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Plantation-grown Eucalyptus pellita in Sabah, Malaysia, was analysed for compression and flexural properties to assess the potential for solid-timber and engineered wood product end uses. It is nec...

Two systems of additive equations were developed to predict aboveground stand level biomass in log products and harvest residue from routinely measured or predicted stand variables forPinus radiataplantations in New South Wales, Australia. These plantations were managed under three thinning regimes or stand types before clear-felling at rotation age by cut-to-length harvesters to produce sawlogs and pulpwood. The residue material following a clear-fell operation mainly consisted of stumps, branches and treetops, short off-cut and waste sections due to stem deformity, defects, damage and breakage. One system of equations did not include dummy variables for stand types in the model specification and was intended for more general use in plantations where stand density management regimes were not the same as the stand types in our study. The other system that incorporated dummy variables was for stand type-specific applications. Both systems of equations were estimated using 61 plot-based estimates of biomass in commercial logs and residue components that were derived from systems of equations developed in situ for predicting the product and residue biomass of individual trees. To cater for all practical applications, two sets of parameters were estimated for each system of equations for predicting component and total aboveground stand biomass in fresh and dry weight respectively. The two sets of parameters for the system of equations without dummy variables were jointly estimated to improve statistical efficiency in parameter estimation. The predictive performances of the two systems of equations were benchmarked through a leave-one-plot-out cross validation procedure. They were generally superior to the performance of an alternative two-stage approach that combined an additive system for major components with an allocative system for sub-components. As using forest harvest residue biomass for bioenergy has increasingly become an integrated part of forestry, reliable estimates of product and residue biomass will assist harvest and management planning for clear-fell operations that integrate cut-to-length log production with residue harvesting.

Plantation-grown, high-value timber species producing high-value end products are key to optimising land utilisation in Sabah and Sarawak states in Borneo, Malaysia, while meeting the demand for do...

New global and domestic policy and regulatory initiatives promoting a circular economy have renewed interest in the beneficial repurposing of commercial waste streams. Likewise, consumer trends and customers’ increased understanding of what they purchase, where it comes from, and what happens to it post-consumption have forced firms to consider reducing and reusing their production waste streams. The forest products industry is an exemplar of becoming more adept at reorganising and exploiting repurposed waste streams for beneficial reuse. This paper explores three case studies from the Australian forestry sector that illustrate how wood waste is being profitably repurposed as an input into other products. We use the lens of the entrepreneurial method to explore how firms recognise, strategically access, and exploit the sustainable opportunities that can range from sustainably sourced inputs to environmental-, social-, and governance-driven consumption and investments. Effectual logic allows the reconceptualisation of forestry waste streams into inputs for use in creating new commercial products and provides a theoretical framework. While the repurposing of wood waste is profitable for the forestry firm, we found that social and economic gains reach far beyond the region in which these activities occur. Innovations often stimulate other innovations, resulting in a virtuous cycle within regional Australia’s emerging circular economy.

Airborne Laser Scanning (ALS) generates accurate data for calculating forest metrics, such as canopy height, yet can be cost-prohibitive. Satellite-based stereo pair photogrammetry has the potentia...

This paper aims to provide a comprehensive but concise review of the various quantitative methods, in particular, optimization techniques, for the efficient management and control of complex forest biomass supply chains. The review is structured around a top-down hierarchical planning approach that includes strategic, tactical, and operational decisions. At each planning level, the review presents and analyses the problem to be solved, the solution (optimization) methods, and the various aspects to take into consideration for the successful implementation and use of these methods by biomass supply chain planners. Forest biomass constitutes one of the various sources of renewable energy with the potential to reduce the consumption of fossil fuels and greenhouse gas emissions. Fo rest biomass supply chains are systems with complex network designs consisting of many supply, demand, and intermediate points where the biomass is collected, stored, processed, and transported. The complexity of these supply chains as well as various factors impact the effective supply of forest-based biomass. For example, the biomass characteristics (e.g., energy content or quality), the variability in the market and economic conditions, and processing of the biomass are the main factors. The complexity requires a good understanding of the methods that exist to manage and optimize forest biomass supply chains. Although substantial research has been done around forest biomass supply chain management and optimization, future research should focus on developing integrated frameworks that allow the optimization of biomass supply chains at the strategic, tactical, and operational level. These studies should also explore and propose approaches for the successful implementation of the proposed optimization methods.

Many parameters can influence the weight of harvesting residues per hectare that remain on plantation sites after extracting sawlogs and pulpwoods. This study aimed at quantifying the impact of the cut-to-length and whole-tree harvesting methods on the weight of harvesting residues using 26 case studies in Australian plantations. A database was created using case studies conducted in different plantations, to measure the weight of harvesting residues per hectare and the components of harvesting residues. An analysis of variance was applied to test the impact made by the harvesting methods. The results confirmed that the cut-to-length harvesting method produced a larger weight of residues (104.0 tonnes of wet matter per hectare (tWM/ha) without additional biomass recovery and 64.7 tWM/ha with additional biomass recovery after sawlog/pulpwood extraction) than the whole-tree harvesting method (12.5 tWM/ha). The fraction test showed that stem wood formed the largest proportion of the harvesting residues in cut-to-length sites and needles were the largest component of the pine harvesting residues in sites cleared by the whole-tree harvesting method. The outcomes of this study could assist plantation managers to set proper strategies for harvesting residues management. Future research could study the impact of product type, silvicultural regime, stand quality, age, equipment, etc., on the weight of harvesting residues.

The utilization of forest harvest residues for renewable bioenergy production and bioproducts has increasingly become an integrated part of forestry that helps to meet the needs of climate change mitigation and a future carbon neutral economy. An essential element in the planning of any harvesting residue recovery operation is a reliable assessment of the quantity and quality of residue biomass and its composition over a harvest area. With the now widely adopted cut-to-length (CTL) at the stump harvesting system in Pinus radiata plantations in Australia, harvesting residues left on site are significantly larger in quantity and spatially more dispersed over a harvest area in comparison to the more traditional whole-tree harvesting. The conventional approach of assessing forest harvest residues through sample plots, transects, or small study blocks has provided site-specific estimates of residue biomass. However, these estimates cannot be readily extrapolated over the plantation landscape, which varies in silviculture, site, and stand conditions. To overcome this limitation, this study relied on harvester data analytics to obtain spatially explicit estimates of residue biomass using an example data set from harvested plantations of three stand types: unthinned (T0), thinned once (T1), and thinned twice (T2). Three methods of integrating biomass equations with harvester data were compared for residue biomass estimation: (1) applying individual tree biomass equations to harvested stems, (2) applying stand-level biomass equations to gridded harvester data, and (3) integrating estimates from the first approach with recorded and estimated waste volumes of harvested stems. The estimates of total residue biomass obtained using the three methods through harvester data analytics varied between 56.2 and 156.4 t/ha in green weight across the three stand types. These estimates were validated indirectly through ex situ sample plots and proved to be comparable to the quantities of residue biomass assessed using conventional sample plots, transects, or small blocks following CTL harvesting of rotation age P. radiata plantations elsewhere in Australia. Among the three methods, the third method made the most intensive use of the harvester data and provided the most realistic estimates of residue biomass. Spatial mapping of the estimated total and component residue biomass will assist the operational planning of residue recovery and site-specific nutrient management for the long-term sustainability of P. radiata plantations.

Mountainous hardwood mixed stands offer challenges to timber harvesting operations in practice, including a harsh climate, variable topography, steep terrain, and large-sized timbers. This paper aims to develop productivity and cost models for a mountain-ground-based harvesting operation across the terrain (e.g., slope conditions), stand (e.g., tree volume) environmental (e.g., weather), and yard (e.g., winching distance) variables and to assess GHG emissions related to the equipment in use. This development was implemented in a timber harvesting practice under single-tree selection in mountainous forests of Iran where a motor-manual chainsaw is used for felling and a rubber-tired cable skidder is used for log extraction. The average delay-free productivity was 4.55 m3 for felling and 14.73 m3 h−1 for skidding. Lower production costs and higher productivity rates were observed over the gentle slopes and in sunny conditions. The average production costs ranged between USD 4.27 m−3 for felling and USD 5.35 m−3 for skidding. The average emissions ranged between 0.96 kg m−3 for felling and 7.06 kg m−3 for skidding in snowy conditions over steep slopes. The study’s results confirm avoiding harvesting operations on steep slopes (greater than 35%) and in extreme weather conditions to obtain higher work efficiency and to minimize adverse effects of machinery on forest ecosystems. The results should be of use to harvest managers and forest planners considering the application of ground-based harvesting operations using a semi-mechanized system on a range of operating conditions in mountain hardwood stands.

This study provides a state-of-the art overview of forest biomass harvesting technologies and supply chains used in North America, Europe and the Southern Hemisphere. The productivity and cost of selected efficient technologies is presented for each country with a brief description about the source of the biomass and harvesting method. Expert opinions on the most successful biomass operations have been presented briefly for each country. The main conclusions from various intentional studies are provided in addition to future requirements for research and development. This report can be a useful high level guide of technology and supply chain selection for industry and academics.

Timber extraction from forest to the roadside/landing can be operated using cut-to-length, whole stem and whole tree. Skidding is one of the options for wood extraction. This paper aimed to review the available studies on work productivity of skidders in Eucalypt plantations. Reviewing the machine productivity information indicated that skidding productivity in Eucalypt plantations may be impacted by tree volume, load size, skid distance, slope of skid trail and power of the machine. Based on the reviewed literatures the machine productivity varied from 11.20 green tons per PMH0 (Caterpillar 528 operating in skidding distance of 251 m tested in USA) to 80.25 green tons per PMH0 (Timberjack 1710D operating in skidding distance of 241 m in Brazil). General productivity model was developed including variables such as skidding distance, tree size and power of machine. Future research could verify the impact of harvesting intensity/yield per ha, plantation layout (landing locations and block shape), operator experience, terrain conditions and availability of chippers/or processors at the landing in the case of hot decking on the productivity of the skidders in Eucalypt plantations.

Steep country harvesting has been identified as the main bottleneck to achieving greater profitability in the forestry sector of New Zealand and Australia. An improvement of efficiency, work safety and environmental sustainability should be realized by developing an advanced steep terrain timber harvesting system based on innovative Austrian technology. To identify the best suitable configuration of a cable yarder for steep terrain harvesting, user preferences based on an online survey (conjoint analysis) have been evaluated to answer the following questions: (1) What attributes of a new yarder design are most important to consumers? (2) Which criteria do stakeholders consider when selecting a cable yarder? (3) What are the weights representing the relative importance of criteria? Using eight specific design scenarios a fourth question, being which cable yarder concept is the best, was also answered. This case study shows that conjoint analyses is an effective tool to assess, rate and subsequently integrate design characteristics. Based on the results of the analysis, a cable yarder prototype will be manufactured in Austria and transferred to New Zealand for testing and demonstration.

The current technology in Australia is mainly large swing tower yarder with grapple. These yarders operate under whole tree or cut-to-length methods in steep terrains of Victoria, Tasmania and South-East Queensland. Cable yarding is often applied in clear fell operations in pine or Eucalypt stands in Australia. Felling operations prior to yarding are carried out manually or using tracked feller-bunchers. Typical terrains for applying cable yarding have slope larger than 30°. There is currently a lack of small to medium size cable yarders that can efficiently operates under different circumstances. Medium size capacity yarders would be required to handle a wide range of situations under uphill and downhill extractions while small capacity highly mobile yarders will be needed for clean-up operations.

The quantity and quality of the harvesting residues in a balsa plantation in East New Britain Province of Papua New Guinea are reported in this paper. The plantation was harvested manually with a chainsaw and manpower to extract the industrial wood at age 6 years. A modified standard harvesting residue assessment method using plots on line transects was applied. The total weight of the harvest residues remaining on the site after wood extraction was 211.7 tGREEN ha−1 (tonnes (green) per hectare). The major component was un-merchantable stem wood (121.3 tGREEN ha−1; 57.3%), followed by bark (59.3 tGREEN ha−1; 28.0%). This level of harvest residue was relatively greater than that reported in other studies, reflecting the combination of the log specification applied and the nature of the stem defects in balsa trees. The level of residues indicates the possibility of additional woody material recovery for bioenergy after consideration of sustainability issues.The average moisture content of the wood c...

Biomass or energy wood harvesting can be integrated with conventional log harvesting (saw log or pulpwood production) to allow more cost-effective energy wood supply. The efficiency of an integrated energy wood harvesting system was evaluated and compared with conventional log harvesting in a 32-year-old Pinus radiata plantation (radiata pine) located in south-west Western Australia. The harvesting system consisted of a harvester and a forwarder. The study included two treatments: a conventional log-harvesting operation where merchantable sawlogs and pulp logs were produced at the stump by the harvester and extracted by the forwarder; and an integrated energy wood operation where the harvester produced sawlogs, pulp logs and energy wood at the stump that were extracted by the forwarder. In the integrated energy wood harvesting plot, 37 m3 ha−1 of energy wood was extracted in addition to the sawlog and pulp log volumes. Extracting the additional energy wood reduced the productivity of the forwarder and increased the cost of extraction (AU$2.7 m−3) compared with the control plot (AU$2.2 m−3). Harvesting system cost was not significantly impacted, with a cost of AU$3.18 m−3 in the control plot and AU$3.23 m−3 in the integrated energy wood harvesting plot. Diameter at breast height (DBH) was a significant factor influencing the working time of the harvester, whereas load volume, extraction distance and extraction type (sawlog, pulp logs, and pulp log/ energy wood) significantly impacted forwarding time. Increasing DBH resulted in longer working cycles for the harvester. Heavier loads and longer forwarding distances increased forwarding cycle time, while extracting sawlogs was least expensive and energy wood extraction was the most expensive. The marginal cost of the energy wood was approximately AU$10.2 m−3 (AU$7.0 extraction and AU$3.2 harvesting), which is about double the cost of the sawlogs. Additional material recovered in the integrated energy wood plot resulted in less residual residues on the plot (103.2 green metric tonnes per hectare [GMt ha−1]) than the control plot (144.2 GMt ha−1).Keywords: cost, energy wood, harvesting, productivity, residue

Different factors can impact on the timber harvesting methods including stand characteristics, ground conditions, extraction distance, climate, silvicultural treatments and social interests. The multiple-criteria analysis is an effective methodology for helping foresters decide what system to apply depending on their operations specifications. Four harvesting methods were compared in Western Australian Eucalypt plantations including cut-to-length (CTL), in-field chipping using a delimbing and debarking flail integrated with the chipper (IFC-DDC), in-field chipping us - ing a chipper with a separate flail machine for delimbing and debarking (IFC-F/C) and whole tree to roadside (WTR). The decision criterions consisted of total operating cost (from stand to mill gate), yield per ha, harvesting residues, fuel consumption and bark content of the chips. The Promethee method was used to evaluate the alternatives using Decision Lab software. Based on the results, the IFC-DCC was the best harvest method while WTR method was the worst harvesting alternative in the case study area. IFC-DCC method resulted in the lowest operating cost and the highest recovered yield per ha compared to the other harvesting methods.

In Australia the use of forest biomass has been developing in recent years and initial efforts are built on adopting and trialling imported European technology. Using a linear programming-based tool, BIOPLAN, this study investigated the impact of five operational factors: energy demand, moisture mass fraction, interest rate, transport distance, and truck payload on total forest residues supply chain cost in Western Australia. The supply chain consisted four phases: extraction of residues from the clear felled area to roadside by forwarders, storage at roadside, chipping of materials by mobile chippers, and transport of chips to an energy plant. For an average monthly energy demand of 5 GWh, the minimum wood supply chain cost was about 29.4 $ t −1 , which is lower than the maximum target supply cost of 30–40 $ t −1 , reported by many industry stakeholders as the breakeven point for economically viable bioenergy production in Australia. The suggested volume available for chipping in the second year was larger than in the first year indicating that the optimisation model proposed storing more materials in the first year to be chipped in the second year. The sensitivity analysis showed no strong correlation between energy demand and supply chain cost per m 3 . For higher interest rates, the total storage cost increased which resulted in larger operational cost per m 3 . Longer transport distances and lower truck payloads resulted in higher transport cost per unit of delivered chips. In addition, the highest supply chain costs occurred when moisture mass fraction ranged between 20% and 30%.

The chipping operation is an important component of harvesting systems producing biomass and pulp chips. This paper aimed to develop a valid model to predict the productivity of chipping as part of these operations. Over a number of years more than 200 different time studies were conducted on chipping operations in Italy and Australia. Multiple regressions and backward stepwise data analysis methods were applied to develop a productivity prediction equation, considering the following variables: machine power (kW), piece size (m3), crew size, harvesting method, species, tree part, wood condition, wood lay-out, chipping type, propulsion, feeding method, point of chipping, season, location of chip discharge, country (Italy or Australia) and type of operation (biomass chip operation or pulp chip operation). The final productivity model included machine power, average piece size, location of chip discharge and type of operation as significant variables. The internal validation test was conducted using five witness samples from Italy and Australia, which confirmed the validity at α 0.05. Additional international case studies from North America, South America, and central and northern Europe were used to test the accuracy of the model, in which 15 studies confirmed the model’s validity and two failed to pass the test.Keywords: average piece size, chipper, power, sensitivity analysis, type of operation, unit costSouthern Forests 2013, 75(3): 129–136

Roadside chipping is a common harvesting system to produce chips in Australian plantations. This study investigated the productivity and cost of road-side chipping operation (chipping logs extracted by forwarder to the road side) using a Morbark chipper with flail delimber in a first thinning of Pinus radiata stands. An elemental time study method was used to collect the time working cycles. The regression approach was used to develop the productivity predicting model based on the log size in different wood piles. The statistical analysis yielded an average productivity of 59.4 GMt/PMH with the corresponding costs of 5.2 AU$/GMt for the Morbark chipper. The details on work time analysis, relocation time and fuel consumption of the machine are documented in this paper. The results provide basic information for planning roadside chipping operations in pine plantations.

The Bruks mobile chipper was tested for chipping extracted non-merchantable stemwood at the road- side in Pine plantation in Victoria. The elemental time study method was used to evaluate the system productivity. The productivity, cost, biomass yield, remaining slash, chip quality (size classification and energy content), and fuel and energy consumption were analysed. Chipping extracted small logs at the roadside yielded a productivity of 43.88 GMt·PMH 0 -1 (19.4 BDT·PMH 0 ). The average cost was about 16.96 USD·GMt -1 (38.36 USD·BDT -1 ).

This paper examines the optimisation of the transport scheduling of woodchips for in-field chipping operations whose efficiency depends on a range of factors. It illustrates the advantages of optimising trucking efficiency and cost in the context of the Australian forest industry. The study was enabled using an adapted version of Simulated Annealing and a forestry domain model, and a simulator based on them, called Fast Truck, was implemented for experimental use. Insights arising from the simulator results are discussed in the context of the Australian industry. The factors worth noting are truck payload and chipper utilisation, which by optimisation, account for 52% and 29% of the total cost savings obtained, respectively. These savings arise when better transport control and management occur in chipping operations. Further work will consider ways to implement these optimisations, primarily, by adapting Fast Truck as an optimiser of daily dispatch schedules.

Time equations are derived for felling with chainsaw, skidding with cable wheeled skidder, loading with grapple hydraulic loader and trucking of logs within a cut-to-length harvesting method. The continuous time study method was applied to collect data for felling, skidding, loading and a transportation model. Multiple regression analysis via SPSS software was applied to develop the time models. Felling time was found to be highly dependent on diameter at breast height. Skidding distance, winching distance, slope of the trail and piece volume were significant variables for the skidding time prediction model. The loading time model was developed considering piece volume. Transportation distance and load volume were used as independent variables in modeling the transportation time. The net production of felling was estimated at 12 trees/h (56.65 m3/h). The net production rates for skidding, loading and traveling averaged 18.51, 41.90 and 3.32 m3/h respectively. The total cost of harvesting from stand to mill was estimated 19.70 €/m3. The skidding phase was the most expensive component of the cut-to-length method. The bucking and delimbing components were less costly than the other logging phases. The results of this study can be used for harvesting planning and productivity optimization.

This research deals with productivity and cost of rock disintegration and side casting of materials with the use of a hydraulic hammer mounted on a PC 220 Komatsu crawler excavator, which is used on rocky slopes of Hyrcanian forests of Iran. A continuing time study was applied during the road construction. To estimate the volume of rock disintegration, the average end area equation was used. The increasing cut-slope height decreased productivity. The productivity of hydraulic hammer averaged at 5.5 m3·h–1 for the mean work volume of 5.07 m3·m–1. The unit cost of the system was 7.7 €·m–3. From the economic point of view a new machine with multipurpose system could be recommended for forest road construction operations in rocky areas.

Cable yarding systems are widely used in mountainous forests of Austria. The goal of this paper is to determine optimal road spacing (ORS) of yarding operations by tower yarder in Styria to help logging planners minimize logging costs. A total of 591 working cycles were used to develop the multiple regression model using stepwise method to predict yarding time per cycle. The production and cost in whole tree uphill yarding were 6.70 m3/PSH and 27.60 Euro/m3, respectively. The roading, yarding and installation cost per cubic meter were computed for different yarding distances and graphed as a function of road spacing. The minimum total cost and ORS were 42.88 Euro/m3 and 261 m, respectively for one-way yarding. For two-way yarding, the minimum estimated total cost, ORS and optimal road density would be 38.48 Euro/m3, 373 m and 26.8 m/ha, respectively. The results showed increasing harvested volume decreases ORS and that increased roading cost increases ORS. The load volume has a significant effect on ORS.

Cable yarding has been used for many years in mountainous forests in central European countries. Tower yarders are common cable yarding systems in Austria. The goal of this study was to develop a general time prediction model for two kinds of tower yarders used in Austria. The multiple regression method was applied. The average production rate was 9.30 m3/PSH0 with a cost of US$25.48/m3. The results also showed that the production rate for downhill yarding was less than uphill yarding using the Syncrofalke tower yarder. The developed time production models can help forest engineers estimate production of tower yarders in similar logging operations.

The Australian forestry industry has historically constrained the role of Information and Communication Technology (ICT) to the office environment. This negates opportunities which exist when ICT are deployed along the supply chain to provide feedback to the strategic layers for optimisations that improve efficiencies and reduce costs. The wood supply chain is largely based in the "environment": forests, roads, or mills and there is much to be gained by integrating ICT within these areas. Our experience working within the Cooperative Research Centre for Forestry (CRCF) has been that ICT systems have been developed with limited for sight around their long term sustainability: lack of consideration around the system in its context of use, placing the onus on the user to learn to adapt their work practises for system usage. This paper proposes applying design approaches found within ubiquitous computing to avoid the above shortcomings. Here the Smart Device Environment Integration (DEI) Model is applied to conceptually explore the benefits of applying a systematic approach to forestry systems design. One outcome is the design process is made easier, another is a more complete understanding of system robustness and the limitation for system acceptance from user-centric points of view.

To minimize the cost of logging, it is necessary to optimize the road density. The aim of this study was to determine optimal road spacing (ORS) in Northern Austria. The stepwise regression method was used in model - ling. The production rate of tower yarder was 10.4 m 3 /PSHo (Productive system hours) and cost of 19.71 €.m -3 . ORS was studied by calculating road construction cost, installation cost and yarding cost per m 3 for different road spacing. The minimum total cost occurred at 39.15 €.m -3 and ORS would be 474 m assuming uphill and downhill yarding. The optimal road density and yarding distance are 21.1 m.ha -1 and 90 m, respectively. A sample logging area was used to plan different roads and, using network analysis, the best solution was found based on a modified shortest path algo - rithm. The network analysis results were very different from the optimal road spacing results that assumed roads and logging corridors could be located anywhere in the planning area at a constant cost. Mixed integer programming was also used to get a real optimal solution.