首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
In Thailand the taungya reforestation method has been practiced primarily in order to rehabilitate wasteland, particularly under the Forest Village Programme. While various combinations of trees and crops are found in the taungya method on a minor scale, the major combinations are teak with upland rice in the north, fast-growing trees with cassava in the northeast, fast-growing trees with maize in the west, and para-rubber or fast-growing trees with fruit trees in the south. These combinations relate to the differences in climatic conditions, mainly the duration of the rainy season.  相似文献   

2.
In Thailand the taungya reforestation method has been practiced primarily in order to rehabilitate wasteland, particularly under the Forest Village Programme. While various combinations of trees and crops are found in the taungya method on a minor scale, the major combinations are teak with upland rice in the north, fast-growing trees with cassava in the northeast, fast-growing trees with maize in the west, and para-rubber or fast-growing trees with fruit trees in the south. These combinations relate to the differences in climatic conditions, mainly the duration of the rainy season.  相似文献   

3.
A shifting cultivation land use system under population pressure in Zambia   总被引:1,自引:0,他引:1  
The status of chitemene shifting cultivation, in northern Zambia was investigated and reviewed. This paper presents results concerning (a) changes in soil nutrients under chitemene shifting cultivation, (b) the relationship between population density and deforestation and (c) how the chitemene shifting cultivation system has survived under conditions of overpopulation relative to the critical population density.In the chitemene shifting cultivation system crops are grown in a small ash garden made by burning a pile of wood cleared from a larger area. The burning increased soil NH3–N content by 40–50%, with a further increase of 15% after 262 mm of rainfall. In contrast, the soil in unburnt plots lost up to 30% NH3–N. The content of other major nutrients, such as, P,K, Ca, Mg, and Na also increased in the top soil immediately after burning. The increase in soil NH3–N after burning is attributed to the reduction in microbacterial activity. These soil nutrient changes appear essential in the production of finger millet.However, the growing rural population in the chitemene shifting cultivation region of northern Zambia has caused deforestation which has resulted in the reduction of (a) the length of the fallow period from 25 years to 12 years, (b) the per person woodland requirement of m 1.1 ha to 0.53 ha and (c) the frequency of clearing new chitemene gardens from yearly to once in two years. These responses to diminishing wood resources have artificially increased the population carrying capacity from 2.4 to 18.7 persons per km2. This has enabled the survival of the chitemene shifting cultivation land use system in northern Zambia.  相似文献   

4.
The recovery process of fallow stands in the mountainous region of Northwestern Vietnam was studied, based on a chronosequence of 1–26-year-old secondary forests after intensive shifting cultivation. The number of species present in a 26-year-old secondary forest attained 49% of the 72 species present in an old-growth forest. Total stem density decreased gradually from 172,500 ha−1 in a 3-year-old forest to 24,600 ha−1 in the 26-year-old stand, but stem density of larger trees (diameter at breast height (D) ≥ 5 cm) increased from 60 ha−1 in a 7-year-old to 960 ha−1 in the 26-year-old forests, which was similar to that of an old-growth forest. Annual biomass increment of the 26-year-old stand was 4.2 Mg ha−1 year−1. A saturation curve was fitted to biomass accumulation in secondary forests. After an estimated time of 60 years, a secondary forest can achieve 80% of the biomass of old-growth forests (240 Mg ha−1). Species diversity expressed by Shannon Index shows that it takes 60 years for a secondary forest in fallow to achieve a plant species diversity similar to that of old-growth forests.  相似文献   

5.
This study reports the effects of shifting cultivation at slashing stage on soil physicochemical properties at Bandarban Sadar Upazila in Chittagong Hill Tracts of Bangladesh. At this initial stage of ...  相似文献   

6.
Soil samples were collected and analyzed from 25 sites of three hilly regions (Rangamati, Banderban and Khagrachari) for an understanding of the impact of denudation and land use on soils in Chittagong Hill Tracts, Bangladesh. There were natural forests, bushy land, slashed sites, slashed and burnt sites, and the sites prepared for shifting cultivation, one year after shifting cultivation and two years after shifting cultivation. The soils were generally yellowish brown to reddish brown, sandy to sandy clay loam, strongly acid, and well to excessively drained on steep slopes with considerable variation among the sites and land use categories. Bulk density was the highest in sites of one year after shifting cultivation (1.52 g·cm-3) and the lowest in forested sites (1.38 g·cm-3). Water holding capacities were, however, statistically similar in all sites. Organic carbon varied from 0.54% (slashed and burnt sites) to 1.55% (forested sites) and total N ranged from 0.05% (shifting cultivation for one year) to 0.13% (forested sites). Available phosphorus (Bray & Kurtz-2 P) was the maximum in forested sites (12.32 mg·kg-1), and it did not differ significantly in other sites. Contents of available Ca, Mg and K were also higher in the bushy lands and forested sites than cleared and shifting cultivated sites.  相似文献   

7.
Rotational swidden cultivation systems, with fallow periods long enough for the regeneration of secondary forests are capable of maintaining forest cover and plant diversity in a dynamic balance in swidden cultivation landscapes. Regeneration of secondary forests through several successional stages and by a combination of coppicing and seedling development is still poorly understood, especially the influence of different swiddening practices and the role of animals as seed dispersers. Swidden cultivators possess a vast knowledge of plants growing in swidden fallows and of fallow dynamics as well. Forest restoration in Thailand has been carried out mainly on the basis of experimental research on the potential of indigenous tree species to promote natural forest regeneration and biodiversity recovery; the so-called framework species. Another viable source of knowledge for forest restoration can be the study of the semi-natural revegetation processes in fallows and the indigenous knowledge of swiddeners of these processes. The research presented here was carried out to attain a better understanding of forest regeneration on fallow swiddens under different swiddening regimes and how it may be applied to practical forest restoration, We investigated the vegetation characteristics of from various stages of secondary succession in fallow swiddens of the Karen and Lawa ethnic groups in the Mae Chaem watershed, Chiang Mai province, northern Thailand. Indigenous knowledge on the use of species and traditional ecological processes in swiddening was recorded by questioning key informants. The data were analyzed and discussed with respect to their application in forest restoration and participatory forest management.  相似文献   

8.
This paper reports on a study of local diversity and variation in indigenous agroforestry practices among Amazonian peasants in a traditional community near Iquitos, Peru. Data were gathered through in-depth interviews with agroforestry-reliant households n = 36) on farming practices, demographic characteristics, income-expenditures and household wealth. Visits to crop fields and forest fallows n = 329) allowed the reconstruction of extensive cropping histories. More in-depth assessments of crop occurrence, density and diversity were conducted on 83 fields. Our results indicate considerable variation in field characteristics, agroforestry-cycles, and household agroforestry portfolios. Agroforestry practice is found to be strongly related to access to land within the community: households holding more land use both potentially more sustainable and more lucrative swidden-fallow agroforestry systems. Our results question the view of indigenous agroforestry systems as intrinsically ‘stable, equitable, and sustainable’, and underscore the importance of studying local variation in indigenous agroforestry practices. Promising avenues are discussed for future research on the factors related to the successful adoption of sustainable agroforestry systems. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

9.
Kerinci is a densely populated valley surrounded by a national park in western central Sumatra, Indonesia. Indigenous agroforestry systems include important cash crops like coffee (Coffea canephora var.robusta) and cinnamon (Cinnamomum burmani), and range from alternate cycles of cash crop monocultures or simple associations, to multispecies and multi-storey gardens; these may include as many as 100 common useful species, comprising many fruit trees and indigenous timber species.After analysing the trends of forest conversion and its causes in the area of Kerinci Seblat National Park, a case study of one particular village is presented in order to describe the evolution of cyclic agroforestry systems (ladang) into complex agroforestry systems (pelak). The composition, structure and management of the various systems have been studied through interviews, botanical surveys and the method of profile diagrams.It is suggested that locally developed complex agroforestry systems evolve partly in response to changes in land availability and labour constraints. Finally the interest of such systems when designing projected buffer zones and their development in relation to new market incentives are discussed.  相似文献   

10.
Shifting cultivation is one of the main factors that has caused forest degradation in many tropical countries. In Sabah, Malaysia, the government has granted land titles to local farmers outside the Forest reserve, and introduced tree cash crops to reduce farmers’ dependence on shifting cultivation. Granting land titles, however, was not always an incentive for farmers to plant tree cash crops. Farmers often planted tree cash crops on land without secure legal rights. The Land Ordinance and illegal logging had introduced exclusive and (semi-)permanent rights to land into this region, and the Forest reserve also was divided among villagers. The Land Ordinance stipulates that planting trees confers permanent heritable and transferable rights of use and occupancy but not within Forest reserves. Local farmers who were anxious about their land rights believed that they could obtain those rights even within the Forest reserve, and applied for land titles. Farmers planted tree cash crops not only for future income but also to secure their land rights. At present, the policy of Forest reserve has nearly collapsed in this region and it is impossible to neglect or remove local farmers if the government utilizes Forest reserves for any purpose. Lands in the interior regions will be reclassified in the near future out of necessity.  相似文献   

11.
汪清林业局采育林经营技术   总被引:1,自引:1,他引:1  
本文对汪清林业局采育林经营技术进行了分析,结果表明:自对天然异龄林实施采育择伐经营技术以来,使经营区的森林覆盖率逐年提高,由1966年的66.60%,上升为2007年的95.95%;采育林生长量6.240 m3.hm-2.a-1,比全局经营林分的平均生长量高出1.650 m3.hm-2.a-1;改善了林分结构,红松、云冷杉、紫椴、水曲柳等主要建群种的比例逐年增加,促进了森林顶级群落的恢复,实现了"青山常在,永续利用"的森林经营目标。  相似文献   

12.
Some studies have attributed forest shrinkage to population growth, economic development, conversion of forest land to agricultural use and harvesting of trees for timber and fuelwood. But the statistical support for these hypotheses is not strong. This paper attempts to test the above hypotheses statistically in the case of Bangladesh. Factor analysis extracted 4 important factors—(a) exploitation of forests for timber, fuelwood, tea, and shrimp production, (b) demographic pressure in agriculture, (c) economic development, and (d) expansion of crop lands—as causes of deforestation. The statistical test supports the hypotheses that the exploitation of forests for timber, fuelwood, tea and shrimp production, and conversion of forests to crop lands have a negative influence on forest cover. Economic development and demographic pressure in agriculture are also negatively correlated with forest cover. Results of regression analysis show the conversion of forests to agricultural land is the most important cause of deforestation. Other important causes, in order of their relative importance, are the relative price of forest products, population growth, economic development, demographic pressure in agriculture, increasing production of shrimps, export of tea and shrimps, increasing production of timber and fuelwood, and expansion of tea lands. The statistical tests support the above relationships.  相似文献   

13.
本文主要介绍了长春净月潭旅游经济开发区退耕还林地的立地类型,设计了与之相应的工程造林类型,分析了不同工程造林类型的综合效益。  相似文献   

14.
Abstract

The Russian forest sector is under transformation, and the Model Forest (MF) concept is used as an innovative approach to regional sustainable development based on forest goods, ecosystem services and values. This study evaluates the development of the MF concept in north-west Russia's Barents region, using Kovdozersky MF in Murmansk region as a case study. This report (1) describe the main historical phases of forest use, (2) summarizes the state and trends of the economic, ecological and sociocultural situation, (3) explores reasons for establishing the MF, and (4) evaluates the main steps towards implementation of the MF concept. Qualitative and quantitative methods were applied. Actors were identified and interviewed to understand the process of MF development. Statistic data were collected and analyzed. The main goal of this MF is to support development through participatory collaboration regarding (1) balancing needs and interests among actors and stakeholders, (2) implementation of sustainable forest management, (3) encouraging the development of ecotourism and bioenergy production in the area, and (4) increasing public awareness with respect to sustainable forest management. Potential challenges for the MF partnership include: (1) domination by partners from the traditional forest sector, with their potentially more narrow needs and interests in the partnership development, and (2) disparity in sharing responsibilities and power between regional and local levels in MF management.  相似文献   

15.
The Forest Stewardship Council (FSC) aims to promote environmentally responsible forest management globally. However, quantifiable evidence of effects of FSC on forest management practices is lacking. FSC has been present in the Russian forestry arena for over 20 years. In this case study, we compare ecological indicators of forest management in FSC-certified and non-certified companies in Primorsky Krai of the Russian Far East. Those indicators include percent of forest cover loss and gain on forest concessions managed by three certified and three non-certified companies. We also interview a range of stakeholders involved with forest management or in forest policy planning in Russia to provide context for this case study. Results indicate no difference between certified and non-certified companies with regard to forest cover loss from 2008 to 2015 or forest cover gain from 2000 to 2012. Stakeholder interviews reveal that while forest certification is viewed positively and considered an efficient mechanism to improve forest management, the stakeholders doubt its ability to stimulate quantifiable changes in forest management practices in Russia and the Far East specifically. We focus on Primorsky Krai because of its unique geographic location, where its neighbors China and Japan significantly influence Primorsky Krai’s export market.  相似文献   

16.
Existing cropping systems in Northern Zambia cause deforestation and soil degradation. To reduce the environmental problems, the potential of alley cropping and pigeon peas replacing the existing cropping systems was analyzed by the use of multi-objective programming models of peasant households. The models were formulated based on the theories of Chayanov and Nakajima which are suitable under conditions of imperfect labour markets. Risk was incorporated in the models in relation to weather and fertilizer supply. The models provide an opportunity to relate key characteristics of new technologies to key characteristics of peasants' preferences and resource constrains. The models may also be used to identify minimum performance levels required for new technologies to be found acceptable.Models of a small male-headed household are presented under varying conditions: for high and low population densities, with and without fertilizer subsidies, and for households with and without access to off-farm employment under high population density conditions.The analysis showed that the alley cropping technology is very unlikely to replace thechitemene system where there is still sufficient woodland for its continuation. The technology may have higher potential in more densely populated areas, where more intensive forms of agriculture are practised and where there is access to inputs such as lime and fertilizer. The removal of fertilizer subsides as a result of the Structural Adjustment Programs, may favour alley cropping because this technology may increase the efficiency of fertilizer use and reduce the need for nitrogenous fertilizers. The potential of the technology depends very much on the management level and location-specific performance of the trees.The pigeon pea technology has high potential if it is accepted as food since it has a very favourable yield per unit of labour, requires no monetary inputs, and can grow, in very poor soils. Pigeon pea also has potential as a cheap source of protein for the urban poor.  相似文献   

17.
湾沟林业局在退耕还林实施过程中,不断加大退耕还林力度,努力加强退耕还林工程的科技创新,逐步提高退耕还林工程的科技含量和总体水平,取得了生态效益、社会效益和经济效益的和谐统一。  相似文献   

18.
About 25% of Laos' four million people practise shifting cultivation (mainly of rice) on a third of the country's cropped area. Official policy is to eliminate shifting cultivation by the year 2000. Diagnostic surveys of shifting cultivation were conducted in Luang Prabang and Oudomsay Provinces in northern Laos to understand the practice from a farmer's perspective, to observe fields, and to identify and give priority to problems and research to address problems. Weeds, low and possibly declining soil fertility, intensification of the cropping cycle, rats (plus birds, wild pigs), and insects lowered rice yields or reduced system sustainability. The forest ecosystem has been degraded by logging, burning, and rice monocropping; and potentials for environmental rehabilitation through natural succession are minimal. Farmers cannot adopt high labor and cash cost innovations; and improved fallow is needed as an intermediate step prior to crop diversification, adoption of agroforestry technologies, and sedentary agriculture.  相似文献   

19.
The forest flora of eastern North America includes many herbaceous plant species traded in domestic and international medicinal markets. Conservation concerns surrounding wild-collection exist and transitioning to cultivation in agroforestry systems has potential economic and ecological benefits. Costs and revenues associated with adopting forest cultivation were modeled for eight North American medicinal forest plants. Sensitivity analysis examined profit potential in relation to (1) discount rates; (2) propagation methods; (3) prices; (4) growing period; (5) production costs; and (6) yields. Results indicate that intensive husbandry of six of eight species would be unprofitable at recent (1990–2005) price levels. Exceptions are American ginseng (Panax quinquefolius L.), and under certain circumstances (e.g., maximum historic prices, low production costs) goldenseal (Hydrastis canadensis L.). Direct marketing to consumers and retailers might improve grower profits, but is undermined by the availability of cheaper, wild-collected product. We suggest that the North American medicinal plant industry could play a key role in facilitating any transition from wild to cultivated product, perhaps through development of a certification and labeling program that brands “forest cultivated” products. This could generate price premiums, to be passed along to growers, but must be accompanied by aggressive consumer education. A “forest cultivated” certification and labeling program has potential to benefit industry and consumers if assurances regarding product identity and quality are a central feature. Plant species that are not viable candidates for commercial cultivation due to limited consumer demand (i.e., species with “shallow,” erratic markets) are best addressed through proactive government and industry initiatives involving targeted harvester education programs.  相似文献   

20.
 In Kemang, a mountain village in West Java, Indonesia, the local people call the hillsides pasir, a term which includes both privately owned hillside land or nationally owned forest land. It is apparent that the national forest lands function as a social safety net, serving as land where the middle-class and the poor can conduct “informal” cultivation, through temporary agreements with the state forestry corporation, or even “illegal” cultivation without permission. In this study, the households cultivating on national forest lands were identified as: (1) having most household members living together; (2) having a relatively young head person; (3) cultivating a small area of rice field; (4) having participated in the former perhutanan sosial system; (5) being dependent on the income from hillside land; (6) taking advantage of the rare opportunities for off-farm income; and (7) having a low total income. Meanwhile, the talun-huma system is dominant on privately owned hillside land, where a part of the talun, or tree garden, is cleared for use as a swidden on a 30-year rotation. In such cases, the land functions as a safety net only for the limited number of people who are permitted access to the land. The function of the privately owned hillside land, through the mutual-aid system, should not be overestimated; it is probably less important than national forest land in terms of income redistribution. It is recommended that the government of Indonesia consider the possibility of formally ensuring the long-term rights of local people to utilize the national forest lands in Java. Received: April 6, 2001 / Accepted: October 24, 2002 Acknowledgments This paper is in part a result of the research activities of the Core University Program in Applied Bioscience between the University of Tokyo and Bogor Agricultural University, sponsored by the Japan Society for the Promotion of Science (JSPS). The authors would like to express their thanks to Prof. Sumiaki Iwamoto, the University of Tokyo, for his kind help. Correspondence to:M. Inoue  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号