A PRELIMINARY SPECTRUM ANALYSIS ON TURBULENCE IN LEESIDE OF WINDBREAKS

The spectrum characteristies of turbulence such as period of fluctuation,frequencyand amplitude of oscillation were discussed by using the method of spectral analysis of turbulencein this paper.The results show that the spectrum density in the range of low frequency is sharply va-riance with the distance from the windbreaks,but it follows the power index law of-5/3 and satis-fies the theory of local isotropic turbulence in the range of high frequency.It also shows by con-necyting with Eulerium autocorrelation analysis that there are small scale,high frequency and shortperiod of turbulence near the leeside of windbreaks,but often large scale,low frequency and longperiod of turbulence far from the windbreaks.     

RS和GIS支持下的土地利用和植被调查

应用遥感技术（RS）和地理信息系统（GIS）技术，对日本国JICA援助的四川省安宁河流域5个重点造林区进行了土地利用现状和自然植被分布状况的调查，摸清区域内各种土地利用类型、自然植被类型以及可供造林绿化的宜林地资源，为区域造林规划、管理和实施提供依据。     

孟加拉国Bhanugach西部保育林用地类型变化(英文)

应用遥感和地理信息系统调查了孟加拉国Sylhet林业分局所辖的Bhanugach西部保育林从1988年到2006年间用地类型的变化。应用了监督和非监督两种方法,用全球定位系统搜集了地面控制点。地理信息系统软件制成地图。结果表明,植被覆盖从1988年的1826hm2大幅地降低到1996年的1714.85hm2,随着协同管理措施的实施,植被覆盖自1996年后逐年增长到2006年的1847.83hm2。在没有其他类型的用地转变成裸地的情况下,裸地变化与植被覆盖间成反比。18年间水体面积从1988年的307.67hm2增加到1996年379.53hm2,96-97年间略有下降,1997年以后直到2006年基本保持不变。本文还提出了将遥感技术和地理信息系统应用于用地类型变化及地理信息系统数据库创建的一些建议。     

GIS技术在年度森林资源监测中的应用研究

GIS是计算机图形处理和数据库管理的技术集成,Mapinfo是森林资源空间属性管理的有效操作平台。在年度森林资源监测中,将GPS技术和GIS技术进行有机结合,可以提高监测精度和工作效率,杜绝重复上报,并为江苏数字林业建设奠定坚实的基础。     

我国GIS的发展及其与测绘的关系

本文简要介绍了GIS在我国的发展概况和GIS与测绘的关系。并指出了面向未来测绘事业的GIS的发展前景。即向智能化、集成化、自动化和网络化发展。以便适合于不同测量工作者的需要。     

Effects of windbreaks on airflow, microclimates and crop yields

The mechanisms by which a porous windbreak modifies airflow, microclimates and hence crop yields are addressed, based upon recent wind tunnel experiments, field observations and numerical modelling. This paper is thus an update to the excellent reviews in Brandle (1988). It shows how a turbulent mixing layer initiated at the top of the windbreak dominates the airflow behind a windbreak. This mixing layer spreads vertically as it moves downwind, growing at a rate determined by the turbulence in the approach flow and the windbreak's ‘permeability’. The roughness of the terrain and land-cover upwind, windbreak height and porosity are thus the main controls on the amount and extent of shelter provided by a windbreak. The changes in temperature, humidity, heat and evaporation fluxes given these changes in turbulence are then described. Based on the turbulent mixing layer model, the highly sheltered ‘quiet zone’ will be typically warmer and more humid while further downwind in the ‘wake zone’, cooler and drier conditions would be expected. The careful experimental studies needed to verify these theoretical predictions have not yet been published. Shade is also shown to modify the heating in the quiet zone and, depending on the orientation of the windbreak, can offset the warming in the quiet zone. Lastly, the mechanisms affecting plant productivity are described in light of these airflow and microclimate changes. A major effect of a windbreak is to reduce the incidence of low frequency, high magnitude damage events such as sandblasting or lodging. Microclimate effects, however, do not always improve productivity. For example, while shelter may improve water-use efficiency in irrigated crops by increasing yields and reducing water-use, this may not be the case in dryland agriculture. This revised version was published online in June 2006 with corrections to the Cover Date.     

利用TM图像进行森林资源现状调查存在的问题及建议

针对利用TM图像进行全国重点生态工程区森林资源现状调查中出现的一些问题，进行分析探讨，提出解决这些疸的一些看法建议。     

Classification of defects in cork planks using image analysis

Summary Image analysis techniques were used on cork surfaces of transverse sections of planks and multivariate analysis was applied to differentiate pores (lenticular channels) from important defects such as nail (horizontal and vertical) and insect galeries. The discriminant analysis showed that the variables area, perimeter, specific length and width, diameters in the radial and in the tangential direction, as well as the optical density could be combined in three discriminant functions that could make the classification. Defect specific classification functions gave good results for the automatic classification of pores, insect galeries and horizontal nail (error <10%), and acceptable for vertical nail (20% error).     

Trees and windbreaks in the Sahel: establishment,growth, nutritive,and calorific values

Tree and windbreak species considered for the Southern Sahelian Zone (SSZ) of West Africa have to be evaluated following multiple criteria such as fast establishment, shelter efficiency, production of feed for livestock, and firewood. An on-station experiment was conducted on a sandy soil in southwest Niger between 1988 and 1993 to assess the establishment, growth, nutritive, and calorific values of seven species considered for windbreaks:Andropogon gayanus, Bauhinia rufescens, Acacia holosericea, Acacia nilotica, Acacia senegal, Faidherbia albida, andAzadirachta indica. Mortality and stem diameter were monitored twice a year. From 20 months after planting (MAP) onwards, species were annually trimmed to 2 m height and to 1 m sidewards of the main stem. Fresh and dry weight of leaves, twigs, wood, and fruits were recorded. Leaves were analyzed for crude protein (CP) and metabolizable energy (ME) content. Wood was analyzed for its gross calorific value and its ash content. At 56 MAP, all species had less than 5% morality, except forA. holosericea, which had a mortality rate of 15.9%.A. indica andA. holosericea showed the highest stem diameter among species with 12.2 and 11.8 cm, respectively, at 56 MAP.A. senegal had the highest dry matter production with 22.3 t ha^–1 at 56 MAP, followed byA. indica (12.0 t ha^–1),A. holosericea (11.7 t ha^–1) andB. rufescens (11.2 t ha^–1), butA. holosericea was most productive at earlier harvests. OnlyA. senegal (6.4 t ha^–1) andA. indica (5.1 t ha^–1) had a significant wood production, whereasA. holosericea (5.7 t ha^–1) had the highest phyllodes production. Leaves ofA. senegal andA. indica had highest CP contents of 258 and 214 g kg^–1, respectively. The leaves of all species exceptA. gayanus had a higher CP:ME ratio than natural pasture in the region. The calorific values of firewood did not differ significantly among the species.A. nilotica, the species with one of the lowest firewood production, had the highest Fuelwood Value Index of 6.6. The choice of species for planting trees and windbreaks in the SSZ must be oriented along these criteria. Further research should be directed towards cost-benefit analyses, land tenure and property rights in combination with surveys on local knowledge of rural people.     

Evaluation of environmental functions of tropical forest in Kinabalu Park, Sabah, Malaysia using GIS and remote sensing techniques: Implications to forest conservation planning

Environmental functions of tropical forest can serve as criteria for forest conservation planning in the tropics. The objective of this study is to evaluate the environmental functions of tropical forest in Kinabalu Park, Sabah, Malaysia, using GIS and remote sensing techniques. Field data, statistical data, including weather data with geographic localities, maps and satellite image are collected. Linear regression models are developed for forests of different geological substrates, based on the relationships between altitude and biodiversity (Fisher’s alpha index). Biodiversity conservation function map is derived with the statistical models and a digital elevation model. Coupling with extensive literature review, an evaluation matrix for evaluating soil and water conservation functions including landslide prevention, flood prevention and drought prevention functions, is constructed. To evaluate the soil and water conservation functions, a weighted linear combination method is used with GIS layers of topography, geology, soil depth, rainfall and slope. Forest areas in Kinabalu Park are derived with land cover mapping using Landsat-TM image. Areas having high values of biodiversity conservation, flood and drought prevention functions are covered with mainly lowland rain forest. On the other hand, areas with high values of the landslide prevention function are covered with mainly subalpine forests. Using the environmental functions, a conservation index is computed to represent forests that are important to conservation. Based on theCI, the lowland rain forest receives highest priority in protection. In fact, it is located in the boundary areas of the park and thus exposed to illegal activities. This study would not be possibly accomplished without the map data as well as other data.     

Monitoring fiber orientation in OSB during production using filtered image analysis

The orientation of oriented strand board (OSB) mats has been practically measured on a commercial factory production line to demonstrate the practical capabilities of the filtered image analysis (FIA) technique. Samples have been cut from OSB panels at a range of angles to the panel axis and these samples have been tested in bending. The factory data and the experimental data have been compared in order to investigate the relationship between the practical condition of fiber orientation in the factory and the bending properties as a function of orientation. The following conclusions can be drawn. Fiber orientation in the production line is good and stable irrespective of position across the width of the production line, time of day and changing line speed. The average value for the orientation angle of the forming mat on the production line is approximately 25°. The general shape of the fiber orientation distribution is similar to a normal distribution, however, at the centre of the fiber mat the sharpness of the distribution is greater than a normal distribution. The average orientations of fibers in commercial board lie at 25° and 60° to the longitudinal and perpendicular directions, respectively. The results suggest that there is potential to improve the mean fiber orientation angle of commercial OSB to improve longitudinal values of MOR and MOE, especially where perpendicular properties are not critical. Received 31 March 2000     

园林用地土壤调查技术及其应用

土壤条件是进行园林绿化施工和树种选择的重要技术参考,该文就园林土壤的调查方法、调查内容和土壤调查指标的确定及分析作了阐述,并以华北地区绿化树种选择为例对土壤调查资料的应用进行了分析论述,以期为园林绿化工作提供一定的技术参考。     

Identification and species-typing of wood rotting fungi using melting curve analysis

A method for identification and typing of wood rotting fungi using the melting temperature [T(m)] of DNA fragments coding rRNA (rDNA) was examined. The T(m)s of four DNA fragments, inter transcribed spacer (ITS) I, ITS II, and two partial fragments of 28S rDNA from each of 20 species of wood rotting fungi, were measured by melting curve analysis. The T(m) variation was large enough between species to enable identification based on the T(m) values. A pair of T(m)s of the ITS I region (between the primers ITS1 and ITS2) and the ITS II region (between the primers ITS3 and ITS4) had the highest resolution for identifying wood rotting fungi. To assess about the diversity of the T(m), intraspecific diversity of these DNA fragment sequences was evaluated using test strain sequences and data from the GenBank/EMBL/DDBJ biological database. The intraspecific diversity of T(m) was considered to be small because the nucleotide diversity of each fragment was small within the species.     

基于数字图像处理技术实现木材横纹压缩过程中构造学形态特征的研究

根据计算机视觉技术,结合横纹压缩木材构造形态特征,提出了适合于木材横纹压缩过程中构造形态特征的图像处理方法。对图像质量的完善较全面地进行了量化,充分表露出计算机视觉技术在实现木材横纹压缩过程中构造学形态特征动态变化分析中的优越性,实现了木材细胞边缘轮廓的跟踪,形态特征的提取,为木材科学的再发展奠定了理论基础。     

Digital image analysis of cross-sectional tracheid shapes in Japanese softwoods using the circularity index and aspect ratio

Image analysis was used in this study to develop a faster, more objective method for quantitatively measuring tracheid shapes on cross section. The morphological features were measured automatically using the circularity index and aspect ratio based on the skeletonized images. The rectangular and hexagonal similarities were introduced to evaluate the tracheid shapes. The results for 18 species of Japanese softwoods showed that the difference in tracheid shapes among the species could be successfully estimated using the quantitative method. In addition, the boundary of latewood might be evaluated based on the change in circularity indexes.The abstract of this study was presented at the 48th annual meeting of the Japan Wood Research Society, Shizuoka, April 1998     

松叶蜂病原真菌的分离鉴定及真菌寄生率的调查

对宁夏、陕西、甘肃的落叶松叶蜂Pristiphora erichsonii、河北的落叶松锉叶蜂P.laricis和落叶松腮扁叶蜂Cephalcia lariciphila、山西靖远松叶蜂Diprion jingyuanensis、陕西松阿扁叶蜂Acantholydaposticalis、云南的祥云新松叶蜂Neodiprion xiangyunicus和南华松叶蜂D.nanhuaensis的幼虫及茧期病原真菌调查统计,并从以上虫茧中分离出真菌13株,初步鉴定球孢白僵菌Beauveria bassiana8株、布氏白僵菌B.brongniatii 4株、青霉属Penicillium sp.1株。选取5株白僵菌以3龄月季叶蜂为试虫进行毒力测试,结果显示1.0×108孢子/mL菌液对试虫有致死作用,校正死亡率69.5%～91%。     

基于GIS的梅城林场地形分析及其应用

以国产软件Geoway为数据加工平台,对安徽省东至县梅城林场1∶10 000地形图等高线进行矢量化采集,然后以Shp格式导入ArcGis,生成数字高程模型(DEM)。利用ArcGis的空间分析功能,对梅城林场坡度、坡向和地面粗糙度等地形因子进行分析。结果表明:极端和非常脆弱的林地面积占林场总面积的28.65%,比较脆弱和一般的林地面积占林场总面积的71.35%,总体生态脆弱度较小;不同坡向面积比例依次是南坡>东南坡>平坡>西坡>东坡>北坡>西南坡>西北坡;地面粗糙度总体在1～1.45之间,但1～1.15之间的面积最大,占梅城林场总面积的78.18%,说明梅城林场总体地形起伏不大,土壤侵蚀程度较小,生态安全性较高。同时,也反映梅城林场总体营造林作业施工难度较低。     

Land suitability evaluation for multiple crop agroforestry planning using GIS and multi-criteria decision analysis: A case study in Fiji

We present novel methods that use geographic information systems (GIS) and multi-criteria decision analysis (MCDA) to evaluate land suitability for a set of seven agroforestry crops, with the aim to differentiate relative land suitability and its potential to achieve different benefit goals for the Sigatoka Valley, Fiji. Our first model (Land Suitability) identifies optimal areas for each crop based on readily available edaphic and environmental cultivation criteria and common GIS datasets. The second model (Weighted Maximum) uses objective approaches for weighting the relative importance of target crops to derive a multi-crop suitability map. We use the analytical hierarchy process (AHP) technique (a form of MCDA) to identify the relative importance of five benefit types (i.e. agroforestry initiative goals/AHP Objectives). AHP criterion weights were used to map the most important crops for different agroforestry goals. Our methods are unique among GIS-MCDA applications of land suitability analysis in that our aim was to investigate and spatially evaluate land use suitability for multiple crops on a per-crop basis, whereas the aim of most GIS-MCDA land suitability analyses is to evaluate relative suitability (e.g. low, medium, high), evaluate potential for different land uses (e.g. production, intensive, or multifunctional) or land suitability for a single crop. We conclude that the methods described can be adapted to agroforestry initiatives and other similar land use suitability applications in the Pacific region and other geographical settings.

     

Analysis of forest cover change at Khadimnagar National Park,Sylhet, Bangladesh,using Landsat TM and GIS data

We mapped the forest cover of Khadimnagar National Park （KNP） of Sylhet Forest Division and estimated forest change over a period of 22 years （1988-2010） using Landsat TM images and other GIS data. Supervised classification and Normalized Difference Vegetation Index （NDVI） image classification approaches were applied to the images to produce three cover classes, viz. dense forest, medium dense forest, and bare land. The change map was produced by differencing classified imageries of 1988 and 2010 as before image and after image, respectively, in ERDAS IMAGINE. Error matrix and kappa statistics were used to assess the accuracy of the produced maps. Overall map accuracies resulting from supervised classification of 1988 and 2010 imageries were 84.6% （Kappa 0.75） and 87.5% （Kappa 0.80）, respec- tively. Forest cover statistics resulting from supervised classification showed that dense forest and bare land declined from 526 ha （67%） to 417 ha （59%） and 105 ha （13%） to 8 ha （1%）, respectively, whereas medium dense forest increased from 155 ha （20%） to 317 ha （40%）. Forest cover change statistics derived from NDVI classification showed that dense forest declined from 525 ha （67%） to 421 ha （54%） while medium dense forest increased from 253 ha （32%） to 356 ha （45%）. Both supervised and NDVI classification approaches showed similar trends of forest change, i.e. decrease of dense forest and increase of medium dense forest, which indicates dense forest has been converted to medium dense forest. Area of bare land was unchanged. Illicit felling, encroachment, and settlement near forests caused the dense forest decline while short and long rotation plantations raised in various years caused the increase in area of medium dense forest. Protective measures should be undertaken to check further degradation of forest at KNP.