Forestry Out-Grower Schemes

Abstract

The trade relationship between suppliers (e.g., growers) and processors often plays an important role in determining the nature and extent of benefits derived from commercial forestry, and the distribution of these benefits. Those interested in forestry development-whether in industrialized or non-industrialized countries-are becoming increasingly aware that positive partnerships between forest companies and growers can provide a means of encouraging forest management which is environmentally sustainable, cost-efficient and equitable. Forestry out-grower schemes describe one type of partnership emerging between growers and processing companies, as the companies with inadequate forest holdings or access to public forests seek to secure additional supplies to meet the increasing global demand for wood products. However, existing out-grower arrangements vary considerably in their ability to be mutually beneficial, achieve sustainable forest management, and meet the social, technical or economic goals of the partners. This paper reports on recent research in which the authors undertook a survey and analysis of 17 forestry out-grower schemes in 11 countries to assess the extent and location of out-grower schemes world-wide and identify key parameters for successful out-growers schemes to provide guidance to forestry developers, decision makers and participants in such schemes.     

江苏省村落系统的空间格局特征与景观背景研究

基于2000年江苏省1：10000地形图及相关自然地理、人口、社会经济等数据,应用点格局分析及冗余分析技术,对江苏省村落的空间格局特征及其与号观背景要素的相关关系进行研究．结果表明：在0—8km的观测尺度上,村落系统总体表现出随观测尺度增加,依次呈均匀分布一随机分布一聚集分布的变化特征,但不同区域存在一定差异分析村落空间格局特征与景观背景要素的相关关系发现：村落在聚落占地率较高、王i￡块密度较大地区趋于均匀分布,在地形要素等限制作用较大及经济水平较高区域多呈随机分布,在自然条件相对优越地区多呈聚集分布,总体上,自然地理要素对村落空间格局特征的影响最显著,社会经济要素的作用其次,区位与交通要素的作用相对较小、     

论晚近中国民主观念赖以生成的三重语境

影响晚近中国民主观念的因素,除了特定的社会政治形势外,还有主要由民族主义、启蒙主义和马克思主义三者所构成的思想语境。它们分别为不同类型的民主观念提供价值规范,在不同程度上影响和制约着民主观念的生成。由于价值观的差异,不同语境虽然可以勉强相容,但更多的是相互挤压,相互竞争,而竞争的结果是马克思主义作为强势语境的胜出。五四以后新民主主义逐渐形成并最终上升为中国社会的主流意识形态,即是这种强势语境作用的结果。     

复杂背景下黄瓜病害叶片的分割方法研究

利用图像处理和模式识别技术进行复杂背景下黄瓜叶部病害的自动识别,需要先把目标叶片从复杂背景中分割出来,才能进行后续的特征提取和病害识别。为实现复杂背景下黄瓜叶片的分割,首先利用K-均值聚类算法去除图片中的非绿色部分,再采用基于laplacian of gaussia(LOG)算子的方法对待分割的叶片进行区域检测,然后进行基于形状上下文(shape context)的模板匹配和分割。为了提高匹配速度,先检测叶片的生长点和叶尖,以确定叶片的位置、尺寸和方向;然后使用基于超像素(superpixel)的最优匹配搜索方法来减少搜索的复杂度。对20幅黄瓜叶部病害图像进行分割测试,并与人工分割法进行对比,结果表明,本文所采用的分割算法能较好地从复杂背景下提取出黄瓜叶部病害图像,分割准确率达94.7%,为后期黄瓜病斑的特征提取等工作奠定了良好的基础。     

Influence of wetland networks on bat activity in mixed-use landscapes

Parks and other protected lands can provide important source habitat and act as valuable dispersal corridors in urbanizing environments. However, most wetlands within protected areas are managed in isolation without consideration of the broader landscape connections. We studied the importance of wetland habitat connectivity and landscape context to bat activity in five National Parks along a gradient of increasing urbanization within the Mid-Atlantic United States. Ninety-six Anabat stations were set up throughout the parks, from which we derived the characteristic spatial scales at which bat activity was associated with wetlands. This information was used in a graph theoretic framework to construct network models of potential landscape connectivity for those species that had positive associations with wetland land cover. We found that the importance of wetlands as a predictor of bat activity varied on a species-by-species basis and increased when network measures were used that accounted for connected area in a broad spatial context. The results demonstrate that both area and connectivity of wetland foraging habitat may act as orthogonal variables to availability of roosting habitat in explaining the distribution of highly mobile species. We use the results to illustrate the value of network analysis to guide the coordinated management of two of the parks’ most valued natural resources - wetlands and bats.     

基于典型叶片模板自动匹配的虫损叶面积测量

为了定量化评估农作物的虫害程度,提出了一种基于典型叶片模板自动匹配的叶片虫损面积测量新方法。先将叶片图像二值化并提取其外轮廓;再对提取的轮廓进行多边形近似,以多边形的顶点为端点将叶片外轮廓划分成若干子轮廓;然后采用形状上下文对完整叶片与虫损叶片之间的子轮廓进行自动配准,找出其间的相互映射关系;最后根据映射关系对虫损叶片进行重建,计算出虫损面积。对10类不同叶片的测量分析表明：该方法平均每叶片耗时0.962 s,最大相对误差为8.22%,平均相对误差为4.78%。其中,形状复杂度高的叶片平均相对误差为7.48%,复杂度中等的叶片为5.99%,复杂度低的叶片为1.84%。结果表明,该方法能准确而快速地测量虫损叶面积。     

城市发展推动下的济南市景观格局变动研究 ——基于2007—2017年景观格局指数的分析

采用2007年的Landsate5TM、2013年和2017年的Landsate8OIL遥感影像,选取分维度、蔓延度、香农多样性指数、香农均匀度指数等指标,从类型水平和景观水平两个方面,对济南市主城区10年间的景观格局进行分析,结果表明:城市整体的斑块丰富度增加,生态系统趋于多样化;未利用地面积逐渐减少,林地与耕地面积显著增加;耕地质心逐渐“北跨”,这与10年间济南市整体的政策定位与城市发展脉络相契合。提出大力推动农村社区规划,严格控制占用林地、狠抓植被恢复,做好城市建设用地规划、预留发展空间等土地利用的建议。     

试论新闻伦理实践精神建构

新闻伦理规范只有能够切实贯彻到新闻实践中才有价值,因此,实践精神是新闻伦理的价值指向。而具体情境、理性协商、实践反思则是建构新闻伦理实践精神的有效路径。     

解构主义者有关言语行为理论的观点

继索绪尔结构主义语言学后,奥斯汀又提出了言语行为理论,它标志着语言理论的转向。擅长从语言入手研究的解构主义学者德里达、德曼、米勒都对言语行为理论有着自己的观点,不同程度地对解构主义言语行为理论做出了贡献。     

文化悲剧与现代性货币——齐美尔距离的生成语境解读

在现代性视域下，齐美尔提出距离理论，认为个体面对物化文化的巨大压力，只有通过与其保持距离才能获得救赎。对齐美尔距离的生成语境可以从两个方面展开分析：文化的悲剧性诊断和货币的现代性表征。