四川盆地薪材树种选择及栽培技术研究

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。     

Evaluation of fuelwood quality of indigenous and exotic tree species of India's semiarid region

The fuelwood potential of indigenous (Acacia nilotica, Azadirachta indica, Casuarina equisetifolia, Dalbergia sissoo, Prosopis cineraria andZizyphus mauritiana) and exotics (Acacia auriculiformis, A. tortilis, Eucalyptus camaldulensis andE. tereticornis) trees were studied. Calorific value variations for components, such as, stump, main stem, treetop, branches, foliage and bark, were determined. Tree components differed highly significantly (P<0.01) among groups (indigenous and exotics) and within species. The calorific means ranged from 18.7 to 20.8 MJ/kg for indigenous tree species and 17.3 to 19.3 MJ/kg for exotics. Besides calorific values, other fuelwood characteristics, such as, density, ash, biomass/ash ratio, moisture and nitrogen content were also studied. It was observed that indigenous tree species are better suited as fuelwood species as they contain high density wood, low ash content and low N percentage. The fuelwood value index (FVI) was found to be high of indigenous tree species and was maximum forCasuarina equisetifolia (2815). The most promising tree species were in the order ofC. equisetifolia, A. nilotica andZ. mauritiana.     

四川省薪材资源评价及分区

薪材在农村能源中占有重要地位,目前全省薪炭林面积71万公顷,森林能源每年合理提供量为904.5万吨标准煤,而实际消费量为1895.8万吨标准煤,消费量是合理提供量的2.1倍,薪材供需矛盾尖锐。预测2000年全省薪材需求量为2184.8万吨标准煤,尚需发展30万公顷薪炭林。为了宏观指导农村能源建设,在分析现状和进行需求预测后,将全省薪材资源划分为4个大类和13个类型区,分别阐述了各区特点和解决途径,最后对我省农村能源发展的重点和措施提出了指导性原则。     

本溪地区薪炭林经营问题及永续利用对策的探讨

日益恶化的环境已经引起全人类的高度重视,保护环境、重建森林以保护我们的家园已经成为全世界共同的呼声,但即使如此,人们对环境和森林的破坏却一天都没有停止,其中由薪炭林砍伐造成的环境问题尤为突出。本文就本溪地区薪炭林经营的实际情况,揭示了山区农村薪炭林经营和发展中存在的问题,探讨了薪炭林可持续发展和利用的对策。     

桤木薪炭林群落学特征及生物量的研究

本文对桤木人工薪炭林群落学特征做了分析,桤木薪炭林是人工造林配置的树种,故群落简单。对估测桤木人工薪炭林乔木层生物量建立了多个数学模型,选用W_(树干)=147.1914D~(2.0616)、W_(枝条)=37.5577D~(2.3962)、W_(叶)=31.0578(D~2H)~(0.7776)和W_(地上部分)=258.6222D~(2.0622)幂函数方程,分别获得各器官的生物量,树干重8895.720kg/ha,枝条重3657.651kg/ha,叶重3345.324kg/ha,乔木层地上部分总重量15898.696kg/ha。对林下灌木和草本植物采用收割法测定,灌木地上部分生物量为2265kg/ha,草本植物地上部分生物量为459kg/ha。所以桤木人工薪炭林的地上部分生物量为18622.696kg/ha。     

Fuelwood consumption of dhabas (temporary hotels) along an altitudinal gradient in a pilgrim and tourist affected protected area of western Himalaya

ABSTRACT

The present study was carried out in a remote area of the Indian Himalayas to assess the biomass use patterns of dhabas (temporary hotels) along an altitudinal gradient in a pilgrimage and tourism affected protected area. The dhaba owners extensively collect fuelwood for various purposes such as cooking, boiling water, and space heating. The study examined factors affecting and resulting from fuelwood usage and collection—including preferred species, gathering patterns, emissions of green house gases due to combustion, and ecological parameters such as density and total basal cover. Open- and close-ended questionnaires were used for interviews with the study subjects. Firewood was reported as the only available energy source in the area. The average fuelwood consumption at three altitudinal sites was 19 kg dhaba^?1 day^?1 at Site I (1,500–2,000 m asl), 26.62 kg dhaba^?1 day^?1 at Site II (2,000–2,500 m asl), and 16.74 kg dhaba^?1 day^?1 at Site III (2,500–3,600 m asl). The five most preferred species for firewood reported by the respondents were: Alnus nepalensis, Lyonia ovalifolia, Quercus floribunda, Pinus roxburghii, and Rhododendron arboreum. The present findings could be used as a baseline for developing various conservation and sustainability measures for protected areas influenced by human populations.     

世界薪材消耗的现状、问题及我国的对策

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。     

积极采取措施加快江西林业三剩物和次小薪材综合利用的步伐

林业三剩物和次小薪材的综合利用，可以减少森林资源的采伐总量，提高其综合利用率，增加林木生产者和综合利用者的收入，还可带动山区经济的发展。应在计划管理、产业结构调整、林业规费减免、税收优惠政策落实等方面采取相应的鼓励措施，以加快综合利用的步伐，从而更好地发挥林业的生态、社会和经济效益。     

海南省中北部丘陵地区优良速生薪材树种的选择

海南省中北部贫瘠丘陵地区20个薪材树种，经4年选择试验，结果表明，马占相思、赤桉、细叶、大叶相思和斑皮桉适应性强，生长快，产量高，燃烧性能性，发热量大，用途广，经济效益高，年年均干生物量为17．5－23．9t/ha，纯利润为1199－2064元／ha，是最适合于当地生长和发展的优良速生薪材料种。     

Benefit-cost analysis of fuelwood management using native alder in Ecuador

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     

Acacia cyanophylla for forage and fuelwood in North Africa

Forage and wood yield of Acacia cyanophylla, also known as Acacia saligna, was studied in a 300–400 mm precipitation zone in Tunisia. Yields were measured during and after drought. This short (2–8 m) evergreen leguminous tree is used as a forage drought reserve in frost free regions where mean annual precipitation exceeds 250 mm. The standing crop of leafy forage builds up year after year for at least four years or until the tree is cut. It rapidly regrows after cutting from coppice shoots. The leaves provide high protein forage for sheep and goats during the long dry summer season typical of the Mediterranean climate as well as emergency forage during drought. The tree is used to stabilize moving sand dunes, and as a windbreak to protect cropland. It also provides fuelwood and increasaes soil nitrogen by fixation. The need for supplemental irrigation during establishment is a major constraint. Research in the 350 mm precipitation zone of Tunisia found 3.2 year old trees to yield over 1400 kg of forage standing crop per hectare after a severe drought. Trees harvested at 2.5 years of age in May, during the worst drought in over 30 years, yielded a standing forage crop of 724 kg per hectare. Forage regrowth 8 months after cutting and 4 months after rains returned was 700 kg/ha. The forage standing crop for trees harvested only once during the 3.2 year period was double the amount of forage regrowth from trees harvested the previous year, but mean annual forage yield similar. This demonstrates that it is possible for forage to be conserved as a living forage reserve for later use during drought. Total wood yield was only 1621 kg/ha for trees cut twice compared to 3683 kg/ha for trees cut only once. Annual cutting will substantially reduce the amount of forage available during drought and reduce the production of fuelwood. It may also reduce the vigor, productivity and life of the tree. Acacia cyanophylla alley cropped on cereal farmland can protect the soil from erosion, protect the associated crop from wind damage, fix nitrogen, provide fuelwood and provide a reserve of high quality forage for use during drought. This work was supported by the Government of Tunisia and the U.S.A.I.D. Tunisia Range Development and Management Project (664-0312.8).     

Agroforestry and soil conservation needs of smallholders in Southern Zambia

An agroforestry and soil conservation needs assessment survey conducted in southern Zambia revealed valuable insight into needs, constraints and development options as perceived by smallholders themselves. Inadequate efforts to conserve soil are due to technical and socio-economic factors, they do not result from a lack of awareness of the widespread erosion threat. Fruit tree planting, windbreak establishment as well as the protection of the natural Faidherbia albida regeneration in cropland are popular agroforestry interventions whose positive effects are widely acknowledged. Forty-two perennial species were found to directly contribute to people's diet. Although local fuelwood and fodder shortages as well as the need for fencing are recognized only few respondents envisage agroforestry solutions such as fuelwood and fodder tree planting or live fencing. Most smallholders are interested in tree planting but have so far only planted few trees. Those planted are usually exotic fruit trees. Drought hardly, termite and browse resistant perennials adapted to smallholder tree planting must be provided by the extension services. The widespread exclusion of women from decision making and the lack of tenure security hampers female participation in agroforestry development and consequently threatens sustainable development altogether.     

Fuelwood demand and supply in Rwanda and the role of agroforestry

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.     

Fuelwood production from Leucaena leucocephala established in fodder crops at Mtwapa,Coast Province,Kenya

Fuelwood production from a high density leucaena-based fodder production experiment at Mtwapa, Coast Province, Kenya is reported. Leucaena with and without other fodder crops namely, Cassava, Bana and Napier grass, formed the main-plot treatments while leucaena densities ranging from 6,250 to 100,000 ha^–1 planted in single- or double-line planting arrangements formed the sub-plot treatments of the split-plot design used. Each treatment was replicated four times. The experiment was established and maintained without the use of fertilizer, pesticides, irrigation. Hand weeding was done only during the first year.After 2.7 years growth, height and diameter measurements were taken before cutting back the leucaena stems to 0.5 m above ground. Utilizable fuelwood (twigs greater than 0.5 mm diameter) was then sun-dried for 3 months and dry weights taken.Fuelwood yields were significantly reduced by the fodder intercrops. Yield from leucaena intercropped with fodder crops were, on average, 30% lower than yield from sole stands of leucaena. Mean yields of the single-line plantings ranged from 13.7 to 21.2 tons ha^–1. Yield from the double-line plantings were lower (on average 10%) than that of single-line plantings and were as well highly variable. Unlike tree heights, diameters in the single-line planting arrangement were not affected significantly by the fodder intercrops. In the single line plantings, yield of fuelwood from sole stand of leucaena was higher at all in-row spacings than the yield from intercropped leucaena. Increase in in-row spacing of leucaena generally led to reduced yield of fuelwood.Fodder yields of intercropped Cassava, Bana and Napier grasses were near normal in the first year but zero or negligible in the remaining 1.7 years. Implications of the prolonged tree establishment period on fodder yields after opening of the canopy are discussed.     

Fuelwood Resources and Forest Regeneration on Fallow Land in Uganda

Abstract

East African forests have been largely converted to agriculture. The remaining forests hold many endangered species but are threatened by the heavy local demand for fuelwood. Here we evaluate fallow land in western Uganda as an alternate fuel source to diverse forests. We quantify the regeneration process on fallows, calculate tree bio-mass increases, and measure grass and woody herb biomass over 44 months. The biomass values we measured were typical or slightly below the average from 11 studies elsewhere in the tropics. Variation in biomass between our neighboring study sites exceeded that between sites on different continents, indicating the sensitivity of vegetation regeneration to local land use. Tree regeneration was extremely slow (0.46 g/m²/year); however, the woody herbs and grasses on a 4 year old fallow of ～0.5 ha can provide much of a family's domestic fuel. Fallow land is generally abundant in western Uganda and can partially alleviate pressure on forests for domestic fuels. Fallows cannot however provide the trees demanded by charcoal, brick, and gin manufacturers. In the future, conserving forests while meeting fuelwood demands will require improving local land tenure security, enhancing the productivity of cultivated and abandoned land, promoting more efficient stoves, stills and kilns, and curtailing illicit, inefficient charcoal manufacture.     

以芳香油和薪材为最终产品的桉树幼林地上部分生物量研究*

在2年生的桉树引种试验林内,对蓝桉和新引种的5种其他桉树的地上部分生物量进行了测定。研究发现,当轮伐期为2年时,不同桉树的芳香油和薪材收获量差异显著,而同一树种的芳香油和薪材产量在不同造林密度之间无显著差异。史密斯桉和贝克桉的芳香油和桉树脑含量均高于蓝桉,是生产桉树芳香油和薪材的优良树种,在我国亚热带地区有进一步试验和推广的价值。     

Women and fuelwood in Lupeta,Tanzania: Constraints to alternative fuels and fuelwood management strategies

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.     

Farmer perspectives on agroforestry opportunities and constraints in cape verde

In the água de Gato Watershed on the island of Santiago, Cape Verde Islands, 51 farmers were surveyed regarding their attitudes and knowledge of agroforestry. The farmers identified eight constraints to agroforestry implementation, with virtually all indicating that a source of loan funds was the major concern. Space or land constraints and availability of tree seedlings were identified as constraints by 94% and 88%, respectively. Despite these concerns, 92% of the farmers expressed a willingness to adopt or improve agroforestry practices in the watershed, with 73% expressing a willingness to establish fruit trees, 53% willing to establish trees or shrubs for fuelwood, and 16% willing to plant trees for shade.     

Households’ Choices of Fuelwood Sources: Implications for Agroforestry Interventions in the Southern Highlands of Tanzania

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.     

Farm woodlots in rural Rwanda: purposes and determinants

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.