西双版纳原始热带季节雨林净初级生产力

研究了西双版纳原始热带季节雨林生物量增量、凋落量、叶虫食量和净初级生产量.该雨林年平均净初级生产量为25.764 t/hm2.a,其中各层次的净初级生产量分别为:乔木层23.972 t/hm2.a(占总净初级生产量的93.04 %)、灌木层0.749 t/hm2.a (占2.91 %)、木质藤本层0.431 t/hm2.a(占1.67 %)、草本层0.612 t/hm2.a(占2.38 %).乔木层净初级生产量分配为:凋落量11.566 t/hm2.a、叶虫食量0.694 t/hm2.a和生物量增量11.712 t/hm2.a.     

川西北地区经济林资源评价及其发展对策

研究表明，川西北地区自然环境复杂，生态类型多样，河谷及部分山地发展经济林木具有环境适宜、类型丰富、消费市场大、土地资源相对充裕等优越条件，但发展缓慢．为发挥资源优势与潜力，从农业结构、管理体制、科学技术等探讨了制约因素，提出了发展对策．     

甘肃胡杨恢复发展的限制因子及对策

甘肃胡杨正处于负向演替的衰退状态,在现存的14590 hm²胡杨林中,衰退林和成熟林就占了73.0%,且大多为胡杨疏林;而树龄小于15年的幼龄林仅占了5.0%,1~5年生天然更新苗十分罕见。影响、限制甘肃胡杨天然林恢复发展的主要因子是林地水土环境的恶化;而胡杨无性繁殖困难、实生苗在生长形态方面表现参差不齐等因素,又限制了胡杨的人工发展。只有在突破胡杨无性繁殖难关的基础上,通过良种繁育调动群众营建人工胡杨林的积极性,才是恢复发展胡杨林的根本出路。     

PETROCHEMICALS AND ECONOMIC DEVELOPMENT: THE IMPLICATIONS OF THE PUERTO RICAN EXPERIENCE*

The oil refining and petrochemical industries have occupied an important role in Puerto Rico's development strategy since the early 1960s. However, the hopes epitomized in various planning models of highly integrated and diversified oil-based industrial complexes have not been fulfilled. This paper attempts to account for the discrepancy between official expectations and subsequent events in Puerto Rico and indicates some of the lessons for other developing countries.     

PERI‐URBAN AGROFORESTRY IN THE BRAZILIAN AMAZON*

ABSTRACT. Together, urbanization and the search for sustainable development present a dilemma in the Brazilian Amazon: how to accommodate an expanding urban population while creating and maintaining sustainable production systems that feed the people and manage the forest. A unique peri‐urban agroforestry project, implemented by a municipal government in western Amazonia and concerned with a citywide influx of rural agriculturalists and former forest‐dwelling extractive producers, is examined as a source of food and self‐determination. Peri‐urban agroforestry seems to be a viable option for other Amazonian cities that are experiencing increasing urbanization and its associated problems.     

AVOIDING THE DEMISE OF GEOGRAPHY IN THE UNITED STATES

This is the second of two articles about challenges that confront geography departments in a changing academic environment. College enrollment trends and tightening budgets are placing geography programs in jeopardy because the discipline is not considered by society to be indispensable. Departmental survival in a period of retrenchment may depend upon successfully demonstrating utility and quality, identifying unfilled niches in individual institutions, developing new interdisciplinary organizational arrangements, or finding ways to strengthen geography's position in governmental definitions of useful academic training.     

邵阳市森林资源特征及林业可持续发展对策

阐述了邵阳市林业生产条件, 分析了邵阳市森林资源特征、林业生产的地位及现存问题, 并对邵阳市林业可持续发展提出了相应的建议。文中重点探讨了林业分类经营问题, 提出了在建设商品林的同时必须注重生态公益林的建设。     

河西防护林体系的持续高效发展

祁连山水源涵养林和河西走廊防风固沙林的持续高效发展,必须通过社会林业和优化林业内部结构来实现。     

广东省森林公园发展态势及对策研究

森林公园及森林生态旅游业已在广东省社会、经济和生活中发挥举足轻重的作用,是广东省林业部门进行森林资源立体开发、综合利用的优势项目,也是广东省全面发挥森林多种效益的一项系统工程。文中介绍广东省森林公园发展的现状特点,借鉴国外森林公园建设的经验教训,在管理、立法、资金、基础设施优化以及精品促销等方面进行了有益的探讨,力求促进广东省森林公园建设事业持续、快速、健康发展和经济、社会、生态三大效益相互协调。     

URBAN STRUCTURE AND THE DEVELOPMENT OF NATURAL SUPPORT SYSTEMS FOR SERVICE-DEPENDENT POPULATIONS*

This paper suggests that the delivery of services to dependent populations can be facilitated by the existing urban structure, particularly the prevailing patterns of homogeneity and heterogeneity. As a complement to formal attempts to improve the delivery of services and alter what often appears to be a spatially and socially unjust urban structure, the paper provides examples of simple interventions that can expand and enhance informal service delivery at the local level.     

INTERMODAL TRANSPORTATION IN NORTH AMERICA AND THE DEVELOPMENT OF INLAND LOAD CENTERS*

This paper analyzes the changes that are transforming intermodal transportation in the United States and Canada. Traffic is being concentrated at a relatively small number of inland load centers that serve as regional truck distribution points, and are linked by high volume dedicated train services. Both theoretical and practical implications of the changes are examined, and a range of research questions are presented.     

区域持续发展与行业开发

持续发展是我国的基本国策，各级政论要使其所在区域实现持续发展的目标，必须考虑在保护环境生态的基础上，通过相应的经济起步和发展措施，逐步提高经济发展水平，以满足人口的不断增长以及相应的物质“享受的需求增长。     

基于物种喜光性划分的热带山地林植物功能群及变化规律

依据物种为对光照不同要求,划分海南岛热带林物种为不同喜光性的功能群,应用NMS、非参数单因素方差分析法(ANOVA)和多重比较法(Post Hoc Tests)等方法,分别研究各功能群与环境因子的关系,及其随热带林不同干扰类型和恢复时间的变化差异.结果表明:(1)海南岛热带山地雨林以耐阴性功能群组成为主,主要分布于沟谷和坡地老龄林中,与热带林的恢复时间、土壤石砾含量、pH、全P和速效K成正相关,与海拔高度和土壤有机质成负相关性.(2)喜光性功能群主要存在于次生林中,与干扰类型、土壤速效和全N成负相关性,与采伐强度成正相关性.(3)随着刀耕火种后山地雨林次生林的恢复时间增加,强耐阴性功能群的分布增加,而喜光性功能群的分布则减少.(4)随着人工采伐后山地雨林次生林的恢复时间增加,各功能群的分布变化不明显.     

SEASONAL FLOODPLAIN‐UPLAND MIGRATION ALONG THE LOWER AMAZON RIVER*

ABSTRACT. A current pattern of seasonal migration, particularly among smallholders, is marked by movement between the Amazon River floodplain and upland bluffs near the city of Santarém, Brazil. Nearly fifty years of jute cultivation “subsidized” residents of the floodplain, enabling them to remain there year‐round. Without this subsidy, annual flooding and the concomitant seasonal dearth of cash‐economy activities make permanent occupancy difficult. The present‐day seasonal migration and complementary use of both upland and floodplain environments has broad implications for theories about past patterns of settlement and for the region's future sustainable development.     

RURAL REGIONAL GOVERNANCE IN THE UNITED STATES: THE CASE OF THE RESOURCE CONSERVATION AND DEVELOPMENT PROGRAM*

Rural governance has drawn considerable attention from both local government officials and scholars in the United States since the early 1990s. It is touted as a way to mitigate the limitations of the traditional government unit‐based approaches to problem solving and decision making and to foster partnerships across both jurisdictional boundaries and sectors (public, private, and nonprofit). Established in 1962, the Resource Conservation and Development (rc&d ) program of the U.S. Department of Agriculture provides a unique model of rural regional governance. Acting as a coalition of governments, private businesses, individuals, and interest groups, the rc&d program provides the flexibility needed to deal with issues at the appropriate spatial scale. It incorporates aspects of both grassroots and governmental organizations and can bring together local interests and expertise with governmental policy and support in service provision, problem solving, and economic development. The approach does not necessarily entail loss of power on the part of the state, but it does provide a mechanism for local people to exercise their agency, to tackle their problems, and to decide which elements of their lives they want to sustain.