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1.
The relation between fuelwood use and fuelwood quality and quantity was studied in two northern Namibian rural communities with different levels of fuelwood availability. Household surveys were conducted and fuelwood quality was assessed through laboratory studies. The study found differences in fuelwood use and adaptation of liveli-hoods to fuelwood availability. Where there was an abundance of quality fuelwood, the community chose fuelwood intuitively in accordance with the optimum physical properties and in a sustainable way. A fuelwood shortage, however, was found to impact negatively on work and social practices and fuelwood was collected through destructive harvesting practices, such as the cutting of green branches, and without consideration for optimum timber properties, such as tree age and calorific value.  相似文献   

2.
Fuelwood demand and supply in Rwanda and the role of agroforestry   总被引：2，自引：1，他引：1  
Fuelwood in Rwanda is assumed to come from forests and woodlands, thus contributing to large-scale deforestation. Available studies on fuelwood demand and supply support this assumption and indicate a continuously rising demand of fuelwood, notably from forest plantations. These assertions are insufficiently substantiated as existing forest stock may not be depleted by rapid increase in demand for food and energy resources resulting from population growth, but rather from the need for agricultural land. Evidence suggests that the demands for fuelwood, in addition to other sources of energy, is supplied from agroforestry systems which has not been quantified so far. This review analyses sources and use of fuelwood in Rwanda, indicating the importance of on-farms trees and woodlots in fuelwood supply. It is concluded that the effect of fuelwood consumption on land use is difficult to disentangle as many other factors including land clearing for agriculture, livestock farming, human settlements, illegal cutting of valuable timber species, the demand for charcoal in towns and past conflicts, contributed significantly to the high rate of deforestation in the country. If fuelwood demand is to be met on a sustainable basis, more fuelwood has to be produced on agricultural lands and in forest plantations through species site matching and proper management.  相似文献   

3.
Scattered trees and woodlots are a prominent feature of agricultural landscapes of Rwanda. However, little is known about their characteristics and their contribution to farmers’ wood needs. Here, we present the results of a survey of (a) the abundance, composition, and size of trees and woodlots in the low, medium and high altitude regions of Rwanda, (b) total woody biomass and biomass for fuelwood at farm and landscape levels, and (c) opportunities for their sustainable use. Scattered trees occurred in all landscapes at minimum densities ranging from 20 to 167 trees ha?1. Of the 56 tree genera recorded, a handful of tree species dominated, with the ten most common species accounting for over 70 % of all trees recorded. Most of them provided fuelwood, fruit and timber to farm owners. Woodlots occurred on about 40 % of the survey farms and consisted for 90 % of eucalyptus coppice. Woody biomass dry weight of scattered trees on agricultural landscape was 0.7 t ha?1 in low altitude region (LAR), 3 t ha?1 in medium altitude region (MAR), and 1 t ha?1 in high altitude region (HAR). Dry weight woody biomass in woodlots (<0.5 ha) was the highest in MAR (221 t ha?1), followed by that in HAR (205 t ha?1) and least in LAR (96 t ha?1). About 80 % of total woody biomass in trees and woodlots on farmland was useable biomass for fuelwood, indicating that the production of fuelwood on agricultural land was important. Woody biomass on agricultural land was higher than that in forest plantations, and was potentially sufficient to reduce the gap between fuelwood supply and demand when the entire agricultural area was taken into account. In order to achieve this on agricultural land, while contributing to food security and environmental conservation as well, smallholder farmers must be provided with incentives to grow woodlots and to adopt agroforestry systems, thereby considering the trade-offs with agricultural production. Strategies to encourage smallholder farmers to increase the use of agroforestry have to account for the farmers’ ecological and socioeconomic conditions.  相似文献   

4.
根据凤冈县的基本情况、能源结构、薪炭林的现状,认为发展凤冈县的薪炭林是解决本地能源短缺问题的一个重要方面。解决的办法:1扩大薪炭林的面积;2选择适宜凤冈自然条件的薪炭林树种;3提高薪炭林单位面积的产量;4建立以自然村为单位的薪炭林基地;5采用集约经营的方式来经营薪炭林。  相似文献   

5.
Biomass plays a vital role in the energy supply of many developing countries. It is the major energy source for the rural population of Nepal, where 70 % of the total energy is derived from woody plant biomass in the form of fuelwood. The main aim of this study is to describe the fuelwood consumption pattern and the role of community forests and trees on private farmland in biomass supply to rural households in Nepal. The study investigates whether demography and socioeconomic attributes of households affect fuelwood consumption. A household survey was conducted, along with measurements of fuelwood mass for six community forest user groups in Dolakha district of Nepal. Average daily household fuelwood consumption was estimated to be 8.4 kg, giving a mean annual consumption of 3060 kg per household. Per capita fuelwood consumption per day was found to be 1.7 kg. Total fuelwood consumption of households is significantly correlated with household size, ownership of cultivated irrigated terraces and number of livestock per household, and negatively significantly correlated with ownership of cultivated rain-fed terraces. Fuelwood consumption varies significantly between seasons. Among various sources of biomass energy, fuelwood from community forests contributes 23 % and trees on private farmland contribute 12 %. The rest is provided from other biomass sources, including the remains of fodder collected from private farmland vegetation, wood previously used for fences and trellises in private farmland, crop residues, and purchased fuelwood.  相似文献   

6.
In the Sahelian and Sudanian ecozones of West Africa, the rainy season lasts only 3–4 months per year, there are steep rainfall gradients with latitude and longitude, the climate is becoming increasingly hotter and drier with more variable rainfall, some fuelwood species are disappearing locally, demand for fuelwood is increasing, and we expect that fuelwood production will be increasingly limited to drier sites in the future. We need a methodology, therefore, to identify the best species for fuelwood production in drier sites. We used a methodology that could be used to identify the best fuelwood species for drier and wetter sites in regions where there are steep rainfall gradients. We investigated variation in growth and fuelwood properties of five species (Balanites aegyptiaca, Combretum glutinosum, Guiera senegalensis, Piliostigma reticulatum, Ziziphus mauritiana) along rainfall gradients. Growth parameters (tree height, stem diameter under bark, mean ring width) and fuelwood properties (basic density, volatile matter, fixed carbon, ash content, moisture content, gross calorific value, gross calorific value per cubic meter, fuel value index) were adjusted for tree age. For each species, linear regressions were used to determine the effects of mean annual rainfall and geographical coordinates, which were correlated with rainfall, on tree growth and fuelwood properties; and the effects of tree growth on fuelwood properties in lower, intermediate and higher rainfall zones. Geographical coordinates explained more variation than rainfall, and relationships with rainfall differed among species. Larger trees had wood with higher basic density, fixed carbon, ash content, moisture content, gross calorific value and/or gross calorific value per cubic meter, but lower volatile matter and/or fuel value index. Relationships between growth and fuelwood properties were not significant in all species and rainfall zones. Based on this study, we recommend producing fuelwood of C. glutinosum and G. senegalensis.  相似文献   

7.
在四川盆地通过引进国内外薪材树种和选择乡土薪材树种,进行栽植密度、始伐年龄、轮伐期等试验研究,结果表明:从引进的8个新材树种中,选择出任豆为适宜生长的树种,新银合欢、黑荆、荆为为适宜部分地区生长的树种;从13个乡土薪材树(草)种中筛选出桤木、刺槐、麻栎、栓皮栎、马桑、卵花甜茅等为比较优良的薪材树(草)种。桤木、刺槐、马桑等薪炭林的合理造林密度为10000株(丛)/ha;麻栎、栓皮栎为6000～7000株(丛)/ha;印花甜茅以行距1m为宜。桤木、刺槐、麻栎、栓皮栎等薪炭林,始伐年龄不超过5年,轮供期3～6年;马桑薪炭林始伐年龄为3～4年,轮伐期2～3年、印花甜茅栽植1年后平茬,以后每年采收。合理的造林密度、始伐年龄、轮伐期,能使选择的几个树种提高生物产量1.0～2.5倍。  相似文献   

8.
The development of farm woodlots as an alternative source of livelihood for smallholder farmers in diverse biophysical and socio-economic conditions is a challenging issue in developing countries, such as Rwanda, where the majority of the population relies on subsistence farming. There is a need to understand why and when farmers decide to grow trees and woodlots on their farms. The objective of this study was to analyse the determinants and the purposes that enhance the propensity to grow woodlots in low, medium and high altitude regions of Rwanda. Necessary information for this study came from a survey of 480 households across these regions. The results showed regional variations in the determinants of woodlot farming, demonstrating the importance of not extrapolating the results between regions. Pooled data across regions indicated that age of the householder, number of salaried household members, farm size, travel distance to fuelwood sources and household location in medium forest cover region had positive significant effects on the propensity to grow farm woodlots. In contrast, household location in low forest cover region, ownership of livestock and monthly frequency of purchasing fuelwood were inversely related to the presence of farm woodlots. Many households planted eucalyptus woodlots for economic reasons, not for environmental purposes. Livestock and crop production were more attractive to rural households than woodlot farming. The findings of the study can be used by policymakers and extension services in order to promote sustainable land use practices by focusing on the challenges of competing land uses, farm size, unemployment, dependence on forests for fuelwood supply and subsistence farming.  相似文献   

9.
Fuelwood is the main energy source for households in rural Africa, but its supply is rapidly declining especially in the densely populated areas. Short duration planted tree fallows, an agroforestry technology widely promoted in sub-Sahara Africa for soil fertility improvement may offer some remedy. Our objective was to determine the fuelwood production potential of 6, 12 and 18 months (the common fallow rotation periods) old Crotalaria grahamiana, Crotalaria paulina, Tephrosia vogelli and Tephrosia candida fallows under farmer-managed conditions in western Kenya. Based on plot-level yields, we estimated the extent to which these tree fallows would meet household and sub-national fuelwood needs if farmers planted at least 0.25 hectares, the proportion of land that is typically left under natural fallows by farmers in the region. Fuelwood yield was affected significantly (P < 0.05) by the interaction between species and fallow duration. Among the 6-month-old fallows, T. candida produced the highest fuelwood (8.9 t ha−1), compared with the rest that produced between 5.6 and 6.2 t ha−1. Twelve months old T. candida and C. paulina also produced significantly higher fuelwood yield (average, 9.6 t ha−1) than T. vogelli and C. grahamiana of the same age. Between the fallow durations, the 18-month fallows produced the most fuelwood among the species evaluated, averaging 14.7 t ha−1. This was 2–3 times higher than the average yields of 6 and 12-month-old fallows whose yields were not significantly different. The actual fuelwood harvested from the plots that were planted to improved fallows (which ranged from 0.01 to 0.08 ha) would last a typical household between 11.8 and 124.8 days depending on the species and fallow duration. This would increase to 268.5 (0.7 years) and 1173.7 days (0.7–3.2 years) if farmers were to increase area planted to 0.25 ha. Farmers typically planted the fallows at high stand densities (over 100,000 plants ha−1 on average) in order to maximize their benefits of improving soil fertility and providing fuelwood at the same time. This potential could be increased if more land (which fortunately exists) was planted to the fallows within the farms in the region. The research and development needs for this to happen at the desired scale are highlighted in the paper.  相似文献   

10.

? Context

There is little information about inter- and intra-specific variation in fuelwood properties of trees/shrubs in West Africa.

? Aims

We studied variation in fuelwood properties of Balanites aegyptiaca, Combretum glutinosum, Guiera senegalensis, Piliostigma reticulatum, and Zizyphus mauritiana in the Sahelian and Sudanian ecozones of Mali.

? Methods

Trees were sampled on different soil (sandy, sandy/loam, or rocky), land use (parkland agroforest or woodland), and terrain (flat, temporarily flooded, or hill slope) types in five regions extending from the drier eastern to the more humid western parts of Mali. Basic density, volatile matter, fixed carbon, ash content, moisture content, gross calorific value, and fuel value index were measured for each tree and adjusted for tree age.

? Results

All fuelwood properties differed significantly among species, but there were significant species by region interactions. Most fuelwood properties of four species differed significantly among regions. Soil and/or land use type had significant effects on a few fuelwood properties of four species.

? Conclusion

In general, fuelwood production is recommended in all regions for G. senegalensis, in drier regions for B. aegyptiaca and C. glutinosum, in more humid regions for Z. mauritiana, and on rocky soils for all species. Fuelwood production of P. reticulatum is not recommended.  相似文献   

11.
The profitability of four farm-level fuelwood management alternatives were examined using benefit-cost analysis. The value of alder wood is based on the market price of a cubic meter of fuelwood sold in Saraguro, Loja, Ecuador. A sensitivity analysis of wage rate, fuelwood price, and project subsidies tests the effects of changes in key economic parameters on project profitability. Present trends in fuelwood demand and social externalities are examined and the subsidy bill is estimated for implementing an alder management plan.School of Renewable Natural Resources, University of Arizona  相似文献   

12.
本文介绍了世界薪材消耗的现状,概述了因薪材紧缺而滥伐森林带来的几个方面的严峻问题,最后提出了符合我国国情的对策。  相似文献   

13.
Agroforestry Systems - This article presents a methodology for the valuation of agroforestry with respect to fuelwood supply for cooking and its opportunity cost. The share of fuelwood consumption...  相似文献   

14.
In 1922, the colonial government introducedAcacia mearnsii in the tobacco-growing region of Wonosobo. Soon this species was accepted by the local people who developed an agroforestry system based on a rotation ofA. mearnsii and agricultural crops.Now, the growing of the black wattle is becoming less popular. To study the prospects for this agroforestry system 143 farmers from 5 villages were interviewed. The functions of this agroforestry system are the production of fuelwood and bark (which contains tannin for the leather industry), soil conservation and soil improvement. The following factors affectA. mearnsii growing: population density (which affects farm size and demand for domestic fuelwood), tobacco-processing (which requires fuel), topography and commercialization. If current trends continue, the contribution of the functions of this agroforestry system to welfare will not be sufficient to compete successfully with subsistence and cash crops like potatoes and tobacco. Therefore,A. mearnsii cultivation is expected to decline further.This article was written within the framework of the cooperation between the two departments in the Forestry and Nature Conservation (FONC) project sponsored by the Netherlands University Foundation For International Cooperation (NUFFIC).  相似文献   

15.
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   

16.
In 1922, the colonial government introducedAcacia mearnsii in the tobacco-growing region of Wonosobo. Soon this species was accepted by the local people who developed an agroforestry system based on a rotation ofA. mearnsii and agricultural crops. Now, the growing of the black wattle is becoming less popular. To study the prospects for this agroforestry system 143 farmers from 5 villages were interviewed. The functions of this agroforestry system are the production of fuelwood and bark (which contains tannin for the leather industry), soil conservation and soil improvement. The following factors affectA. mearnsii growing: population density (which affects farm size and demand for domestic fuelwood), tobacco-processing (which requires fuel), topography and commercialization. If current trends continue, the contribution of the functions of this agroforestry system to welfare will not be sufficient to compete successfully with subsistence and cash crops like potatoes and tobacco. Therefore,A. mearnsii cultivation is expected to decline further. This article was written within the framework of the cooperation between the two departments in the Forestry and Nature Conservation (FONC) project sponsored by the Netherlands University Foundation For International Cooperation (NUFFIC).  相似文献   

17.
The women in Lupeta, Tanzania use fuelwood as the primary source of fuel. The choices and constraints women face in fuelwood collection were examined using walks with women and semi-structured interviews. Women primarily use fuelwood with limited charcoal use. They would prefer to use more charcoal but costs, limited income, competition and ownership of trees, and land constrains them in both fuelwood collection and alternative strategies.  相似文献   

18.
Fuelwood is the main source of energy for various household uses in many developing countries; and management of tree resources where it is obtained can be best undertaken when household choice patterns are understood. In this paper, households’ decision to obtain fuelwood for domestic consumption as influenced by household and fuelwood source characteristics is analyzed using a multinomial probit regression model. Data is obtained from 254 randomly selected household drawn from Mbarali district, south-western Tanzania. Results indicate that households are heavily dependent on natural forests for household energy provision and that the choice to obtain fuelwood from the forest, farm or market depends, among other factors on the availability of preferred fuelwood tree species at these sources. Acacia tortilis, Brachystegia spp. and Faidherbia albida are the significantly preferred tree species and hence affect the decision of where to obtain fuelwood. This revelation highlights the pressure applied to surrounding forests as well as to the aforementioned tree species which require immediate management interventions. The gender of the household head and whether the household lives in peri-urban or rural areas also influence choice of fuelwood source. Promotion of tree planting and on-farm management of tree species similar to preferred species found in natural forests is recommended. To the extent that consumer preferences are likely to change over time, further research using panel datasets is necessary to unravel inter-temporal preferences for fuelwood sources.  相似文献   

19.
This community forestry case study examines village forest councils (van panchayat) in India’s northern state of Uttarakhand. We describe forest stocking levels of 20 community forests and address the question of whether these forests are in a position to provide commodity resources, such as fuelwood and fodder, on a sustainable basis. In addition, we report on the perceptions of the villagers on whether their respective community forest is meeting their fuelwood and fodder needs. At the biophysical level, none of the community forests were in a position to provide fuelwood and fodder on a sustainable basis. Most forests did not have adequate overstory stocking, and there was no evidence of deliberate management to improve the situation. Interviews with 400 villagers (20 in each village) supported the field findings. Villagers unanimously reported that their respective community forest was inadequate in supplying commodity needs. Furthermore, they wished the Forest Department would provide more technical and financial assistance to guide them with forest management needs. Women are a critical part of community forestry as they are the primary gatherers of fuelwood and fodder. Although the perceptions of women toward forest management issues are important, our interviews with female villagers indicate they play a passive role in decision-making. Decentralization in natural resources management sounds good at the theoretical level as it provides villagers with some authority and autonomy, but it cannot be effectively implemented without professional guidance coupled with resources. The villagers are ready and willing to improve the situation, but they do not have the resources to make change unilaterally—they need professional and financial support from the Forest Department.  相似文献   

20.
The relationship between competing vegetation characteristics (above and below ground dry weights, length and surface area) and loblolly pine (Pinus taeda) seedling characteristics were examined on a southern coastal plain soil of north-west Louisiana. Four site preparations techniques were used as treatments; chop and burn, windrow, fuelwood harvest, and fuelwood harvest followed by an application of herbicide. The more intensive site preparation treatments (chop and burn, windrow, and fuelwood harvest followed by a herbicide) had less root and above ground competition than the fuelwood treatment. The fuelwood treatment ranked lowest in pine seedling height, ground line diameter, pine root length, and pine root surface area and highest in terms of competing vegetation characteristics. Regression relationships between pine roots and competing vegetation root characteristics indicated that seedling ground line diameter is inversely related to quantities of competing vegetation roots.  相似文献   

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