Analyzing the effectiveness of alternative fuel reductions of a forested landscape in Northeastern China

Successful management of forest fire risk in the Northeastern China boreal forest ecosystem often involves trade-offs between fire dynamics, fire hazard reduction, and fiscal input. We used the LANDIS model to study the effects of alternative fuel reduction strategies on fire dynamics and analyzed cost effectiveness for each fuel reduction strategy based on cost–benefit theory. Five levels of fuel treatment area (2, 4, 6, 8, and 10% for each decade) and two fuel treatment types (prescribed burning [PB] and mechanical treatments in combination with prescribed fire [PR]) under current fire suppression simulated by LANDIS were compared in a 5 × 2 factorial design over a 300-year period. The results showed that PR scenarios are more effective at reducing the occurrence and burn area of catastrophic fires than PB scenarios. In addition, area burned by high intensity fire can be tremendously reduced by increasing low intensity fires with a higher level of treatment area under the various PR scenarios. The cost effectiveness of alternative fuel reduction strategies is strongly dependent on treatment area. In general, PB scenarios will be more cost effective in larger treatment areas and PR scenarios in smaller. We recommend mechanical treatments in combination with prescribed fire, with 4% of landscape treated in each decade (PR04) to be the optimal fuel reduction strategy in the study area based on risk control and cost efficiency analysis. However, the most challenging work in China is to make local forest policy makers and land managers accept the ecological function of fire on forest ecosystems.     

Cost-productivity analysis of South African pine sawtimber mechanised cut-to-length harvesting

The South African forestry industry is experiencing an increase in the number of fully mechanised timber-harvesting systems. Understanding the productivity of these systems, for which data is currently limited for South Africa, is an important step to maximise the utilisation of machines being used. A time study of a mechanised cut-to-length system was conducted in Pinus elliottii sawtimber plantations in the Southern Cape forestry region of South Africa. A harvester and a forwarder were studied with the intention of analysing the division of work time amongst work elements, modelling each machine’s productivity and cost, and estimate fuel consumption. For the harvester’s productivity, a multiple regression model was developed using diameter at breast height (DBH), average distance moved per work cycle and slope class as predictors (adjusted R²? = 0.80). The harvester had a mean productivity of 33.6 m³ per productive machine hour (PMH₀) under the current conditions with most of the productive time being used in the moving element. It consumed 25.5 L PMH₀ ^?1 of diesel on average. The forwarder’s fuel consumption was calculated as 16.8 L PMH₀ ^?1, while productivity was 46.8 m³ PMH₀ ^?1. The forwarder spent the longest portion of the work cycle in the loading and unloading phases. A productivity regression model was created that included load size and distance moved during the driving in the loaded phase (adjusted R?² = 0.78).     

Cost analysis of a satellite terminal for forest fuel supply in Finland

As forest fuel demand increases, new logistical solutions are needed. Most of the increase in use is expected to take place in large heat and power production units which set special requirements for the supply as both procurement volumes and transport distances increase. Biomass fuel terminals broaden the spectrum of available supply options by offering cost-effective large-scale biomass storage and processing options for securing the fuel supply in all conditions. This study aimed to study different costs of a satellite terminal and to produce important concept and cost information for developing forest fuel logistics based on future terminals. The figures indicate that terminals do not create direct cost benefits per se: direct supply chains are more economical compared to supply through terminals. However, there are several indirect benefits that can be reached via fuel supply through terminals: regional fuel procurement can be widened to a national scale, security of supply increases through easily available storages, large supply volumes can be delivered by an individual operator, prices remain more stable and a more even quality of delivered fuel can be achieved.     

森林采运系统动力学模型研究

为了分析森林采运系统的效率和成本,本文选择系统中关键的采—集过程,利用系统动力学的方法建立模型,进行计算机仿真模拟。结果显示,以特定时间范围内完成一定工作量为前提,系统运行的效率和成本与初始设备的投入量关系不大,与设备条件、外部条件、林木条件等关系很大。但初始采造设备的投入量会影响集材设备的运行效率和成本。在实际生产中,首先应根据林木条件和外部条件选择合适的设备,这样才能使得运行效率最高而成本最低;其次在设备的安排上,应充分保障采造设备,但也不应使其生产力与集材设备的生产力相差过大,否则会造成后期集材设备需求激增等问题。     

林火碳排放研究进展

火是森林生态系统主要的干扰因子, 森林火灾的频繁发生不仅使森林生态系统遭到破坏, 同时也造成了含碳温室气体的大量释放。综述了火烧面积、森林可燃物以及燃烧效率等主要因子对森林火灾排放碳量估计的影响, 分析了这一领域未来研究发展趋势。大量研究表明:1)卫星遥感是估测大尺度上森林过火面积的主要手段, 随着高分辨率卫星的应用, 森林火灾面积的估计精度不断得到提高。目前的研究主要集中于大尺度上林火面积的估计和估算方法的改进。2)遥感数据是目前估计大尺度可燃物燃烧量的有效手段, 利用遥感数据的同时结合有效可燃物计算模型, 运用多元线性与非线性分析结合等方法提高对可燃物燃烧量的估计。3)燃烧效率是决定可燃物消耗量的主要因子, 也是估计森林火灾释放含碳气体量的关键。未来的研究是利用高分辨率的遥感数据, 结合复杂的可燃物计算模型, 更精确地估计林火碳排放。     

Forest product trade,wood consumption,and forest conservation—the case of 61 countries

Trade barriers of forest products are often advocated in the name of protecting forest resources. Whether the promoting of trade of forest products will increase or decrease the global forest resources is still a matter of debate. We offer an assessment of how forest product trade helps shape observed forest change, by relating wood consumption change to trade of forest products based on cross-section data from 61 countries in 2010. The result shows that wood outputs have positive effects on wood consumption. Compared to domestic production, the result suggests that imports of forest products can help reduce wood consumption. This may indicate that trade liberalization can promote the allocation efficiency of timber resources across the global, which can improve the utilization efficiency and reduce the wood consumption in the world to protect the global forest resources. It is suggested that the high-efficient harvest and wood-processing technological transfer should be advocated in the international community to contribute to global forest conservation.     

毛竹林机械化生产装备的开发与应用

竹林经营设备的研发是提高竹林经营效率、降低经营成本、增加农民收入的关键。综合运用现代科学知识和技术,成功研发了毛竹伐桩处理机、竹林翻耕机和毛竹采伐锯3种设备,并已应用于毛竹林经营的许多方面,取得了显著成效。对进一步需要开发的竹林经营机械提出了初步构想。     

Co-operative forest fuel procurement strategy and its saving effects on overall transportation costs

Abstract

Minimum procurement cost is an essential element for the competitiveness of the forest fuel supply chain. This paper compares one co-operative procurement strategy with several non-co-operative strategies by measuring the cost gap. For a study region consisting of five Austrian provinces, forest fuel supply potential and transportation costs were investigated concerning 28 newly built combined heat and power (CHP) plants. In the case of co-operation, the minimum total transportation cost was derived by solving the corresponding transportation problem. In non-co-operative supply chains, CHP plants compete for forest fuel. This case was illustrated by analysing three different clearly non-co-operative procurement strategies, because CHP plants guard their real supply sources as business secrets. The minimum procurement cost for all CHP plants is provided by the co-operative strategy. It comprises a total transportation cost of €17 million and an average procurement distance of 122 km. Co-operation between CHP plants lowers forest fuel transportation costs by 23% on average and reduces average transportation distances by 26%. The resultant cost-cutting potential stresses the importance of co-operation between CHP plants in order to allocate forest fuel supplies efficiently. Establishing partnerships and working alliances for forest fuel procurement therefore has important management implications for achieving efficiency in forest fuel supplies and strengthening the competitiveness of wood-fuel-based energy production.     

Application of a Small-Scale Equipment System for Biomass Harvesting

The small-scale harvesting equipment system has been and continues to grow in use in forestry operations in some regions in the world. This harvest system can include a range of equipment types, such as feller-bunchers or chainsaws, skidders or farm tractors, and chippers. These machines are generally smaller, lower cost and less productive than larger, more advanced forestry machines. The objective of this project was to investigate the feasibility of a small scale harvesting system that would produce feedstock for a biomass power plant. The system had to be cost competitive. A boom-type feller-buncher, a small grapple skidder and a chipper were tested as a small-scale system. In this study, feller-buncher and skidder productivity was determined to be 10.5 m³ per productive machine hour, and production for the chipper was determined to be 18 m³ per productive machine hour. Production from the system did not reach the desired levels of 4 loads/day (25 m³/load); however, the system was able to produce about 3 loads/day. The results showed that the system currently could fill a roadside van for $16.90/m³, but suggested machine modifications could potentially reduce the system cost to $12.73/m³. Residual stand damage was minimal, especially on flatter ground and not operating on a slash layer. Soil disturbance from the harvesting system was predominantly undisturbed or classified as a shallow disturbance.     

保山市高黎贡山周边社区森林能源现状与供需对策

通过对保山市高黎贡山周边社区森林能源现状调查分析 ,结果表明 :该区现有森林资源 192 3万m3 ,每年的薪材消耗量为 16万m3 ,占总资源量的 0 83%。目前可能提供的薪材量为 7 6万m3 ,仅为需求量的 4 7 5%。作为主要薪材来源的杂灌木林 ,每公顷产柴量只有 4m3 ,仅为一般薪炭林产量的 4 3%。依据该区的经济及资源状况、消费结构、薪材供需和经营现状认为 ,要解决社区薪材供需矛盾 ,需要增加科技投入 ,加大低产林分改造力度 ,提高单位面积产柴量 ,限额开山采樵利用 ,加强经营管理技术     

森林可燃物调控技术方法研究进展

基于森林可燃物调控技术方法的国内外研究现状,从森林可燃物调控技术方法、景观尺度上的可燃物处理以及可燃物调控技术的生态效应3个方面进行系统论述。以此为基础,探讨适合的森林可燃物调控的技术方法。建议在进行森林可燃物调控时,应以营林技术为主要手段,加大景观水平的可燃物管理,综合考虑可燃物调控技术方法对生态环境的影响,实现森林可燃物的生态调控。     

基于森林碳汇视角的能源消费可持续性研究

能源燃烧释放的CO₂已被认为是温室效应的最直接原因, 但森林生态系统的储碳效应在很大程度上延缓了CO₂直接排放于大气的过程, 因而考虑两者之间的内在联系更加有利于实现能源可持续消费。文中利用能源生态足迹方法, 以2007年市场一般均衡状态下的真实能源中间投入与商品进出口数据为基础, 估算各部门中间投入能源足迹以及最终商品消费内含能源足迹, 全面地核算当年我国的能源生态足迹, 并且估算当年的森林生态系统碳汇功能承载力, 从而为判断我国能源消费是否具有可持续性提供依据。结果显示:2007年我国能源生态足迹远远大于森林生态系统的碳汇功能承载力; 从静态角度分析, 我国当年的能源消费不具有可持续性; 随着能源消费量增加, 能源生态足迹将进一步扩大, 而森林生态系统的碳汇功能承载力基本保持不变甚至有小幅下降。因此, 降低能源碳排放将是中国实现能源可持续消费的关键目标。     

伊春林区贮木场原木生产线机械使用情况的分析

通过伊春林区贮木场原木生产线机械使用情况的调查,研究了该林区原木生产线产量级、各工序机械能力利用系数和权均利用系数,并依此对原木生产线机械利用情况进行了分析。文中又以原木生产线工序机械能力损失最小为目标,研究了该林区的7种机械组合型式和17个方案。对龙门起重机输送机组成的原木生产线(LmiS_i-Y)的各方案进行了分析比较,获得了最佳的组合方案。     

Characteristic fuel consumption and exhaust emissions in fully mechanized logging operations

A study was done using eight different logging machines (harvesters and forwarders) in clear-felling operations to quantify the associated fuel consumption, and to define the inherent relationship between engine output power and fuel consumption. Exhaust emissions were also calculated on the basis of mean fuel consumption values, obtained by measurements, and from the developed regression and correlation model for diesel and rapeseed methyl ester (RME) fuels. The calculation considered exhaust emissions associated with the manufacture, distribution, and combustion of the respective fuels. It was found that carbon dioxide emissions amounted to 9.63 kg/m³ of delivered timber for diesel fuel, and to 10.64 kg/m³ for RME. It was also found that when using RME only 2.82 kg/m³ of carbon dioxide emissions originated from fossil resources, therefore, it is only this amount that can be deemed an environmental load, confirming RME as a lesser environmental pollutant.     

Energy Audit of Wood Harvesting Systems

A computer-based model for the evaluation of energy use in mechanized wood harvesting systems (EnergyCalc) was developed with aid of life cycle analysis methodologies. The system boundaries were determined "from stump to roadside" with wood volume over bark (m³) as the functional unit. The computer model (based on a database system) used a Visual Basic program, and the energy audit was based on fuel and oil consumption, and the energy consumed in the manufacture of the machines and replacement parts. The general scenario from the literature, results from Sweden and a preliminary study from Ireland are presented. In the overall energy audit of mechanized wood harvesting systems in Ireland, fuel consumption was the most significant item (82%), followed by oils (7%) and machine repairs and replacement (11%). The mean energy use from the data for Ireland was found to be 16% higher than the equivalent in Sweden (120 vs 103 MJ m^?3). An energy reduction strategy that has the potential to reduce overall energy consumption for Irish systems by up to 13% was suggested.     

基于Pro/E的链式原条造材机锯截机构的设计

实现自动化原木生产是提高贮木场原木生产效率和经济效益的重要措施.东北林区处于高纬度地区,常年低温寒冷,且目前我国尚未有适用于在低温户外作业的造材机,因此需要设计相关的造材机进行作业,提高东北林区木材资源的利用.主要根据贮木场的工作环境和效益,对链式原条造材机的锯截机构进行设计.通过计算及机械手册选取标准的零件,并运用Pro/E软件对锯截机构和关键零件进行建模,完成总体装配图.在建模的过程中介绍锯截机构的工作过程和各组成部分的作用.     

论工业人工林的生态经济特点

作者认为工业人工林是生态林业发展模式实施的重要环节,在我国林业发展中将扮演重要角色,但其生态结构单一,稳定性差,是一个高度输入输出的开放型林分。在各国的实践中,经济效益的高低并无定论。必须依据我国的国情选择适宜的发展方式,以保证其健康发展。     

Improvement and evaluation of the feller-buncher head

The high quality forest machines have recently become very popular in Japan. Many improvements on these machines have been made to fit the Japanese forests. This report describes the improvement and evaluation of the feller-buncher head of the prototype machine: FG-35. This head is mounted on the telescopic and knuckle-boom carrier. The prototype machine was improved to cut the trees, felled down on the ground or felled side ways by the storm as in the Kyushu district. And also the machine was improved so that it could be driven well without crashing the chainsaw-bar by the beginners. The testing operation of this machine carried out in Sumita-chou in Iwate and in Kuzu-chou in Oita. The productivity of the machine can be estimated at about 20 m³/h. The results of the improvement on the machine can be said to be good. A portion of this report was presented at the 106th Annual Meeting of the Japanese Forestry Society (1995).     

Technical change in forest sector models: the global forest products model approach

Technical change is developing rapidly in some parts of the forest sector, especially in the pulp and paper industry where wood fiber is being substituted by waste paper. In forest sector models, the processing of wood and other input into products is frequently represented by activity analysis (input–output). In this context, technical change translates in changes over time of the input–output (I–O) coefficients and of the manufacturing cost (labor, capital, and materials, excluding wood and fiber). In the case of the global forest products model, the I–O coefficients and the manufacturing costs are determined empirically from historical data, while correcting for possible reporting errors. The method consists of goal programming. The objective function is the sum of the weighted absolute value of the deviations from estimated and observed production in each country of interest. The constraints express the relationship between the multiple output (sawnwood, panels, pulp, paper) and input (wood, waste paper, other fiber) and prior knowledge on the limits of the I–O coefficients. The paper presents observed technical changes from 1993 to 2010 and projections to 2030 with their consequences for the global forest sector in terms of prices, production and consumption, value added, and carbon sequestration in forest biomass.     

Simulation of harvester productivity in selective and boom-corridor thinning of young forests

Abstract

Forest management practices may change in the future, due to increases in the extraction of forest fuel in first thinnings. Simulation models can be used to aid in developing new harvesting systems. We used such an approach to assess the productivity of innovative systems in various thinnings of young stands with wide ranges of mean breast height diameter (1.5–15.6 cm), stems per hectare (1000–19,100), and mean height (2.3–14.6 m).

The results show that selective multiple-tree-handling increases productivity by 20–46% compared to single-tree-handling. If the trees are cut in boom-corridors (10×1 or 2 m strips between strip roads), productivity increases up to 41%, compared to selective multiple-tree-handling. Moreover, if the trees are felled using area-based felling systems, productivity increases by 33–199%, compared to selective multiple-tree-handling. For any given harvesting intensity, productivity increased the most in the densest stands with small trees.

The results were used to derive time consumption functions. Comparisons with time study results suggest that our simulation model successfully mimicked productivity in real-life forest operations, hence the model and derived functions should be useful for cost calculations and evaluating forest management scenarios in diverse stands.