库区主要经济林水源涵养功能分析

以刺槐林和灌丛草地为对照,研究了黄前库区流域主要经济林类型柿树林和板栗林对降水的截留和分配作用,研究结果表明:4种植被类型的涵养水源,保持水土功能总体比较为刺槐林>柿树林>板栗林>灌丛草地,即经济林的涵养水源,保持水土作用介于森林和灌丛草地之间。     

Perceptions of land‐degradation,forest restoration and fire management: A case study from Malawi

Understanding local perceptions of degradation and attitudes to fire management are critical for gaining support for restoration work and improving livelihoods. Deforestation and annual burning are causing significant land degradation problems in the area around Bandawe, northern Malawi. We mapped evidence of soil erosion and remaining areas of woodland. Gully erosion was common and primarily associated with heavily utilised footpaths. Areas between gullies showed signs of significant soil movement. Remnant patches of native woodland existed but were small, degraded and isolated. We interviewed local households to understand local awareness and impacts of land‐degradation, its perceived cause and preferred methods for restoration. All households were aware of the presence of gullies and reported associated problems of flood damage. Most households believed erosion was a result of deforestation. Burning practices were seen to have exacerbated erosion problems. Changing fire management practice was not seen as realistic as it risked reducing the productivity of grasses and fires were perceived to be too difficult to control. Tree planting was the community's preferred approach to tackling erosion. Their focus was on planting exotic fruit and timber trees around houses and they often requested that such work be done by volunteers. Such attitudes may have been influenced by recent extension work and a desire to secure ownership of utilisable resource. Ecologists in the miombo zone should focus on improving fire management practices and involving communities in creating diverse secondary woodlands that provide a range of goods and services. Copyright © 2010 John Wiley & Sons, Ltd.     

Habitat conservation priorities in British and European woodlands

Five types of British woodland are particularly important for habitat conservation, namely; relicts of medieval wood-pasture management; ‘native’ pine and birch woods in the Scottish Highlands; some coppices on ancient woodland sites; woods on inaccessible sites; and woods with a long period of natural structural development. The case for these priorities rests on the concepts of non-recreatability and past-naturalness, which are discussed. Together these woods form no more than 20% of existing woodland. Comparison with woodlands and forestry practice in Czechoslovakia and France shows how much the definition of priorities depends on the particular climate, woodland history and current forestry practices of Britain. The same concepts can apply to other semi-natural habitats in some circumstances.     

Tobacco cultivation as a driver of land use change and degradation in the miombo woodlands of south‐west Tanzania

Miombo woodlands support agriculture, biodiversity, and multiple ecosystem services across an extensive part of sub‐Saharan Africa. Miombo is frequently overutilised with deforestation and degradation resulting in significant land use and land cover change (LULCC). Understanding the drivers of LULCC is essential to achieving sustainable land management in miombo woodland regions. Within a remote miombo area of south‐west Tanzania in the Kipembawe Division, Mbeya Region, social survey and ecological data were used to identify the direct and indirect drivers of LULCC. Our findings show that tobacco (Nicotiana tabacum ) production results in an estimated annual deforestation rate of 4,134 ± 390 ha of undisturbed miombo woodland, of which 56.3 ± 11.8% is linked to the post‐harvest curing process. This deforestation represents 0.55 ± 0.06% of the wooded area of the Kipembawe Division. The perception of high incomes from tobacco cultivation has encouraged migration of both agriculturalists and pastoralists into the area, resulting in higher livestock numbers that lead to further degradation. Higher human populations need more woodland resources such as fuelwood and building materials and more farmland for food crops. Continued deforestation will reduce the long‐term profitability of tobacco cultivation due to a lack of fuel to cure the crop and could render production unviable. Action is urgently needed to conserve globally important biodiversity resources while enabling agricultural and pastoral activities to continue. Improved governance, together with sustainable land management strategies and diversification of livelihood strategies, can reduce dependence on tobacco cultivation and contribute to a sustainable future for this ecoregion.     

Altered vegetation structure and composition linked to fire frequency and plant invasion in a biodiverse woodland

Relationships between fire history, vegetation structure and composition, and invasion by introduced plant species have received limited attention in Australian woodlands. A study in a Mediterranean, fire adapted urban Banksia woodland remnant in the biodiversity hotspot of southwest Australia investigated: (1) Have significant changes occurred in the woodland tree canopy between 1963 and 2000? (2) Do correlations exist between fire frequency and canopy cover? (3) If there is a difference in the vegetation composition of Banksia woodland invaded by the South African Ehrharta calycina (PCe) and Pelargonium capitatum (PCp) compared to largely intact remnants (GC)? and (4) Do correlations exist between vegetation condition, composition, fire frequency and invasion? Aerial photography, processed in a Geographical Information System, was used to establish fire history and changes in canopy cover over time (1963–2000). PCe and PCp sites experienced the greatest number of fires, with a net reduction in canopy cover in all areas experiencing four or more fires (60% of all woodlands). Frequent fire corresponded with a decline in native cover, richness and diversity, a shift from native to introduced species, changes in the relative importance of fire response categories, and loss of native resprouting shrub cover. Life forms of introduced species, which included no trees, shrubs and perennial sedges, contrasted strongly with those of native species, which had poor representation of annual and perennial grasses. Clear ecological and conservation consequences due to the loss of species diversity, changes in fire ecology and invasion have occurred in the Banksia woodlands. This study provides an understanding of the invasion process, enhancing conservation knowledge to improve the adaptive management of the key threatening process of invasion in biodiverse communities.     

A risk analysis methodology for assessing natural resources degradation

Risk analysis has been employed, amongst other things, both to estimate the probability of future water demand emergencies in reservoir systems (using simulation modelling), and to estimate environmental and public health risks (using empirical data). We assert that this framework, when coupled with simulation modelling, can be applied to examine and compare the impacts of resource exploitation, land use and production strategies which may cause land degradation. Our representation of risk analysis relies on the assumption that each land use strategy is associated with a risk of the system (i.e., social system, production system, ecosystem) attaining a subjectively unacceptable environmental condition (e.g. poor human nutrition, crop failure, degradation of a natural resource) sometime during a management planning period. The research methodology entails: (1) the identification of critical variables in the social and biological environment that are affected by exploitation and management of resources; (2) the identification through interviews, surveys, and research of regions of unacceptability in these variables that determine the dynamics of local environmental degradation; (3) the translation of resource policy and practice into a computer model of impact on the resource system; (4) many iterations of simulation of the system to determine the ‘risk of failing’ in each of the critical variables. The presentation of risk probabilities to decision-makers represents a reduction of many simulations into an understandable estimate of environmental impact. More importantly, risk analysis is potentially a learning tool for human system studies, and an interface for applied social science and ecological research.     

我国飞播林资源及可持续经营对策

飞播造林是我国偏远山区困难立地重要的植被恢复模式,探明我国飞播林资源及其经营中存在的关键问题对阐明其生态功能,认识其发展规律,以及制定营林措施,均具有重要意义。结合50 a来我国飞播造林发展的历史阶段和飞播林群落的特点,系统地分析了飞播林经营现状及存在的问题,从技术层面上提出了改善飞播林质量的思路与对策,以便为飞播林可持续经营提供参考。     

提高森林水土资源保育功能的最佳管理措施

 首先阐述台湾水源涵养保安林集水区与坡地所面临的问题,并指出:必须时时更新仪器设备,以提高资料品质;宽编基础研究经费,以获取连续性的现场即时资料;建立计算机资讯网路,以加速促进资讯交换。其次,为强调集水区内的主体作用,应尽可能地参与集水区管理的决策、规划、实施和监测评估的各个阶段,以促进土地使用者对集水区管理的认识和技术交流。再根据资讯系统的理论,针对集水区管理资讯系统开发的可行性及必要性进行系统分析与设计。由于水土资源为支持人类发展的重要因素,水土资源退化将严重影响社会经济发展而危及永续性,提出了相关最佳管理措施的标准作业程序。     

不同经营年限山核桃林地枯落物和土壤的水文效应

为探讨山核桃(Carya cathayensis Sarg.)—常绿阔叶混交林转变为山核桃纯林过程中林地枯落物和土壤水文效应的变化,利用相邻样地比较采样法,研究了山核桃—阔叶混交林0,5,10,20a山核桃纯林的水源涵养能力差异。结果表明,林地枯落物层持水量、吸水速率与浸水时间的关系分别符合对数函数和指数函数;0a林地的枯落物层蓄积量、最大持水量和有效拦蓄量显著高于5,10,20a的山核桃林地;随着经营年限的延长,林地枯落物层蓄积量、最大持水量和有效拦蓄量呈下降的趋势,与0a相比,分别下降了38.2%~54.6%,58.1%~69.7%,21.0%~33.2%;土壤容重、非毛管孔隙度、毛管孔隙度和总毛管孔隙度及持水力等指标在不同经营年限山核桃林地之间的差异并不显著,与0a土壤的持水力(21 450.0t/hm2)相比,经过不同年限的经营,持水力分别下降了10.6%~20.4%。总体上,山核桃—常绿阔叶混交林转变为山核桃纯林后,降低了林地枯落物和土壤的水文效应。     

Modeling soil organic carbon dynamics in Oxisols of Ibirubá (Brazil) with the Century Model

Introduction of conservation practices in degraded agricultural land will generally recuperate soil quality, especially by increasing soil organic matter. This aspect of soil organic C (SOC) dynamics under distinct cropping and management systems can be conveniently analyzed with ecosystem models such as the Century Model. In this study, Century was used to simulate SOC stocks in farm fields of the Ibirubá region of north central Rio Grande do Sul state in Southern Brazil. The region, where soils are predominantly Oxisols, was originally covered with subtropical woodlands and grasslands. SOC dynamics was simulated with a general scenario developed with historical data on soil management and cropping systems beginning with the onset of agriculture in 1900. From 1993 to 2050, two contrasting scenarios based on no-tillage soil management were established: the “status quo” scenario, with crops and agricultural inputs as currently practiced in the region and the “high biomass” scenario with increased frequency of corn in the cropping system, resulting in about 80% higher biomass addition to soils. Century simulations were in close agreement with SOC stocks measured in 2005 in the Oxisols with finer texture surface horizon originally under woodlands. However, simulations in the Oxisols with loamy surface horizon under woodlands and in the grassland soils were not as accurate. SOC stock decreased from 44% to 50% in fields originally under woodland and from 20% to 27% in fields under grasslands with the introduction of intensive annual grain crops with intensive tillage and harrowing operations. The adoption of conservation practices in the 1980s led to a stabilization of SOC stocks followed by a partial recovery of native stocks. Simulations to 2050 indicate that maintaining “status quo” would allow SOC stocks to recover from 81% to 86% of the native stocks under woodland and from 80% to 91% of the native stocks under grasslands. Adoption of a “high biomass” scenario would result in stocks from 75% to 95% of the original stocks under woodlands and from 89% to 102% in the grasslands by 2050. These simulations outcomes underline the importance of cropping system yielding higher biomass to further increase SOC content in these Oxisols. This application of the Century Model could reproduce general trends of SOC loss and recovery in the Oxisols of the Ibirubá region. Additional calibration and validation should be conducted before extensive usage of Century as a support tool for soil carbon sequestration projects in this and other regions can be recommended.     

Determinants of cryptogamic epiphyte diversity in a river valley (Flanders)

We studied cryptogamic epiphytes in a river valley in northern Belgium in order to investigate the effects of potential environmental and ecological determinants on epiphyte diversity. The study was done on ecotope level. In practice different habitat types, historical variables (forest history, tree age) and ecological indicator values of the epiphytes were used as explaining variables. The environmental variables were linked with ecological indicator values by means of canonical correlation analysis. Thereby correlations between indicator values and epiphyte diversity were calculated in a qualitative as well as in a quantitative sense. Classification and regression trees were applied to study the importance of the different environmental variables for epiphyte diversity. Cryptogamic epiphyte diversity of old forests proved to be low, contradicting the ‘ecological continuity’ hypothesis, while forests or shrubs with a high quantity of young trees were most suitable for epiphytes. These woodlands have a short forest history and are situated on alluvial soils in the centre of the valley, on former pastures. Main reasons for a high diversity in the young forests are elevated (air) humidity levels as well as the prominent presence of (several types of) wet broad-leaved forests, causing a high (micro)habitat diversity and diverse site conditions. As also structural aspects are important for the α-diversity of cryptogamic epiphytes, right actions should be implemented in management practices.     

Factors affecting site occupancy by woodland bird species of conservation concern

Significant biodiversity loss is characteristic of agricultural landscapes worldwide. Biodiversity recovery efforts in such landscapes can be hamstrung by a paucity of information on factors affecting species’ distributions, particularly for threatened and/or declining species. The temperate woodlands of south-eastern Australia have been extensively modified for agriculture and numerous bird taxa are declining. We have explicitly identified habitat and landscape attributes of woodland remnants affecting site occupancy by 13 woodland bird species of conservation concern.Using case-control data and linear logistic regression, we found that site occupancy for each species was related to both habitat and landscape variables. Habitat variables of particular importance included those in the ground layer (an abundance of leaf litter, an intact surface crust of mosses and lichens and a scarcity of annual grasses) and overstorey (a scarcity of eucalypt dieback and an abundance of mistletoe). Landscape variables strongly affecting site occupancy included the number of paddock trees and the area of native grass within 500 m of a site. Many of our study species were found most often in regrowth remnants.Our findings indicate a gap between current conservation practices and the actual habitat requirements of woodland bird species of conservation concern. Successful management will require protection and/or rehabilitation of the ground layer and overstorey of woodland remnants and sympathetic management of the surrounding landscape. It also will require managers to go beyond current practices of conserving old growth remnants and establishing replantings to maintaining and creating stands of woodland regrowth.     

森林土壤学科研究进展与展望

重点论述森林土壤学科自新中国成立以来研究工作进展与未来的展望。近60年来,我国森林土壤科学工作者调查、研究了我国森林土壤资源的分布、土壤理化性质和生物学活性,提出了保护和合理利用森林土壤资源的综合技术途径与经营措施。在认识森林土壤分布规律的同时,不断地揭示不同立地条件下森林与土壤之间相互作用的动态变化规律。并依据森林土壤功能与其组成、结构、性质一致性原理,阐明人工林土壤质量演化过程与作用机理,调控森林土壤性质的动态变化,改良土壤性质,维护和恢复森林土壤功能,提高森林土壤生产力,不断地为林业生产实践提供科学依据和有价值的经营措施,实现永续经营。     

Land use,deforestation and reforestation in the Zambian Copperbelt

Temporal and spatial changes in land use, vegetation cover, deforestation and reforestation in the Zambian Copperbelt were studied using a combination of aerial photograph analysis, literature review and inquiries among relevant government institutions. The study showed that between 1937 and 1984 loss of natural woodlands in the Copperbelt of Zambia (total area of Copperbelt: 9,615 km²) amounted to 41 per cent woodland area (8,419 km²). The major causes of this deforestation are woodfuel collection (for firewood and charcoal), cultivation and replacement of natural woodland with forest plantations. These accounted for 38 per cent, 37 per cent and 15 per cent of the total deforestation, respectively. Before 1962 the copper mining industry used large quantities of firewood to generate electricity and this resulted in the loss of 150,413 ha of woodland between 1937 and 1961. When the mining industry switched to hydroelectricity, urban households became the major users of woodfuel. The urban population in the Copperbelt increased from 0.412 million in 1960 to 1.400 million in 1984 and its consumption of woodfuel led to the deforestation of at least 89,436 ha between 1962 and 1984. Deforested areas are left to regenerate naturally. However, due to poor management about 34 per cent of the area deforested before 1962 has failed to regenerate. Although 50,200 ha have been reforested with exotic trees, only 5,020 ha of this is on land previously deforested. Thus only about 10 per cent of reforestation efforts have contributed to the rehabilitation of damaged land. Ninety per cent of the reforestation has actually replaced standing indigenous woodland. Uncontrolled bushfires have destroyed forest plantations and have also caused the failure of woodland regeneration in deforested areas. These observations indicate that if forest resources in the Copperbelt of Zambia are to be properly managed it will be necessary:

• 1 to effectively regulate land use changes and;
• 2 to control bushfires.

     

IMPACT OF INTEGRATED NUTRIENT MANAGEMENT ON TOMATO YIELD QUALITY AND SOIL ENVIRONMENT

Sustainable agricultural production incorporates the idea that natural resources should be used to generate increased output and incomes, especially for low income groups without depleting the natural resource base. Integrated nutrient management (INM) integrates the use of all natural and man- made sources of plant nutrients, so that productivity and nutrient status of food increases in an efficient and environmentally benefiting manner without sacrificing soil productivity of future generations. Integrated nutrient management relies on a number of factors including appropriate nutrient application and conservation and the transfer of knowledge about INM practices to farmers through extension personal. Tomato is the most popular home garden and the third most consumed crop in the world. It is very much beneficial for health because of its high nutrient status. Integrated nutrient management effects on its yield and quality parameters to a great extent. This review paper therefore, present review on various aspects of INM use to improve soil environment and tomato yield and quality parameters.     

Dragon’s blood tree - Threatened by overmaturity, not by extinction: Dynamics of a Dracaena cinnabari woodland in the mountains of Soqotra

Age determination of tropical trees, and monocotyledons in general, is not an easy task. Representatives of the Dracaena genus have survived in woodlands on dry margins of the Tethys tropical forest since the Tertiary Period. Here we present analyses of Dracaena cinnabari (DC) stand dynamics via direct and indirect methods of age determination. The direct method has taken advantage of historical photographs of DC mountain woodlands from Soqotra during an Austrian scientific expedition in 1899 by comparing these with the woodland stage in 2004. A decline in the number of tree individuals is obvious, but considering the little that is known about dynamics of DC woodland, one cannot simply state that such decline means forest destruction. The results from this direct method are compared to an indirect mathematical method of age determination using data from 2003. Indirect age determination values differed only about 6.5% from those obtained with the direct method, indicating that the indirect methodology is quite precise.     

湖南省生态环境变化及驱动机制

分析了湖南省生态环境变化的总体特征：水土流失加剧，土地资源退化严重；林地面积减少，森林质量下降；动植物物种减少，一些珍稀物种难见踪影；天然湿地面积减少，湖泊水质污染加重，氮磷浓度越来越高；城镇空气质量总体基本稳定，江河水质污染普遍，噪声处于中等污染水平；农村化学用品的使用量逐年上升，环境污染愈加严重。人口大幅度增长和经济的非持续发展方式是其直接原因，要坚定不移地走社会经济可持续发展道路，从根本上解决高环境代价式的经济发展与掠夺式资源开发造成的生态环境问题，实现资源环境与经济社会的可持续发展。     

Woodland structure,destruction and conservation in the Copperbelt area of Zambia

Between 1937 and 1983 a total of 391 400 ha of woodland, representing 51% of the 768 900 ha in the Zambia Copperbelt, had been deforested for industrial and household woodfuel. This has occurred in spite of a forest reservation programme that increased the area in forest reserves from 31 707 ha in 1942 to 252 715 ha in 1965. Between 1965 and 1980 the reserved forests were reduced to 246 930 ha and since then the area has remained static. The rapidly growing demand for charcoal by the increasing urban population, and the growing problem of acid dust and rain pollution from copper smelters, pose serious threats to forest conservation in this industrial region of Zambia. Current forest conservation is restricted to the establishment of exotic forest plantations and recently deforested areas are left to regenerate naturally.Forest destruction and conservation in the Copperbelt area were studied and the structure of old-growth and coppice woodland stands at 9 and 14 sites, respectively, investigated during 1982–1984. The Copperbelt vegetation is dominated by Brachystegia-Julbernardia woodland. Mean species diversity of 24·40·1 ha⁻¹ in coppice stands was higher than that of 18·9 found in old-growth stands. Stem density in coppice was 3·3 times that observed in old-growth woodlands. The majority of species (over 50%) in both old-growth and coppice were represented by less than 11 stems per sampling plot. Mean basal area at breast height in coppice aged 19–23 years was 14·33 m², which was 95% of the mean basal area of 15·15 m² found in old-growth woodlands.     

Application of a bioeconomic strategic planning model to an industrial forest in saskatchewan

Contemporary approaches to the issue of the allocation, conservation and management of forested land require forest managers to demonstrate the sustainability of the flow of economic, ecological and social benefits accruing from industrial use of forest resources. The integration of data sets defining these disparate resource benefits requires that they be expressed in commensurate terms such that trade-offs can be undertaken in the search for a management strategy which provides a publicly acceptable mix of benefits. To accomplish this, a new optimisation model was developed and tested for a 1.7 Mha commercial forest in west central Saskatchewan, and then used to develop 8 different forest management alternatives which were then subjected to formal evaluation procedures leading to the selection of a preferred forest management alternative.     

Using geomorphologic mapping to strengthen natural resource management in developing countries. The case of rural indigenous communities in Michoacan, Mexico

This paper describes the use of geomorphologic knowledge for resource management in rural areas of less developed countries. Specifically, we discuss the contribution of geomorphologic mapping (coupled with landscape knowledge) to natural resource management using geographic information systems (GIS) and remote sensing techniques. We describe a case study conducted at Nuevo San Juan Parangaricutiro, an indigenous forest community in the Paricutin area, in Michoacan, Mexico.The analysis described in this paper was used to improve the mapping of forest quality units, and to explore the relationships between land suitability and land utilisation requirements for potential diversification of economic activities in the indigenous community. The approach proved useful for the management of natural resources and was made operational by the actual managers of the resources. The community of Nuevo San Juan was granted the green certification (Smart Wood) by the Forest Stewardship Council (FSC) and produced a fully automated resource management plan.