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ABSTRACT China is the largest importer of waste paper in the world and is highly dependent on the international market. Thus, the relationship between Chinese and international waste paper markets affects the supply of fiber materials in China’s paper industry. This study examined the dynamic relationship between the two markets and the impact of newly implemented policies on both markets. We used unit root tests, cointegration test, vector error correction model (VECM) and frequency-domain Granger causality test to investigate the integration between Chinese and international waste paper markets and identify which of the two markets is the price leader. The results revealed that the two markets were integrated after controlling for structural breaks, and the Chinese market acted as the price leader. Since the supply of waste paper and wood pulp is insufficient in China to meet the fiber demand of the paper industry, waste paper import restrictions have significantly affected the supply of fiber materials in China’s paper industry. Therefore, the Chinese government should fully consider the benefit of market integration and make full use of international waste paper resources to satisfy the large domestic demand for paper products. 相似文献
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就桤木商用种植的生产潜力、制浆造纸和材性研究现状等进行综合评述。桤木是一种商用种植较有发展前景的阔叶树种,生长迅速、固氮能力强,木材性质类似于杨木和桦木,可用来开发研制不同的浆种,与针叶木浆或其它阔叶木浆配抄可以生产高质量的印刷纸和书写纸等。鉴于我国丰富的桤木遗传资源和现有的生产经营水平,大力发展桤木纸浆原料林,开发利用桤木木浆具有广阔的前景,对于缓解针叶木浆之不足,降低纸浆生产成本,使我国造纸业 相似文献
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露天煤矿排土场植被调查与自然恢复研究(英文) 总被引：2，自引：0，他引：2
通过分析辽宁省海州露天煤矿排土场植被组成、物种多样性及重要值的变化,研究了排土场植物群落恢复与演替的一般规律。结果表明:排土场共有植物63 种,分属于23 科,其中菊科15 种、豆科11 种、禾本科8 种;蒺藜+水稗草+猪毛菜、水稗草+大籽蒿+黄蒿、水稗草+披硷草+黄蒿+大籽蒿+黄花草木犀、芦苇+披硷草+水稗草+狗尾草分别是年限为5、10、20、40 梯田层群落的优势种群;重要值对植被重建中物种筛选有指示性,蒺藜在排土场人工恢复中可做为先锋种,披硷草、芦苇、水稗草可做为重要的优势种;排土场植被自然恢复速度缓慢,为了尽快改善生态环境,应该筛选并合理配置先锋植物和适生植物,进行植被重建,加强抚育管理,缩短演替进程。表2 参17。 相似文献
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WANG Shu-li WEN Jing YANG Zhen MA Feng-ming 《林业研究》2006,17(3):255-258
Plot sampling was conducted in the second cultivation areas ofLarix olgensis in Heilongjiang Province, China. By analyzing plot investigation data, wood properties, and kraft pulps of 840 plots and 248 sample trees in industrial plantations of L. olgensis on different sites, we examined the growth process of L. olgensis industrial plantation with suitable structure, the wood fiber feature, chemical composition, physical performance and pulp characteristics. It is suggested that site conditions have major effects on plantation growth, fiber contains, fiber length, rate between fiber length and fiber width, pulping rate and pulp physics intensity. The best site for L. olgensis industrial plantation growth is site class Ⅰ and site class Ⅱ, which are on lower locations. Site condition has an obvious influence on the wood characteristics. Within the range of site conditions and stand densities studied, the worse the site condition, the less the fiber contains, the shorter the fiber length, and the more the 1% NaOH extraction. This kind of relationship becomes more obvious as stand age increases. However, the influence of site condition on pulping rate and pulp physics intensity is not obvious. The result provides theoretical base for cultivation of industrial fiber plantation of L. olgensis. 相似文献
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《Wood material science & engineering》2013,8(3):105-111
Abstract Compression creep experiments of hybrid poplar (Populus deltoides×Populus trichocarpa) were performed in a pressurized vessel equipped with a heated hydraulic press. The viscoelastic response at various stress levels (2–7 MPa), a temperature of 170°C and transient steam conditions was studied. Moisture content and oven-dry density of compressed specimens were determined. While some recovery of compression strain occurred, compression resulted in permanent deformation and increased wood density. The influence of stress level on the amount of set recovery of compressive deformation was evaluated after 24 h water soaking. Applied stress level had a significant effect on the compression deformation. The initial strain, as well as creep strain, varied depending on the applied stress level. The highest oven-dry density was obtained at a stress level of 6.9 MPa. Lower stress levels resulted in lower moisture content after the compression process, while the equilibrium moisture content of compressed specimens was not significantly affected by stress level. Set recovery increased from 20% to 65% with increased stress level from 1.7 MPa to 4.1 MPa, then decreased to 53% for specimens compressed at 6.9 MPa. Moisture content after the compression process significantly affected the set recovery. 相似文献
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方勤敏 《绿色中国(A版)》2005,(24):58-60
过去的100多年中,芬兰林业与纸业的关系经历了3个不同的发展阶段。在最初的自然发展阶段,由于砍伐树木忽视了对森林的保护,企业成长与森林立法成为关注的焦点。在国家扶持阶段,处理好企业发展、森林主利益以及生态环境保护之间的关系成为主要任务,这个过程中,政府及其林业部门起到了鼓励企业与林业共同发展以及协调企业与林主利益关系的重要作用。在国际化与全球化发展阶段,林纸关系的重心开始转向在全球范围内配置森林资源,其中,在国外实施林纸一体化成为企业关注的一个热点。 相似文献
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中国造纸产业原料基础薄弱因而高度依赖纸浆进口, 降低进口风险、实现进口的多元化是保障产业稳定发展的重要议题。文中借鉴能源供给安全指数建立了纸浆进口风险指数和结构优化模型, 用以评价中国纸浆进口风险状况以促进进口更加多元化。对进口风险评价结果表明, 木浆的进口风险整体变化平稳、波动幅度较小, 废纸的进口风险呈下降趋势。对纸浆进口结构优化分析结果说明, 通过调整进口各国纸浆的数量可以有效降低进口风险。造纸产业应分散进口来源、降低进口集中度、减少从高风险国家的进口量以降低木浆和废纸的进口风险, 实现纸浆的稳定供给。 相似文献
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利用相关性分析和主成分分析的方法,分析了冰核细菌溃疡病发生特点与环境条件的之间的关系,选出了影响杨树病害发生的主要影响因子。同时综合分析病害流行的主因和诱因,提出东北地区杨树冰核细菌溃疡病危险等级划分标准,并将东北地区分为重发区、常发区、偶发区和安全区4个不同等级冰核细菌溃疡病发生区。6种模型曲线的非线性回归分析表明,冰核细菌溃疡病流行的时间动态以理查德生长模型为最优生长模型。运用逐步回归分析方法,建立了多元线性的中期预报方程,可以预测第二年的病情指数。根据病情指数随时间增长的趋势,选用灰色方法建立GM(1,1)数学模型,可做出中长期预报。 相似文献
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[目的]为预测未来我国马尾松毛虫的潜在变化趋势,以2002-2012年全国范围内马尾松毛虫的地级逐年平均发生率作为预测指标,[方法]运用偏最小二乘回归方法,获得马尾松毛虫平均发生率与相关气象因子的回归方程,并结合地理空间数据与未来气象数据,得到马尾松毛虫平均发生率空间格局模型.[结果]表明:以筛选后的12个气象因子建立的马尾松毛虫平均发生率空间格局模型精度达到86.98%,具有较强的可靠性.据此预测2020s,2050s,2080s的马尾松毛虫平均发生率空间格局,并与2002-2012年的空间格局相比,结果显示:华东及华中地区虫害中度和重度发生面积均明显增加,有扩散的趋势;华东地区的轻度发生面积总体为缩减;而华南部分地区虫害轻度发生面积扩增.[结论]以偏最小二乘回归方法所得的空间格局模型具有实际预测意义,可以预测我国未来马尾松毛虫平均发生率的变化趋势. 相似文献
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Nitrogen was the main limiting nutrient of net primary production in the southeastern Keerqin Sandy Lands, Northeast China. Species richness declined and biomass increased after five consecutive years of nitrogen fertilization of these sandy grasslands （2004-2008）. After fertilization had been stopped for three years （2009-2011）, we surveyed vegetation on previously fertilized plots to quantify changes in commu- nity composition. Respect species richness showed an increasing trend over time since the cessation of fertilization. Respect vegetation height and coverage showed decreasing trends over time since the cessation of fertilization. Species composition changed after fertilization ceased, the dominant species shifting from Cannabis sativa, Phragmites communis and Chenopodium acuminaturn in 2008 to Cannabis sativa, Phragmites communis and Artemisia scoparia in 2011. Dominance of dominant species declined from 66.2% in 2008 to 57.5% in 2011. The importance value of annual plants in the earlier nitrogen addition plots was higher than in control plots, but the differences were not significant in 2011. The importance value of perennial plants differed significantly between treatments from 2009 to 2011. The reversion rate not only differed be- tween community characteristics, but also between functional groups in the same community characteristic. Although the residual effect of nitrogen addition on vegetation was still observed three years after fertilization ceased, the vegetation showed signs of recovery. 相似文献
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Using the multi-temporal Landsat data and survey data of national resources, the authors studied the dynamics of cultivated
land and landcover changes of typical ecological regions in China. The results of investigation showed that the whole distribution
of the cultivated land shifted to Northeast and Northwest China, and as a result, the ecological quality of cultivated land
dropped down. The seacoast and cultivated land in the area of Yellow River Mouth expanded by an increasing rate of 0.73 km·a−1, with a depositing rate of 2.1 km·a−1. The desertification area of the dynamic of Horqin Sandy Land increased from 60.02% of the total land area in 1970s to 64.82%
in 1980s but decreased to 54.90% in early 1990s. As to the change of North Tibet lakes, the water area of the Namu Lake decreased
by 38.58 km2 from year 1970 to 1988, with a decreasing rate of 2.14 km2·a−1.
Foundation Item: This paper was supported by National Natural Science Foundation of China (Grant No. 39900084) and KZCX1-10-07.
Biography: ZHANG Jia-hua (1966-), male, Ph. Doctor, Associate professor in START, Institute of Atmospheric Physics, Chinese Academy
of Sciences.
Responsible editor: Chai Ruihai 相似文献
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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。 相似文献
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对废纸再生的几点思考 总被引：1，自引：0，他引：1
结合当前纸业原料结构和我国生态保护的现状 ,分析了废纸再生的重要意义。简要介绍了国际、国内废纸再生的发展概况 ,并对我国废纸再生事业的发展提出了几点建议。 相似文献
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在1997-1999年间,利用Bier, X.H、波钦诺克、王敬文、史瑞和等人的研究方法,分别对不同品种杨树如:美×青、A100、小黑14、黑小2、613、北京605等接种冰核活性细菌,并对接种前后树皮含水量、相对膨胀度、木质素、苯丙氨酸解氨酶(PAL)活性、电解质渗出率以及无机元素等进行了测定。结果表明:冰核细菌溃疡病发生后,树皮含水率降低,而膨胀度(RT值)升高;树皮内电解质渗出率增加,而在-4 C和5 C时渗出率最高;木质素的含量也有所增加,且与品种的抗病性呈正相关;苯丙氨酸解氨酶活性也有所增加,且与品种的抗病性呈正相关;Cu、Fe含量显著下降,K、Zn含量显著增加,但Mn、Ca、Mg含量变化不大。 相似文献