Bruce Talbot

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(+47) 948 86 791
bruce.talbot@nibio.no

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Ås - Bygg H8

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Høgskoleveien 8, 1433 Ås

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Productivity of a mechanized P. patula cut-to-length harvesting operation was estimated and modelled using two methods of data collection: manual time study and follow-up study using StanForD stem files. The objective of the study was to compare the productivity models derived using these two methods to test for equivalence. Manual time studies were completed on four different machines and their operators. Two Ponsse Bear harvesters fitted with H8 heads, and two Ponsse Beaver harvesters, fitted with H6 heads, were included. All machines were equipped with Ponsse Opti2 information system. All four operators had approximately 1 year of experience working with their respective machines. The four machines worked in separate four-tree-wide harvesting corridors, and they each harvested 200 trees. Individual tree diameter at breast height (DBH), and height measurements were made manually. Subsequently, data on the trees in each study were extracted from the StanForD stem reports from each of the harvesters. Cycle times in the stem reports were determined based on the difference between consecutive harvest timestamps. The two methods were compared in terms of their abilities to estimate equivalent measures for tree DBH, volume, and productivity. In all four cases, significant differences were found between the DBH and volume measures derived using the two methods. Subsequently, the volume measures from the manual methods were used as the basis for productivity calculations. Results of the productivity comparisons found no significant differences between the models developed from the two methods. These results suggest that equivalent productivity models can be developed in terms of time using either method, however volume discrepancies indicate a need to reconcile bark and volume functions with the high variability experienced in the country.

Sammendrag

The effectiveness of generating virtual transects on unmanned aerial vehicle-derived orthomosaics was evaluated in estimating the extent of soil disturbance by severity class. Combinations of 4 transect lengths (5–50 m) and five sampling intensities (1–20 transects per ha) were used in assessing traffic intensity and the severity of soil disturbance on six post-harvest, cut-to-length (CTL) clearfell sites. In total, 15% of the 33 ha studied showed some trace of vehicle traffic. Of this, 63% of was categorized as light (no visible surface disturbance). Traffic intensity varied from 787 to 1256 m ha−1, with a weighted mean of 956 m ha−1, approximately twice the geometrical minimum achievable with CTL technology under perfect conditions. An overall weighted mean of 4.7% of the total site area was compromised by severe rutting. A high sampling intensity, increasing with decreasing incidence of soil disturbance, is required if mean estimation error is to be kept below 20%. The paper presents a methodology that can be generally applied in forest management or in similar land-use evaluations.

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The objective of this study was to establish an operational model of productive work time per tree (work efficiency) for high-pruning of young European beech and pedunculate oak depending on tree species, pruning height, branch characteristics, pole saw type and operator. The final model included all of these independent variables with branch characteristics specified in terms of number of live branches and cross-sectional area of the thickest branch at the cut. Work time increased with increasing values of each of the three numeric variables. For a given pruning height the size of the largest branch was for all practical purposes more influential than the number of live branches. Beech took 28% longer to prune than oak. The German Ergo-Schnitt saw was 21% slower than the Japanese Silky Hayauchi saw. The variation in worker performance within our study was larger than that attributed to tree species and pruning equipment.

Sammendrag

Unmanned aerial vehicles (UAVs) are increasingly used as tools to perform a detailed assessment of post-harvest sites. One of the potential use of UAV photogrammetric data is to obtain tree-stump information that can then be used to support more precise decisions. This study developed and tested a methodology to automatically detect, segment, classify, and measure tree-stumps. Among the potential applications for single stump data, this study assessed the possibility (1) to detect and map root- and butt-rot on the stumps using a machine learning approach, and (2) directly measure or model tree stump diameter from the UAV data. The results revealed that the tree-stumps were detected with an overall accuracy of 68–80%, and once the stump was detected, the presence of root- and butt-rot was detected with an accuracy of 82.1%. Furthermore, the root mean square error of the UAV-derived measurements or model predictions for the stump diameter was 7.5 cm and 6.4 cm, respectively, and with the former systematically under predicting the diameter by 3.3 cm. The results of this study are promising and can lead to the development of more cost-effective and comprehensive UAV post-harvest surveys.

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This paper provides an overview of recent developments in remote and proximal sensing technologies and their basic applicability to various aspects of forest operations. It categorises these applications according to the technologies used and considers their deployment platform in terms of their being space-, airborne or terrestrial. For each combination of technology and application, a brief review of the state-of-the-art has been described from the literature, ranging from the measurement of forests and single trees, the derivation of landscape scale terrain models down to micro-topographic soil disturbance modelling, through infrastructure planning, construction and maintenance, to forest accessibility with ground and cable based harvesting systems. The review then goes on to discuss how these technologies and applications contribute to reducing impacts on forest soils, cultural heritage sites and other areas of special value or interest, after which sensors and methods necessary in autonomous navigation and the use of computer vision on forest machines are discussed. The review concludes that despite the many promising or demonstrated applications of remotely or proximately sensed data in forest operations, almost all are still experimental and have a range of issues that need to be addressed or improved upon before widespread operationalization can take place.

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Cable yarding is a semi-mechanized timber harvesting system that relies on human machine interaction where a considerable share of the work is done by forest workers. The system is used in mountain forests around the world. Automation of one or more functions could contribute to increased productivity, reduced physical workloads and improved safety conditions. This paper presents a method for sensor data fusion in order to automatically distinguish work phases using Partial Least Squares Discriminant Analysis (PLS-DA). The Robot Operation System (ROS) is implemented to allow for real-time data processing with a maximum latency of 0.16 s. Global Positioning System (GPS), Inertial Measurement Unit (IMU) and camera integration provided a robust solution for 78% correct process segmentation. These results provide a basis for further development from which there is a possibility of expanding this approach for semi-automation, remote control, and autonomous operation.

Sammendrag

This project considers the conditions under which it might be beneficial to use terrain-going cable-yarders as opposed to building forest roads and yarding the timber directly to roadside. Yarding in the terrain implies that the timber still needs to be forwarded to roadside. However, the relatively low productivity rates achievable with cable yarders increases the cost of forwarding due to long waiting times when distances are short. These systems are found to be a competitive option when small volumes must be harvested far from a forest road, when there are other considerations to be taken account of in avoiding road construction, or in playing an important role in connection with catastrophes such as widespread wind-fall where road construction cannot be carried out in time to extract the timber.

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We demonstrate the efficacy of using close-range photogrammetry from a consumer grade camera as a tool in generating high-resolution, three-dimensional coloured point clouds for detailed analysis or monitoring of wheel ruts. Ground-based timber harvesting results in vehicle traffic on 12–70 per cent of the site, depending on the system used, with a variable probability of causing detrimental soil disturbance depending on climatic, hydrological and soil conditions at the time of harvest. Applying the technique described in this article can reduce the workload associated with the conventional manual measurement of wheel ruts, while providing a greatly enhanced source of information that can be used in analysing both physical and biological impact, or stored in a repository for later operation management or monitoring. Approaches for deriving and quantifying properties such as rut depths and soil displacement volumes are also presented. In evaluating the potential for widespread adoption of the method among forest or environmental managers, the study also presents the workflow and provides a comparison of the ease of use and quality of the results obtained from one commercial and two open source image processing software packages. Results from a case study showed no significant difference between packages on point cloud quality in terms of model distortion. Comparison of photogrammetric profiles against profiles measured manually resulted in root mean square errors of between 2.07 and 3.84 cm for five selected road profiles. Maximal wheel rut depth for three different models were 1.15, 0.99 and 1.01 m, and estimated rut volumes were 9.84, 9.10 and 9.09 m3, respectively, for 22.5 m long sections.

Sammendrag

Råte påfører norske skogeiere og skogbruket årlige tap estimert til rundt 100 mill. NOK (Solheim og Stamnes, upubl.). Basert på den siste nasjonale råteundersøkelsen i granskog (Huse m.fl. 1994), var det mest råte i granas naturlige utbredelsesområde (Aust-Agder, Østlandet og Midt-Norge opp til Saltfjellet), hvor i gjennomsnitt nesten hvert fjerde tre var råteinfisert ved slutthogst. I enkelte granbestand kan råtefrekvensen ved slutthogst komme opp mot 60- 70 %. I skogreisingsstrøk (Vest-Agder, Vestlandet og Nord-Norge nord for Saltfjellet) var bare opptil hvert tiende hogstmodent grantre råteinfisert. I 2014 ble det utført en liten spørreundersøkelse for å kartlegge hvor bevisste de forskjellige aktørene i skogbruket er på råteproblemet, om de mener problemet har endret seg de senere årene og i hvilken grad det brukes forebyggende kontrolltiltak mot råte.

Sammendrag

A trial combining a 7th row and selective thinning was conducted in a young spruce stand. The small trees resulted in a high unit volume price, but the cost is somewhat offset by the saving of relocating both harvester and chipper twice. Results showed that it was possible to carry out the early thinning at no net cost to the forest owner.

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This case study examines the performance of the Igland Hauler employed in small diameter Eucalyptus clear-cut operations in Guangxi, China. A yarding crew of eight persons was monitored by a snap back elemental time study for 19.23 SMH (scheduled machine hours), with 159 yarding cycles and a yarded log volume at landing of 49.4 m³ solid over bark. A gross-productivity of 2.50 m³/SMH and net-productivity of 5.06 m³/PMH0 (productive machine hours excluding delay times) was achieved, leading to a machine utilization rate of 49.5%. The costs of the yarder and associated overhead as well as the personnel costs of a large crew with eight people sum up to extraction costs of 50.24 USD/m³. The high costs make it difficult to compete economically with the locally common manual extraction system as long as abundant labor at a low hourly rate is available in the region. Further performance improvement through skill development, but also technical and organizational system modification in conjunction with rising wages and decreasing labor force in rural primary production will determine the justification of employing such yarding systems. However, new silvicultural regimes with extended rotations and supply requirements of the forest products industry in China demand new operational systems.

Sammendrag

This paper reviews emerging technology-based engineering solutions that may reduce the impact of forest operations on the environment while increasing the efficiency of operations resulting in an overall higher level of forest ecosystem service provision. Advances in forest machine control and automation systems, and the availability of remotely-sensed high resolution data now provide considerable potential to improve the management and precision of forest operations.

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An assessment of the benefits of a fully integrated yarder-processor was made against the alternative of splitting the yarding and processing functions onto two base machines. The effect of productivity rates, specific costs, and crew sizes on the relative performance of each working configuration was investigated. The systems analysis showed that for the integrated yarder machine, a two-man crew was considerably cheaper than a three-man crew at all yarding distances, although the difference became less pronounced with increasing mean tree volumes. The single integrated machine with a 2-man crew was cheaper than the modelled 2-machine system at medium and longer extraction distances, as the processor base machine in the 2-machine systems incurred a considerable cost penalty in waiting idly for the yarder. At shorter distances (75 m) the 2-machine system was cheapest, but became less competitive with increasing mean tree volume. For mid-sized trees (0.38 m3) on a medium corridor length of 150 m, overall system productivity rates ranged from 5.2 m3 per productive system hour (PSH) for the single machine system to 9.4 PSH−1 for the 2-machine system, although the specific net costs were almost identical at 31.5 € m−3. A sensitivity analysis showed that reduced labour costs would promote use of the 2-machine system, suggesting that the optimum system configuration would be country specific. Despite being marginally more costly in small trees at short corridor lengths (75 m), the single fully-integrated machine was considered the working configuration of choice under Norwegian conditions.

Sammendrag

This report covers some of the work done on the mechanised harvesting of young oak stands for the production of whole tree chips as a bioenergy feedstock. Two thinning methods, a double row thinning and a combined single row and selection thinning were tested. Results showed overall production costs of roughly 7 € GJ-1 delivered into containers at roadside, with a difference of about 1 € GJ-1 between the two methods. As the production cost equated to the maximum delivered sales price, the mobilization of this feedstock would need to be incentivized.

Sammendrag

In this study, the performance of two terrain-going cable yarders was studied and used in a system analysis which included processing then forwarding to roadside, or whole-tree skidding and processing at roadside. The potential application for such systems was evaluated in GIS, and the investment costs in appropriate machinery was compared with the cost of extending the road network for access to conventional yarders.

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Anvendelse av gravemaskinmonterte, bardunfrie taubaner er blitt mer vanlig i flere land. Under spesielle forhold har denne type taubane flere fordeler i forhold til ordinære kabelkraner med tårn. Spesielt det at en ikke behøver å bardunere gjør at en sparer tid og krefter ved montering av banen, noe som har stor betydning der hvor mengden tømmer for hvert enkelt oppsett er liten. Det at taubanen kan flyttes uten å måtte rigge ned er også en klar fordel der velteplassen har en begrenset størrelse eller der en lastebil skal passere velteplassen. Noen ganger må man grave ned jordanker eller bore ned fjellbolter for å feste bardunene på tradisjonelle taubaner. Andre ganger er terrenget så bratt at man ikke får de nødvendige 45 grader mellom tårn og bardun. Her har bardunfrie taubaner store fordeler. Muligheten til å bruke maskinen som gravemaskin er også en fordel. Det store antallet og ulike varianter av gravemaskiner, samt relativt lave investeringskostnader, gjør derfor dette til et interessant konsept. Denne rapporten diskuterer fordeler og ulemper med gravemaskinmonterte, bardunfrie taubaner ved ulike tekniske løsninger og utfordringer. Rapporten viser og diskuterer resultatene fra en elektronisk spørreundersøkelse som er gjennomført med 40 utvalgte deltakere som uttrykte sin mening om viktigheten av forskjellige funksjoner/løsninger på et slikt konsept. Resultatet fra undersøkelsen viste at det er mange ulike meninger, men også at det er noen få viktige funksjoner som alle er enige om nødvendigheten av. Rapporten inkluderer også oppsummeringer fra en studiereise til hhv. Japan og Skottland hvor formålet var spesifikt å se på disse bardunfrie maskinene. Dertil kommer en kort gjennomgang av beregninger på et maskinkonsept som ikke er realisert. Sist i rapporten finnes det en oversikt over aktuelle maskinkonsepter på markedet.

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Den 3-tromlede, gravemaskinmonterte taubanen fra Zöggeler i Østerrike ble studert i drift i et blandet gran-/furubestand ved Kvam i Gudbrandsdalen. Maskinen er unik i det den er utstyrt med både vinsj og opparbeidingsaggregat. Da maskinen ikke er bardunert og vinsjen kjøres med løpende liner, kan det ikke opparbeides og vinsjes samtidig som man ellers kan gjøre på f.eks. en lastbilmontert Mounty kabelkran. Maskinen bemannes derfor typisk med en maskinfører og en feller/stropper. Fellingen foregår samtidig med at maskinen opparbeider et parti trær (15-20 stk.), hvoretter det neste parti vinsjes inn. Under vinsjingen fungerer felleren som stropper...

Sammendrag

Whole trees from energy thinnings constitute one of many forest fuel sources, yet ten widely applied supply chains could be defined for this feedstock alone. These ten represent only a subset of the real possibilities, as felling method was held constant and only a single market (combustion of whole tree chips) was considered. Stages included in-field, roadside landing, terminal, and conversion plant, and biomass states at each of these included loose whole trees, bundled whole trees or chipped material. Assumptions on prices, performances, and conversion rates were based on field trials and published literature in similar boreal forest conditions. The economic outcome was calculated on the basis of production, handling, treatment and storage costs and losses. Outcomes were tested for robustness on a range of object volumes (50–350 m3solid), extraction distances (50–550 m) and transport distances (10–70 km) using simulation across a set of discrete values. Transport was calculated for both a standard 19.5 m and an extended 24 m timber truck. Results showed that the most expensive chain (roadside bundling, roadside storage, terminal storage and delivery using a 19.5 m timber truck) at 158 € td−1 was 23% more costly than the cheapest chain (roadside chipping and direct transport to conversion plant with container truck), at 128 € td−1. Outcomes vary at specific object volumes and transport distances, highlighting the need to verify assumptions, although standard deviations around mean supply costs for each chain were small (6%–9%). Losses at all stages were modelled, with the largest losses (23 € td−1) occurring in the chains including bundles. The study makes all methods and assumptions explicit and can assist the procurement manager in understanding the mechanisms at work.

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The ground-based harvesting system consisting of a harvester and a forwarder is the dominant harvesting system in parts of the world, due to its high productivity. Both machines usually operate along extraction trails, and are equipped with cranes that can reach some distance from the extraction trail. In this work we optimize the layout of an extraction trail network by considering how terrain topography influences the cost of forwarding. Given the complexity of finding optimal machine trails for terrain transportation, traditional optimization methods might be limited due to the problem size. In this study, the optimization is done with a greedy constructive heuristic and a Greedy Randomized Adaptive Search Procedure (GRASP) metaheuristic, and the results of the two solution techniques are compared. Both the greedy heuristic and the GRASP metaheuristic were examined for a semi-random terrain and a smooth cone-shaped terrain, and provided useable extraction trail layouts in terms of how a forest machine operates on slopes. The objective value of the solution found by the GRASP metaheuristic was 5.6% better than the greedy heuristic in the semi-random terrain, and 2.3% better in the cone-shaped terrain. The result of this study showed that the GRASP metaheuristic is useful for finding feasible routes in the terrain, increasing efficiency. The method could be useful for planning feasible routes in the terrain, thereby increasing efficiency, or for acquiring a better estimate of the cost of terrain transport in price setting.

Sammendrag

This chapter provides an introduction into the harvesting and supply of biomass from timber plantations. It considers the main sources of utilizable biomass and their properties and discusses harvesting equipment, machinery and systems that could potentially be applied for moving these resources to a landing and eventually the conversion plant. Important supply processes such as storage and drying, quality assurance, transport and simple trade models are also presented. Management of feedstock supply is discussed and illustrated with two examples integrating concepts included in this chapter. This chapter will provide the reader with an overview of the techno-economic factors to be considered for biomass procurement, how these interact with each other, and how they can be applied in developing supply models to provide strategic insight into the harvesting and transport of woody biomass.

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The Irish government has undertaken to reduce national CO2 emissions through a range of measures put out in their Biomass Action Plan and the National Renewable Energy Action Plan. The conversion of peat fired power plants to co-fire with renewable biomass is one of these. This paper considers how the adoption of sweeping policies impact on other actors presently supplying or utilizing woody biomass resources. The SAWMILL sector (18 sawmills), BOARD sector, 3 board plants, and ENERGY sector (3 peat fired power stations) were included in a Linear Programming (LP) based transportation study. Specific transport costs between each residue producing sawmill and each board and energy plant were modeled and used in finding the minimum delivered cost for a number of scenarios. Scenario 2015 represented the status quo, while Scenario 2030 represented a situation with 30% co-firing with woody biomass equivalents in the energy plants. For each time horizon, the problem was solved from the perspective of society at large (GLOBAL), for the benefit of the board sector (BOARD) or with emphasis on minimizing the cost to the energy sector (ENERGY). The cost of transporting alternative sources of renewable energy was varied between €100 and €500 TJ−1. Results showed how overall supply costs increase with increasing alternative energy cost, but also how the dynamics between sectors focus worked. The cost of transport to the Energy sector ranged from €306,043 to €996,842 in Scenario 2015, while the increased demand in 2030 led to a range of between €1,132,831 and €4,926,040, depending on the alternative cost selected. For the Board sector, whose absolute demand remained constant, the total transport cost ranged between €868,506 and €3,454,916 in Scenario 2015. The unchanged demand showed that the transport costs also remained the same for the 2030 Scenario, however, the optimization focusing on the Energy sector, increased the delivery cost to the Board sector by up to €693,730 per year by 2015 and €842,271 per year by 2030, indicating how intervention would be necessary if political ambitions of a 30% co-firing should happen without detriment to other important wood based industries.

Sammendrag

Effekten av å bruke gravemaskin til å lage driftsveger ble evaluert i 9 drifter på Vestlandet. Evalueringen bestod hovedsakelig i registrering av omfanget av driftsveger i driftene. Registrering av stigning og lengde på de enkelte segmenter av veien, og volum av masseforflytting etter driften. Registreringen bestod av GPS tracking av driftsvegen og analyse høy oppløselige terreng modeller fra ArcGIS og RoadEng programvare. Registreringene ble utført sommeren 2011. Resultatene fra registreringene viste at det er nødvendig med en vegtetthet opp mot 600 m/ha ved å benytte dette systemet. Dette kan sees opp mot taubanedrifter som tilnærmer 0 m/ha. Pilot studiet viste at hogstmetoden i forskjellig grad kan gi miljøpåvirkninger. Det var store forskjeller som ble påvist ved visuell registrering, men de ble ikke målt direkte eller tallfestet på annet vis. Nøyaktige målinger av jorderosjon er tidkrevende og krever mye planlegging. En delautomatisert metode til beregning av driftsveglengde og masseforflytting basert på flyfoto ble utviklet under forprosjektet. I et eksempel fra Langedal som er beskrevet i rapporten var masseforflytting beregnet til 1600 m3, en forholdsvis stor mengde som må antas å øke risikoen for skade. Ettersom driftsprisen er den viktigste grunnen til at hogstmetoden velges bør denne kvantifiseres og verifiseres gjennom et større data materiale enn det som er tilfelle i dag. Metoden har også klare arbeidsbesparende fordeler sammenlignet med taubanedrifter, og en videreutvikling av hogstmetoden må derfor betraktes som viktig for næringen. Det kan være ønskelig å involvere et bredere fagmiljø i en evaluering og sammenligning med andre hogstmetoder.

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I dette studiet sammenlignes 10 ulike forsyningskjeder for flisproduksjon basert på heltrevirke fra ungskog og kulturlandskap. Alle kjedene starter med felling av virke i bestand og slutter hos sluttforbruker (dvs flislager hos varmeprodusent). Virke leveres varmeanlegget i form av tørr flis, noe som innebærer at virke lagres over minst en tørkesesong (april – august) før det flishogges og leveres sluttkunde. To av kjedene kjennetegnes ved at virke transporteres som heltre fra lunne på vegkant til terminal med tømmervogntog. Fire av kjedene minner om heltre-transport kjedene, med den forskjellen at virke buntes og transporteres som bunter til terminal. I de fire siste kjedene flishogges virke på vegkantlunne eller terrenglunne, med påfølgende flis-transport til terminal eller varmeverk....

Sammendrag

Hovedmålet med prosjektet er å utarbeide en prioritert investeringsplan for utbygging av tømmerkaier langs norskekysten, slik at forholdene legges til rette for en rasjonell tømmertransport fra skog til industri. Vi har benyttet matematisk programmering til å identifisere det optimale antall, størrelse og lokalisering av tømmerkaier - i dag og over en tidshorisont på 20 år. Modellen er tilpasset slik at den tar hensyn til dagens og fremtidens avvirkningsvolum, infrastruktur, kostnader og tariffer, og for øvrig andre målbare faktorer som påvirker samlede transportkostnader. Ved hjelp av modellen har vi identifisert en skissemessig plan for lokalisering, dimensjonering, og utbygging av tømmerkaier langs norskekysten, samt en følsomhetsanalyse for viktige drivere. Den viser at investeringskostnad for kaier, kundenes lokalisering og tilhørende etterspørsel, og kostnad for lastebiltransporten og endret veikvalitet / bruksklasse (foruten totalt avvirkningsvolum) har størst effekt på resultatet og totalkostnaden. Prosjektet har også vurdert andre miljø- og samfunnsgevinster av en slik utbygging langs kysten. Flere kaier (for samme mengde avvirket tømmer), og tilhørende redusert antall kilometer tømmertransport med lastebil ser ut til å være gunstig med tanke på miljøutslipp. Det er også potensial for å utvikle modellen til å analysere flere ting enn hva som ligger inne per i dag. Et aspekt som bør inkluderes er profittmaksimering (overskudd) og verdikjedeoptimering.

Sammendrag

In the coastal region of Norway, large volumes of relatively inaccessible plantation timber are maturing for harvest. The economic feasibility of accessing much of this timber has limited the level of harvesting activity considerably. Harvesting planners are faced with the classic dilemma of finding the appropriate level of investment in infrastructure, as against inoptimal transportation. In this paper, we present results from a simple deterministic simulation carried out to illustrate the efficiency frontiers of three transport methods, one of which requires a substantial investment in road upgrading. Results depend on assumptions made, but clearly show that in these conditions, upgrading roads for truck+trailer transport should be evaluated on a cases by case basis. Forest road length and condition, public road distance to conversion site, and investment level all play important roles in the decision structure. In the coastal regions, road upgrades would generally need to be justified by benefits other than timber harvesting alone.

Sammendrag

This study examined the difference in workload brought about by exchanging a 3.5mm steel rope with a 4.0 mm synthetic fiber rope when dragging a strawline up a 300 m corridor in setting up a new cable-yarding line. Physiological workload was monitored through heart rate measurement, while the physical forces acting on the subject (rope mass and friction) were quantified using a dynamometer attached to a belt. While there was a substantial difference in force between rope types at full extent (140 N vs. 40 N), the result was less significant when seen against the total work required in moving the subjects own body mass up the slope. The direction of the resultant force vector appears to play an important role in the way that strain is experienced. It was discovered that 300 m was the maximum hauling distance for a single person using this rigging method with a steel wire strawline, whereas for the synthetic rope, the same tensile force would only be reached at 1200 m. This alone has important implications for labor saving amongst small cable logging teams.

Sammendrag

Large volumes of spruce-dominated forests established on steep terrain are maturing in western Norway. The level of harvesting needed in utilising these forests calls for investments in cable yarding, processing and transport systems, and updated knowledge on the appropriate technology for Norwegian conditions. In the yarding-processing-truck transport operation, the processor cannot operate if the cable yarding system does not supply trees at a sufficient rate or when the buffer storage becomes full. As a result, the productivity of the whole system is often substantially lower than those of the individual parts in the system. Discrete-event simulation has been applied successfully in the analysis of a wide variety of wood harvesting and transport systems, where the productivities of different parts in the supply chain are interlinked .....

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This study investigated the feasibility of extracting and chipping hardwood crowns for energy after motor-manual thinning in stands of common beech. Large crowns were extracted and chipped from stands where only sawlogs had been produced, while small crowns were extracted and chipped from stands where sawlogs and firewood had been harvested. The fuel chip yield was 15 m3 solid ha-1 when extracting and chipping large crowns, while it was 8 m3 solid ha-1 when extracting and chipping small crowns. The productivity for extracting and chipping large crowns was 8.5 m3 solid per workplace hour, and for small crowns was 5.9 m3 solid per workplace hour. Extracting and chipping large crowns gave a net income of €167 ha-1 (€11 m-3 solid), while extracting and chipping small crowns gave a lower net income of €23 ha-1 (€3 m-3 solid). The study showed that extracting and chipping large hardwood crowns is feasible and can make a substantial contribution to woody biomass feedstocks. Four product-mix alternatives were considered, but the marginal differences in outcome led the authors to recommend that in addition to sawlogs only one product, firewood or chips, should be produced in each stand.

Sammendrag

This paper builds on findings from the recently finalised work package 3.9 of the EU Indisputable Key project. Three institutes cooperated in developing intricate models spanning from the standing tree to the dispatch yard of a Swedish window manufacturer. Numerous timber properties were assigned to RFID tags, applied to the log at felling by a specially adapted harvester head. Logs were allocated to each of seven sawmills according to their timber properties using an LP based optimisation procedure. Simulation was then used to compare the fate of traced timber throughout the production lines of one of the sawmills and its downstream manufacturers.....