城市建筑环境中绿色基础设施对大气颗粒物的影响

城市树木与森林作为街道、公园和其他绿色公共可达空间等城市景观的重要组成部分,是控制城市大气污染、改善城市空气质量、促进居民健康的重要环境工具,提高城市绿色基础设施的比例是解决城市空气污染问题的重要策略与手段之一,在不同建筑环境中如何配置、设计绿色基础设施,以达到最佳的空气污染治理效果,需要充分评估多种因素的影响。文章系统分析了街道峡谷、开阔道路和建筑围护结构3种城市建筑环境中绿色基础设施对空气质量的影响,阐述了在不同建筑环境中开展绿色基础设施建设需要考虑的重点问题,为在城市建筑环境中更好地设计和建设绿色基础设施提供参考。     

Peoples’ Perception Towards Urban Forestry and Institutional Involvement in Metropolitan Cities: A Survey of Lalitpur City in Nepal

Universally, trees have been recognized as an important component of urban landscapes for millennia because they provide a wide range of benefits to society. Although the planting of trees has been an integral and important part of human settlements in Nepal, the concept of urban forestry is poorly understood and often neglected. This paper investigates urban peoples?? perceptions towards urban forests as well as the perceived benefits related to the use and existence of urban forests in Lalitpur, Nepal. A survey was conducted among residents and visitors to an urban park. Most respondents held positive attitudes towards urban forests and were aware of the benefits provided. Despite involvement of various agents from both government and non-governmental organizations in promoting urban forests, greenery was declining in the city. The loss and degradation of urban forests adversely affected the ecosystems because the city is suffering from water, air and soil pollution. In recent years, the local government has promoted urban greenery; however, there are no accompanying legislation or regulations governing urban forestry. Therefore, concrete scientific and professional knowledge is required in order to manage the forestry in the city.     

The integration of planted and natural forests in a regional landscape

The 10,700 km² region of northwestern Oregon, USA, is dominated by mountainous forested landscapes fringed by agricultural lands and rapidly expanding urban areas. The Douglas-fir/western-hemlock trees, admixed with other species, in the mild, moist regional climate with rich soils are among the most highly productive of temperate forests. Timber harvest has been the dominant land use for much of this century. Many current forest stands are planted, and have the potentials to be managed and shaped for a variety of traditional and evolving forestry objectives. The ages, resilience and productivity of these forests and mosaics of land ownerships permit a variety of future scenarios of forested landscapes, constrained largely by capacities of social organizations to plan and execute management for desired future conditions. This revised version was published online in June 2006 with corrections to the Cover Date.     

厦门城市防护林体系的规划与建设

通过对厦门城市防护林现状和存在问题的分析,提出了防护林建设的原则、树种选择和规划。       

Urban Forestry as a Vehicle for Healthy and Sustainable Development

1 INTRODUCTIONGLOBALURBANISATIONUrbanisation is a worldwide phenomenon; the WorldResource Institute (2001) estimated that in 2025 morethan 50% of the African and Asian populations wouldbe living in urban areas. In Central and South Americathese figures will be between 75% and 85%. Urbanareas in developing countries will account fornearly 90% of the projected world populationincrease of 2.700 million people between 1995 and2030 (Figure 1) .Managing urban population change will b…     

北京城市森林康养资源供给能力提升建议

城市森林是位于城市范围内与居民健康关系最为密切的森林类型,对于提升城市居民的健康福祉具有重要作用。作为康养功效发挥的重要物质基础,森林康养资源与传统的林业资源具有一定的差异性,它是专指对人类身体健康有改善作用的森林资源。在以往的管理或供给能力评估中,往往更多关注森林物质资源和环境资源,而忽略了服务资源。因此,为了更好地发挥北京城市森林的康养价值,文中阐述城市森林康养资源的概念,分析北京城市森林康养资源供给现状,并在此基础上提出提升供给能力的建议:1)加强宣传,重视服务资源的保障性功效;2)加大科技支撑,构建评价指标体系;3)强化能力建设,培养专业人才;4)加大动态监测,实现“4D”实时发布。     

Trees outside forests: agro-, community,and urban forestry

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.     

森林与可持续发展

可持续发展是人类社会全方位的发展、进步、优化选择,而森林是可持续发展的保障。当今,水土流失,耕地退化,土地沙化,水资源不足等诱发的生态环境恶化,是制约我国实施可持续发展战略的障碍因素,以及“温室效应”,无不与森林有关,最好,最有效的方法是造林种草。当今全世界人民齐声大合唱的最强音,是保护环境,保护森林。森林,是民族繁荣的标志。     

果树在城市林业建设中的应用及展望

文章论述了果树在园林中应用的历史和现状,阐述了果树在城市林业建设中的特殊功能及应用前景,并提出了有关的应用建议。       

The ecology of mixed severity fire regimes in Washington, Oregon, and Northern California

Forests characterized by mixed-severity fires occupy a broad moisture gradient between lower elevation forests typified by low-severity fires and higher elevation forests in which high-severity, stand replacing fires are the norm. Mixed-severity forest types are poorly documented and little understood but likely occupy significant areas in the western United States. By definition, mixed-severity types have high beta diversity at meso-scales, encompassing patches of both high and low severity and gradients in between. Studies of mixed-severity types reveal complex landscapes in which patch sizes follow a power law distribution with many small and few large patches. Forest types characterized by mixed severity can be classified according to the modal proportion of high to low severity patches, which increases from relatively dry to relatively mesic site conditions. Mixed-severity regimes are produced by interactions between top-down forcing by climate and bottom-up shaping by topography and the flammability of vegetation, although specific effects may vary widely across the region, especially the relation between aspect and fire severity. History is important in shaping fire behavior in mixed-severity landscapes, as patterns laid down by previous fires can play a significant role in shaping future fires. Like low-severity forests in the western United States, many dry mixed-severity types experienced significant increases in stand density during the 20th century, threatening forest health and biodiversity, however not all understory development in mixed-severity forests increases the threat of severe wild fires. In general, current landscapes have been homogenized, reducing beta diversity and increasing the probability of large fires and insect outbreaks. Further loss of old, fire tolerant trees is of particular concern, but understory diversity has been reduced as well. High stand densities on relatively dry sites increase water use and therefore susceptibility to drought and insect outbreaks, exacerbating a trend of increasing regional drying. The need to restore beta diversity while protecting habitat for closed-forest specialists such as the northern spotted owl call for landscape-level approaches to ecological restoration.     

行道绿化树种选择及其栽培管理中的经济学原则

相对于其它城市森林类型,行道树的功能突出,而其生长环境却最为恶劣。在相同的立地条件和相近的抚育管理条件下,行道树树种的选择与栽培管理对街道绿化、美化的景观效果以及行道树体系在减少地表径流、改善小环境气候、净化空气、节能降耗、房地产增值等方面的社会、生态与经济综合效益的发挥起着决定性作用。行道树树种的选择除了要遵循景观规划中的美学原则和适地适树的生态学原则之外,栽培管理方便、综合效益高、经营管理效益成本比值大的经济学原则,也应该成为行道树树种规划选择和栽培管理的重要原则。     

油松过密林分超强度间伐试验研究

通过对油松(Pinus tabuliformis)过密林分采取超强度间伐试验,结果表明,对过密林分实施超强度间伐不仅可极大地改善林木生长环境和卫生状况,而且能促进保留林木快速生长发育,对提高林木质量、增加单位面积林木生长蓄积,防止病虫害的发生和入侵都十分有利,超强度间伐27年后,Ⅰ、Ⅱ级木所占比例为71%～75%,比常规间伐区高46～48个百分点。     

抚育间伐对林木生长及其稳定性的影响

不论是在人工林还是天然林管理中,抚育间伐都是一种极为常见的育林手段,在林木生长过程中具有非常重要的作用.大量实践证明,抚育间伐不仅能提高林木生长质量还有利于生态环境的改善.基于此,立足抚育间伐概念解析,分析了抚育间伐对柳杉生长和稳定性的影响,阐述了现阶段我国抚育间伐存在的问题,并提出了抚育间伐建议,以期能够为林木经营提...     

城市森林健康与监测评价研究进展

城市森林作为城市生态系统的重要组成部分,具有重要的生态功能和社会功能。城市森林健康是保证其各项功能发挥的前提。城市森林的健康状况将直接影响城市的可持续发展。城市森林健康是一个综合概念,要求不仅满足自身生态系统的健康,还应满足人类社会的经济、文化等各方面的需求。文中分析了影响城市森林健康的因素,城市环境的特殊性和人类活动是影响城市森林健康的主要原因。介绍了我国城市森林健康监测评价指标的筛选和评价方法的选择,认为其还处于实验和摸索阶段,尚未形成一套成熟的体系。城市森林结构的破碎化等特征严重影响了城市森林的自我修复能力。为保证城市森林的健康生长,众多学者从宏观尺度和个体尺度上研究城市森林健康的维护措施。文中指出城市森林健康及其监测评价研究存在的不足之处,在总结前人研究成果的基础上提出几点建议。     

Effect of the season and forest management on the visual quality of the nature-based tourism environment: a case from Finnish Lapland

The growth of nature-based tourism has raised the need to better understand tourists’ expectations towards outdoor recreation environments. There is little knowledge, however, of international tourists’ attitudes towards forest management practises or of their effect during winter. This study investigated how commercial forests correspond to the environmental expectations of international nature-based tourists and how the season affects tourists’ landscape preferences. Altogether 750 foreign visitors to Finnish Lapland responded to a survey and evaluated photographs presenting various types of forest landscapes in summer and winter. Beautiful scenery was the most important motive for the choice of travel destination and for participating in outdoor recreation. The results highlight the strong impact of seasons on the perceived quality of the landscape in commercial forests. Seasonal differences are largest in regeneration areas as snow cover mitigates the effects of forestry operations. Even-aged, middle-aged and mature forest stands were considered to be suitable for tourism in both summer and winter. There is a demand for adapted management regimes in commercial forests targeting year-round nature-based tourism. In conclusion, forestry and tourism can coexist in the same area with good planning and with management actions that take visual quality and recreational values of the environment into account.     

Sustaining family forests in rural landscapes: Rationale,challenges, and an illustration from oregon,USA

Family forests are critical components of rural landscapes, societies and economies. In Oregon, where nonindustrial private forests comprise only 16% of the forestland base, the ecological, social and economic impact of this ownership category is disproportionately large. This is due to the landscape position these lands occupy, the diversification they contribute to forest cover and local economies, and the political and cultural connections they provide to urban populations. The significance of this ownership category is even greater in the United States as a whole, where nonindustrial private forests comprise nearly two-thirds of the commercial forestland base, dominating rural landscapes in many regions of the country. Despite the important role family forests play, their ability to contribute to the wellbeing of rural areas is challenged by several dynamic factors, including industrial consolidation in global wood markets, loss of family forestland to corporate ownership, and parcelization and fragmentation of family forestland at the urban fringe. Moreover, family forestry does not enjoy a strong social contract with the American public, which is largely ignorant of the existence of this ownership class. A foundation of broad social approval and appreciation for family forestry is prerequisite to development of policies which can sustain family forestland ownerships and the contributions they make. This paper draws from recent research in Oregon to argue that, whereas most research on nonindustrial private forests has focused on economics and management at the individual producer level, these challenges demand greater attention to the role of family forests in the wider context of landscape, culture and rural economy.     

Effects of forest management on structural features important for biodiversity in mixed-age hardwood forests in Australia's subtropics

The contiguous forest landscapes of the Brigalow Belt Bioregion in Australia's subtropics, known as ‘the western hardwood forests’ are thought to be important for biodiversity conservation through the provision of continuous habitat features in an otherwise extensively cleared region. However, these forests have a long management history, as they are also important for timber production and stock grazing. Knowledge of the effect of these and other disturbances on the distribution and abundance of key structural or habitat features are limited and forest management activities thus continue uninformed. To address this knowledge gap, we investigated the effects of prescribed and non-prescribed disturbances on the distribution and abundance of six key habitat features (live and dead trees with hollows, large mature live trees, shrub abundance, downed coarse woody debris and litter cover) at 120 sites located in spotted gum Corymbia citriodora dominant forests within the western hardwoods.     

Emerging forests on abandoned land: Puerto Rico’s new forests

The species composition of forests change continuously as the earth’s biota evolves and adjusts to environmental change. Humans are accelerating the rate of species turnover by moving species around the planet and dramatically changing environmental conditions. Our focus is on new forests in Puerto Rico that emerge naturally on abandoned lands previously converted to agriculture and degraded. These forest stands have combinations of species that are new to the island’s landscapes. New forests exhibit high species dominance during forest establishment, which includes dominance by alien tree species. These alien tree species establish and maintain forest cover, which may facilitate regeneration of native tree species. Landscape analysis and literature review revealed that these emerging stands are highly fragmented (60% were <1 ha in 1991), function as refugia for native organisms, and at 60–80 years old have similar species richness and structural features as native stands of similar age. However, the island’s new forests exhibit important differences from mature native forests on unconverted forestlands. New forests have fewer endemic species and fewer large trees (≥55 cm dbh) than mature native forests; they have higher soil bulk density and lower soil carbon and litter stocks; and they accumulate aboveground biomass, basal area, and soil carbon more slowly than native forests of similar age. We suggest that new forests will become increasingly prevalent in the biosphere in response to novel environmental conditions introduced to the planet by humans.     

The tree planting and protecting culture of cattle ranchers and small-scale agriculturalists in rural Panama: Opportunities for reforestation and land restoration

To examine the opportunities available for designing diverse tree planting and land restoration initiatives in agricultural landscapes that contain tropical dry forests, the tree planting and protecting practices of cattle ranchers and small-scale agriculturalists were examined in two study sites in rural Panama. Ninety-nine tree species were identified that they utilize, plant, or protect on their land, the majority of which are native to Panama. The farmers had diverse reasons for maintaining trees, including improving the environment, providing food and shade for cattle, and generating a source of wood for construction, furniture, and firewood. Most of the trees mentioned in the study provide multiple uses and values and the majority of farmers wanted to plant additional trees. Some differences in species preferences and motivations for planting and protecting trees were seen between sites, thereby suggesting that land restoration and tree planting projects should be site specific. Our data indicate that there are ample opportunities to increase native tree cover in our study sites and highlight the need to incorporate farmer input into project design, implementation, and evaluation as a necessary and continuous feature throughout projects.     

长兴县城市森林建设总体规翅

1长兴县及规划区概况 1．1自然概况 长兴县位于长江三角洲中心地带,地处浙江省北端,东临太湖,北接江苏宜兴市,西邻安徽广德县,西南和东端毗连本省安吉、湖州市区。