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Assessing forest sustainability trajectory with temporal changes in timber output and ecological reserve: the case of China

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Journal of Forestry Research 2018年第1期29卷 171-176页

作者： Jianwei Bai Yang Zhao Longyu Shi Fengri Li School of Forestry Northeast Forestry University Department of Forest Resources State Forestry Administration Key Lab of Urban Environment and Health Institute of Urban Environment Chinese Academy of Sciences

We classified forest resources into four modes：high timber output and high ecological reserve（Mode T-E）; high timber output and low ecological reserve（Mode T-e）; low timber output and low ecological reserve（Mode t-e）; and low timber output and high ecological reserve（Mode t-E）. Ecological reserve is stand volume per unit area of natural forests and total area of natural forests;timber output is defined as total area of timber forests and unit area of timber production. We used this classification system to examine forest development in China between1950 and 2013. Data were acquired mainly from forest inventory statistics published by China’s Forestry Administration between the 1970 s and 2013. I Information from the 1950 s was acquired from relevant literature. Our analysis suggests that China’s forest resources transitioned from Mode t-E to Mode T-e during the period between the early 1950 s and late 1970 s, resulting in the destruction of both ecological vigor and timber resources. During the following 20 years, strategies were implemented to improve the ecological reserve and increase timber supply,resulting in a decline in the rate of forest degradation. Over the past decade, China’s forest resources have reached Mode T-E as a result of improvements in both the ecological reserve and the timber supply. Currently, the total area of timber forests is relatively low, representing the limiting factor for improvement in overall forest functionality. Nevertheless, along with increased efforts to protect natural forests and develop fast-growing forest plantations, it is hopeful that China’s forest resources will achieve a sustainable state. The four-mode TOER（timber output, ecological reserve） method introduced in this paper is a simple but an effective approach for characterizing the overall quality and quantity of forest resources. The data used for this type of evaluation are typically easy to obtain and reliable. This methodology has potential to be applied to fore

关键词： Ecological vigor Forest assessment Natural forests Sustainable forestry timber

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Deterioration models for prediction of remaining useful life of timber and concrete bridges:A review

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Journal of Traffic and Transportation Engineering(English Edition) 2020年第2期7卷 152-173页

作者： Ishwarya Srikanth Madasamy Arockiasamy Department of Civil Environmental and Geomatics EngineeringFlorida Atlantic UniversityBoca RatonFL 33431USA

Bridge deterioration models are used for prioritization and maintenance of *** models can be broadly classified as deterministic and stochastic *** are mechanistic models(or physical models)as well as Artificial Intelligence(AI)-based models,each of which can be stochastic or deterministic in *** though there are several existing deterioration models,state-based stochastic Markov chain-based model is widely employed in bridge management *** paper presents a critical review of different bridge deterioration models highlighting the advantages and limitations of each *** models are applied to some case studies of timber superstructure and concrete bridge *** are illustrated for arriving at bridge deterioration models using deterministic,stochastic and Artificial Neural Network(ANN)-based models based on National Bridge Inventory(NBI)*** first example is based on deterministic model and the second on stochastic *** deterministic model uses the NBI records for the years 1992-2012,while the stochastic model uses the NBI records for one year(2011-2012).The stochastic model is state-based Markov chain model developed using Transition Probability Matrix(TPM)obtained by Percentage Prediction Method(PPM).The two deterioration models(i.e.,deterministic and stochastic models)are applied to timber highway bridge superstructure using NBI condition data for bridges in Florida,Georgia,South Carolina and North *** illustrated examples show that the deterministic model provides higher accuracy in the predicted condition value than the stochastic Markov chain-based *** the model is developed based on average of transition probabilities considering the data for the period 1992 to 2012,the prediction accuracy of stochastic model will *** data filtering of condition records aids in improving the accuracy of the deterministic *** third example illustrates the ANN-based deterioration model for r

关键词： Bridge engineering timber and concrete bridge Deterioration model Markov chain Artificial Neural Network

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Comparison of three processing methods for laminated bamboo timber production

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Journal of Forestry Research 2019年第1期30卷 363-369页

作者： Edi Suhaimi Bakar Muhammad Nadzim Mohd Nazip Rogerson Anokye Lee Seng Hua Faculty of Forestry Universiti Putra Malaysia Institute of Tropical Forestry and Forest Products (INTROP) Universiti Putra Malaysia

Three processing techniques, split-squaring(SS),V-grooving(VG), and split-edging(SE), were evaluated and compared in terms of their processing time and recovery. Semantan bamboo(Gigantochloa scortechinii Gamble) was used as a raw material and the results showed that the VG-method required the longest processing time(32.1 min), followed by the SS-method(18.2 min), and the SE-method(17.9 min). However, the VG-method showed the highest recovery(82.0%) compared to the SS-method and SE-method, 31.0 and 49.4%, respectively. When both processing time and recovery factors were combined with the same weighing factor, the highest value was recorded with the VG-method(49.1), while the SE-method had values of 31.1 and the SS-method 12.8. The results suggest that the VG-method is the best option. However, the V-grooving machine is still a prototype and therefore the SE-method could be an alternative option until the improved V-grooving machine is available.

关键词： Bamboo culm Laminated bamboo timber Vgrooving method Split-squaring method Split-edging method

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Determination of the Properties of Some Selected timber Species for Structural Application

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World Journal of Engineering and Technology 2023年第2期11卷 319-334页

作者： Asimiyu Amobi Oyediran Catherine Mayowa Ikumapayi Babatola Olufemi Department of Civil and Environmental Engineering Federal University of Technology Akure Nigeria Department of Forestry Federal University of Technology Akure Nigeria

One of the alternative sustainable and green construction materials to concrete is timber. timber is of numerous varieties, and this acts as a barrier to the extent of its usage, especially in structural application. Despite many researches on wood’s mechanical and physical properties, only a few are geared toward the structural application of wood. The present work investigated the mechanical properties of five timber species;Gmelina arborea, Tectona grandis (Teak), Terminalia superba (Afara), Ayin (Anogeissus leiocarpus), and Acacia (Robinia pseudoacacia), to determine their suitability for constructing long-span roof trusses. These are available in the South Western part of Nigeria. Their mechanical properties;bending strength, compressive strength, shear strength, tensile strength, Modulus of Elasticity (MOE), Modulus of Rupture (MOR), and density, were determined in the laboratory. The results obtained showed that all the timber types, except Terminalia superba (Afara), have higher values of mechanical properties than the values that are obtainable for classes of strength D30 to class D70 in the British Code of Practice. It means these species are of higher quality than the stipulated strength classes in the British code. The results also show that the order of relevance of the species for structural design (or work) is Acacia (Robinia pseudoacacia), Ayin (Anogeissus leiocarpus), Gmelina Arborea, and Tectona grandis (Teak). Terminalia superba (Afara) is not recommended for structural works.

关键词： timber Wood Species Bending Strength Compression Mechanical Properties

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Geomorphic impacts of timber harvesting

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Chinese Science Bulletin 2001年第S1期46卷 1-4页

作者： Olav SlaymakerDepartment of Geography, The University of British Columbia, Vancouver, B. C. V6T 1Z2, Canada (e-mail: olav@geog.ubc.ca) Department of Geography The University of British Columbia Vancouver Canada

timber harvesting influences (a) forest hydrology; (b) fluvial geomorphology; (c) terrain stability; and (d) integrated watershed behavior. Impacts on forest hydrology are well understood and include increased average runoff, total water yield, increased storm runoff and advances in timing of floods. Stream channels and valley floors are impacted differently by fine sediment, coarse sediment and large woody debris transport. Terrain stability is influenced through gully and mass movement processes that are accelerated by timber harvesting. Impacts on integrated watershed behavior are assessed through disturbed sediment budgets and lake sediments.

关键词： timber harvesting forest hydrology stream channel hillslope stability.

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From file to factory: Innovative design solutions for multi-storey timber buildings applied to project Zembla in Kalmar, Sweden

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Frontiers of Architectural Research 2019年第1期8卷 1-16页

作者： Alex Kaiser Magnus Larsson Ulf Arne Girhammar Division of Wood Science and Engineering Lulea University of Technology 931 87 Skelleftea Sweden Former Lulea University of Technology Sweden

A "file-to-factory" process of computer technology is a way to both maximise efficiency throughout the building process, in crease a buildi ng's performance, and be able to add interesting architectural possibilities throughout the design phase. The authors investigate a novel approach that produces a set of building trajectories rather than a set of buildings, yet yields a series of build-able examples of those trajectories. This paper evaluates how this series of stacked multi-storey timber buildings can be both incorporated within a file-to-factory process, and give rise to creating new innovative solutions throughout the entire design and manufacturing process. This process is applied to a real Swedish project called Zembla. It redefines the notion of sprawl, turning it into a progressive tactics for linking the dty fabric to rural areas. It is a postsustainable file-to-factory-produced timber ground-scraper;soaring above ground and water, suggesting a new way of making city-sized buildings for the future. A plug-in grid-shell structure is designed to contain a minimal amount of timber elements, beams make up the lattice, cross-laminated panels add structural support, surfaces come together to form the living capsules. Having the structure undulate across the topography and touching the ground in as few places as possible uses the dichotomy between landscape and urbanism, bringing the city to the people living in less densified areas. Each living unit is customised to its topological conditions within the grid.

关键词： Multi-storey timber buildings File-to-factory Modular systems Grid shells Slotting Living capsules

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EFFECT OF timber DENSITY ON RETENTION OF WOOD PRESERVATIVES

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Journal of Northeast Forestry University 1993年第1期4卷 53-59页

作者： Zhang Shirun Bian Liping Northeast Forestry University Northeast Forestry University China

The amount of CCA fixed in the southern pine treated with CCA have been *** conclusions from these experiments are:with the timber density increases,the reten-tion based on weight/weight will decrease,but the retentio... 详细信息

关键词： timber density Retention Wood preservation

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Market analysis for timber and forest products in China

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Journal of Forestry Research 1999年第2期10卷 124-126页

作者：陆文达王冬香凌楠

This paper introduces the general condition of forestry resources of China and the demand and supply of timber and forest products. The market for timber and forest producls has borne dual pressure because of the population explosion and growth of the domestic economy. A major contemporary strategy for sustainable forestry includes the promotion of the Forest Products Industry (FPI), the substitution of other materials for timber,and the encouragement of imports of timber and forest products. The author analyzes the effect of these policies on the market for timber and forest products. In addition, the difficulties encountered by most mid-to large -scale state- owned forest enterprises during the transition from a centrally-planned economy to a market economy are examined. Finally, the author points out the countermeasures and means for reform of these old forest enterprises with a view toward future prosperity of the market for timber and forest products.

关键词： timber Forest products Wood based panels (WBP) Pulp & paper Forest Products Industry (FPI)

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An Effective Wood DNA Extraction Protocol for Three Economic Important timber Species of India

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American Journal of Plant Sciences 2018年第2期9卷 139-149页

作者： Tanzeem Fatima Ashutosh Srivastava Vageeshbabu S. Hanur M. Srinivasa Rao Tree Improvement and Genetics Division Institute of Wood Science and Technology Bangalore India Division of Biotechnology Indian Institute of Horticultural Research Bangalore India Policy Research Policy and Management Institute of Wood Science and Technology Bangalore India

Extraction of DNA from fresh tissues is routine in studies of tropical forest species, but DNA extraction from wood is considered as difficult due to its highly degraded nature and adequate quality of genomic DNA extraction is essential for molecular studies. Very few studies have validated the potential for isolating DNA from dried wood (Heartwood and Sapwood). Wood genomic DNA extraction is difficult from mature timber (Teak (Tectona grandis f;verbanaceae), Black Rosewood (Dalbergia latifolia f;Fabaceae) Ben Teak (Lagerstroemia lanceolata f;Lytheraceae) tissues due to presence of high quantity of secondary metabolites polyphenols, tannins and terpenoids and protein inhibitors. Mostly in laboratories DNA extraction kits are available but by using kits, DNA yield is very low and it is quite expensive too. We have standardized and validated the DNA extraction through manual protocol which is applicable for Bark, Sapwood and Heartwood samples of tree species which contains huge amount of inflexible tissues and fibers. The quality of the DNA was tested by spectrophotometer, gel electrophoresis and PCR (ISSR and SSR) amplification. An avrage DNA yield for heartwood ranges from 0.186 - 0.166 μg/μL and sapwood was ranges from 0.26 - 0.244 μg/μL. Modification of CTAB method was by addition of polyvinylpyrrolidone (PVP) appx 0.25%, variation in Rnase concentration, proteinase treatment with different concentration and incubation time. In order to evaluate the standardized wood genomic DNA extraction protocol, we compared it with the mature leaf and core samples (heartwood and sapwood) of the same timber species. The outcome was also quantified and proved by means of polymerase chain reaction analysis by using ISSR and SSR microsatellite markers conducted with isolated pure DNAs. This modified protocol made increased yield and purity of wood total genomic DNA and facilitate the important application of forensic timber species effort.

关键词： Wood Genomic DNA Plant DNA Kits timber ISSR and SSR Markers

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Refurbishment of Significant timber Structures in Slovakia

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Journal of Civil Engineering and Architecture 2014年第8期8卷 1009-1016页

作者： Jaroslav Sandanus Kristian Sogel Department of Steel and timber Structures Slovak University of Technology Bratislava 81368 Slovakia

The paper presents an analysis and a subsequent refurbishment of significant buildings in Slovakia. The analysis focuses on the load-bearing timber roof-structures. There are three sacral objects and one long-span sporting hall presented. The paper tries to introduce the background of difficult refurbishment process. Before the refurbishment, a thorough process of investigation is required This process includes four basic steps. General information about the load-bearing structure is obtained from the geodetic survey that foregoes the process of diagnostic inspection. The diagnostic survey focuses on the defects of the structure, their degree and possible origin. Modem methods of computer modelling help to understand the structural operation and help to find reserves of carrying capacity. Structural analysis should take into account all detected defects and the joint types, which can influence the transfer of forces. The refurbishment project is usually a brief, but clear summary for fulfilling the needs of Monument Board and building process. All the steps require knowledge from different fields and require professional approach.

关键词： timber diagnosis refurbishment sacral architecture

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