巫溪林业发展基本思路

巫溪足一个林业大县，全县幅员面积40．26万公顷，林业用地面积29．77万公顷(占幅员面积的73．9%)，其中森林16．06万公顷，活立木蓄积814．34万方，森林覆盖率39．9%，比1996年提高6．7个百分点。2003年当年实现林业总产值1．15亿元，占全县国内生产总值的l0．4%。林业其他各项工作也取得了较好的成绩。     

环境问题与中国农村发展

一、我国农业发展的巨大成就与环境的巨大代价当前农业发展和环境之间的矛盾和冲突已经到了非常尖锐的程度 ,存在着四个方面的突出问题。第一个方面的问题 ,农业的自然资源越来越短缺。我们都知道中国是一个人多地少的国家。对于耕地资源的短缺 ,全民都有这个认识。根据农业普查资料 ,我们现在实有耕地面积总量１９．２亿亩 ,将近１．３亿公顷 ,人均耕地只有０．１公顷 ,相当于世界平均水平的４５ %左右 ,耕地资源显然非常短缺。然而 ,现在人们也越来越多地认识到水资源的短缺比耕地资源的短缺更为突出。我国人均拥有的水资源大约为２０００…     

发展重庆果品业的几点思考

重庆市果品业经过四十多年的发展．已经成为全市农业和农村经济发展中仅次于粮食和生绪的第三大支往产业。至1999年．全市果树面积达20万公顷．总株数3．5亿株,总产量90万吨．产值14亿元,其中柑桔面积12万公顷,产量67万吨,名列全国第七位。果树良种比例由原来的30％提高到70％,     

数字舆情

正森林资源10月22日,国家林业局、统计局联合发布的中国森林资源核算研究成果显示,全国林地林木资产总产值为21.29万亿元,相当于我国国民人均拥有森林财富1.57万元。5年来,人均森林财富增长了38.9%。根据森林生态系统服务核算结果显示,第八次森林资源清查期间,全国森林生态系统每年提供的主要生态服务的总价值为12.68万亿元。     

揭开瑞典人长寿之谜

瑞典人是世界上寿命最长的民族之一。最新统计资料表明,该国的女性和男性的寿命已分别高达81.4岁和76.3岁。是什么原因使瑞典人长寿呢? 特殊的地理环境:一踏上瑞典的国土,犹如进入人间仙境,群山滴翠,绿树成荫,生机盎然。瑞典以林木资源丰富而享有"森林之国"的美称,森林覆盖面积占全国土地面积的64%,平均每个公民拥有3公顷多的森林。瑞典境内大大小小星     

市场经济条件下多元化多渠道的林业投融资机制研究──以广东省林业为例

随着市场经济体系的逐步建立，我国林业取得了长足发展。第五次全国森林资源清查结果表明，我国森林面积和蓄积量都保持了良好的增长势头，林业产值也由１９７８年的４８．１亿元增长到１９９９年的８８６．３亿元，增长了约１８．５倍。与此同时，林业产业的发展却越来越受到投融资的制约。融资渠道不畅、林业投资不足已严重影响到我国林业的进一步发展。如何摆脱资源与资金的困境，建立符合市场经济的现代林业投融资机制，已成为当前林业可持续发展中亟待解决的问题。在这一方面，广东省林业部门进行了有益的尝试，并取得了一定的成果，为…     

警钟长鸣——我国的资源现状

一、我国的资源现状我国以世界9%的耕地,6%的水资源,4%的森林资源养活了22%的世界人口。而中国膨胀的人口和粗放型的经济增长方式,却早已超过自然环境合理的承载能力。空气、     

创新推动跨越 永林再创辉煌

福建省永安林业(集团)股份有限公司创立于1994年1月,1996年12月6日在深交所挂牌上市(股票代码000663),是全国首家以森林资源为主要经营对象的上市公司。公司总资产10亿元,森林经营面积181万亩。主要产品有木材、纤维板、强化木地板、胶合板、甲醛、胶     

新农村观察

我国林地资源"红线"为46.5亿亩国家林业局局长贾治邦最近在全国森林资源管理工作会议上提出,按照中央确定的到2050年森林覆盖率达到并稳定     

南川区林权制度改革的成功探索

南川区幅员面积2602平方公里,人口66万,辖31个乡镇、3个街道。全区林业用地212．2万亩。是耕地的3．5倍,占幅员面积的54．5％。全区重点公益林54．4万亩,地方公益林48．2万亩．商品林109．6万亩,森林覆盖率47．2％。全区集体林地面积191．6万亩,涉林户数15．5万户。森林资源年增长量40．7万立方米．活立木蓄积500万立方米。     

土地制度的供求冲突与其改革的框架性安排

中国农村社会和农业经济向城市社会和工商业经济转型,计划经济向市场经济转轨,以及可持续发展和西部大开发,对土地制度的供给及其功能提出了特殊的需求。就目前来看,两种公有、高度集中和行政色彩较浓的土地所有和配置制度与结构转型和市场经济的要求发生了尖锐的冲突,特别是土地集体所有的虚无性衍生出一系列的经济社会问题。据此,本文提出了中国土地制度改革的框架性安排:土地的两种公有制并轨,国家拥有所有土地的终极所有权,分解国家所有的占有、使用、处置等权力,实行较长的使用年期财产权制度,农民和一部分国有企业的土地使用年期财产与社会保障挂钩,发挥市场配置土地资源的基础性作用,政府管理主要用来弥补市场配置土地资源的缺陷。     

农业土地规模经营的条件与效果研究:以东北农村为例

本文是以现代企业理论为研究基础,以东北农村为例,对农业土地规模经营问题的一项经验研究。研究适合我国农业生产的前提条件、经营规模、经营效果,探讨适合中国农业现代化发展的道路。根据3组不同情况的样本分析,得出土地规模经营受制于土地流转速度和集中程度、农村劳动力转移速度和转移数量的结论。如果土地流转速度和流转数量加快,土地的集中度就提高,从而土地规模经营将发展和扩大;同样,如果农村劳动力转移速度和数量加快,土地集中度就提高,土地的规模经营就成为可能。文章研究了农业机械化和生化技术使用情况,得出农业机械化是对农村劳动力的替代,替代的界限依赖于农业机械与农业劳动力的相对价格变化或相对成本变化。生化技术是对土地和劳动力的节约或替代,这两种技术代表了现代化农业发展的两条道路,但是这两种技术在农业生产中是相容的结论。本文另一个重要的研究成果是小块土地经营并没有排斥农业机械化,农业机械化只与劳动力的相对价格有关,而与土地经营的规模大小无关,这个结论与中国的现实是相符合的。     

The breakdown in rural communities—Can we stop it?

Urban and suburban growth in the United States has had a significant impact upon land use, real estate speculation, property taxation and the agricultural sector of the country. Highly productive agricultural lands are being converted to non-agricultural uses; the costs of providing public services are increasing; large quantities of potentially productive farmland are lying idle between rural subdivisions; and the sale of land in remote rural areas of the country for ‘investment’ and second home purposes creates stress in rural communities, undermines the economic viability of agriculture and limits the amount of productive farmland available for food production. This study provides a planning strategy to regulate and monitor this rural-to-urban conversion process.     

不同农村土地非农化模式的利益分配机制比较研究

随着我国城市化进程的推进,大量的农村土地正在转化为非农业用地,失地农民数量也在急速增加,并对社会稳定与发展构成了很大的压力。与此同时,农地在非农化过程中形成了巨额地租。如何根据稳定与发展的需要构建协调各级政府、集体,失地农民、企业等相关主体的利益分配机制已经成为非常重要的问题。本文提出,要协调好相关主体的利益,应当遵循社会稳定标准和社会公正标准。然后,通过对国家征地模式、集体土地直接非农化模式和国家征地并部分返还的模式进行比较,探讨了其利益分配特征及其效应。在此基础上,提出了有关政策。     

The nature conservancy's forest bank: a market-based tool for protecting our working forestland

Non-industrial forest lands represent thirty percent of the U.S.'s private forest land. Totaling 118 million acres, these areas constitute the bulk of land harvested for timber and are suffering from rapid turnover and fragmentation—a critical economic concern for the owners and a problem for the environment health of the land. Only five percent of non-industrial forest land owners have a management plan for their woods, and this number is much lower for parcels under one hundred acres.In an effort to become more creative in preserving this forest land and other areas, The Nature Conservancy has begun to develop creative tools for achieving its conservation goals. The Center for Compatible Economic Development (CCED), within the conservancy, was developed to generate economically viable ways of conserving threatened areas. One of the promising concepts developed by CCED is The Forest Bank.The Forest Bank was designed to offer landowners a new option that gives them the financial liquidity they need in the short-term, while managing their resources sustainably over the long-term. It builds on the local focus that the Nature Conservancy has already established. At the same time, the Forest Bank uses the brand identity of the conservancy to grow a business model that can be effective at protecting forest ecosystems throughout the United States and the world.     

EVALUATING THE ECONOMIC COST OF ENVIRONMENTAL MEASURES IN PLANTATION HARVESTING THROUGH THE USE OF MATHEMATICAL MODELS

An important issue being discussed for Chilean pine plantation policies is the application of environmental protection measures when managing its timber areas. Typical measures, already in place in more developed countries, include imposing riparian strips and protecting fragile soils from the use of heavy machinery. While environmental protection measures have been considered vital for decades, so far there has been almost no attempt to quantify both the benefits and costs of these measures. This paper attempts to measure the costs associated with the main measures which can help both the forestry firms and the government evaluate the cost impact of the new environmental protection regulations being studied. The analysis for different environmental scenarios is carried out by modifying a mixed integer LP, currently used for tactical planning by one forestry firm.     

Floods and Climate Change: Interactions and Impacts

Whether the floods experienced during the last decade in Germany and in other European countries are triggered or worsened by human activities has been the subject of a great deal of debate. Possible anthropogenic activities leading to increased flood risk include river regulation measures, intensified land use and forestry, and emissions of greenhouse gases causing a change in the global climate. This article discusses the latter by reviewing the existing knowledge on the subject. First, the relevance, capabilities, and limitations of climate models for the simulation and analysis of flood risk under aspects of the anthropogenic climate change are described. Special consideration is given here to differences between the "typical" spatial scale of climate models and hydrological flood models. Second, observations of trends in climate variables relevant for river flooding issues are summarized. Special emphasis is put on the Rhine and other German catchment areas. Third, the possibilities of modeling the different parts of the "cascade of flood risk" are summarized, introducing the special features of meteorological, hydrological, and river hydraulic models.     

Optimal decisions for salvage logging after wildfires

Strategic, tactical, and operational harvesting plans for the forestry and logging industry have been widely studied for more than 60 years. Many different settings and specific constraints due to legal, environmental, and operational requirements have been modeled, improving the performance of the harvesting process significantly. During the summer of 2017, Chile suffered from the most massive wildfires in its history, affecting almost half a million hectares, of which nearly half were forests owned by medium and small forestry companies. Some of the stands were burned by intense crown fires, which always spread fast, that burned the foliage and outer layer of the bark but left standing dead trees that could be salvage harvested before insect and decay processes rendered them unusable for commercial purposes. Unlike the typical operational programming models studied in the past, in this setting, companies can make insurance claims on part or all of the burnt forest, whereas the rest of the forest needs to be harvested before it loses its value. This problem is known as the salvage logging problem. The issue also has an important social component when considering medium and small forestry and logging companies: most of their personnel come from local communities, which have already been affected by the fires. Harvesting part of the remaining forest can allow them to keep their jobs longer and, hopefully, leave the company in a better financial situation if the harvesting areas are correctly selected. In this work, we present a novel mixed-integer optimization-based approach to support salvage logging decisions, which helps in the configuration of an operational-level harvesting and workforce assignment plan. Our model takes into account the payment from an insurance claim as well as future income from harvesting the remaining trees. The model also computes an optimal assignment of personnel to the different activities required. The objective is to improve the cash position of the company by the end of the harvest and ensure that the company is paying all its liabilities and maintaining personnel. We show how our model performs compared to the current decisions made by medium and small-sized forestry companies, and we study the specific case of a small forestry company located in Cauquenes, Chile, which used our model to decide its course of action.     

Ambient Asbestos Fiber Concentrations and Long‐Term Trends in Pleural Mesothelioma Incidence between Urban and Rural Areas in the United States (1973–2012)

Over the past 40 years, measured ambient asbestos concentrations in the United States have been higher in urban versus rural areas. The purpose of this study was to determine whether variations in ambient asbestos concentrations have influenced pleural mesothelioma risk in females (who generally lacked historic occupational asbestos exposure relative to males). Male pleural mesothelioma incidence trends were analyzed to provide perspective for female trends. Annual age‐adjusted incidence rates from 1973 to 2012 were obtained from the SEER 9, 13, and 18 databases for urban and rural locations, and standardized rate ratios were calculated. Female rural rates exceeded urban rates in almost half of the years analyzed, although the increases were not statistically significant, which is in line with expectations if there was no observable increased risk for urban locations. In contrast, male urban rates were elevated over rural rates for nearly all years examined and were statistically significantly elevated for 22 of the 40 years. Trend analyses demonstrated that trends for females remained relatively constant over time, whereas male urban and rural incidence increased into the 1980s and 1990s, followed by a decrease/leveling off. Annual female urban and rural incidence rates remained approximately five‐ to six‐fold lower than male urban and rural incidence rates on average, consistent with the comparatively increased historical occupational asbestos exposure for males. The results suggest that differences in ambient asbestos concentrations, which have been reported to be 10‐fold or greater across regions in the United States, have not influenced the risk of pleural mesothelioma.     

建设用地指标和建设用地的序贯拍卖定价机制研究

现行建设用地指标定价机制未能有效反映其真实价值，使得农民缺乏复垦闲置宅基地来提供建设用地指标的意愿。针对指标和建设用地的互补性特点，以及指标价值是开发商私人信息的特征，本文构建第一价格和第二价格两种密封拍卖下的互补品序贯拍卖模型，研究建设用地指标和建设用地的定价机制。理论和仿真分析得出两种拍卖下的建设用地指标和建设用地价格，并通过对比分析得出不同目标下的最优定价机制。研究发现，两种拍卖下，竞标人的建设用地指标报价均随着土地价格增值系数增加而提高，随着竞标人数递增而降低；序贯二价下的竞标人建设用地指标及建设用地的报价均高于序贯一价；序贯二价下，持有建设用地指标的竞标人获得建设用地的概率更高。因此，地方政府可采用适当提高土地闲置费用的方法，以此提高失地农民复垦权益，激励农民复垦闲置宅基地，增加建设用地指标供给；同时，采用序贯二价拍卖，提高建设用地指标和土地的利用效率。