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The structural diversity of different tree-crop associations were studied at Gachabari Sal forest area of Madhupur Garh on Buffer and Peripheral Zone during 2006. The total density, basal area of trees in the Buffer and Peripheral Zone were 155.5 trees·hm^-2, 795.4 trees·hm^-2 and 3.9 m^2·hm^-2, 5.8 m^2·hm^-2, respectively. No regeneration and natural trees were found in Peripheral Zone and the Zone is totally occupied by exotic species where the Buffer Zone comprised of both natural and exotic trees. The Peripheral Zone belonged to younger and smaller trees whereas the Buffer Zone belonged to mixture of smaller, taller, younger and mature trees simultaneously. For the practicing of different agroforestry systems both Zones have lost their original characters of Sal forest. 相似文献
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Economic contribution of participatory agroforestry program to poverty alleviation: a case from Sal forests, Bangladesh 总被引：2，自引：0，他引：2
In the Forest Department of Bangladesh, a Participatory Agroforestry Program (PAP) was initiated at a denuded Sal forests area to protect the forest resources and to alleviate poverty amongst the local poor population. We explored whether the PAP reduced poverty and what factors might be responsible for poverty alleviation. We used three poverty measurement methods: the Head Count Index, the Poverty Gap Index and the Foster-Greer-Thorbecke index to determine the extent poverty reduction. We used a linear regression model to determine the possible differences among factors in poverty reduction. Data were collected through semi-structured questionnaires and face to face interviews within the study area. PAP proved effective at poverty alleviation, considerably improving the local situation. The linear regression model showed that PAP output explained the income differences in poverty reduction. Participants identified bureaucracy and illegal money demands by forest department officials, an uncontrolled market system, and underdeveloped road infrastructure as the main obstacles to reduction of poverty. Overall, PAP is quite successful in alleviating poverty. So this program might be ofinterest at other degraded forest areas as a tool to alleviate poverty. 相似文献
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林分间隙形成后季节性干旱的娑罗双树原始林物种多样性及苗木再生(英文) 总被引：1，自引：1，他引：0
本文调查了尼泊尔季节性干旱的娑罗双树原始林两种生态位(间隙和全郁闭)下树种多样性及苗木再生情况,并对物种多样性指标和苗木再生属性与林分间隙特征进行了相关性分析。结果表明,间隙生态位下乔木和灌木立木度高于全郁闭。间隙生态位下娑罗双树和榄仁树的幼苗密度也高于全郁闭,但是油榄仁和海南蒲桃的比较结果恰好相反。在幼苗层物种多样性指标(complement of Simpson index,Evenness index,and species-individual ratio)在间隙生态位要低于全郁闭条件。间隙大小能够解释物种丰富度和物种建立速率。多年多样伐木形成的林分间隙下娑罗双树幼苗密度要高于同一年内单一或多样伐木。结论:林分间隙的物种多样性通过增加幼苗密度来维持,并且适于娑罗双树再生。此外,林分间隙的其它属性也会影响物种多样性和苗木再生。 相似文献
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Species diversity and regeneration of old-growth seasonally dry Shorea robusta forests following gap formation 总被引：1，自引：0，他引：1
Diversity and regeneration of woody species were investigated in two ecological niches viz. gap and intact vegetation in old-growth seasonally dry Shorea robusta (Gaertn. f.) forests in Nepal. We also related varieties of diversity measures and regeneration attributes to gap characteristics.
Stem density of tree and shrub components is higher in the gap than in the intact vegetation. Seedling densities of S. robusta and Terminalia alata (B. Heyne ex Roth.) are higher in the gap than in the intact vegetation, while contrary result is observed for T. bellirica (Gaertn. ex Roxb.) and Syzigium cumini (L. Skeels) in term of seedling density. The complement of Simpson index, Evenness index, and species-individual ratio in
the seedling layer are lower in the gap than the intact vegetation. Gap size can explain species richness and species establishment
rate. Gaps created by multiple tree falls in different years have higher seedling density of S. robusta than gaps created by single and/or multiple tree falls in the same year. In conclusion, gaps maintain species diversity by
increasing seedling density, and favor regeneration of Sal forests. In addition to gap size, other gap attributes also affect
species diversity and regeneration.
Foundation Project: The study was supported by Swedish International Development Cooperation Agency (SIDA). 相似文献
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《Southern Forests》2013,75(4):201-208
For many years foresters have been using statistical probability density functions to describe and characterise stand structure. Predicting the current and future yields of a stand is essential for successful stand and timber management. Implicit prediction of current yield is accomplished by using diameter distribution methods. All diameter distribution yield systems predict the number of trees per unit area by diameter class. In this study, the normal, lognormal and the three-parameter Weibull probability density function were compared to characterise the diameter distributions of Sal (Shorea robusta) plantations grown at Tilagarh Eco-park, Bangladesh. Data from 70 plots, established in three plantations, were used for this study. The Weibull parameters were estimated by the maximum likelihood and moments estimator methods. A one-sample Kolmogorov–Smirnov test was used for the goodness of fit for all models. The Kolmogorov–Smirnov test results showed that both lognormal and Weibull distributions were suitable to characterise the diameter distributions of Sal plantations in the study area and may be applicable for other Sal forests in Bangladesh. 相似文献
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N. Vedaraman Sukumar PuhanG. Nagarajan B.V. RamabrahmamK.C. Velappan 《Industrial Crops and Products》2012,36(1):282-288
Many research reported vegetable oil as a potential substitute for diesel engines with its ester form known as biodiesel. The biodiesel can be prepared by different process using vegetable oil and alcohol. The common process used for biodiesel preparation is known as transesterification. This paper presents the transesterification of Sal oil (Shorea robusta) into Sal oil methyl ester (SOME) and its performance in direct injection diesel engine. Several process parameters such as catalyst quantity, molar ratio of alcohol, reaction temperature and reaction time were studied and the optimized process conditions are amount of catalyst (NaOH) - 0.25 wt%, alcohol (methanol) - 150% excess, reaction temperature - 65 °C and reaction time - 1.5 h. The studies with SOME as fuel in the direct injection diesel engine shows that the exhaust emissions such as CO, HC and NOx are reduced by 25%, 45% and 12%, respectively compared to diesel without significant difference in thermal efficiency. Based on this study it is concluded that the SOME can be used as fuel without any modifications in the engine and hence this biodiesel can be a potential substitute to standard diesel fuel. 相似文献
7.
We investigated the spatial distribution, advanced regeneration and stand structure of five Shorea robusta-dominated forests in 25 1-ha plots subject to disturbances of different intensities. We aim to elucidate the relationships of advanced regeneration and spatial patterns of the tree species with degree of disturbance magnitude. Sixty-seven tree species were recorded in the forest plots; 41 species were found in the least disturbed forests, while only 10 species were found in the heavily disturbed forests. We found 5320 trees with >1.5 cm diameter at breast height, in total, and found that moderately disturbed forests contained the highest advanced regeneration (sapling)/pole densities. No significant differences were observed in stem basal area among forests. The overall stand density changed quadratically across the disturbance gradient. A strong inverse relationship was found between the overall stand density and diameter class in the least disturbed and moderately disturbed forests. Ten species showed variation in their dispersion patterns across the disturbance gradient. Most of the socio-economically important tree species analyzed showed little or no regeneration in the least and most heavily disturbed forests. Individual species showed different responses to disturbance ranging from ‘tolerant’ (Shorea robusta, Lagerstroemia parviflora and Symplocos spp.) to ‘sensitive’ (Trewia nudiflora, Adina cardifolia and Terminalia alata). We concluded that moderate disturbance intensity not only ensures high stand density, but also enhances the advanced regeneration of socio-economically important tree species and affects their dispersion patterns. Future management strategy must balance the consumptive needs of the local community with those of species conservation by allowing regulated access to the forests. 相似文献
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盐分胁迫对烟草种子发芽的影响 总被引：7，自引：1，他引：6
对１０个烟草品种在５种盐分的７个浓度水平下进行发芽试验,结果表明,黄花烟种子较其他参试种子发芽受抑制程度最轻;而Ｎａ２ＣＯ３较其他盐分对种子萌发有更大影响。当盐分浓度达到得３００ｍｏｌ／Ｌ时,所有种子萌发停止。 相似文献
9.
《Southern Forests》2013,75(2):89-101
The government of Bangladesh has placed the utmost priority on participatory forestry (PF) since the 1980s, and this approach was commenced in the degraded Sal forest areas through a donor-funded project in 1989. These forest reforms aim to eliminate the main causes of forest depletion as well as alleviate poverty through the participation of local people, who depend on the forests for their livelihoods. This study explores the impact of PF initiatives on the livelihoods of the local ethnic and non-ethnic populations, drawing empirical data from the participatory forestry programs (PFPs). The findings indicate that the most common feature of PFPs were the contribution of financial capital to the participants, whereas other livelihood capitals faced constraints and difficulties. In addition, inequity issues and social capital differences were created between the ethnic and non-ethnic participants, and a lack of commitment by the local Forest Department resulted in PFPs having limited success in creating sustainable livelihoods for the participants. The overall situation revealed that PFPs alone were not sufficient to conserve and develop the Sal forests or assure people's basic needs. Therefore, a long-term-integrated approach by the Forest Department is necessary to address the diversified needs of low-income forest-dependent people in a more sustainable way. 相似文献
10.
Khondokar H. Kabir Andrea Knierim Ataharul Chowdhury Beatriz Herrera 《Journal of Sustainable Forestry》2019,38(2):149-170
Participatory forest management is credited for supporting social learning processes and fostering capacity of forest users for collaboration and collective actions. Despite more than a decade of practice, the empirical evidence substantiating the contribution of participatory management for the capacity development of forest users is scarce. This study assesses a participatory forest management program in Madhupur Sal forest, Bangladesh, by comparing the capacity of de-facto groups of participants and nonparticipants and identifies factors that influence the capacity development. Data were collected using a mixed method approach which combines both qualitative and quantitative methods of data collection. Results indicate that participants differed from nonparticipants significantly in terms of various capacity dimensions related to collective actions. Extension services, credit support, trust within society, information and communication influence the level of capacities in tribal population to adapt and respond to changes. The initiatives to manage natural resources are likely to be more successful if the forest management program initiators consider several factors that influence the capacity development of resource users. 相似文献
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