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1.
Portable sawmilling trials with Acacia aneura (mulga) and A. cambagei (gidgee) have been undertaken to estimate the private landholder costs associated with small-scale timber production from woodlands in western Queensland, Australia. A time study of harvesting and milling operations facilitated estimation of landholder labour input requirements. The scarcity and small size of millable logs, coupled with the prevalence of timber defects, make harvesting and portable sawmilling of western Queensland acacias an expensive undertaking for landholders. The cost of producing sawn timber that meets the High Feature (HF) grade of Australian Standard AS2796 is estimated at between A$3,000/m3 and A$3,400/m3 of HF timber.  相似文献   

2.
Both model and field estimations were made of the damage inflicted to coffee plants due to the harvest of timber shade trees (Cordia alliodora) in coffee plantations. Economic analyses were made for different coffee planting densities, yields, and both coffee and timber prices.Damage due to tree felling and log skidding should not be a major limitation to the use of timber shade trees in coffee plantations. The timber price that would balance all discounted losses and benefits to zero, for scenarios with and without trees ranged between 8–20 US $/m3 (current overbark log volume at the saw mill yard is US$ 66/m3). There will be lower margins for coffee damage in high yielding plantations, specially in years of good coffee prices. Nevertheless, the use of timber shade trees is recommended even in these scenarios.  相似文献   

3.
范嵩 《林产工业》2020,57(2):76-78
家具生产企业是我国制造业的重要组成部分。随着我国家具进出口贸易的不断发展,国际木材价格波动对我国家具生产企业的发展造成了严峻挑战。基于国际木材价格波动现状,分析国外木材原料的价格波动特征对国内木材原料市场异常价格波动带来的影响,以规避潜在的市场风险,促进国内家具企业的发展,在此基础上,有针对性地提出对策建议。  相似文献   

4.
Abstract

An integrated simulation tool, formed by integrating the InnoSIM sawing simulation system with the RetroSTEM simulator, was used to convert available wood raw materials from final felling into sawn timber, allowing for calculation of the three-dimensional wood properties of individual stems (stem geometry, heartwood formation, knottiness) as well as the volume, quality and value of sawn timber in a Norway spruce stand with different thinning regimes (unthinned, normal and intensively thinned). Based on the input data of sawing patterns, the simulations indicate that there are relatively small differences (<8%) in the volume yield (m3ha?1) of sawn goods resulting from sawlogs available from final felling with different thinning practices. However, intensive thinning yielded the largest stem diameters and the greatest volumes (m3ha?1) of large-sized centre goods (thickness: 50, 63, 75 mm) of rather poor quality. Normal thinning yielded the largest volume of A-grade side boards and centre goods (m3ha?1), as well as the best total value ([euro]ha?1) of sawn timber. Differences observed in sawn timber quality distribution can contribute to even more significant variation in value yields, if pricing mechanisms of timber products change to favour higher grade timber products.  相似文献   

5.
A model was developed to estimate the stable timber output from shade stands of Cordia alliodora in coffee farms. The model predicts, for stand densities between 120–290 trees/ ha, timber yields of 9–24 and 6–15 m3/ha/yr of total and commercial overbark volumes, respectively. Current harvest rates in four sample farms are below these figures.The model is used to describe the transient trajectory (in terms of timber output over time) of Cordia alliodora stands with different initial DBH distributions. Practical recommendations are derived as to how farmers should manage their trees to achieve stable timber outputs in the shortest time possible.  相似文献   

6.
This review on the use of hardwoods for the production of LVL revealed that a large number of research studies have been carried out, particularly in North America and three Asian countries (Japan, Malaysia and China). However, the studies have been restricted to species of low to medium density, i.e. 290 to 693 kg/m3. Two major potential uses of hardwood LVL have been investigated in these studies: domestic and industrial structures, and various furniture components. The production of structural LVL in North America and Asia was based predominantly on low density hardwoods. A study currently carried out in Europe aims at using medium density hardwoods for structural LVL. The LVL used for furniture components was produced from medium density hardwoods. No work has been undertaken outside Australia on the use of high density species for LVL. In Australia, studies undertaken on the production of LVL and hardwood plywood from eucalypts revealed that there were significant problems in gluing the dense raw material which often had a high level of extractives. Peeling low quality, small diameter eucalypt logs also created problems when the traditional plywood processing techniques were used. Received 7 July 1997  相似文献   

7.
Abstract

Growing markets for chopped firewood have created alternative uses for the by-products of sawmills. Based on empirical data and simulated results, the potential of birch (Betula pendula Roth, Betula pubescens Ehrh.) from commercial thinnings for combined industrial production of sawn timber and firewood billets was investigated. In the simulations, different sawing patterns were used for logs intended to combine production of sawn timber and billets for chopped firewood (‘sawlogs’), and for logs intended only to firewood production (‘firewood logs’). Finally, economical feasibility analysis was done concerning the differences between the sawmills’ traditional business concept and the novel concept combining sawn wood and firewood production. The bucking results for the volume yield of different timber assortments varied only slightly between the different bucking options, i.e. the combinations of timber assortments. The main differences in the volumes of timber assortments were due to the stand type where the birch trees were sampled (planted, naturally regenerated, mixed birch–spruce). In the sawing procedure, the output of sawn timber varied between 24% and 42% of the log volume in the sawlogs, depending on the log diameter class. As the volume yield of sawn timber and firewood billets was counted together in the case of sawlogs, the log consumption was c. 1.75 m3 of roundwood per 1 m3 of sawn timber and firewood billets. In the case of the firewood logs, the log consumption rate was considerably lower, only c. 1.35. The economic calculations showed that using the firewood approach in sawing may increase the net added value of products by €1.9–5.4 m?3 of logs, depending on their diameter class. As a conclusion, parallel production of sawn timber and firewood from logs from the first and second commercial thinning of birch-dominated stands is a concept that could work as an alliance between a sawmiller and a firewood entrepreneur. The concept could be competitive compared with both traditional sawmilling and production of chopped firewood.  相似文献   

8.
Queensland, Australia, has a proud pastoral history; however, the private and social benefits of continued woodland clearing for pasture development are unlikely to be as pronounced as they had been in the past. The environmental benefits of tree retention in arid regions of the State are now better appreciated and market opportunities have arisen for the unique timbers of western Queensland. A financial model is developed to facilitate a comparison of the private profitability of small-scale timber production from remnant Acacia woodlands against clearing for pasture development in the Mulga Lands and Desert Uplands bioregions of western Queensland. Four small-scale timber production scenarios, which differ in target markets and the extent of processing (value-adding), are explored within the model. Each scenario is examined for the cases where property rights to the timber are vested with the timber processor, and where royalties are payable. For both cases of resource ownership, at least one scenario generates positive returns from timber production, and exceeds the net farm income per hectare for an average grazing property in the study regions over the period 1989–1990 to 2000–2001. The net present value per hectare of selectively harvesting and processing high-value clearwood from remnant western Queensland woodlands is found to be greater than clearing for grazing.  相似文献   

9.
In commercial forestry, regular terrestrial enumerations of the growing stock are required for the valuation, sustain-able management and planning of current and future timber supplies. In this study we examined whether the combination of synthetic aperture radar (ALOS PALSAR) and optical satellite (SPOT 4) image data can accurately predict the timber volume of even-aged Eucalyptus plantations located in South Africa. Results from this study show that the combination of ALOS PALSAR and SPOT 4 produces a R 2 value of 0.68 for the planted model, whereas the coppiced model produced a R 2 value of 0.55. However, by including stand age as an independent variable in the stepwise model, there was a 15% improvement for the planted model, whereas the coppiced model produced a 27% improvement. The final model developed in this study produced a R 2 value of 0.83 and a RMSE of 31.71?m3 ha?1 for planted stands, whereas the model for coppiced stands produced a R 2 value of 0.82 and a RMSE of 27.70?m3 ha?1. As it is not practical or financially feasible for commercial forestry companies to carry out terrestrial enumerations for all plantations on an annual basis, the model developed in this study presents an alternative and accurate method to calculate timber volume for even-aged Eucalyptus plantations.  相似文献   

10.
This paper reports findings of surveys into small-scale sawmilling and timber processing in Phu Tho Province and the Tam Dao National Park buffer zone in northern Vietnam. The objective of these surveys was to examine the extent to which small sawmills and timber processors utilise farm-grown timber, so as to explore the prospects for expansion of farm-grown timber markets. The operational scope, supply chain and value chain of the industry are reported. Resource availability and current and future perspectives are discussed. Timber prices were found to vary greatly between species and study areas. Species most in demand by enterprises are Artocarpus heterophyllus, Melia azedarach, Manglietia conifera, Acacia spp., Chukrasia tabularis and Erythrophloeum fordii. Small-scale sawmilling and timber processing activities fit well with rural communities in Vietnam and have potential for further development if current constraints can be overcome. Further tree planting is needed to meet the presently unsatisfied timber demand and to create income and employment. Information from sawmillers and timber processors suggests the types of species that farmers should be considering for their plantings.  相似文献   

11.
Longitudinal sawn wood are usually selected as samples in the study of sound properties of a musical instrument board. But in real production, radial sawn timber are cut and are also widely used as vibration component. Therefore, it is very important to evaluate the vibration properties of the board in the round, especially for the sound radiation characteristic of radial sawn timber and its relationship to longitudinal sawn timber. However, for the national and international experts, researches on radial sawn timber and its role and function in sound emission have not yet been developed. This paper describes a study of seven important spruces that grow up in the Sichuan and Heilongjiang provinces of China, and one Picea sitchensis specimen from North America. Under the high bending vibration mode, resonance frequency and other parameters of longitudinal and radial wood were tested. Analysis result disclosed the relationship between longitudinal and radial wood vibration property. An important conclusion of wood for musical instruments with proper anisotropy, fine toughness, and weak shear of longitudinal and radial vibration was inducted. __________ Translated from Scientia Silvae Sinicae, 2006, 42(3): 21–24 [译自: 林业科学, 2006, 42(3): 21–24]  相似文献   

12.
A silvopastoral model that combines the production of pasture herbage with valuable native timber species has potential to simultaneously address the multiple goals of reforestation, conservation of native species and enterprise intensification. The objective of this study was to design, establish and monitor early growth of a silvopastoral experiment on a dairy farm in the north Atlantic zone of Costa Rica. Two indigenous timber species, Vochysia guatemalensis and Hyeronima alchorneoides were planted with and without the tropical pasture legume, Arachis pintoi in a split plot design, (2 × 2) factorial arrangement of treatments with four replications. After the first two years, V. guatemalensis was significantly taller (3.1 m) than H. alchorneoides (2.5 m). The mean root collar diameter for V. guatemalensis was significantly larger (6.5 cm) than H. alchorneoides (4.5 cm). Two-year establishment was acceptable for the tree component (83 to 85% survival) but poor for A. pintoi (2 to 8% of the sward). The most important pest affecting the establishment of the timber species was the leaf cutter ant, Atta cephalotes. An insect larvae, Cosmopterix sp., severely damaged 39% of the V. guatemalensis trees by repeatedly attacking their apical meristems. The two-year establishment data was insufficient to accurately predict future wood volume. A hypothetical economic analysis concluded that the silvopastoral system must average at least 1.2 m3 wood volume/paddock/year (20 m3/ha/year) throughout the first ten years of growth to assure a positive economic return from timber. The experiment is planned for a ten year period, which corresponds to the estimated rotation length for harvesting the timber species. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

13.
《Southern Forests》2013,75(4):311-318
Average wood density of 38-year-old Cariniana legalis (Mart.) Kuntze, a Brazilian native forest species, was found to increase with faster growth and lower stocking, while decreasing from pith to bark. A complete randomised block design was planted with five blocks. Ten trees were harvested in each of three spacing treatments. We hypothesised that the stand stemwood production would not significantly differ depending on tree spacing. However, tree growth would be higher in the wider spacing and wood density would be higher in the narrower spacing. The diameter growth of trees was higher at 3 m × 2.5 m than at 3 m × 2 m and 3 m × 1.5 m. Nevertheless, this higher individual tree growth at 3 m × 2.5 m did not compensate for the greater tree stock density at 3 m × 1.5 m with stand stemwood production at 38 years of 530 m3 ha?1 and 649 m3 ha?1, respectively. These results suggest that C. legalis, which can produce up to 17 m3 ha?1 y?1 of medium-to high-density timber – about 800 kg m?3 – is a promising native species for forest plantations in Brazil.  相似文献   

14.
In 1987–89 the CATIE-GTZ Agroforestry Project set up experiments with five timber tree species planted in single lines on twelve farm boundaries in cooperation with local farmers. When the trees were five years old, their height, diameter and total stem volume were: Acacia mangium 17 m, 19 cm and 67 m3 km–1, Cordia alliodora 14 m, 20 cm and 46 m3 km–1, Eucalyptus deglupta 22 m, 24 cm and 85 m3 km–1, Tectona grandis 17 m, 20 m and 64 m3 km–1, Terminalia ivorensis 18 m, 23 cm and 104 m3 km–1. Considering these excellent growth rates, planting of Cordia alliodora, Eucalyptus deglupta and Tectona grandis in lines on farm boundaries should be promoted. T. ivorensis and A. mangium are not recommendable for sites with impeded drainage because of mortality caused by root rot, mostly due to Rosellinia sp.  相似文献   

15.
The structure of Japanese timber markets has changed drastically during recent decades. After the introduction of a large amount of imported softwood products. Japanese timber producers have faced global competition with foreign timber suppliers such as Canada, the US, and recently Nordic countries. In this paper, we present a forest sector model for lumber markets with a focus on eight aggregate regions (Tohoku, Kanto, Hokuriku, Chubu, Kinki, Chugoku, Shikoku, and Kyushu) in Japan. The proposed model is based on the Samuelson-partial equilibrium formulation, which searches for an optimal solution by maximizing the net social payoff subject to demand and supply constraints. A nonlinear programming solution technique is incorporated into the proposed model. Three types of lumber are considered,i.e., domestic lumber, the lumber processed in Japan from imported logs, and imported lumber from the US and Canada. Using data for 1998, our analysis indicates that the derived equilibrium solution has a higher price for the imported lumber supply in all regions, and a lower price for the other two products in most regions than the actual current price in 1998. The derived net social payoff gains 1.6% compared with the one derived with the current set of prices and quantities. This is research was supported by the Grant-in-Aid for scientific Research (No.11691090) from the Ministry of Education, Culture, Science, Sports, and Technology of Japan.  相似文献   

16.
Sawn hardwood exports from Tanzania have declined drastically from a peak of 24 000 m3 in 1969 to 640 m3 in 1984. Factors influencing this trend include scarcity of fine hardwoods which have been overexploited, production and distribution problems which have led to very high free-on-board supply prices, and unprofitable shipments for export. In addition, inadequate export handling facilities and the absence of direct shipping routes to many potential markets have worsened export prospects, at least for the immediate future.  相似文献   

17.
For the southern Appalachian Mountains U.S.A., the development of a stand of cove hardwoods dominated by yellow-poplar (Liriodendron tulipifera L.) is described beginning with its inception after clearcutting in 1913, followed by a severe fire in 1916, and a cleaning in 1923. No subsequent treatments were imposed; natural mortality was the only factor affecting stand development since 1923. Stand density, basal area, and average stem diameter by individual species are shown for six stand ages. Diameter distribution of the 247 largest trees per ha is also shown for six stand ages. In 60 years, the cleaned stand produced 701 m3/ha of timber compared with 558 m3/ha for the uncleaned stand. Total basal area was greater by 8.58 m2/ha in the cleaned stand.  相似文献   

18.
开展不同施肥量对交趾黄檀幼树生长影响的试验。结果表明,5年生交趾黄檀胸径、树高、材积、冠幅生长量最大的为处理3(350 g/株),分别为7.12 cm、5.96 m、0.012 8 m3、3.20 m,分别比林分平均胸径6.24 cm、树高5.23 m、材积0.009 2 m3、冠幅3.06 m提高14.1%、13.96%、39.13%、4.58%。应用层次分析法得到综合得分最高的为处理2(250 g/株),表明在合理范围内增加施肥量可加速幼树生长,但交趾黄檀冠幅大,侧枝发达,易受风害,不是施肥量越大越好,应适当控制施肥量。  相似文献   

19.
A computer model was developed for the economic analysis of the damage caused to cocoa plants (Theobroma cacao) due to the harvest of timber shade trees (Cordia alliodora), based on field estimations from cocoa farms in the indigenous region of Talamanca, in the south east of Costa Rica. An economic cost-benefit analysis was carried out considering cocoa planting densities, yields, timber volumes and both cocoa and timber prices. Damage to cocoa plants was quantified in terms of severity levels and then translated into yield losses and their corresponding economic values. From the 49 harvested timber trees observed, 196 cocoa plants were affected, of which 4% required replanting and 38% coppicing. Tree trunks were involved in 55% of the damage cases (109) and tree crowns in 45% (89). Nevertheless, the revenue obtained from timber sales easily offset the costs of damage to the cocoa crop. The economic analysis showed that on average, the net gain derived from timber harvesting was around US316 per tree. For all considered scenarios, the timber market price that would balance discounted costs and benefits to zero ranged between US316 per tree. For all considered scenarios, the timber market price that would balance discounted costs and benefits to zero ranged between US22 and US$66 m−3 (current market price for C. alliodora is US$66 m−3 (current market price for C. alliodora is US128 m−3). There would be lower margins due to higher costs of cocoa damage in high yielding, high price cocoa scenarios. However, the study shows that damage due to tree felling should not be a major objection of farmers to the use of timber shade trees in cocoa farms even in these scenarios.  相似文献   

20.
以国家开发银行贷款建设200 hm2黑木相思与速生桉用材林培育为例,采用动态经济分析方法进行财务净现值、内部收益率等指标及投资不确定性分析,研究两者投资经营的经济效益。结果表明,计算期（13a）内,黑木相思和速生桉用材林的内部收益率、投资利润率和资本金利润率均高于行业基准收益率（8%）,项目可行。黑木相思的财务净现值、内部收益率高于速生桉,其经济效益好,盈利能力和抗风险能力强。  相似文献   

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