退耕还林工程补偿机制研究--以陕西延川退耕还枣为例

由于国家在退耕还林工程中,要为参与项目实施的农户提供补偿,因此,随着工程规模的扩大,用于退耕还林补助方面的开支也日益增加,这给国家财政造成了巨大的负担。该文以陕西延川参加退耕还枣的农户为例,通过成本-收益分析得出结论,认为现行的补助标准高于国家实际应支付的补助额,即退耕还林补助开支存在一定的节约空间。在此基础上,文章提出政府应降低现行的补助标准,把全国统一的补偿标准制度改为由各地分别制定,以及调整退耕资金的使用方向等政策建议。     

森林文化建设问题初探

森林文化是人类在社会实践中创造的森林物质财富和精神财富的总和,该文特指森林精神财富。加强森林文化建设,既是落实科学发展观、构建和谐社会的重要举措,又是推进生态建设和林业发展、发展先进文化的必然要求。森林精神文化建设主要包括森林哲学、森林自然科学和森林社会科学3项内容。建设我国特色社会主义森林文化要批判地继承古今中外的森林文化成果,认真总结当代森林建设的经验教训,并进行理论创新,尤其是要大力弘扬祖国优秀的森林文化传统。建议今后加强相关学术研究与交流,举办科普宣传活动,建设文化载体,加强人才培养。     

广东现存明清时期涉林碑刻的历史启示

该文从研究碑文的内容入手,深入剖析了广东现存明清时期60通涉林碑刻丰富的人文内涵,并对此一时期广东森林资源的变迁与严重水患等自然灾害之间的紧密联系,进行了较为深刻的历史反思。     

重庆市林木种苗生产现状分析

随着我国“六大林业工程”的全面启动以及城市绿化面积的增加,市场对苗木的需求量呈逐年上升趋势。尽快推进林木种苗产业化发展,是适应现代化林业工程造林的需要的,本文通过对重庆市林木种苗生产现状的分析,针对其中存在的问题,提出了促进重庆市种苗产业化的一些建议。     

Predicting risk for adverse health events using random forest

Estimation of person-specific risk for adverse health events in medicine has been approached almost exclusively using parametric statistical methods. Random forest is a machine learning method based on tree ensembles that is completely nonparametric and for this reason may be better suited for risk prediction. An introduction to a random forest is provided with a focus on its application to risk prediction. Using data from a total joint replacement registry, we illustrate risk prediction for the binary outcome of 90-day mortality following implantation, as well as time to device failure for aseptic reasons with the competing risk of mortality. Using the methods described in this paper, the random forest could be applied to risk prediction in a wide variety of medical fields. Issues related to implementation are discussed.     

Land-use planning to conserve habitat for area-sensitive forest birds

Models predicting the occurrence of area-sensitive bird species in forests were developed from bird survey data from 499 forests in Prince George's County, Maryland. The predicted probabilities of occurrence for species were integrated with forest cover data for the County in a Geographic Information System (GIS). This information was used in combination with local zoning and forest conservation requirements to develop a preliminary forest conservation plan for the watershed of the Western Branch of the Patuxent River. We identify forests patches most likely to support breeding populations of area-sensitive birds, and use the GIS to devise ways to consolidate and link them. Forests that do not contribute significantly to the integrity of these priority forests are designated as sites in which development could occur. The resulting conservation plan will maintain and enhance breeding habitat for area-sensitive forest birds, while still allowing for additional development as human populations increase.     

The natural South Florida system I: Climate,geology, and hydrology

Developing hypotheses for sustainability requires an understanding of the natural forces that shaped the historical Everglades prior to extensive engineering of the landscape. The historical Everglades marsh covered 10,000 km² in a 100-km-long basin that has an extremely low gradient (slope of only 3 cm · km^-1). The region is characterized by a heterogeneous landscape that has developed over the past five millennia, functioning as an interconnected mosaic of wetland, upland, estuarine, and marine ecosystems. The boundaries of this system were defined as the historic drainage basin from the Kissimmee River system through Lake Okeechobee, the Everglades, Florida Bay, and out through the Florida Keys to the coral reef tract. This geographic area is interconnected through the regional hydrology, with its unifying surface and subsurface freshwater transport system. However, in the final analysis, the interaction of geologic and climatic processes determine the system's hydrology, a major determinant of community and landscape structure and the point of connectivity between natural and human systems. This review examines the role of climate, geology, soils and sediments, topography, and hydrology in shaping and modifying ecological systems through time. However, it is clear from the wetland nature of this system that the predrainage hydrologic features were critical to the sustainability of the Everglades. Important hydrologic features include sufficient water quantity, storage, and sheetflow, and the appropriate hydroperiod and timing of water releases over both annual and interannual variations in precipitation.     

森林生态系统文化服务功能评价与发展对策——以老君山自然保护区为例

为了促进自然保护区森林生态系统文化服务功能开发利用,以河南老君山自然保护区为研究对象,基于半结构式访谈及地理空间数据,利用SolVES模型和核密度工具对森林生态系统文化服务功能进行评价并提出对策建议。建立的包括森林美学、自然历史、自然教育、森林文化和森林游憩5个评价指标均呈现聚集分布状态,可以用来对研究区进行森林生态系统文化服务功能分区,其中森林美学和森林游憩的功能标识点数量分别达到324和279个,占全部功能标识点数量的31.55%和27.17%。森林文化区森林生态系统文化服务功能丰富度指数、多样性指数和稀有度指数均最高,分别为13.95、0.98和1.67,是研究区提供森林生态系统文化服务功能的核心区域。研究结果可为森林自然保护区及国家公园文化服务资源的优化布局及合理开发利用提供借鉴和指导。     

国际森林生态补偿制度创新的比较与借鉴

系统地介绍和比较了美国、德国和日本在森林生态补偿方面的制度创新活动,并积极借鉴国际经验,针对中国森林生态补偿制度存在补偿责任承担公平性不足、补偿主体过于单一、补偿标准偏低、补偿时象范围不够宽泛、补偿资金溃乏等问题提出解决方案。建议中国政府：重新设计补偿制度,以受益者承担原则打破公共责任原则,确保补偿责任公平分担;以政府补偿为主,以市场补偿为辅,改变补偿主体单一现状;在明确林权的同时,考虑增加对其他国有公益林乃至私有林的补偿;采取成本补偿与机会成本补偿相结合原则,提高补偿标准并实施有差别补偿;通过开征生态税、设立风险准备金、实施碳汇交易和开通生态交易服务市场等,以获得稳定的补偿资金来源。     

多重视角下中国省域科技产出的影响因素研究

基于区域经济发展、科技人力资源投入、科技财务资源投入、科技物资资源投入和科技环境等多重视角,以2012—2016年中国31个省、市、自治区(香港、澳门、台湾地区除外)科技产出为被解释变量,以滞后1期的科技产出影响因素为解释变量,运用最大信息系数和随机森林回归进行分析。研究结果表明:我国科技产出总体呈上升趋势,但各区域的差异不断扩大;科技产出与部分影响因素之间存在较强的非线性关系;科技产出主要受仪器和设备经费、R&D经费支出用途、R&D人员和工作量、高技术产品进口贸易额等因素的影响,受其他变量影响较小。据此,建议加强科技资源优化配置,重视科技人才的引进和培养,不断提升自主创新能力和核心竞争力。