中国环境污染与经济增长关系的实证分析

运用主成分分析法、格兰杰因果分析法、基于VAR模型的广义脉冲响应函数法与方差分解法对我国1989-2009年期间环境污染与经济增长的动态关系进行了研究.结果表明,经济增长是导致我国环境污染的重要原因,发展经济带来的环境恶化具有滞后性;经济增长的代价是环境污染,且这种交换是一种长期模式.然而,环境污染带来的经济增长却是短暂的,其动力很快将会消失殆尽,并长期反作用于经济增长,制约经济的长期发展.     

乡村社区-旅游景区共生模式研究

合理科学的开发模式既能够深化旅游开发研究,又能够对旅游开发实践加以正确引导.在解读乡村旅游已有开发模式的基础上,较全面地阐释了社区-景区共生模式的内涵、演化过程以及模式构成,梳理了社区-景区共生模式的基本运作过程,并对该模式的效益进行评估.     

Impact of closed-loop network configurations on carbon footprints: A case study in copiers

Growing concerns about the environment make a supply chains’ eco-footprint increasingly important, presuming that footprints are a more effective (policy) instrument than those currently in use. The eco-footprint comprises all kinds of environmental impact, but often is narrowed down to one aspect; e.g. the carbon footprint, material footprint, the water footprint, and so on. Although returns give rise to an additional goods flow from customers back to producers, it usually improves the eco-footprint due to the substitution effect. The reverse channel supplies high quality (recovered) products, components and materials to the forward channel thereby reducing the need for virgin sourcing and production. We refer to this as closed-loop recovery, as opposed to recovery for cascade markets which lacks substitution. To maximize substitution, the recovered items must re-enter the original supply chain. The feasibility of closed-loop recovery depends partly on the geographical proximity of forward and reverse facilities. We develop a decision framework for optimizing closed loop network configurations, i.e. the combined disposition and location–transport decision. We apply the framework to a single case study concerning one type of footprint (namely the carbon footprint) of a copier (closed-loop) supply chain. The main implication is that a regional network, with combined forward and reverse facilities per continent, proves most efficient and most robust in view of uncertain exogenous variables, but only when a full set of closed-loop options is available (including closed-loop recycling). As an embedded case, main contribution value of it lies in the discovery of a new phenomenon with generic implications; namely that not only the closed-loop supply chains footprint strongly depends on the substitution effect, but that in turn the feasibility of closed-loop recovery options depends heavily on the network design. From delineations of the study we derive issues for further research.     

基于Markov模型的南京土地利用时空变化研究

利用江苏2000年、2008年遥感数据,采用ArcGIS和Excel测算出南京市辖区8年土地利用的Matkov转移矩阵,从数量、空间和结构角度分析2000-2008年的土地利用变化状况,预测2016年的各类用地面积.结果表明,2000-2008年研究区的城镇和工矿交通用地扩张较快,农村居民点用地略有减少,呈集中态势;耕地、草地、林地、水域减少,未利用地减幅最大.在空间上,研究区的建设用地扩张由"同心圆状"变为"纺锤状",土地利用集中度和强度都增大.2016年预测显示,城镇用地比重达44.76%,耕地减少23.47%,其余用地基本保持前8年的变化趋势,但动态度有所减小,仅农村居民点用地减幅增大.     

陕西旅游资源富集县县域经济发展模式研究——以华阴市为例

陕西省作为我国的旅游资源大省,通过着力发展比较优势明显的旅游产业来促进县域经济发展本是大势所趋,但目前旅游业与工农业发展的孤立性又是约束县域经济发展的一道"紧箍咒",如何在旅游大发展的背景下实现旅游产业与县域经济的互动发展具有极为重要的理论与实证意义.通过分析华阴市2002--2009年旅游产业对县域经济的贡献能力,切实考虑当前该市县域经济发展中存在的主要问题,从旅游产业的视角出发,归纳出陕西旅游资源丰富地区县域经济发展的模式,以期为陕西省县域经济的发展提供对策和建议.     

成都龙泉山地区建设用地生态适宜性评价

随着景观格局与生态过程之间的关系日益受到重视,传统的评价方法已经不能满足生态适宜性评价的发展需要。本文以成都市龙泉山地区为例,从景观类型、生态功能、生态价值、土壤侵蚀敏感性和地质灾害敏感性5个方面建立评价指标体系,分别采用最小累积阻力模型和模糊综合评判法描述水平生态过程和垂直生态过程下的生态适宜性,综合两种评价结果进行建设用地的生态适宜性评价。研究结果表明,模型机理的差异使评价结果有着很大的区别,两种方法的综合应用可以有效弥补彼此的不足,本文将研究区的生态适宜性评价结果划分为禁止开发区、严格限建区、一般限建区、重点开发区和优化开发区5个分区,各区的面积分别为259．70km^2、793．89km2、1220．35km2、739．68km2和490．42km2。以往的生态适宜性评价方法往往单一地考虑水平或者垂直生态过程,本文构建的这种综合水平和垂直生态过程的评价方法为生态适宜性评价的方法研究提供了有益的尝试和补充。     

A harvest failure approach to assess the threat from an invasive species

We present the idea of using potential infringements on annual allowable harvest targets as an approach to estimate threats from invasive species to the forest products sector. The approach uses present-day harvest levels as a reference level to estimate when and where the impact of a nonnative forest pest could become economically damaging. We use a generic model that simulates spread and damage by nonnative invasive species, basic harvest and forest growth through time. The concept is illustrated with a case study of a new nonnative invasive pest, Sirex noctilio Fabricius on pine resources in eastern Canada. Impacts of invasion on wood supply, in particular, the point at which present-day harvest levels are not attainable, were identified for 77 non-overlapping geographical regions that delimit the primary wood supply areas around large mills and wood processing facilities in eastern Canada. The results identify the minimum area of a pest outbreak that could trigger harvest shortages (approximately 12.5–14 M ha of pine forests in Ontario and Quebec). Beyond this level, the amount of host resource available for harvesting in any given year declines rapidly. The failure to sustain broad-scale harvest targets may be an attractive and intuitive indicator for policy makers and regulators interested in developing control and “slow-the-spread” programs for non-native forest pests.     

Determining advanced recycling fees and subsidies in "E-scrap" reverse supply chains

Primarily due to environmental concerns and legislative mandates, the disposition of end-of-life (EOL) electronics products has attracted much attention. Advanced recycling fees (ARFs) and government subsidies may play important roles in encouraging or curtailing the flows of recycled items. We present a Stackelberg-type model to determine ARFs and socially optimal subsidy fees in decentralized reverse supply chains where each entity independently acts according to its own interests. The model consists of one leader (the government) and two followers (a group of manufacturers, importers, and sellers (MISs) and a group of recyclers). To maximize social welfare, the government determines the ARFs paid by MIS and the subsidy fees for recyclers when MIS sells new products and recyclers process EOL products. We find that MIS and recyclers behave at the equilibrium status by choosing optimal selling quantity in the market and optimal reward money for customers bringing EOL products to recyclers. Under this approach the two fees achieve the maximum of social welfare at the equilibrium status, while both MIS and recyclers gain the maximum of profits. For comparative purposes, we also develop a conceptual model describing the current practice by which ARFs and the subsidy fees are determined on the basis of fund balance between revenues and costs along with recycling operations. We conclude that our results outperform current practice.     

Relationships between net primary productivity and stand age for several forest types and their influence on China's carbon balance

Affected by natural and anthropogenic disturbances such as forest fires, insect-induced mortality and harvesting, forest stand age plays an important role in determining the distribution of carbon pools and fluxes in a variety of forest ecosystems. An improved understanding of the relationship between net primary productivity (NPP) and stand age (i.e., age-related increase and decline in forest productivity) is essential for the simulation and prediction of the global carbon cycle at annual, decadal, centurial, or even longer temporal scales. In this paper, we developed functions describing the relationship between national mean NPP and stand age using stand age information derived from forest inventory data and NPP simulated by the BEPS (Boreal Ecosystem Productivity Simulator) model in 2001. Due to differences in ecobiophysical characteristics of different forest types, NPP-age equations were developed for five typical forest ecosystems in China (deciduous needleleaf forest (DNF), evergreen needleleaf forest in tropic and subtropical zones (ENF-S), deciduous broadleaf forest (DBF), evergreen broadleaf forest (EBF), and mixed broadleaf forest (MBF)). For DNF, ENF-S, EBF, and MBF, changes in NPP with age were well fitted with a common non-linear function, with R(2) values equal to 0.90, 0.75, 0.66, and 0.67, respectively. In contrast, a second order polynomial was best suitable for simulating the change of NPP for DBF, with an R(2) value of 0.79. The timing and magnitude of the maximum NPP varied with forest types. DNF, EBF, and MBF reached the peak NPP at the age of 54, 40, and 32 years, respectively, while the NPP of ENF-S maximizes at the age of 13 years. The highest NPP of DBF appeared at 122 years. NPP was generally lower in older stands with the exception of DBF, and this particular finding runs counter to the paradigm of age-related decline in forest growth. Evaluation based on measurements of NPP and stand age at the plot-level demonstrates the reliability and applicability of the fitted NPP-age relationships. These relationships were used to replace the normalized NPP-age relationship used in the original InTEC (Integrated Terrestrial Ecosystem Carbon) model, to improve the accuracy of estimated carbon balance for China's forest ecosystems. With the revised NPP-age relationship, the InTEC model simulated a larger carbon source from 1950-1980 and a larger carbon sink from 1985-2001 for China's forests than the original InTEC model did because of the modification to the age-related carbon dynamics in forests. This finding confirms the importance of considering the dynamics of NPP related to forest age in estimating regional and global terrestrial carbon budgets.     

Sustainable recycling model: A comparative analysis between India and Tanzania

Higher economic growth in developing countries has caused higher amounts of wastes. Local government authorities in these countries usually fail to provide adequate services to dispose the increasing amounts of waste, resulting in threats for both the population and environment health. There is therefore an urgent need for recycling as a form of waste management in order to stop the devastating effects of solid waste in developing countries. Using a qualitative method of analysis, this study presents a model to measure and rank the sustainability of recycling programs in India and Tanzania. The model consists of six main constructs including “production, economic, governmental, social, technological, and international factors”. The results showed that India outperforms Tanzania in sustainable recycling programs: per capita waste generated per day in Delhi is higher than in Dar es Salaam; the government of India focuses more on developing recycling plans and techniques as compared to the government of Tanzania where the country is not actively involved in the recycling process; and the solid waste management planning in India is being performed better than Tanzania.