Papers by Mohammad Reza Ghaffariyan
Forests, 2022
The utilization of forest harvest residues for renewable bioenergy production and bioproducts has... more 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 lands...
Investment in thinning as part of forest management is generally for one of three purposes: impro... more Investment in thinning as part of forest management is generally for one of three purposes: improved<br>future stand growth and quality to produce higher value products for later final harvest, removal of fuels to<br>reduce fire risk or to meet ecological goals such as increasing biodiversity. The focus of this paper is on the<br>thinning operations in Australian pine and eucalypt plantations, which are almost exclusively conducted<br>by harvester-processors and forwarders. The Australian Forest Operations Research Alliance (AFORA) has<br>conducted research projects on assessing the productivity of harvester-processors and forwarders in pine and<br>eucalypt plantations in different sates/regions. All-time study data collected in different case studies have<br>been consolidated into a data base called ALPACA (Australian Logging Productivity and Cost Appraisal).<br>The data were used to develop the general productivity predicting models ...
Forests, 2021
Mountainous hardwood mixed stands offer challenges to timber harvesting operations in practice, i... more 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 fo...
Sustainability, 2022
New global and domestic policy and regulatory initiatives promoting a circular economy have renew... more 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 logi...
Research Highlights: This research determines the potential contribution of utilising forest biom... more Research Highlights: This research determines the potential contribution of utilising forest biomass resources for bioenergy production. A strategic method was developed integrating spatial and programming techniques to examine the theoretical, available, technological, economical and environmental potential of forest biomass.
Journal of forest science, 2018
This research compared roadside chipping and road side processing systems. Two sites planted with... more This research compared roadside chipping and road side processing systems. Two sites planted with Eucalyptus globulus were selected to study these harvesting systems. A time and motion study was applied to collect the data for both harvesting systems. The working cycles for each machine were recorded as well as the variables af - fecting the working productivity. Using the multiple regression method the appropriate models were developed. The results showed that the productivity of feller-buncher and processor was significantly affected by tree size. Productivity of skidders was dependent on extraction distance and load weight. Productivity for road side processing was higher than for road side chipping, which resulted in a lower unit cost. The unit cost (from stand to the mill) for road side processing and road side chipping averaged 22.68 AUD · t -1 and 21.07 AUD·t -1 , respectively.
Transporting woody products by timber trucks is costly due to long travel distances between plant... more Transporting woody products by timber trucks is costly due to long travel distances between plantations and mills. Transportation cost accounts for more than 25% of the forestry costs (Svenson and Fjeld, 2016). Higher operating costs may occur due to increased fuel costs. Higher fuel usage will also cause significant emissions to the environment. Transportation is the most fuel consuming element of a wood supply chain in Australia and other countries (Ghaffariyan et al. 2015; Griffin and Brown, 2010). For instance, in Sweden, secondary timber transport consumed about 50% of total fuel usage while harvesting and extraction operations consumed 33‐40% (Lindholm, 2006). To reduce the fuel consumption costs, it is important to understand the impact of the different factors such as transport distance, truck weight and payload. This report aimed to review previous studies to achieve the following objectives;
Silva Balcanica, 2021
Loading is considered a bottleneck of the forest harvesting system as it acts as a connection bet... more Loading is considered a bottleneck of the forest harvesting system as it acts as a connection between primary transport and secondary transport (from roadside/ landing to mills or central yards). Any delay during the loading component can cause delay in the primary wood extraction and/ or secondary transportation. This article reviewed the current knowledge on loading productivity studies. Based on the results, the main variables impacting the loading productivity include log size, log lengths, load volume per truck, number of logs (or pieces) per truck and number of safety straps. The productivity of loading operations ranged from 3.4 m3/PMH0 in a manual loading to 168.9 m3/PMH0 using mechanised loaders. The results of this review can assist the academic and industrial users for predicting, controlling and managing the productivity of loading operations.
Croatian Journal of Forest Engineering : Journal for Theory and Application of Forestry Engineering, 2016
A project was carried out to investigate the impact of four different weighing methods on over/ u... more A project was carried out to investigate the impact of four different weighing methods on over/ under loading of forestry trucks operating in Forestry Corporation of New South Wales under two types of roads; gazetted (approved for higher legal gross vehicle weight limits) and non- gazetted (standard public road gross vehicle weight limits). For all the technologies tested, it was found that there was a substantial under-loading issue ranging from 5.3 to 6.4 tonnes per load on gazetted roads, while the same technology achieved a much better outcome on non- gazetted roads with a range of 1.4 tonnes under-loaded to 0.1 tonnes over-loaded on average. There was clearly a large under-loading issue on the gazetted routes. As the same operators with the same technology achieved a much more reasonable outcome on the standard access routes, these results suggest that the GVML available was technically not achievable on the gazetted routes (i.e. not enough volume available to add the weight) o...
Globally, about 20 million ha of land area is occupied by plantations of Eucalyptus. Motor-manual... more Globally, about 20 million ha of land area is occupied by plantations of Eucalyptus. Motor-manual tree harvesting techniques (using chainsaws) are still applied in eucalypt plantations, especially in difficult terrains or for largesized trees where mechanised felling may not be an effective and safe possible option to apply. There is little information available on motor-manual felling in eucalypt stands. This article reviewed available literature on the productivity of motor-manual felling. The results were classified into four regions, including Africa, Asia/ Oceania, America and Europe. Results of international studies indicate that the main factors impacting the productivity of motor-manual felling include diameter at the breast height (DBH), travelling distance to trees, understory density and terrain slope. Operator experience also plays a key role in felling operations. The range of reported productivity varied from 0.6 m/PMH0 to 48.9 m /PMH0 in different regions. This articl...
ABSTRACT: This research deals with productivity and cost of rock disintegration and side casting ... more ABSTRACT: 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.
Mallee plantations have been integrated into wheat farms in Western Australia as a large-scale an... more Mallee plantations have been integrated into wheat farms in Western Australia as a large-scale and multi-purpose woody crop since the 1990s. Mallee describes the growing habit of certain eucalypt species that grow with multiple stems shooting from an underground crown root (lignotuber), usually to a height of up to 10 meters. These types of plantations could be a considerable source of biomass to produce renewable energy. In this project the supply chain of Mallee was modelled using BIOPLAN's linear programming model to investigate the im- pact of tree size, extraction distance and transport distance on supply chain costs. The harvest- ing system included a feller-buncher, front end loader, in-field chipper and truck. The mobile Bruks chipper was found to be more efficient than Peterson Pacific to chip Mallee trees. The results indicated that harvesting larger tree sizes can slightly diminish chipping cost. Extrac- tion cost was very sensitive to the extraction distance in this ...
Silva Balcanica, 2021
Reforestation can be carried out using natural regeneration or artificial regeneration. There are... more Reforestation can be carried out using natural regeneration or artificial regeneration. There are vari-ous methods for the artificial regeneration, including manual planting, mechanical planting and aerial/or ground seeding. This article aimed to review the current reports on the productivity of mechanical planting to provide a summary of productivity rates for the planting machines. According to the review’s results, mechanical planting productivity may vary from 143 to 475 seedlings per productive machine hours depending on the machine type, environment (such as surfaces obstacles and stoniness) and the operator experience. Employing skilled operators and selecting suitable worksites can help increasing the work productivity. Integrating and optimising the whole planting chain, from the nursery to the plant-ing phase, can assist also with reducing the cost and improving the productivity. As mechanical planting machines get more widely adopted in different countries, their overall ...
Forests, 2021
Many parameters can influence the weight of harvesting residues per hectare that remain on planta... more 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 ha...
Journal of Forestry Research, 2021
Two systems of additive equations were developed to predict aboveground stand level biomass in lo... more 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 for Pinus radiata plantations 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-b...
European Journal of Forest Engineering, 2020
Timber extraction from forest to the roadside/landing can be operated using cut-to-length, whole ... more 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 PMH 0 (Caterpillar 528 operating in skidding distance of 251 m tested in USA) to 80.25 green tons per PMH 0 (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.
Silva Balcanica, 2020
Skidding is an important element of harvesting operations, which contributes to the extraction of... more Skidding is an important element of harvesting operations, which contributes to the extraction of wood. A skidder can be used in different types of harvesting operations, such as thinning, clear fell, native forest thinning or salvage work. The main goal of this article was to review the available stud-ies on productivity of skidding operations in coniferous forests/ plantations. Information on skid-der productivity was collected from publications and then was classified in three regions, including North America, Europe and the Southern Hemisphere. The parameters affecting machine productivity included machine type/ size, tree volume/ log volume/ load volume, average skidding distance and slope of the ground for each reported productivity. The average productivity reported in the published reports ranged from 9.3 m3/PMH to 78.0 m3/PMH. Detailed information and conclusions collected from various studies can be of use to forest academic and industry users to gain knowledge about vari-...
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Papers by Mohammad Reza Ghaffariyan