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1.
Abstract

The search for alternative energy sources has increased the interest in forest biomass. During the past few years, the severe infestation of the mountain pine beetle (MPB) within the forests of interior British Columbia (BC) has led to huge volumes of dead wood that exceed the capacity of the lumber industry. One way to make the most value of the surplus wood is to use it as the feedstock for bioenergy. The high costs associated with harvest and transport, and uncertainty in supply logistics are issues related to forest biomass utilization. This paper presents the development of a forest biomass supply logistics simulation model and its application to a case of supplying MPB-killed biomass from Quesnel timber supply area (one of the most infested areas in the interior BC) to a potential 300 MW power plant adjacent to the city of Quesnel. It provides values of quantity, cost and moisture content of biomass which are important factors in feasibility study of bioenergy projects. In the case of a conventional harvesting system, the biomass recovered from roadside residues in 1 year will meet only about 30% of the annual demand of the power plant with an estimated delivered cost of Can $45 per oven-dry tonne of woodchips. Sensitivity analyses were also performed.  相似文献   

2.
The effect of changes in roundwood harvests in Norway on the harvests in rest of the world is examined using a global forest sector model. About 60–100% of the harvest change in Norway is offset by an opposite change in the rest of the world. Such leakage rates vary over time, wood category, background scenario, and the size of the harvest change. Asymmetries between the effects of increasing and decreasing the harvests also exist. Hence, the magnitude of leakage rate is case specific, though considerable. Under tightening wood supply there is less need/room to respond to harvest increase/decrease in Norway with incremental/reduced harvests elsewhere. When the use of global forest resources intensifies with increasing wood demand in the future, leakage rates can be smaller than today. It is important to account for harvest leakage in order to avoid overestimating the climate benefits of policies that decrease or increase roundwood harvests. For instance, for full carbon sequestration benefits of increasing harvests for harvested wood products, creating fresh additional demand for these products should be prioritized. Else the origin of raw material and the place of production for these products may change instead of their stock.  相似文献   

3.
ABSTRACT

Logging operations in Cameroon are based on the extraction of wood from natural forests. In this article, we assessed the carbon stock in a forest management unit (FMU) located in East Cameroon from field inventory to postfelling operations up to sawmill and export terminals. Tree basal area and aboveground biomass were calculated based on trees inventoried in the annual allowable cut. We observed that from an exploitable tree potential of 0.696 trees ha?1 inventoried within a diameter range of 50–110 cm, 0.141 tree ha?1 (i.e., 20% of the inventoried trees) were logged. In other words, out of 6.78 tC ha?1 inventoried, 1.84 tC ha?1 (i.e., 27% was logged), 1.62 tC ha?1 arrived in the log yard and 1.3 tC ha?1 arrived in sawmill, while 0.32 tC ha?1 reached the export terminal. In terms of damages caused on vegetation, 4.45% of all the annual allowance cut (AAC) were affected during logging activities, this represents almost 33,188.07 tons of carbon. These findings show that the implementation of reduced-impact logging (RIL) could reduce these losses throughout the logging steps and help propose a process for the valuation of wood waste in the forest and sawmill. In this context, reducing emissions from deforestation and degradation will be engaged with the right approach.  相似文献   

4.
近自然森林经营在德国的应用成效分析   总被引:1,自引:0,他引:1       下载免费PDF全文
[目的]分析德国推行近自然森林经营20年来的经营效果,总结德国推行近自然森林经营的经验。[方法]在明晰近自然森林经营原则的基础上,基于两期(间隔期10年)资源清查数据对比,对德国大面积推行近自然森林经营20年的经营效果进行分析。[结果]两期资源清查数据表明,德国采用近自然经营20年后,针叶林如挪威云杉和欧洲赤松的面积显著减少,阔叶林和针阔混交林面积持续增加;阔叶树种蓄积平均增长量约为15 m~3·hm~(-2),针叶树种蓄积平均增长4 m~3·hm~(-2),挪威云杉是唯一蓄积下降的树种,下降了5 m~3·hm~(-2);近自然度等级变化表明,人工林面积在减少,而近自然森林的面积在增加,甚至符合原始林等级的森林面积也在增加。[结论]实现近自然森林经营的目标是一个长期的过程,联邦政府促进和保护森林的政策以及林场主所采用的先进的森林经营技术也是德国森林每公顷蓄积达到336 m~3的重要原因;在近自然森林经营的原则下,德国森林中针阔混交林比例显著增加;将近自然程度不高的人工林经营转化为近自然的森林生态系统是德国森林经营所面临的主要问题。  相似文献   

5.
We used national scenario analyses to examine the effects of harvesting intensity on the development of forest resources, timber supply, carbon balance, and biodiversity indicators of Finnish forestry in nine 10-year simulation periods (90-year simulation period) under the current climate. Data from the 11th National Forest Inventory of Finland were used to develop five even-flow harvesting scenarios for non-protected forests with the annual harvest ranging from 40 to 100 million m3. The results show that the highest annual even-flow harvest level, which did not decrease the growing stock volume over the 90-year simulation period, was 73 million m3. The total 90-year timber production, consisting of harvested volume and change in growing stock volume, was maximized when the annual harvest was 60 million m3. Volume increment increased for several decades when harvested volume was less than the current volume increment. The total carbon balance of forestry was the highest with low volume of harvested wood. Low harvested volume increased the values of biodiversity indicators, namely volume of deciduous trees, amount of deadwood and area of old forest.  相似文献   

6.
Climate change and carbon mitigation through forest ecosystems are some of the important topics in global perspective. Tropical dry forests are one of the most widely distributed ecosystems in tropics, which remain neglected in research. The soil organic carbon (SOC) stock was quantified on a large scale (30 1-ha plots) in the dry deciduous forest of the Sathanur reserve forest of Eastern Ghats. The SOC stock ranged from 16.92 to 44.65 Mg/ha with a mean value of 28.26 ± 1.35 Mg/ha. SOC exhibited a negative trend with an increase in soil depth. A significant positive correlation was obtained between SOC stocks and vegetation characteristics viz. tree density, shrub basal area, and herb species richness, while a significant negative correlation was observed with bulk density. The variation in SOC stock among the plots obtained in the present study could be due to differences in tree abundance, herb species richness, shrub basal area, soil pH, soil bulk density, soil texture etc. The present study generates a large-scale baseline data of dry deciduous forest SOC stock, which would facilitate SOC stock assessment at the national level as well as to understand its contribution on a global scale.  相似文献   

7.
  • ? This study describes the scenarios of likely development of carbon pools in managed forest ecosystems of the Czech Republic. The analysis was based on a matrix scenario model (EFISCEN), adopting a novel parameterization based on forest stand site types and forest typology. The model was constrained by practical management rules as prescribed by the Czech Forestry Act and used to assess production potential for the next five decades under three management and three climate scenarios. The analysis provided data on carbon pool development, including both tree biomass and soil compartments.
  • ? For the tested scenarios of sustainable forest management (wood removals not exceeding increment) the model indicated a slight increase of soil carbon pool. For the possibly largest removals (maximum sustainable felling scenario), soil carbon stabilized within two or three decades reaching a mean value of about 8.1 kg/m2 for. At the same time, the mean carbon stock held in biomass reached about 10.2 kg/m2 including belowground parts. No decline of soil carbon was observed for any of the tested scenarios.
  • ? We conclude that it is reasonable to assume that soil carbon is not a source of carbon under the current management constraints as implemented in the Czech forestry practice.
  •   相似文献   

    8.
    Over the last decade, while the size of China's economy more than doubled, China has simultaneously become a major producer and exporter of forest products. Although China's domestic supply of wood is significantly constrained both by a limited natural supply and by conservation-oriented policies, the country is increasingly regarded as the world's “wood workshop.” Furthermore, China is the largest driver of demand for the trade in tropical logs and is becoming a significant driver of demand for trade in coniferous logs. In this paper, we describe a spatial equilibrium model adapted to study forest sector markets and policies that affect them. We present the model and the result of two alternative future scenarios. The first scenario analyzes the impact on global forest products markets of a US recovery in wood markets. The second scenario examines the effect on global forest products markets of decelerating growth in Chinese demand for wood products. Through these two scenarios, the modeling output sheds light on the role China's wood products markets have on resource supply and trade around the world. The trade model shows substantial potential changes in global prices, production, and trade activity associated with the recovery in domestic demand in the USA.  相似文献   

    9.
    Abstract

    Agri-environmental schemes' ability to increase the provision of environmental goods has been questioned because such schemes may pay landowners for something they would have done anyway. Contributing to this discussion, the aim of this paper is to investigate how financial compensation changes forest owners' declared willingness to set aside productive forest areas for nature conservation. The study is based on a survey of forest owner attitudes and ownership objectives in Denmark. First, it was analyzed how forest owners' declared willingness to set aside productive forest area for nature conservation changed when they were offered financial compensation. The majority of forest owners (64%) increased their willingness to set aside forest when offered financial compensation, whereas for others, compensation resulted in no change or, for a few respondents, even decreased the willingness. Hence, financial compensation may help to increase the provision of environmental goods but it is necessary to be aware of groups not motivated by financial incentives. Secondly, a binary logit model showed that the greatest likelihood of financial compensation increasing the motivation for setting aside forest is observed for owners who are young, female, live in the western part of Denmark and own farmland. Policy makers can use such information to target subsidy schemes at particular groups.  相似文献   

    10.
    [目的]通过制定森林管理参考水平,计量并核算森林管理活动的合格净碳汇清除量。[方法]采用核证减排标准中农业、林业和其他土地利用项目的自愿碳标准,选取其中改善森林管理的项目方法学标准,并结合不可抗力及湖南会同县的杉木人工林林地资源现状,进行计量和核算湖南会同县杉木人工林的合格碳汇量。该方法学标准包括4个碳库,即地上部分、地下部分、枯死木和木质林产品。[结果]对30年生和23年生杉木人工林进行森林管理活动后,林分碳储量变化量和碳汇量都有明显增加。森林管理参考水平在考虑皆伐的碳排放后的净碳汇量为-82.79 t二氧化碳当量·hm~(-2),30年生和23年生的总碳汇量分别为441.00、715.46 t二氧化碳当量;实际合格总碳汇量分别为606.59、881.06 t二氧化碳当量。[结论]不同的森林管理采伐强度对30年生和23年生林分碳汇量的影响差异显著。本文分别基于湖南会同森林生态实验站第1代杉木人工林建立参考水平和生态站2代杉木人工林制定参考水平核算会同县杉木人工林碳汇量,结果是基于后者参考水平核算的会同县杉木人工林合格的碳汇量比基于前者参考水平核算的多30 t二氧化碳当量·hm~(-2)。  相似文献   

    11.
    Estimation of accurate biomass of different forest components is important to estimate their contribution to total carbon stock. There is lack of allometric equations for biomass estimation of woody species at sapling stage in tropical dry forest (TDF), and therefore, the carbon stored in this forest component is ignored. We harvested 46 woody species at sapling stage in a TDF and developed regression models for the biomass estimation of foliage, branch, bole and the total aboveground part. For foliage and branch biomass, the models with only stem diameter as estimator showed greater R 2. For bole and aboveground biomass, the models including wood specific gravity or wood density exhibited higher R 2 than those without wood density. Also, the model consisting of wood density, stem diameter and height had the lowest standard error of estimate for bole and aboveground biomass. Moreover, the R 2 values are very similar among models for each component. The measurement error of height and the use of a standard value of wood density together may introduce more than 2 % error into the models. Therefore, we suggest using diameter-only model, which may be more practical and equally accurate when applied to stands outside our study area.  相似文献   

    12.
    Abstract

    Red wood ants of the Formica rufa group, as well as their nests, form a vital part of the ecosystems of both European and Siberian boreal and temperate forests. It has been well documented that the nests of red wood ants in clear-cuts do not perform as well as those deeper in the forest. However, clear-cuts may not be a homogeneously poor habitat for such forest-dwelling ants because the distance of the nest site to the edge of the remaining forest may be a significant factor affecting the nest performance. In this study, I compared the probability of nest survival and sexual offspring production between the nests of Formica aquilonia (Yarrow, 1955) in a forest edge zone (distance to the forest edge <9.2 m) and a clear-cut centre zone in 18 different clear-cut areas. Although the nests were generally smaller, the probability of sexual offspring production and nest survival was higher among those nests in the edge compared to the centre zone. Since the proximity to the forest edge increased the performance of a nest, selective logging and smaller scale clear-cuts may not be as harmful to red wood ants as clear-cutting over a large area.  相似文献   

    13.
    Over the coming decades, climate change will increasingly affect forest ecosystem processes, but the future magnitude and direction of these responses is uncertain. We designed 12 scenarios combining possible changes in tree growth rates, decay rates, and area burned by wildfire with forecasts of future harvest to quantify the uncertainty of future (2010-2080), timber growing stock, ecosystem C stock, and greenhouse gas (GHG) balance for 67 million ha of forest in British Columbia, Canada. Each scenario was simulated 100 times with the Carbon Budget Model of the Canadian Forest Sector (CBM-CFS3). Depending on the scenario, timber growing stock over the entire land-base may increase by 14% or decrease by 9% by 2080 (a range of 2.8 billion m3), relative to 2010. However, timber growing stock available for harvest was forecast to decline in all scenarios by 26-62% relative to 2010 (a range of 1.2 billion m3). Forests were an annual GHG source in 2010 due to an ongoing insect outbreak. If half of the C in harvested wood was assumed to be immediately emitted, then 0-95% of simulations returned to annual net sinks by 2040, depending on scenario, and the cumulative (2010-2080) GHG balance ranged from a sink of −4.5 Pg CO2e (−67 Mg CO2e ha−1) for the most optimistic scenario, to a source of 4.5 Pg CO2e (67 Mg CO2e ha−1) for the most pessimistic. The difference in total ecosystem carbon stocks between the most optimistic and pessimistic scenarios in 2080 was 2.4 Pg C (36 Mg C ha−1), an average difference of 126 Tg CO2e yr−1 (2 Mg CO2e yr−1 ha−1) over the 70-year simulation period, approximately double the total reported anthropogenic GHG emissions in British Columbia in 2008. Forests risk having reduced growing stock and being GHG sources under many foreseeable scenarios, thus providing further feedback to climate change. These results indicate the need for continued monitoring of forest responses to climatic and global change, the development of mitigation and adaptation strategies by forest managers, and global efforts to minimize climate change impacts on forests.  相似文献   

    14.
    确定一个地区的最大森林覆盖率受制约的因素很多,有自然因素、政治因素、经济因素、社会因素、传统习俗。但在一个地区林地规模衡定后,影响一个地区的最大森林覆盖率主要通过当地经济、社会的变化,来影响林地的内部构成而发生变化。通过黔东南不同地貌环境(简称地貌类型)和黔东南村级单位森林面积占林地比例(简称村级)两个体系,分别分析影响全州最大森林面积的约束条件,用Excel 2010进行了规划求解并计算得出最大森林覆盖率64%左右。黔东南最大森林覆盖率的确定,将对制定林业战略发展方向,取得关键性作用。  相似文献   

    15.
    Mapping forest dynamics under climate change: A matrix model   总被引:1,自引:0,他引:1  
    Global climate change may be affecting forests around the world. However, the impact of climate change on forest population dynamics, especially at the landscape or regional level, has hardly been addressed before. A new methodology was proposed to enable matrix transition models to account for climate impact on forest population dynamics. The first climate-sensitive matrix (CSMatrix) model was developed for the Alaska boreal forest based on observations from over 15 years of forest inventory. The spatially explicit model was used to map climate-induced forest population dynamics across the region. The model predicted that the basal area increment in the region under natural succession would be hindered by global warming, more so for dry upland areas than for moist wetlands. It was suggested that temperature-induced drought stress could more than offset a predicted increase of future precipitation in the region to lower overall forest productivity. At the same time, stand diversity would increase across the region through transient species redistribution. Accounting for climate conditions made the CSMatrix model more accurate than conventional matrix models.  相似文献   

    16.
    Abstract

    This research reports the major evaluation results from an operational stand-based forest inventory using airborne laser scanner data carried out in Norway. This is the first operational inventory in which data from two separate districts are combined. Laser data from two forest areas of 65 and 110 km2 were used to predict six biophysical stand variables used in forest planning. The predictions were based on regression equations estimated from 250 m2 field training plots distributed systematically throughout the two forest areas. Test plots with a size of 0.1 ha were used for validation. The testing revealed standard deviations between ground-truth values and predicted values of 0.58–0.85 m (3.4–5.6%) for mean and dominant heights, 2.62–2.87 m2 ha?1 (9.3–14.3%) for basal area, and 18.7–25.1 m3 ha?1 (10.8–12.8%) for stand volume. No serious bias was detected. For 10 of the 12 estimated regression models there were no significant effects of district.  相似文献   

    17.
    Abstract

    Several uncertainties are associated with the future development in Russia. The aim of this study is to analyse the effects of some of them on the forest sectors in Russia and the European Union. In particular, we examine the impacts of increasing prices set on atmospheric CO2 emissions and the changing investment climate in Russia on the use of forests in the EU and Russia as well as on the export of forest products from Russia to the EU. In the analysis, we use a numerical forest sector model, EUFASOM. The results suggest that a more intensive utilisation of the vast forest resources in Russia call for rapid improvements in the investment climate. Otherwise, the growth of pulp and paper production in Russia would mainly be directed at satisfying the domestic demand. It is hard to penetrate the EU markets which are suffering from excess capacity and a slow demand growth. Russia's importance as a supplier of energy wood to the EU is likely to increase, unless for instance export tariffs or tighter climate policies in Russia hinder such a development. The results demonstrate large differences in the harvesting and use of wood in the EU and Russia across the alternative future scenarios.  相似文献   

    18.
    Abstract

    Climate change effects such as storms and droughts are leading to increased risk of forest damage in central Europe. The aim of this paper was to evaluate forest fuel sourcing models including climate change-induced risks on forest fuel supply. Stochastic risk events, such as storms and bark beetle infestations, were modelled by means of a Monte Carlo simulation, and the economic performance was evaluated for two fuel-sourcing models supplying a single combined heat and power plant (CHP). The first sourcing model depicted a common sourcing model for Austrian CHPs, where only forest chips provided by long- and short-term suppliers were stored. The second sourcing model additionally enabled the storage of salvaged pulpwood to supply forest fuel from the plant's own inventory during shortage periods. Simulation results showed that storing salvage pulpwood as feedstock considerably reduced supply chain risks and resulted in lower procurement costs (1–3% less than normal delivered cost without storing salvaged pulpwood).  相似文献   

    19.
    根据湖南省森林资源现状,对全省森林面积、蓄积增长潜力进行了分析论证,到2020年全省可增加森林面积273.70万hm2、活立木蓄积15 208.32万m3,分别占全国新增森林面积4 000万hm2的6.8%和新增森林蓄积量13亿m3的11.70%。并提出了实现森林面积、蓄积增长的主要措施。  相似文献   

    20.
    A forest biomass yield table based on an empirical model   总被引:1,自引:0,他引:1  
    We report an empirical model for estimating unutilized wood biomass, and its application to Cryptomeria japonica D. Don and Larix kaempferi in Tohno City, Iwate Prefecture, northeast Japan. Outputs from the model are the quantity of unutilized wood biomass and merchantable volume produced by timber harvest. The unutilized wood biomass is divided into stumps, tops, branches, foliages, small trees, and unutilized stems due to their defects. Inputs to the model are mean diameter at breast height (DBH), mean tree height, trees per unit area, and timber utilization standards. DBH distribution, DBH–height curve, stem form, bark thickness, and relationship of stem biomass to foliage and branch biomass could be described by the proposed model, indicating its validity. The proposed model enables us to develop the forest biomass yield tables modified from the existing stem volume yield tables. The developed forest biomass yield tables indicated that the unutilized wood biomass due to defects accounted for the largest part of the whole unutilized wood biomass, and that the ratio of unutilized parts in stem volume to total stem volume could vary with stand age and site productivity class. Based on a comparison of the developed forest biomass yield tables with those reported previously, we concluded that the proposed model-based forest biomass yield table would be useful for estimating the quantity of unutilized wood biomass.  相似文献   

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