大利亚,又称澳州金合欢,在我省引种有三十多年的历史。种植黑荆树的主要目的,是为了从黑荆树皮提取栲胶,减少黑荆栲胶的进口,增加皮革制品出口创汇的能力,如果黑荆树仅利用树皮提取栲胶,其经济效益是不理想的,如把黑荆树木材、枝桠材、树叶全部综合利用起来,经济效益就会得到显著地提高。为此,我们开展     

黑荆树引种与栽培技术

<正> 一、经济价值黑荆树是鞣料植物中含单宁量很高的树种。由于它生长迅速,树皮含单宁量高,生产栲胶原料周期短,生产栲胶成本低(生产1吨固体栲胶需要黑荆树皮2.5吨,如果用落叶松树皮要13吨)。鞣革渗透性快、沉淀少(制革工业用1吨的黑荆树栲胶就可抵1.4吨的落叶松栲胶)。我场1956年引种的7—9年生黑荆树皮经前泉州栲胶厂和原省森林工业研究所化     

黑荆树的用途及经济价值——兼答读者问

《广西林业》1993年第3至第6期刊载了我写的《黑荆树栽培技术讲座》之后,我收到许多读者来信,要求能详细介绍黑荆树的用途及经济价值。现答复如下: 1.树皮是生产优质栲胶的原料。据科学工作者测定,黑荆树的树皮含单宁44％～49％,纯度一般可达82％,品质优良,栲胶色泽光滑透明,溶解度高,渗透快,沉淀少,缓冲性和鞣透速度都较好。树皮产量     

柚柑、杨梅栲胶亚硫酸盐处理

在伟大领袖毛主席“独立自主、自力更生”的方针指引下,为了贯彻落实中央农林部关于提高栲胶质量的指示,不断提高栲胶质量,争取尽快地用国产栲胶代替进口栲胶鞣制出口革,并积极扩大栲胶出口,满足社会主义建设和外贸的需要。在广西区林业局、轻工局和各级领导的支持下,1973年8月武鸣栲胶厂与南宁市制革厂、广西区林业设计队组成了有生产、使用、科研单位参加的三结合试验小组,针对武鸣栲胶厂的具体条件,开展了改进柚柑、杨梅栲胶质量的试验。在批林批孔运动的推动下,经过几个月的试验,取得了一定成效,质量指标达到1974年三部联合通知的出口要求。用改进后的柚柑栲胶在南宁制革厂鞣制出口栲里革初步成功,证明了改进后的柚柑栲胶可以代替进口栲胶。其鞣制的栲里革与进口荆树栲胶相近。     

橡椀栲胶改性及其性能的初步研究

近年,军工、民用的制革者反映,橡椀栲胶用于少浴速鞣中,应努力改进其渗透、结合和抗热性能。提高渗透速度,可以扩大橡椀用量,代替一部分杨梅栲胶;增进抗热性能,可以提高军用革质量。采用化学改性方法,在橡椀栲胶生产过程中,添加适量的氨基苯磺酸(Sulfa-nilic acid),以降低栲胶粘度,增进胶粒分散性,使鞣液透入裸皮速度得到改善。但在鞣制中,随改性栲胶用量的增加,成革的耐潮热稳定性下降。为了既有利于渗透,又有利于抗温和结合,经选用氨基苯磺酸与四硼酸钠混合处理后,收到明显效果。试验证明:在军用水牛肉底革鞣制工艺条件下,证明两种改性橡椀栲胶(5-1,5-2型)的渗透速度和成革耐潮热性比普通橡椀有明显的提高。在水牛肉底革初鞣阶段代替33％杨梅栲胶,可以满足军用水牛肉底革植鞣工艺要求。     

发展黑荆树、提供优质栲胶原料

<正> 黑荆树(Acacia Mearnsii de willd)又称澳洲金合欢,是一种速生、多用途的树种,属含羞草科金合欢属,乔木,亚热带山地树种。黑荆树的皮、根、枝和叶都含有单宁,尤其是树皮的单宁含量都在40%以上,纯度不低于83%。黑荆树皮单宁含量高,鞣透性好,二吨半树皮可提炼一吨优质栲胶,是一种具有价值的鞣料的树种。一、栲胶的用途和黑荆树在栲胶中的地位     

坚持科学试验提高栲胶质量

<正> 一、我厂栲胶生产现况及质量上存在的问题。我厂自1972年10月投产以来,共计生产栲胶12000吨,一级品率平均达90％以上。近年来,我厂生产的栲胶主要是供制革厂作鞣皮剂。随着制革工艺的发展,将别是较大的制革厂多采用“干浴转鼓速鞣”鞣制重革,较长的鞣期只七、八天时间,上海、武汉等地只用24     

我国黑荆树引种的调查研究

<正> 我国凝缩类优质栲胶原料,长期以来,主要依靠野生资源。经过多年的采集,资源日益减少。栲胶的供销缺口越来越大,影响了轻工业,特别是制革工业的发展。建立凝缩类栲胶原料基地,已成为燃眉之急。黑荆树(Acacia mearnsii de Wild)生长迅速,伐期短,树皮单宁含量40％以上,是优质凝缩类栲胶原料。目前,我国进口的斑马、象牌等优质凝缩类栲胶都是用其皮制成。黑荆树材质坚硬,有韧性,纹理细,可做家具、建     

加速发展优质栲胶原料树种黑荆树

一、简述黑荆树是世界公认的优质栲胶原料树种,原产澳大利亚.十八世纪引入南非人工种植,十九世纪,肯尼亚、罗得西亚和坦桑尼亚先后发展了黑荆树.五十年代到六十年代巴西、印度、摩洛哥、印尼、日本、美国等相继引种栽培.黑荆树具有生长快、木材用处大、树皮单宁鞣性好,适生范围广等优点.黑荆树皮栲胶比利用木材为原料的坚木、栎木,和用青杠树的果实壳斗为原料的橡碗栲胶产量高.产量占世界总产量的1/5以上,国际贸量由廿世纪初的第七位跃居第一位.南非荆树皮栲胶在国际市场竞争中一贯保持优     

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.