Effect of utilization standard on wood supply and lumber yield

ABSTRACT

Although sustainable forest management is accepted worldwide in concept, challenges in the methods of implementation remain. Using local data sets from Alberta, Canada, we show that a simulation approach can assist the implementation of sustainable forest management by improved understanding of product potential and other forest ecosystem goods and services that forests can provide for a given forest inventory. This will assist facilitating trade-offs among them for an optimal wood utilization strategy to achieve sustainable forest management. In this example, effects of wood utilization standard on merchantable volume, lumber volume, and number of trees that can produce at least one piece of lumber are quantified, and a conversion method for wood volumes under different wood utilization standards is presented. Wood utilization standard is the combination of stump height and diameter inside bark at merchantable height, which considerably influences available volume quantity of forest resource. However, such influences have not been quantified for sustainable forest management implementation. Our results not only confirmed that merchantable and lumber volumes increased with decreasing stump height and diameter inside bark at merchantable height, but also revealed that this trend will not hold when diameter inside bark at merchantable height is less than 7 cm.     

Modelling of knots in logs

A geometrical model was derived to describe knots in logs and on the surface of lumber beams sawn from those logs. Each knot is defined by 7 parameters related to the shape and position in the stem. A computer simulation program was written to study knot shapes on a variety of observation planes.An initial investigation on the shape of knots in Scots pine logs and lumber beams suggests that the model is sufficiently accurate to describe knottiness in this species. Potential applications of this model include automated lumber grading, computerized log reconstitution and yield optimization studies.This research was carried out when the author was a Visiting Scientist at the Technical Research Centre of Finland (VTT), Forest Products Laboratory, P.O. Box 207, SF-02151 Espoo, Finland. Technical assistance of U. Saarelainen, A. Usenius and C. O. Sommardahl from VTT is gratefully acknowledged. This work was partially supported by Forestry Canada and the Natural Sciences and Engineering Research Council of Canada     

Mapping dead wood distribution in a temperate hardwood forest using high resolution airborne imagery

Dead wood, in the form of coarse woody debris and standing dead wood, or snags, is an essential structural component of forest ecosystems. It plays a key role in nutrient cycling, ecosystem functions and provision of habitat for a wide variety of species. In order to manage dead wood in a temperate hardwood forest, an understanding of its availability and spatial distribution is important. This research evaluates airborne digital camera remote sensing for mapping temperate forest dead wood across an area within Gatineau Park, Canada. Two approaches were evaluated: (1) direct detection and mapping of canopy dead wood (dead branches and tall snags) through the combination of three techniques in a hybrid classification: ISODATA clustering, object-based classification, and spectral unmixing, and (2) indirect modelling of coarse woody debris and snags using spectral and spatial predictor variables extracted from the imagery. Indirect modelling did not provide useful results while direct detection was successful with field validation showing 94% accuracy for detected canopy level dead wood objects (i.e. 94% of validation sites with canopy dead wood were detected correctly) and 90% accuracy for control sites (i.e. 90% of validation sites with no canopy level dead wood were identified correctly). The procedures presented in this paper are repeatable and could be used to monitor dead wood over time, potentially contributing to applications in forest carbon budget estimation, biodiversity management, and forest inventory.     

Modeling annual production and carbon fluxes of a large managed temperate forest using forest inventories, satellite data and field measurements

We evaluated annual productivity and carbon fluxes over the Fontainebleau forest, a large heterogeneous forest region of 17,000 ha, in terms of species composition, canopy structure, stand age, soil type and water and mineral resources. The model is a physiological process-based forest ecosystem model coupled with an allocation model and a soil model. The simulations were done stand by stand, i.e., 2992 forest management units of simulation. Some input parameters that are spatially variable and to which the model is sensitive were calculated for each stand from forest inventory attributes, a network of 8800 soil pits, satellite data and field measurements. These parameters are: (1) vegetation attributes: species, age, height, maximal leaf area index of the year, aboveground biomass and foliar nitrogen content; and (2) soil attributes: available soil water capacity, soil depth and soil carbon content. Main outputs of the simulations are wood production and carbon fluxes on a daily to yearly basis. Results showed that the forest is a carbon sink, with a net ecosystem exchange of 371 g C m(-2) year(-1). Net primary productivity is estimated at 630 g C m(-2) year(-1) over the entire forest. Reasonably good agreement was found between simulated trunk relative growth rate (2.74%) and regional production estimated from the National Forest Inventory (IFN) (2.52%), as well as between simulated and measured annual wood production at the forest scale (about 71,000 and 68,000 m(3) year(-1), respectively). Results are discussed species by species.     

Cost-effectiveness analysis of subsidy schemes for industrial timber development and carbon sequestration in Japanese forest plantations

This study uses simulations to investigate the effects of implementing two different Japanese forestry subsidy systems on timber production and carbon stock, and examines the consequences for harvesting strategies. An existing Local Yield Table Construction System (LYCS), a wood conversion algorithm, and a harvesting cost model were used in the simulations to test the applicability of different subsidies to the thinning of stands. Using forest inventory data collected by local government staff, simulation output was used to calculate forestry profits, carbon stocks, subsidies, the amount of labor required, and the cost effectiveness of investing in subsidies. By comparing the output of simulations based on two scenarios, we found that both the clear-cutting area and the amount of harvested timber were larger under Scenario 2, in which the rules governing subsidy allocations are more relaxed, than under Scenario 1, in which the rules are more restrictive. Because the harvested timber under Scenario 1 was mainly produced by clear-cutting, the forestry profits and the subsidy predicted in the early period of the simulation, were larger under Scenario 1 than under Scenario 2. In contrast, the carbon stock was larger under Scenario 2 than under Scenario 1. The simulation model is likely to be useful for improving Plan-Do-Check-Act cyclesimplemented in Japanese forest management systems.     

A multivariate cointegration test of the law of one price for Canadian softwood lumber markets

The law of one price (LOP) has been used extensively to study market integration of forest products. This paper applies the Johansen multivariate cointegration procedure to test the law of one price for five regional markets (Atlantic Canada, Quebec, Ontario, Prairies and British Columbia) of softwood lumber in Canada using quarterly data for the 1981–1997 period. The order of integration of each price series was determined using the augmented Dickey–Fuller test with and without the possibility of structural breaks. The results from both tests showed that all five price series were I(1). The hypothesis that the LOP holds for all five regional softwood lumber markets was not supported by the Johansen multivariate test. Pairwise testing of the LOP under the single cointegration vector identified in the data showed no evidence that the markets for softwood lumber in Canada are integrated. The results suggest that there is no single market for softwood lumber in Canada, but rather, a series of geographically distinct markets.     

Optimization potential for perception-oriented appearance classification by simulated sawing of computed tomography-scanned logs of Norway spruce

Abstract

Wood, as a natural material, has favourable properties in both technical and aesthetic aspects. Due to its inherent variability, production of high-quality sawn timber demands adequate control of log conversion, which is feasible with computed tomography (CT) log scanning. Existing appearance grading rules for sawn timber might not fully reflect people's visual perception of wood surfaces, and therefore, an alternative, more perception-oriented appearance classification could be beneficial. An appearance classification of sawn timber based on partial least squares discriminant analysis (PLS-DA) of knot-pattern variables was developed and tested. Knot-pattern variables derived from images of board faces were used in training PLS-DA models against an initial classification of the board faces previously established by aid of cluster analysis. Virtual board faces obtained from simulated breakdown of 57 CT-scanned Norway spruce logs were graded according to the developed classification. Visual assessment of the grading results indicated that the classification was largely consistent with human perception of board appearance. An initial estimation of the potential to optimize log rotation, based on CT data, for the established appearance grades was derived from the simulations. Considerable potential to increase the yield of a desired appearance grade, compared to conventional log positioning, was observed.     

Determining optimal primary sawing and ripping machine settings in the wood manufacturing chain

for wood manufacturers around the world, the single biggest cost factor is known to be its raw material. Maximum volume recovery of this raw material is, therefore, of key importance for the industry. The wood products industry consists of several interrelated manufacturing steps for converting trees into logs and logs into finished lumber. Each operation usually optimises its functionality in isolation from the preceding and following operations. It is a well documented fact that the optimisation of decisions through the whole chain of operations is considerably more profitable than the optimisation of individual operations. The objective of this study was to determine the optimal machine settings for two interrelated operations, namely the sawing and ripping operations which have tradition? ally been optimised individually. A model, having two decision variables, was developed which aims to satisfy market demand at a minimal cost. The first decision was how to saw the log supply into different thicknesses by choosing specific sawing patterns. The second was to decide on a rip saw's priority value settings, which determines how the products from the primary sawing operation are ripped into products of a certain thickness and width. The techniques used to determine the machine settings included static simulation with the SIMSAW software to represent the sawing operation and mixed integer programming to model the ripping operation. A metaheuristic, namely the Population Based Incremental Learning algorithm, was used to link the simulation and mixed integer models and to determine the optimal settings for the combined process. The model's objective function was to minimise the cost of production. This cost included the raw material waste cost and the over or under production cost. The over production cost included the stock keeping costs and the under production cost was estimated as the buy?in cost of under supplied products from another wood supplier. The model performed well against current decision software available, namely the Sawmill Production Planning System package, which combines simulation and mixed integer programming techniques to maximise profit. The model added further value by modelling and determining the ripping priority settings in addition to the primary sawing patterns.     

Impacts of bucking and delimbing alternatives on pulpwood and energy wood yields in young thinning stands in Finland

The supply of energy wood from young forests could be enhanced by altering the harvesting methods in integrated pulpwood and energy wood thinnings. In this study, effects of different bucking and delimbing options on the biomass division into energy wood, pulpwood and logging residue were estimated in integrated thinnings of young stands dominated by Scots pine (Pinus sylvestris), Norway spruce (Picea abies) or birches (Betula spp.) in Finland. Thinning options were simulated in the harvestings of model stands created on the basis of forest inventory data. Increasing the minimum top diameter of pulpwood (MTDP) expectedly increased energy wood and decreased pulpwood yields. Depending on tree species, energy wood yield increased by 36–65% when the top diameter was increased from the regular level (6 or 7 cm) to 8 cm in whole-tree harvesting, and was more than doubled when the top diameter was increased to 10 cm. Delimbed energy wood yield was increased by 240–280% when the top diameter was increased to 10 cm. Total harvesting yield in whole-tree thinnings was slightly increased by increasing top diameter. These increments in harvesting yields and reallocations of tree biomass could have an impact on large-scale forest energy potentials.     

Identifying the inter-market relationships of forest products in the Pacific Northwest with cointegration and causality tests

We identify various inter-market relationships of forest products using cointegration and causality tests together. Of the six Douglas fir domestic sawlog, export sawlog, and lumber markets in the Pacific Northwest, we find that the two log markets and the two lumber markets are integrated, respectively. However, the two export log markets are not, nor is any cross-grade combination. In conjunction with cointegration restrictions, our causality tests demonstrate that export and lumber prices lead the movement of domestic sawlog prices; and similarly, the movements of domestic lumber prices follow the movements of export log prices. A close examination further reveals that export log prices for Region 1 lead the price formation process in all the lumber markets and log markets. We believe that these results have significant implications for understanding and thus dealing with forest products market behavior and price forecasting.     

我国森林生态系统植被碳储量估算研究进展

文章从时空尺度、分布特征以及影响因子三方面总结了我国森林生态系统植被碳储量估算研究进展.阐述了在国家尺度、区域尺度和林分尺度的研究现状;分析了我国森林生态系统植被碳储量的地域分布、在不同植被类型中的分布、龄级分布、林分内的分布以及时间动态变化;探讨了经济和人口、气候条件、造林和抚育、林龄、林型种类等对植被碳储量的影响....     

中国的木材工业与国民经济的可持续发展

用大量的事例和数据论述了建国50多年来,特别是改革开放后的20多年,在我国的国民经济发展的同时,钢材、水泥两大原材料的生产也同步快速增长。由于我国森林资源短缺,木材的生产量却呈现了负增长。但是,由于同期快速发展的木材工业,大大提高了中国的木材利用水平,降低了木材消耗;利用部分木材、采伐和加工剩余物及多种非木质材料制造人造板,成为世界第二大人造板生产国;进口部分原木和锯材作为补充,这三种措施的综合结果,每年可为我国经济发展带来近2亿m3木材的实际效益,技术进步和发达的木材工业为国民经济可持续发展提供了技术支撑。     

基于森林资源连续清查样地数据的林分林木生长模型研制

以广西森林资源连续清查固定样地的复测样木和样地数据为原始数据,对马尾松、杉木、阔叶树单木和林分生长率模型进行拟合。建立单木生长率模型,预估样地中采伐木生长量,求算其自然状态下未经采伐的样地林分生长量,以此为基础拟合林分生长率模型,初步选出3个较优模型,通过拟合与优化以及精度检验,最终选出最佳模型。在全区样本建模基础上,针对马尾松和杉木不同区域生长差异性,按一元立木材积模型适用区域同步进行分区组织样本建模,结果表明分区建模精度均高于全区样本拟合精度,其能更好地表达林分生长状况。     

天然林保护工程对木材相关行业的影响及对策

天然林保护工程实施后,我国木材产量将调减1236万m3,到2000年,中国木材供需缺口将达5600万m3,其中大径材缺口将超过2000万m3.森工企业面临转型,传统木材工业调整经济结构,林业商品生产重点南移,木材相关行业如造纸业、家具业、建筑业及新兴的室内装饰业将受到严重影响。为解决国家木材供需矛盾,我国仍将立足国内,扩大进口,大力发展速生丰产林,挖掘其它资源,并加强木材节约代用。面对此形势,林产工业应采取先进加工工艺,调整产品种类和产品结构,满足市场和用户需求。     

间伐小径木指接技术研究

间伐材指接胶合加工，变短材为长材，弯材为直材，为合理，有效利用间伐材开辟了新路。对间伐材木材含水率，指接端压的大小和时间，指接后养护时间，涂胶量，指榫规格等对指接材抗弯强度的影响进行了研究，并测定了苯酚，间苯二酚，甲醛树脂胶胶合的指接材快速老化性能。     

Response of saproxylic insect communities to logging history,tree species,stage of decay,and wood posture in the central Nearctic boreal forest

Saproxylic insect assemblages are essential functional components of forest ecosystems that can be affected by forest management.We used a split-plot ANOVA design to analyze differences in selected saproxylic insects(all arthropod orders and dipteran and parasitic hymenopteran families) emerging from dead wood of sites with different logging histories(horse-logged,mechanically-logged and unlogged),tree species(Populus and Picea),stage of decay(early-and late-decay stages) and posture(standing and downed logs) in the boreal forest of central Canada.No clear effects of logging history were seen for the studied taxa; however,interaction between logging history and other dead wood features was apparent.Cecidomyiidae consistently emerged more from Populus than from Picea dead wood.Most of the studied saproxylic families were more abundant in late-decay than in early-decay wood.Dipterans of the Cecidomyiidae,Ceratopogonidae,Empididae,Mycetophilidae and Sciaridae families,and hymenopterans of the Diapriidae and Ichneumonidae families were significantly more abundant in downed than in standing dead wood.In contrast,Mymaridae was most abundant in standing dead wood.Our study provides evidence that some insects at high taxonomic levels respond differently to dead wood quality,and this could inform future management strategies in the boreal forest for the conservation of saproxylic fauna and their ecological functions.     

Logistics of supplying biomass from a mountain pine beetle-infested forest to a power plant in British Columbia

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.     

Application of the wood properties of large-diameter Sugi (<Emphasis Type="Italic">Cryptomeria japonica</Emphasis>) logs to sorting logs and sawing patterns

The purposes of this study were to accumulate fundamental data on wood properties within large Sugi logs and to take applicable variations in wood properties into consideration for sorting logs and sawing patterns. The characteristics of basic density, moisture content, growth ring width, and microfibril angle (MFA) were measured and the relationship with log and lumber quality was examined. It was considered reasonable to estimate the lumber moisture content based on the moisture content of heartwood rather than that of whole logs, especially when producing large-sized lumber. The MFA reached a constant value before the 15th ring, and within a distance of 10 cm or less from the pith. Since the E _fr of lumber correlated with that of the log affected by MFA, it would be possible to produce lumber with a higher E _fr from the outer position of the log, based on selecting a log above the E _fr . Since the MFA would also affect the lumber warp, a sawing pattern avoiding the area around the pith or enlarging the rough sawn size when a large warp was expected could be effective in improving the lumber quality. To improve the lumber quality, not only one but also multiple wood properties must be applied to the sawing pattern.     

利用FAKOPP评价树干杨氏弹性模量可行性研究

杨氏弹性模量是反映树干或板材抗弯、抗压强度的重要指标,是开展林木材质育种研究的重要内容。笔者通过对多株树分别采用FAKOPP(应力波速度测定机)和敲打法2种不同方法测量同一树干的杨氏弹性模量,并对2种测定数据进行相关性分析,检验用FAKOPP测量立木状态下树干弹性模量的准确性。通过对杨树试验证明:二者具有很强相关性,说明利用FAKOPP的方法能准确评价树干杨氏弹性模量大小。     

Carbon budget of Ontario's managed forests and harvested wood products, 2001–2100

Forest and harvested wood products (HWP) carbon (C) stocks between 2001 and 2100 for Ontario's managed forests were projected using FORCARB-ON, an adaptation of the U.S. national forest C budget model known as FORCARB2. A fire disturbance module was introduced to FORCARB-ON to simulate the effects of wildfire on C, and some of the model's C pools were re-parameterized using data from Canadian forests. Forest C stocks were estimated using allometric equations that represent the relationships between C and net merchantable volume and forest age based on forest inventory statistics. Other pools were included using results from ecological studies related to forest inventory variables. Data from future forest development projections adopted in approved management plans were used as model input to produce forest C budgets for the province's Crown forest management units. The estimates were extended to other types of managed forests in Ontario: parks, measured fire management zones, and private forest lands. Carbon in HWP was estimated in four categories: wood in use, wood in landfill, wood burned for energy, and C emitted by wood decomposition or burning without energy generation. We projected that the C stocks in Ontario's managed forests and HWP (in use and in landfills) would increase by 465.3 Mt from 2001 to 2100, of which 47.9 Mt is from increases in forest C and 417.4 Mt is from HWP C.