共查询到20条相似文献，搜索用时 15 毫秒
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Zhang Hongjiang COllege of Soil Water
Conservatin Beijing Forestry University Beijiig P.R.China 《中国林学(英文版)》1994,(2)
ＡｂｏｕｔＳｏｉｌＥｒｏｓｉｏｎａｎｄＳｏｉｌａｎｄＷａｔｅｒＬｏｓｓＺｈａｎｇＨｏｎｇｊｉａｎｇＣＯｌｌｅｇｅｏｆＳｏｉｌａｎｄＷａｔｅｒＣｏｎｓｅｒｖａｔｉｎ，ＢｅｉｊｉｎｇＦｏｒｅｓｔｒｙＵｎｉｖｅｒｓｉｔｙＢｅｉｊｉ１ｉｇ１０００８３，Ｐ．Ｒ... 相似文献
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CHEN Peng ZHAO Guangjie College of Material Science Technology Beijing Forestry University Beijing P.R.China 《中国林业科技(英文版)》2007,(2)
There are many advantages of bended wood,such as good-looking shape,simple process and low cost.The product,however,is easy to get recovery,which is urgent to be dealt with.This paper concludes the features of deformation and recovery of bended wood and wood-based composites and summarizes four treating methods to keep dimensional stability.Compared to bended solid wood,some elementary perspectives on the research of bended wood-based composites are presented.The purpose of this paper is to suggest:1)to investigate the optimum heating time and temperature that bended wood and wood-based composites need from the formation of deformation to the recovery and to the permanent fixation,according to its changes of dimensional stability such as curvature radius;2)to measure the composites comprised of wood and adhesives on the changes of stress relaxation,dynamic viscoelasticity and crystal1ization field;3)to quantitatively analyze changes of the major components in wood cell wall polymers as well as the composites under heat/steam treatment and untreated conditions.It will be helpful for subsequent research to clarify on the mechanisms of permanent fixation of bended wood and also contribute to that of wood-based composites. 相似文献
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Magdalena Kutnik Ed Suttie Christian Brischke 《Wood material science & engineering》2014,9(3):122-133
AbstractStandardization work in the field of wood durability and preservation is managed, at the European level, by the technical committee TC 38 ‘Durability of wood and wood-based products’ of the European Committee for Standardization (CEN). Producing sustainable wood-based materials is challenging. A crucial aspect of their provision is reliable standards that take consideration of both the expectations of end-users and the broad set of parameters that may influence the service life of wooden components such as exposure to moisture, climatic variations and design. In order to reach these objectives, most CEN/TC 38 standards are currently being revised based on the recent scientific, technological and legal developments in the field of wood protection. There is an increasing need for performance classification of wood products in construction and to radically consider how wood durability test methods and standards can inform on service life and how they might be translated into a performance classification system. This paper describes the changes during the past 5–10 years in Europe and how the trajectory of standards development is now on a different pathway. Classification and service life demands are described as well as current approaches to consider key issues such as material resistance, moisture risk and adaptation of existing standards. 相似文献
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《林业与社会》2000,(2)
NaturalforestresourcesisthemainbodyofChina'sforestresources,itplaysamainbodyroleintheaspectsofmaintainingecologicalbalance,elevatingenvironmentalqualityandprotectingbio-diversitywhichcannotbereplaced,andhasagoodecologicalandenvironmentalbenefits.Sinceearly1997,China'sStateForestryAdministration,inaccordancewiththedirectivesoftheleadersofthePartyCentralCommitteeandtheStateCouncil,workedoutimplementingPlanofNaturalResourcesProtectionProjectinKeyState-OwnedForestAreasandstartedin1998.Afte… 相似文献
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《林业与社会》2001,(1)
China are Developing Natural Forest Protection Project andReturning Cultivated Land to ForestsChina's Ministry of Finance declared notlong ago that for the sake of supportinga smooth implementation of the country'snatural forest protection project, theexpenditure of the central finance wasamounted to 22.257 billion yuan (US2.68 billion) for the project. According tothe relevant official in charge of theMinistry, out of this expenditure a sumof 10.78 billion yuan (US$1 .3 billion) wasarra… 相似文献
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Multi-storey timber construction has been developed and promoted in Finland since the 1990s. Despite these efforts, the share of timber frames in multi-storey construction has remained very low. Construction business is also very resource intensive and accounts for a large share of greenhouse gas emissions. Increasing the use of renewable materials, mainly wood, in buildings, could make construction more sustainable and a part of bioeconomy. This study aimed at identifying barriers to the adoption of multi-storey timber construction, ways in which wood could compete with established solutions and possibilities for partly integrating construction into bioeconomy. Based on 18 interviews of representatives from the entire value chain, this study presents insights into introducing new solutions into a conservative field. Our results indicate that multi-storey timber construction could offer competitive solutions for more sustainable construction, even though barriers to its adoption still exist. 相似文献
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《林业与社会》2000,(1)
Chinahasmadeamasterplantofenceallof48millionha.ofmountainareasandsandyareaswhicharesuitableforreafforestatingandplantinginthecoming12years.Accordingtothemasterplan,5.3millionha.to6.6millionha.ofmountainandhillyareaswillbereafforestatedorrevegetatedin1999.ItisestimatedthatthemainrivercoursesattheupperreachesoftheYangtzeRiver,theYellowRiver,theZhujiangRiver,theHuaiheRiver,theSonghuajiangRiver,theHaiheRiver,theLiaoheRiverandtheirbranchestributariesaredesignedtobeplanted.Asthefirststep,mount… 相似文献
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《林业与社会》2002,(2)
Danjiangkou City of Hubei Provincebegan to implement participatory povertyrelief in 30 key poor villages since 2002,Dujiawan Village of Tuguanya Townshipbecame the first participatory poverty reliefpilot village of the city.Immediately after thespring festival,the staff of city’s povertyrelief office came to the village,and gottogether with household representativesunder an ancient tree,discussing the existingdifficulties and the approaches of poverty 相似文献
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《林业与社会》2001,(2)
Funded by The Ford Foundation, the Workshop on the Method of Conflicting Management in the Management and Utilization of Natural Resources, hosted by Forestry and Society Network, was held on April 24 - 25, 2001 in Beijing, more than 20 representatives from Hebei, Anhui, Hunan, Yunnan, Zhejiang Provinces and Beijing participated in the workshop. The representatives consisted of governmental officials, professors of higher learning institutions, experts of research institutes, foresters… 相似文献
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《中国林业科技(英文版)》2011,(4):36-40
Based on the data from 2002 to 2010, the paper analyzed the situation of timber supply and demand in China, and concluded that supply-demand could be balanced basically if taking accounting of timber import. Based on the data from the Seventh National Forestry Inventory, the potential of providing timber from natural forest and plantation was analyzed. The paper also forecasted the future features and trend of timber supply and demand in China. In the end, strategic measures and technological and policy gua... 相似文献
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Heimo Karppinen 《Small-Scale Forestry》2012,11(1):15-26
This literature review focuses on two groups of landowners in the US and Finland: those current family owners who have recently
become forest owners, with a relatively short duration of ownership, and private individuals who can be expected to become
forest owners in the future are compared. The former group is called “new owners,” and the latter “future owners,” respectively.
This study aims to find what can be concluded about future owners from studies of new owners based on the assumption that
new owners are interpreted to represent future owners in these studies. The data consists of eight studies conducted after
the mid 90s. 相似文献
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SHI Shizheng WANG Baosong PAN Mingjian GUO Qun Jiangsu Academy of Forestry Nanjing P.R.China 《中国林业科技(英文版)》2007,6(4):38-46
For the high biomass and adaptability, application of willow on cultivating bioenergy forest and phytoremediation had been gotten more recognition in the world wide. Integrated with our research practice, we introduced the germ plasm of high biomass willow in China, and the new varieties with high biomass and their cultivated techniques were summarized in this article. Moreover, we reported the development up to date in breeding and cultivation on well-bred willow with high biomass and analyzed the foreground of establishing industrial willow with high biomass in China. 相似文献
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The highest deforestation and forest degradation rates in Africa occur in the dry forests and woodlands where pressure for land is increasing, poverty is rampant, livelihood options are few and climate change effects are severe. This paper examines factors that cause land and forest degradation in the Sahel and dry forests and woodlands of eastern and southern Africa and highlights some successful restoration practices, technologies and approaches. In the Sahel, enclosures are used to protect young growing trees while in East Africa enclosures are implemented on degraded land as a mechanism for environmental rehabilitation with a clear biophysical impact. The choice of techniques for rehabilitating specific degraded areas depends first on the priorities and management objectives of stakeholders followed by the costs and benefits associated with available rehabilitation techniques and the economic, social, and environmental values of the land resources in their current and desired future states. In the Sahel, sustainable land management is considered to be an imperative for their sustainable development and the practices include soil and water conservation activities and structures. In all regions, natural forest rehabilitation has used both natural and assisted regeneration to promote the growth of especially indigenous species through coppice regrowth and root suckers rather than seeds. Assisted regeneration was especially prevalent in the Sahel where indigenous tree species have been identified to dominate the degraded sites during early stages of secondary forest succession. The success of any rehabilitation activities depends on community-based natural resources management. In addition, the forest policies and their related policies need to be enabling in order to address issues of concern, including (1) the full participation of communities, (2) clear land and tree tenure and (3) equitable benefit sharing. 相似文献
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