Evaluation of potential land productivity in Wulushan,West China

The general situation of the total land resources in Wulushan, West China was studied by field investigations with the aid of a GIS software, called Region Manager. The current status of land use in Wulushan is described. The potential land productivity was evaluated by a fuzzy comprehensive method, We take each plot as a basic unit of evaluation on the basis of an index system of land resources in Wulushan which was developed from the investigation data. Evaluation of potential land productivity is the key part of land management. A guideline is presented in this paper for a proper utilization of the land resources and to develop the productive capacity of the land.     

Effect of thermo-mechanical refining on properties of MDF made from black spruce bark

The effects of thermo-mechanical refining conditions on the properties of medium density fiberboard (MDF) made from black spruce (Picea mariana) bark were evaluated. The bark chips were refined in the MDF pilot plant of Forintek Canada Corporation under nine different refining conditions in which preheating retention time was adjusted from 3 to 5 to 7 min and steam pressure was set at either 0.6, 0.9 or 1.2 MPa. The resulting bark fibers were blended with 12% UF resin (based on oven-dry fiber weight) using a mechanical blender. The resinated fibers were manually formed into fiber mats and hot-pressed into MDF panels using consistent parameters. Two panels for each refining condition were produced, resulting in a total of 18 panels. Analysis of variance (ANOVA) was used to analyze the significance of factors. Regression coefficients and 3D contour plots were used to quantify the relationship between panel properties and the two test factors. The results from this study indicated that the preheating retention time was a significant factor for both modulus of rupture (MOR) and modulus of elasticity (MOE), the steam pressure was a significant factor for internal bond strength (IB), MOR and MOE, whereas both factors were insignificant for thickness swelling, water absorption and linear expansion. The properties of MDF panels were quadratic functions of retention time and steam pressure. Compared to the ANSI standard for 120-grade MDF, most panels with a nominal density of 950 kg/m³ had very high IB (>1 MPa) and acceptable MOR, MOE and dimension stabilities. These results suggest that black spruce bark residues can be considered as a potentially suitable raw material for manufacturing MDF products.     

贵州苏铁研究进展

本文对贵州苏铁研究在形态特征、生物地理学、生殖生物学特性、细胞学和分子生物学等几个方面开展的科研工作进行综述。     

5种化学杀虫剂防治椰心叶甲试验

对珠海市椰子树林发生的椰心叶甲，使用10％氯氰菊脂、48％乐斯本乳剂、16％虫线清乳剂、81％马拉松乳剂、90％敌百虫等5种化学杀虫剂，进行施药防治对比试验。结果显示：喷施10％氯氰菊酯乳剂0．67ml/L与48％乐斯本乳剂1ml/L的混合液、16％虫线清乳剂5ml/L，杀虫平均死亡率分别为94．2％和93．8％，降低林木受害程度的防治效果分别为76．81％和78．26％，显著高于其它药剂处理的效果。     

神农架地区珍衡植物沿河岸带的分布格局

Due to the importance of riparian zone in maintaining and protecting regional biodiversity, increasingly more ecologists paid their attentions to riparian zone and had been aware of the important effects of riparian zone in basic study and practical management. In this study, 42 sampling belts (10 m×100m) parallel to the bank of Xiangxi River at different elevations in Shennongjia Area were selected to investigate the riparian vegetation and rare plants. 14 species of rare plants were found distributing in riparian zone, accounting for 42.4% of the total rare plant species in Shennongjia Area. The main distribution range of the 14 rare plant species was the evergreen and deciduous mixed broadleaved forest at elevation of 1200–1800 m, where, species diversity of plant community was the maximum at the moderate elevation. The analysis of TWINSPAN divided the 14 rare species into 3 groups against the elevation, namely low elevation species group, moderate elevation species group, and high elevation species group. The analysis of DCA ordination showed similar results to that of TWINSPAN. In the paper, the authors discussed the reasons forming the distribution pattern of rare plant species, and pointed out that the important function of riparian zone on rare plant species protection. Foundation item: This project was supported by National Natural Science Foundation of China (NSFC39970123), and Changbai Mountain Open Research Station, Chinese Acadamy of Science. Biography: JIANG Ming-xi (1965-), male, associate professor in Wuhan Institute of Botany, Chinese Academy of Sciences, Wuhan 430074, P. R. China Responsible editor: Chai Ruihai     

杉木幼林年生长节律划分和相关气候因素分析

杉木幼林年生长规律及气候因素对生长的影响,是合理制订杉木产区区划,改善杉木造林规划设计布局,正确实施经营管理措施的基础。 本项研究,将全国杉木西部试区的四川高县作为试验点,从1985～1988年,连续4年在5～8年生不同密度林分中,作了胸高直径及树高生长的旬期定期观测。经对这些实验数据作均值处理,聚类分析,关联分析和多元回归分析结果表明:对生长在中国杉木中带西部产区,处于中亚热带湿润气候区环境条件下的杉木幼林年生长规律的论证及对影响生长的主要气候因子的分析判断和预测,具有可靠性和区域代表性。     

藜蒴主要病虫害及防治技术探讨

藜蒴是我省优良的乡土阔叶树种,具有速生、耐寒、适应性广等特点,也是一种良好的造纸原料资源。近年来,随着我省藜蒴面积增大,其病虫害种类多,危害也日趋严重。文章探讨了藜蒴的主要病虫害及其防治技术,旨在更好地保护藜蒴森林资源。     

林火对景观格局的影响及其应用

运用林火生态和景观生态学理论,通过林火生态特性、生态过程及景观研究方法,阐述了林火对景观格局的影响;分析了林火与景观结构、功能、动态、格局和景观多样性的相互关系;简要概括了目前对林火与景观格局的研究和应用现状。     

10.2%阿维·三唑磷微乳剂防治瓜亮蓟马药效初探

瓜亮蓟马（Thrips flavus Schrank）属缨翅目,蓟马科。别名菜田黄蓟马、棉蓟马、忍冬蓟马,是瓜类、茄果类和豆类蔬菜上的主要害虫之一,分布河南、江苏、安徽、湖北、四川、台湾及长江以南各省。它以成、若虫刺吸植株幼嫩叶片、果实汁液,严重影响蔬菜产量和品质。     

几种斜纹夜蛾防治剂田间药效试验

斜纹夜蛾是烟草生长中后期一种暴食性主要害虫.2010年在郴州市烟草试验基地上采用7种防治药剂进行了田间斜纹夜蛾防治效果筛选试验.结果表明:在生物防治药剂中,核多角体病毒株(郴州株)对斜纹夜蛾的防效最理想,施药后第8 d防效达84.83%,并且是较安全的生物药剂;在化学药剂中,25 g/L好乐士乳油防效最好,施药后第8 ...