城市森林效益与可持续性研究展望

正确认识城市森林的功能和效益 ,探索不同管理措施对城市森林效益的影响 ,对实现城市森林的可持续性具有十分重要的意义。本文综述了城市森林对生态环境和生态过程产生的影响及生态和社会效益 ;分析了城市森林可持续性的内涵及特征 ;对城市森林可持续性模式及评价标准、城市森林生态学等领域的研究成果和发展方向进行了归纳分析。在分析目前我国城市生态环境面临的问题的基础上 ,进一步提出城市森林是构建城市绿色空间的主体。建设可持续城市森林是实现城市经济和环境可持续发展的重要途径。     

Silphids in urban forests: Diversity and function

Many ecologists have examined the process of how urbanization reduces biological diversity but rarely have its ecological consequences been assessed. We studied forest-dwelling burying beetles (Coleoptera: Silphidae)—a guild of insects that requires carrion to complete their life cycles—along an urban-rural gradient of land use in Maryland. Our objective was to determine how forest fragmentation associated with urbanization affects (1) beetle community diversity and structure and (2) the ecological function provided by these insects, that is, decomposition of vertebrate carcasses. Forest fragmentation strongly reduced burying beetle diversity and abundance, and did so far more pervasively than urbanization of the surrounding landscape. The likelihood that beetles interred experimental baits was a direct, positive function of burying beetle diversity. We conclude that loss of burying beetle diversity resulting from forest fragmentation could have important ecological consequences in urban forests.     

清代棚民问题侧论

农民背井离乡,到山间开垦并种植山地,开发种种山林资源,以谋生存,被称为棚民.清代棚民,数量庞大.政府为了维持社会稳定,对棚民采取安辑的政策.棚民对山地等山林资源的开发,严重破坏了生态环境,造成了严重的后果.对社会维稳和生态维护的两难选择,包世臣的应对策略,很有意义.     

西部民族地区退耕还林还草的法律保障探讨

自然生态环境是人类赖以生存的基本条件,是经济社会发展的根本基础。自然生态环境的不断恶化,已成为制约西部地区经济社会持续发展的严重问题之一。我国制定“退耕还林还草”战略决策最主要的目的,就是为了给西部地区人民营造一个新的生存和发展空间。实施“退耕还林还草”的战略决策,必须尊重群众意愿,确保林草的成活率;必须遵循自然规律,因地制宜,宜林则林,宜草则草,实行综合治理;必须严格执行国务院关于“退耕还林、封山绿化、以粮代赈、个体承包”的法规措施;必须认真落实保护农民土地经营权的法律规范,树立生态环境可持续发展的法律协调观;必须建立和健全西部地区生态效益补偿机制,充分利用价格杠杆的作用促进西部地区的生态平衡。西部大开发要维护经济发展与生态的良性循环,建设山川秀美的新家园,让西部地区人民群众脱贫致富奔小康。     

二十世纪日本学者对云南少数民族历史文化的研究

介绍和评析了鸟居龙藏等日本学者对云南的田野调查、华南民族史、傣族史、南诏和大理国史、倭族之源、照叶树林文化、神话、民间故事、民间信仰和民间祭祀等方面的研究成果,并系统地分析了日本学者对云南少数民族历史文化研究的全貌、学术研究的轨迹及新动向。     

Forest leaf litter quantity and seedling occurrence along an urban-rural gradient

Leaf litter, by modifying microenvironmental conditions, can alter plant population distributions and is considered to be a major force in structuring many plant communities. Comparative studies of urban, suburban, and rural forests in the New York City (NYC) metropolitan area have identified numerous biotic and abiotic differences among these forests, including several involved in leaf litter decomposition. These differences in decomposition among the forests could result in differences in litter quantity on the forest floor and hence microenvironmental conditions and safe sites for germination of different plant species. We conducted a survey of forest floor leaf litter quantity in forests located along an urban-to-rural land-use gradient originating in urban NYC and extending to rural Connecticut. Mean litter depth, mass, and density increased significantly with increased distance of the forest from NYC.We also surveyed woody seedlings and compared the litter depth in which they naturally occurred to the mean litter depth of the surrounding forest. Seedlings of small-seeded species were much more likely to be located in litter shallower than mean forest litter depth than were seedlings of large-seeded species. Taken together, these results suggest that environmental changes associated with urbanization may have profound effects on long-term patterns of forest regeneration.     

Bias-corrected random forests in regression

It is well known that random forests reduce the variance of the regression predictors compared to a single tree, while leaving the bias unchanged. In many situations, the dominating component in the risk turns out to be the squared bias, which leads to the necessity of bias correction. In this paper, random forests are used to estimate the regression function. Five different methods for estimating bias are proposed and discussed. Simulated and real data are used to study the performance of these methods. Our proposed methods are significantly effective in reducing bias in regression context.     

黑龙江省发展碳汇林业对策研究

全球气候变化主要源于二氧化碳等温室气体的人为排放累积产生的温室效应,而森林在生长过程中能起到减少温室气体累积的作用。为了应对全球气候变化,在发展低碳经济的今天,森林的吸碳功能越来越吸引人们的青睐和重视。黑龙江省具有丰富的森林资源,在低碳经济转型期间,应把握林业对气候变化发展大局的重要影响,努力探索如何发展碳汇林业,将绿色能源转化为发展的动力,充分发挥自身优势,以林业带动地区环境、经济及社会全面协调可持续发展。     

云南省南华县彝族松茸山林权安排和 利益分配机制

采用参与式乡村评估的方法,通过对云南省南华县4个自然彝族村寨的案例调查,展示了在传统和现代交织中彝族村民自发的松茸山确权过程,分析了乡土利益分配机制的合理性,得出"权不是赋的,而是争的".认为在集体林权改革过程中,需要注意集体林权改革的复杂性和森林的多功能性,理解林权以当地人可触及的方式存在于人们生活中,需要赋予当地社区群众争取权利的空间和制度平台.