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1.
Koch  Niels Elers  Skovsgaard  J.P. 《New Forests》1999,17(1-3):11-22
Following the introduction of planned forestry and the regular high forest system more than 250 years ago, forests in Central Europe became increasingly shaped by plantation silviculture. Many natural woodlands were replaced by planted forests, and forest plantations are still being established through afforestation of extensive land areas. Nowadays, forests are managed for many different purposes, including wood production, recreation, ecological, cultural, and amenity values, biodiversity, and soil and groundwater protection. This brings new challenges to forest management and silviculture. To reach a sustainable forestry, in the sense of Brundtland (WCED 1987), we are now reshaping European forestry toward a more nature oriented silviculture. Maybe forestry in the United States and elsewhere can benefit from the mistakes made in Europe during the last two centuries and take a shortcut toward sustainable forestry.  相似文献   

2.
Trees outside forests: agro-, community,and urban forestry   总被引:5,自引:0,他引:5  
Long  Alan J.  Nair  P.K. Ramachandran 《New Forests》1999,17(1-3):145-174
Planted forests are often considered to consist of tree plantings at a scale large enough to satisfy such objectives as commercial production of timber and fiber, protection of watersheds, and preservation of natural habitats. However, trees are planted also at greatly reduced scales in agroforestry systems or as community woodlots to provide a mixture of products and services to resident households, local communities, and regional cultures.Agroforestry systems represent a major form of small-scale tree planting, where trees are grown in purposeful combinations with agricultural crops and/or livestock in order to take advantage of tree-crop interactions, and thereby enhance crop production, diversify farm output, stabilize or improve soils, or ameliorate harsh environmental conditions. Some important examples of these systems in tropical countries include homegardens, alley cropping, improved fallows, intercropped trees for shade and fodder production, and trees planted in hedgerows and along fence lines. Throughout the tropics, there is a large variety of indigenous practices and species mixtures that represent adaptations of these systems to meet localized needs and opportunities. Research and development programs have supported the expansion and refinement of many of these systems during the last 20 years, but substantial constraints on tree planting still exist in the form of land-tenure practices, population pressures that relegate agroforestry practices to degraded lands, subsistence needs that prevent extended periods of tree growth, and insufficient technical information or technology dissemination.Agroforestry systems in temperate, industrialized countries include combinations of trees, pasture, and livestock; fruit or nut trees interplanted with vegetable or grain crops; windbreaks and shelterbelts; multispecies riparian buffer strips; and forest farming systems for specialty crops. Compared to the tropics, however, temperate-zone systems tend to focus on one or two high-value crops, often involve some level of mechanization, and frequently represent an opportunistic approach to improving the economic profitability of farms rather than meeting subsistence needs. In both tropical and temperate regions, agroforestry systems and community woodlots will be an important component of new sustainable agriculture and environmental protection programs.Although species diversity is an essential feature of all agroforestry systems, community forests generally involve planting only a few species in small woodlots near farms, around villages, along roads, and as riparian buffers. Provincial or state governments and the local populace are often involved in landownership and plantation establishment. Major objectives of these forests are production of fuelwood for local consumption and of other tree products for market; soil stabilization, reclamation, or improvement; and protection of water quality. As with many other planted forests, the number of species widely used in community forests has been relatively small, with the genera Eucalyptus, Pinus, and Acacia providing the bulk of the species. Major issues with these planted forests focus on rights for use of the products, tending responsibilities once trees are established, protection until trees are large enough for their designated use, increasing interest in using native species, and greater community involvement in planning and management.Trees planted along streets and waterways, or as woodlots in parks and other public places, represent a major group of planted forests in many urban and periurban landscapes. In addition to providing many of the same environmental services that agroforests and community forests do, these urban plantings have unique aesthetic and recreational value. For much of the world's ever-increasing urban population, these may be the only tangible reference points for understanding planted forests.These relatively little-recognized forms of planted forests -- planted trees, to be more appropriate -- are now receiving much greater attention. There are, however, some serious technical and sociopolitico-institutional constraints to their development as more widely adopted systems in both tropical and temperate regions.  相似文献   

3.
关于发展人工林与建立人工林业问题探讨   总被引:13,自引:1,他引:12  
王豁然 《林业科学》2000,36(3):111-117
全世界森林面积为 34 5 4× 1 0 8hm2 ,其中 3%是人工林。人工林是重要的森林生态系统 ,在木材生产、环境保护和景观建设中具有重要功能和作用。人工林在生产功能方面的补偿作用 ,使天然林可以更好地发挥生态环境价值、森林娱乐和生物多样性保护功能。人工林可持续经营的前提是遗传材料的正确选择与营林实践艺术的结合以及保证这种结合的林业政策。愈来愈多地使用外来树种营建人工林是全球趋势。人工林对于环境和生物多样性的影响 ,可以通过合理的规划和经营措施得到解决。林木育种与遗传改良和经营制度的技术创新是不断提高人工林生态系统生产力的动力。人工林的可持续经营是一个十分复杂的问题 ,中国人工林实现可持续经营面临技术和体制两方面的挑战 ,但是 ,根本出路在于林业经济体制的改革 ,象农业那样 ,在市场经济环境中实行人工林产业化经营 ,建立人工林业 (Forestplantationindustry)。  相似文献   

4.
论林木引种与森林可持续经营   总被引:6,自引:0,他引:6  
森林是实现环境与发展相统一的关键和纽带,在实现国家可持续发展中具有不可替代的作用。外来树种是森林遗传资源的重要组成部分,具有一些乡土树种难以替代的优势。外来树种人工林可持续经营的核心问题是树种与种源的正确选择,为此,保存和丰富必要的基因资源就显得极为重要。外来树种具有一定程度的环境风险,但并没有人们想象的那样大。对当地生物多样性的影响有利有弊,关键是如何科学运作,包括确定合适的地域范围,与乡土树种的合理空间布局,以及如何使之在当地生态系统中形成密不可分的生物链。最危险的情况出现于因检疫不严而带来的病虫危害。  相似文献   

5.
世界热带林现状及发展战略(续篇)   总被引:4,自引:1,他引:4  
作者认为世界工业人工林发展的基本战略趋势是:布局基地化、林工一体化、培育定向化、经营集约化、效益综合化和市场国际化。  相似文献   

6.
Industrial forest plantations are playing an increasingly important role in meeting world wood requirements. Recent successes with plantations in the tropics and Southern Hemisphere suggest potential for considerable expansion. The results of a detailed investigation of the comparative economics of industrial forest plantations in twelve regions of the globe, including nine in the tropics and Southern Hemisphere, are reported. The important factors are identified and discussed and formal investment criteria are applied. In general, the analysis suggests that the economics of plantation forests in the regions of the Southern Hemisphere examined are quite favorable, provided that the development costs, which may be substantial, can be adequately covered.  相似文献   

7.
国外针叶树种间杂交研究进展   总被引:9,自引:0,他引:9  
杂种在工业用材林中的作用越来越受到世界各国重视。数十年来不少国家都开展过广泛的针叶树种间杂交研究,为选出各自适用的种间杂种,在理论、方法和实用性方面取得重大进展。通过种间杂交创造新的、对特殊生境更有适应力的杂种对引入树种更有效果。若干外域树种引入我国后表现良好,并成为主要造林树种,探索它们的杂种利用,对开展边沿低质土地的造林有重大实用性。通过推行“杂种林业”,提高我国工业人工林的经营效益,今后将成为遗传改良的一个重要领域。本文概述世界一些国家在这一领域的经验,供实施中借鉴。  相似文献   

8.
Sedjo  Roger A. 《New Forests》1999,17(1-3):339-360
This study examines the performance and potential of intensively managed plantation forests as a source of industrial wood, and their environmental implications. The perspective of the study is global. Although it includes the United States and parts of Europe, much of the focus is on what are called the emerging plantation regions -- countries largely in the semitropical areas of the southern hemisphere -- which have not historically been important wood producers, but are growing in importance as a result of the productivity of their planted forests. The first section of this paper documents the growing importance of plantations as a source of industrial wood since the late 1970s. The study finds that plantations from nontraditional (new) regions have been growing rapidly in size and economic importance, and, thus, have been playing an increasing role as a source of the world industrial wood. Furthermore, experience seems to suggest that plantations are playing an environmentally beneficial role in (1) reducing pressure on greater areas of natural forests and (2) generating positive environmental effects as they replace degraded marginal agricultural lands. The second section of the paper examines the likely role of plantation forests in the future, and includes an assessment of financial, political and environmental considerations. This section pays particular attention to the concerns frequently expressed by environmentalists regarding plantations. Many of the objections directed at forest plantations on environmental grounds appear to ignore the substantial beneficial role of plantations on the environment. Plantations, which are financially very attractive in many locations, offer the potential of meeting large portions of the world industrial wood needs even while reducing substantially the disturbances on large areas of natural forests. This is possible because the very high productivity of plantation forests requires less area to produce industrial wood.  相似文献   

9.
发展木材工业,促进林业可持续发展   总被引:7,自引:4,他引:7  
本文从发展木材工业的七个不同层面,论述了木材工业发展与生态建设和林业可持续发展的关系,指出发展木材工业与生态建设和林业可持续发展是相互依存、相互促进的,不仅可增加林产品供给,还可大量节约木材,保护森林资源,推动林木培育,增加森林资源,有力地支持生态建设,促进林业可持续发展.  相似文献   

10.
社会林业与五指山的自然保护   总被引:1,自引:0,他引:1  
周燕华  包焱 《热带林业》2001,29(2):73-80
五指山自然保护区是世界上现存地势最高的原始热带雨林之一,是我省目前面积最大的自然保护区,也是海南三大河流的发源地。但由于保护区横跨琼中、通什、保亭三县、市,紧邻保护区还生存着众多贫困的黎、苗族村民。因此,保护区与周边社区的联系是十分紧密的,社区的发展也直接影响到五指山热带天然林的保护。海南省林业局中德海南热带林保护和恢复项目在社会林业与五指山森林的保护上做出了有益的尝试,就在全省来说,也是首次对社会林业与森林保护上进行的探索。五指山地区社会林业的研究,对保护海南热带雨林也有着积极的意义。特对社会林业与五指山的森林保护进行了阐述、分析和设想。  相似文献   

11.
The current forest planning system of Japan has been in place since the formulation of the Forest Law back in 1897. During this time, although addressing specified forests as demonstrated in the system for protection forests, in a more general sense, the execution of the forest planning system has placed forestry management at the core. In other words, it has instead been forest administration delivered in a manner relevant to forestry management. This trend is exhibited in, for instance, policies for the reorganization of common forest, the forest management planning system, forest owners associations, the proceeds-sharing reforestation system, cooperative silviculture management, and valley forestry revitalization; which have all been implemented.In this paper I review the results of these practices and explore the contemporary forest owners pattern of behavior. I also discuss the passive attitudes among forest owners, especially in comparison with the attitudes prevalent during the postwar reforestation era, continuing up to the 1960s, and the current tendency towards neglect in the afforested areas, as well as the increasing number of forest owners giving up forestry practice.In the postwar era (up to the 1960s), forestry had been following an upward trend of development that motivated forest owners to afforest, as this was the optimal choice for increasing the familys stocks for future generations (in the manner of holding an asset), and thus a rapid expansion of plantation forests resulted. By the 1970s, when domestic wood supply became less than a half of all domestic wood demand (it is still declining now), forest owners gradually began to lose interest in reforestation and care of the forest as a method of increasing assets. The current share of domestic wood supply in total consumption has dropped to 20%, and the annual cut volume is only 23% of the annual volume increment.Forests are as much a public property as they are private and, moreover, represent a globally significant resource. Active stewardship, such as materializing internationally agreed notions of sustainable forest management, promoting forest certification systems, and complying with the Kyoto Protocol, are now important issues, both domestically and internationally.The paradoxical gap between current forestry trends and public aspirations for forests is widening with each year, thus creating a grave social problem. I have been focusing on forestry revitalization as the primary step towards the resolution of this issue. As the logical basis for executing this policy, I review the relations between forest resource policies and forestry policies.At the same time, by reviewing the forest planning system and its developmental process, I sought to investigate what new policies would fulfill the need to realize the public functions of forests while revitalizing forestry, form the point of view of forestry policies and their influence on the forest planning system. I have concluded that there is a case for separating forest management from forest ownership in units of forest compartments; namely to establish an incorporative management system by which forest owners can invest in their stands.  相似文献   

12.
在过去的20年里,亚洲林业经历了引人注目的转型,包括从计划经济到市场经济的转变,从天然林供给木材到人工林供给木材的转变,木材替代品与非木质林产品的增加,地方分权与当地群众的参与,生态时代的发展与生态系统管理。在促进亚洲可持续森林资源管理中,市场工具、社区参与和环境服务都得到了应用。亚洲林业的转型表现出多样化,其森林、社会与环境之间的联系是丰富多彩的。  相似文献   

13.
The encroachment rate in forests in Bangladesh is high and increasing — accelerated by rural poverty and the demand for dwelling space and forest products — causing environmental degradation as well as loss of forest cover and productivity. The forests are managed by the Forest Department, although a substantial area of marginal land belongs to other semi-public agencies including Roads and Highways and the Water Development Board. This marginal land has been left unused or underutilized. In contrast, nongovernmental organizations have an appropriate accessibility and technology disseminating ability to utilize this land in reducing poverty and enhancing rural livelihood, and have been highly active and successful in rehabilitating encroached forests. NGOs have added a new dimension to forest management, which has ensured community participation and protection of the forests, both planted and natural. This study evaluates the social forestry activities of four large NGOs, namely BRAC, Proshika, Caritas and CARE-Bangladesh, as well as national social forestry activities. By adopting a common partnership between public and private authority, property right conflicts have been resolved and rural livelihoods enhanced, and scope has been created for utilizing marginal land. The NGO partnership has been effective in reducing poverty and improving livelihoods. As an outcome of this common partnership, 33,472 km of roadside planting and 53,430 ha of reforestation activities have been carried out during the last two decades.  相似文献   

14.
在过去的20年里,亚洲林业经历了引人注目的转型,包括从计划经济到市场经济的转变,从天然林供给木材到人工林供给木材的转变,木材替代品与非木质林产品的增加,地方分权与当地群众的参与,生态时代的发展与生态系统管理。在促进亚洲可持续森林资源管理中,市场工具、社区参与和环境服务都得到了应用。亚洲林业的转型表现出多样化,其森林、社会与环境之间的联系是丰富多彩的。  相似文献   

15.
Most research on carbon content of trees has focused on temperate species, with less information existing for tropical trees and very little for tropical plantations. This study investigated factors affecting the carbon content of nineteen tropical plantation tree species of ages seven to twelve and compared carbon content of Khaya species from two ecozones in Ghana. For all sample trees, volume of the main stem, wood density, wood carbon (C) concentration and C content were determined. Estimated stem volume for the 12-year-old trees varied widely among species, from 0.01 to 1.04 m3, with main stem C content ranging from 3 to 205 kg. Wood density among species varied from 0.27 to 0.76 g cm?3, with faster growing species exhibiting lower density. Significant differences in wood density also occurred with position along the main stem. Carbon concentration also differed among tree species, ranging from 458 to 498 g kg?1. Differences among species in main stem C content largely reflected differences among species in estimated main stem volume, with values modified somewhat by wood density and C concentration. The use of species-specific wood density values was more important for ensuring accurate conversion of estimated stem volumes to C content than was the use of species-specific C concentrations. Significant differences in wood density did exist between Khaya species from the wet and moist semi-deciduous ecozones, suggesting climatic and site factors may also need to be considered. Wood densities for these plantation grown trees were lower than literature values reported for the same species in natural forests, suggesting that the application of data derived from natural forests could result in overestimation of the biomass and C content of trees of the same species grown in plantations.  相似文献   

16.
Summary

Over the past decades, Central America has suffered some of the highest deforestation rates worldwide. Vast tracts of forest have been converted to agriculture and pasture, encouraged by ill-designed government policies and perverse incentives. Recently, however, progress has been made toward more sustainable use of forest resources by adjusting forest policies, decentralizing forest administration, and providing conducive incentives through environmental service payments and forest certification. Valuable forest management experiences have been gained by indigenous and peasant communities. Community forestry in Central America is being increasingly recognized by national governments. Examples include the community concessions in Peten, Guatemala, and community-based forest operations in Honduras and Nicaragua. Stakeholder networks have been established that strengthen horizontal and vertical alliances among wood producers and manufacturers and that help promote both community development and forest conservation. However, illegal logging, poor law enforcement, and lack of economic viability of forest management involving nontraditional species still provide barriers to the sustainable management of tropical broadleaved forests in the region. Future challenges include improved governance through decentralized forest administration, private sector involvement, and third-party certification. To improve traceability and value adding, development of integrated supply chains of forest and wood products is recommended.  相似文献   

17.
McCullough  Rex B. 《New Forests》1999,17(1-3):111-118
Privately owned tree farms and plantations share many characteristics of natural forests, multiple purpose forests, and fiber plantations. Tree farms and plantations are managed primarily for the sustainable production of solid wood and fiber; however, they increasingly play an important role in protecting all forest values. This rapidly changing role poses a challenge to forest managers -- to increase productivity to meet spiraling worldwide demand while satisfying public expectations for preserving and enhancing a full range of forest resources.These heightened expectations are prompting tree farm and plantation managers to modify proven management regimes in order to protect water quality, fish and wildlife habitat, soil productivity, and aesthetics. Proactive measures, such as establishing goals for each stewardship objective, defining measurement criteria, and third-party endorsement or certification, are helping forest managers identify and address improvement opportunities. Each of these stewardship objectives, though, can imply trade-offs in terms of yield and utilization, thus reducing the economic attractiveness of the forestry investment.In this period of rapid change, one effective strategy is to engage the public in the front end of the forest planning process. By listening and responding to public concerns, establishing common values, and allowing the public to judge us by our actions, we can begin to create awareness and trust. Only then will we attain the stable regulatory platform that is imperative for making long-term forestry investments and implementing science-based mechanisms for meaningful ecosystem enhancement.  相似文献   

18.
芬兰、瑞典林业经营管理考察报告   总被引:1,自引:0,他引:1  
芬兰和瑞典在长期的林业生产活动中,在林业可持续发展方面进行了不断的探索和实践,制定了许多行之有效的林业政策和措施,比较妥善地解决了环境保护和森林利用的矛盾,确保了森林的生产力和永续性,对我国实施以生态建设为主的林业可持续发展战略有着十分重要的借鉴意义。  相似文献   

19.
西双版纳天然林保护工程的实施对制止区内的环境退化和资源危机,协调人与自然的关系具有重要的作用.在天然林保护工程的实施过程中,对区域的经济、社会和文化造成了一定的影响.为保障社区林业的可持续发展,针对天然林保护给社区带来的影响,提出了发展非木材产品,加强经济林果的发展以及营造速生丰产林和薪炭林的对策,以实现西双版纳的天然林保护和林业可持续发展.  相似文献   

20.
热带森林生态系统具有重要的生态系统服务功能和价值,然而人类社会发展正影响着其完整性和稳定性。以巴布亚新几内亚、菲律宾和斐济为代表的太平洋岛国拥有丰富的热带森林资源,但森林资源的过度采伐和土地资源的不合理利用正在导致热带森林面积急剧减少。文中介绍了巴布亚新几内亚、菲律宾和斐济这3个太平洋岛国的森林资源现状,着重分析和比较了这些国家的森林资源现状、林业管理体制、政策与机构,以及林业生产与贸易状况,以期为在“一带一路”倡议下我国开拓太平洋岛国地区国际市场提供重要信息支撑。  相似文献   

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