Current issue: 53(2)

Under compilation: 53(3)

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Silva Fennica 1926-1997
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Acta Forestalia Fennica
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Articles containing the keyword 'bioenergy'.

Category: Research article

article id 9902, category Research article
Perttu Anttila, Vesa Nivala, Olli Salminen, Markus Hurskainen, Janne Kärki, Tomi J. Lindroos, Antti Asikainen. (2018). Regional balance of forest chip supply and demand in Finland in 2030. Silva Fennica vol. 52 no. 2 article id 9902. https://doi.org/10.14214/sf.9902
Highlights: The impact of increasing forest chip demand in 2030 was analyzed in Finland; Demand of small trees may exceed potential at the national level; Surplus potential will remain in logging residues and stumps; Hot spots of demand call for efficient logistical solutions.

According to the National Energy and Climate Strategy of Finland in 2016, the demand for forest chips, that is, wood chips made of forest biomass directly for energy use, could even double by 2030 compared to the present situation. A spatially explicit impact analysis of regional supply and demand balances for forest chips was carried out. The balances were calculated as the difference between technical harvesting potentials and demand. First, the technical potentials were estimated based on the national forest inventory data. Secondly, three demand scenarios were defined for 2030 and subsequently deducted from the potentials. The results suggested that there would be increasing competition for feedstock in southern and western Finland, whereas in eastern and northern Finland there would still be surplus potential. Moreover, due to the remarkable deficit of small trees in southern Finland, there might be pressure towards using more pulpwood-sized and/or imported wood in energy production. The results also showed that, in particular, large new plants consuming substantial amounts of forest chips could have a significant effect on the regional availability of forest chips. Moreover, with increasing transport distances, new logistical solutions will be needed.

  • Anttila, Natural Resources Institute Finland (Luke), Yliopistokatu 6, FI-80100 Joensuu, Finland ORCID ID: http://orcid.org/0000-0002-6131-392X E-mail: perttu.anttila@luke.fi (email)
  • Nivala, Natural Resources Institute Finland (Luke), Eteläranta 55, FI-96300 Rovaniemi, Finland ORCID ID:E-mail: vesa.nivala@luke.fi
  • Salminen, Natural Resources Institute Finland (Luke), Latokartanonkaari 9, FI-00790 Helsinki, Finland ORCID ID:E-mail: olli.salminen@luke.fi
  • Hurskainen, VTT Technical Research Centre of Finland Ltd, Koivurannantie 1, FI-40400 Jyväskylä, Finland ORCID ID:E-mail: markus.hurskainen@vtt.fi
  • Kärki, VTT Technical Research Centre of Finland Ltd, Koivurannantie 1, FI-40400 Jyväskylä, Finland ORCID ID:E-mail: janne.karki@vtt.fi
  • Lindroos, VTT Technical Research Centre of Finland Ltd, Vuorimiehentie 3 (Espoo), P.O. Box 1000, FI-02044 VTT, Finland ORCID ID:E-mail: tomi.j.lindroos@vtt.fi
  • Asikainen, Natural Resources Institute Finland (Luke), Yliopistokatu 6, FI-80100 Joensuu, Finland ORCID ID:E-mail: antti.asikainen@luke.fi
article id 1377, category Research article
Raul Fernandez-Lacruz, Fulvio Di Fulvio, Dimitris Athanassiadis, Dan Bergström, Tomas Nordfjell. (2015). Distribution, characteristics and potential of biomass-dense thinning forests in Sweden. Silva Fennica vol. 49 no. 5 article id 1377. https://doi.org/10.14214/sf.1377
Highlights: Biomass-dense thinning forests (BDTF) cover 2.1–9.8 M ha in Sweden, which represents 9–44% of the country’s productive forest land area, depending on the constraints applied; 65% of BDTF area is found in northern Sweden; Analyses revealed a yearly harvesting potential of at least 4.3 M OD t of undelimbed whole trees (3.0 M OD t of delimbed stemwood including tops).

Understanding the characteristics of unutilized biomass resources, such as small-diameter trees from biomass-dense thinning forests (BDTF) (non-commercially-thinned forests), can provide important information for developing a bio-based economy. The aim of this study was to describe the areal distribution, characteristics (biomass of growing stock, tree height, etc.) and harvesting potential of BDTF in Sweden. A national forest inventory plot dataset was imported into a geographical information system and plots containing BDTF were selected by applying increasingly stringent constraints. Results show that, depending on the constraints applied, BDTF covers 9–44% (2.1–9.8 M ha) of the productive forest land area, and contains 7–34% of the total growing stock (119–564 M OD t), with an average biomass density of 57 OD t ha–1. Of the total BDTF area, 65% is located in northern Sweden and 2% corresponds to set-aside farmlands. Comparisons with a study from 2008 indicate that BDTF area has increased by at least 4% (about 102 000 ha), in line with general trends for Sweden and Europe. Analyses revealed that the technical harvesting potential of delimbed stemwood (over bark, including tops) from BDTF ranges from 3.0 to 6.1 M OD t yr–1 (7.5 to 15.1 M m3 yr–1), while the potential of whole-tree harvesting ranges from 4.3 to 8.7 M OD t yr–1 (10.2 to 20.6 M m3 yr–1) depending on the scenario considered. However, further technological developments of the harvest and supply systems are needed to utilize the full potential of BDTF.

  • Fernandez-Lacruz, Swedish University of Agricultural Sciences (SLU), Department of Forest Biomaterials and Technology (SBT), Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID: http://orcid.org/0000-0001-9284-8911 E-mail: raul.fernandez@slu.se (email)
  • Di Fulvio, Swedish University of Agricultural Sciences (SLU), Department of Forest Biomaterials and Technology (SBT), Skogsmarksgränd, SE-901 83 Umeå, Sweden; International Institute for Applied Systems Analysis (IIASA), Ecosystems Services and Management Program (ESM), Schlossplatz 1, A-2361 Laxenburg, Austria ORCID ID:E-mail: Fulvio.di.Fulvio@slu.se
  • Athanassiadis, Swedish University of Agricultural Sciences (SLU), Department of Forest Biomaterials and Technology (SBT), Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: Dimitris.Athanassiadis@slu.se
  • Bergström, Swedish University of Agricultural Sciences (SLU), Department of Forest Biomaterials and Technology (SBT), Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: Dan.Bergstrom@slu.se
  • Nordfjell, Swedish University of Agricultural Sciences (SLU), Department of Forest Biomaterials and Technology (SBT), Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: Tomas.Nordfjell@slu.se
article id 1347, category Research article
Paulo Borges, Even Bergseng, Tron Eid, Terje Gobakken. (2015). Impact of maximum opening area constraints on profitability and biomass availability in forestry – a large, real world case. Silva Fennica vol. 49 no. 5 article id 1347. https://doi.org/10.14214/sf.1347
Highlights: We solved a large and real world near city forestry problem; The inclusion of maximum open area constraints caused 7.0% loss in NPV; Solution value at maximum deviated 0.01% from the true optimum value; The annual energy supply of 20–30 GWh estimated from harvest residues could provide a small, but stable supply of energy to the municipality.

The nature areas surrounding the capital of Norway (Oslomarka), comprising 1 700 km2 of forest land, are the recreational home turf for a population of 1.2 mill. people. These areas are highly valuable, not only for recreational purposes and biodiversity, but also for commercial activities. To assess the impacts of the challenges that Oslo municipality forest face in their management, we developed four optimization problems with different levels of management constraints. The constraints consider control of harvest level, guarantee of minimum old-growth forest area and maximum open area after final harvest. For the latter, to date, no appropriate analyses quantifying the impact of such a constraint on economy and biomass production have been carried out in Norway. The problem solved is large due to both the number of stands and number of treatment schedules. However, the model applied demonstrated its relevance for solving large problems involving maximum opening areas. The inclusion of maximum open area constraints caused 7.0% loss in NPV compared to the business as usual case with controlled harvest volume and minimum old-growth area. The estimated supply of 20-30 GWh annual energy from harvest residues could provide a small, but stable supply of energy to the municipality.

  • Borges, Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, 1432 Aas, Norway ORCID ID:E-mail: paulo.borges@nmbu.no (email)
  • Bergseng, Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, 1432 Aas, Norway ORCID ID:E-mail: even.bergseng@nmbu.no
  • Eid, Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, 1432 Aas, Norway ORCID ID:E-mail: tron.eid@nmbu.no
  • Gobakken, Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, 1432 Aas, Norway ORCID ID:E-mail: terje.gobakken@nmbu.no
article id 962, category Research article
Paul A. Klockow, Anthony W. D'Amato, John B. Bradford, Shawn Fraver. (2014). Nutrient concentrations in coarse and fine woody debris of Populus tremuloides Michx.-dominated forests, northern Minnesota, USA. Silva Fennica vol. 48 no. 1 article id 962. https://doi.org/10.14214/sf.962
Highlights: We examine effects of size, species, and decay on woody debris nutrient concentrations; Results indicate wide variation in nutrient concentrations across the factors examined; Fine woody debris nutrient concentrations were greater than in coarse woody debris; Coarse woody debris nutrient concentrations generally increased as decay progressed; Results suggest high fine woody debris stocks can represent an important nutrient source.
Contemporary forest harvesting practices, specifically harvesting woody biomass as a source of bioenergy feedstock, may remove more woody debris from a site than conventional harvesting. Woody debris, particularly smaller diameter woody debris, plays a key role in maintaining ecosystem nutrient stores following disturbance. Understanding nutrient concentrations within woody debris is necessary for assessing the long-term nutrient balance consequences of altered woody debris retention, particularly in forests slated for use as bioenergy feedstocks. Nutrient concentrations in downed woody debris of various sizes, decay classes, and species were characterized within one such forest type, Populus tremuloides Michx.-dominated forests of northern Minnesota, USA. Nutrient concentrations differed significantly between size and decay classes and generally increased as decay progressed. Fine woody debris (≤ 7.5 cm diameter) had higher nutrient concentrations than coarse woody debris (> 7.5 cm diameter) for all nutrients examined except Na and Mn, and nutrient concentrations varied among species. Concentrations of N, Mn, Al, Fe, and Zn in coarse woody debris increased between one and three orders of magnitude, while K decreased by an order of magnitude with progressing decay. The variations in nutrient concentrations observed here underscore the complexity of woody debris nutrient stores in forested ecosystems and suggest that retaining fine woody debris at harvest may provide a potentially important source of nutrients following intensive removals of bioenergy feedstocks.
  • Klockow, Department of Forest Resources, University of Minnesota, St. Paul, MN 55108, USA ORCID ID:E-mail: klock039@umn.edu (email)
  • D'Amato, Department of Forest Resources, University of Minnesota, St. Paul, MN 55108, USA ORCID ID:E-mail: damato@umn.edu
  • Bradford, US Geological Survey, Southwest Biological Science Center, Flagstaff, AZ 86001, USA ORCID ID:E-mail: jbradford@usgs.gov
  • Fraver, School of Forest Resources, University of Maine, Orono, ME 04469, USA ORCID ID:E-mail: shawn.fraver@maine.edu
article id 86, category Research article
Mats Jonsell, Jesper Hansson. (2011). Logs and stumps in clearcuts support similar saproxylic beetle diversity: implications for bioenergy harvest. Silva Fennica vol. 45 no. 5 article id 86. https://doi.org/10.14214/sf.86
Stumps from clear cuts are increasingly used for bioenergy. Extracting this wood will reduce the habitat available for saproxylic (wood-living) organisms. As little is known about the species assemblages that will be affected, we investigated the diversity of saproxylic beetles in stumps on clear-felled sites and as a reference, we compared it with the diversity in downed logs. Stumps and logs of aspen (Populus tremula L.), birch (Betula pubescens Ehrh. and B. verrucosa Ehrh.[syn. B. pendula Roth]), spruce (Picea abies (L.) Karst.) and pine (Pinus sylvestris L.) were examined in clear cuts of two different ages: one summer old and 4–5 years old. The beetles were sampled by sieving bark (0.25 m2) peeled from the wood. The samples were taken in pairs of one log and one stump situated close together and of the same tree species, age since death and diameter. In total 3348 saproxylic beetles belonging to 124 species were found in 176 samples. The stumps had a similar number of species to the logs both as measured per sample and as an accumulated number. Exceptions were 4–5 years old wood of birch and pine where the number was significantly higher in the stumps. The number of red-listed species was also similar between stumps and logs. Species composition was more different between the stumps and logs of conifers than of deciduous trees. We conclude that clear-felled stumps have a diverse saproxylic insect fauna. This has to be taken into account if large scale extraction of logging stumps is implemented.
  • Jonsell, Swedish University of Agrarian Sciences, Dept of Ecology, Uppsala, Sweden ORCID ID:E-mail: mats.jonsell@ekol.slu.se (email)
  • Hansson, Swedish University of Agrarian Sciences, Dept of Ecology, Uppsala, Sweden ORCID ID:E-mail:
article id 135, category Research article
Ola Lindroos, Marina Henningsson, Dimitris Athanassiadis, Tomas Nordfjell. (2010). Forces required to vertically uproot tree stumps. Silva Fennica vol. 44 no. 4 article id 135. https://doi.org/10.14214/sf.135
Stumpwood attracts renewed interest due to increased use of forest biomass for bioenergy. In Nordic countries stumps are generally uprooted with crawler excavators, which have strong cranes (ca. 400 kNm gross lift torque), but are not designed for moving in forest terrain. Their use is based on practical experience with available and tested machine types rather than thorough examinations of requirements, partly due to limited knowledge of force requirements for uprooting of stumps. Therefore, in this work mean and maximum forces required to vertically uproot stumps of Norway spruce (Picea abies) and birch (Betula spp.) were quantified together with the effects of various soil types and uprooting methods. The used excavator’s crane-mounted uprooting device enabled comparisons between usage of solely crane force, and a method in which preparatory loosening forces were applied prior to crane force. Uprooting stumps in single pieces proved difficult; 61% split unintentionally. Force requirements were similar across tree species, increasing curve-linearly with stump diameter, and stumps uprooted in a single piece required more force than split stumps. Preparatory loosening reduced crane force requirements and, surprisingly, less force was required to uproot stumps from a mesic, till soil than from a moist, finer-textured soil. No stump required more than 60 kN crane force and functions for maximum force requirements indicate that powerful harvesters and forwarders (gross crane lifting capacity of 273 and 155 kNm, respectively) should be able to uproot all stumps with ≤ 61 cm and ≤ 32 cm diameter, respectively, in one piece. Larger stumps could be managed if it is acceptable that stumps are split before uprooting.
  • Lindroos, Department of Forest Resource Management, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden ORCID ID:E-mail: ola.lindroos@srh.slu.se (email)
  • Henningsson, Komatsu Forest AB, Box 7124, SE-907 04 Umeå, Sweden ORCID ID:E-mail:
  • Athanassiadis, Department of Forest Resource Management, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden ORCID ID:E-mail:
  • Nordfjell, Department of Forest Resource Management, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden ORCID ID:E-mail:
article id 134, category Research article
Dan Bergström, Urban Bergsten, Tomas Nordfjell. (2010). Comparison of boom-corridor thinning and thinning from below harvesting methods in young dense Scots pine stands. Silva Fennica vol. 44 no. 4 article id 134. https://doi.org/10.14214/sf.134
At present, only a small proportion of the potential extractable bioenergy from young dense forests in Sweden is utilized. The conventional mechanized first thinning systems used in such stands suffer from low productivity, so the operation is only profitable in stands with bigger trees and high standing volumes. Conventional harvesters are used for this operation equipped with accumulating felling heads designed for handling several trees during each crane cycle. In thinning from below the felling and bunching work requires many time-consuming non-linear crane movements to avoid felling or damaging of future crop trees. However, higher productivity can be achieved when trees between strip roads are harvested in about 1 m-wide corridors with a length corresponding to the reach of the crane. We refer to this operation as boom-corridor thinning. The objective of this study was to compare felling and bunching productivity in young dense stands when employing thinning from below or boom-corridor thinning. Experiments were performed using a randomized block design involving between 4400 and 18 600 trees x ha-1 with a corresponding average tree size of 7.2 and 3.2 cm dbh, respectively. Based on the average tree being removed at a dbh of 5.7 cm, the productivity (ODt x PW-hour-1) was significant (almost 16%) higher for the boom-corridor thinning than for thinning from below treatment. At the same time, the time taken for the work element “Crane in-between” (the period between the loaded crane starting to move towards a tree and the felling head rapidly slowing down for positioning) was significantly reduced, by almost 17%. The positive results were achieved even though the operator was new to the method. To achieve a significantly higher efficiency during the felling and bunching operation, development of new harvesting equipment and operating techniques seems crucial.
  • Bergström, Swedish University of Agricultural Sciences, Dept of Forest Resource Management, Section of Planning and Operations Management, Umeå, Sweden ORCID ID:E-mail: dan.bergstrom@srh.slu.se (email)
  • Bergsten, Swedish University of Agricultural Sciences, Dept of Forest Resource Management, Section of Planning and Operations Management, Umeå, Sweden ORCID ID:E-mail:
  • Nordfjell, Swedish University of Agricultural Sciences, Dept of Forest Resource Management, Section of Planning and Operations Management, Umeå, Sweden ORCID ID:E-mail:
article id 141, category Research article
Per Kristian Rørstad, Erik Trømborg, Even Bergseng, Birger Solberg. (2010). Combining GIS and forest modelling in estimating regional supply of harvest residues in Norway. Silva Fennica vol. 44 no. 3 article id 141. https://doi.org/10.14214/sf.141
New and ambitious targets for renewable energy production put attention to increased supply of biomass. Harvest residues are only to a limited extent demanded by the traditional forest industries and represent an unutilized resource for increased production of renewable energy in Norway. The overall objective of this paper is to study how GIS and forest modelling can be combined to improve estimates of the supply of harvest residues, taking different environmental and economic constraints into consideration. The analyses are based on a case study of a forest area of more than 40 000 ha in Southern Norway divided into about 500 private forest properties. The study was carried out by computations of timber harvest using the forestry scenario model SGIS based on extensive forest inventory data at stand level. In the studied area energy utilization of harvest residues is not profitable below an energy price of about EUR 3.2/GJ (NOK 0.10 /kWh) when the distance from roadside to industry is 20 km. Above this level supply increases rapidly over a rather narrow price range and is nearly inelastic above EUR 4.1/GJ (NOK 0.12/kWh). We did not find significant negative shifts in the residues supply caused by changes in location of roundwood harvest over time. Exclusion of collection from stands with a site index (H40) below 14 reduced the potential supply of residues by 16–27%. The optimisation method combined selection of exogenous variables in order to map observed harvesting level and is probably the best approach to map future harvest.
  • Rørstad, Norwegian University of Life Sciences, Dept of Ecology and Natural Resource Management, Ås, Norway ORCID ID:E-mail: per.kristian.rorstad@umb.no (email)
  • Trømborg, Norwegian University of Life Sciences, Dept of Ecology and Natural Resource Management, Ås, Norway ORCID ID:E-mail:
  • Bergseng, Norwegian University of Life Sciences, Dept of Ecology and Natural Resource Management, Ås, Norway ORCID ID:E-mail:
  • Solberg, Norwegian University of Life Sciences, Dept of Ecology and Natural Resource Management, Ås, Norway ORCID ID:E-mail:
article id 140, category Research article
Jussi Laurila, Risto Lauhanen. (2010). Moisture content of Norway spruce stump wood at clear cutting areas and roadside storage sites. Silva Fennica vol. 44 no. 3 article id 140. https://doi.org/10.14214/sf.140
Norway spruce (Picea abies (L.) Karst.) stump wood is a potential source of bioenergy in Finland. The heating value of stump wood depends on, among other things, the moisture, carbon and ash content of the wood. In this study the moisture content of Norway spruce stump wood was examined immediately after harvesting at the clear cutting area and after different drying times at the roadside storage sites. Immediately after stump harvesting the average moisture content (wet basis) was 53%. The stump wood dried fairly fast during spring and summer. One month after stump harvesting, the average moisture content was about 31%. If the stump wood had dried well once, water absorption became very weak and the moisture content increased only slightly in the late autumn. Each spring and summer the moisture content of the stumps was lower than during the previous year. Annually the lowest moisture content was observed at the beginning of July and the highest at both the beginning and the end of the year. The moisture content of stump wood followed an upwards opening parabola over a one year period and was repeated each year. Three years after harvesting the heating value of the stump wood was still 5.241 MWh/ton. Overall, when harvesting took place in the spring or early summer, the stump wood was combustible after a one month drying period immediately after harvesting.
  • Laurila, Seinäjoki University of Applied Sciences, School of Agriculture and Forestry, FI-63700 Ähtäri, Finland ORCID ID:E-mail: jussi.laurila@seamk.fi (email)
  • Lauhanen, Seinäjoki University of Applied Sciences, School of Agriculture and Forestry, FI-63700 Ähtäri, Finland ORCID ID:E-mail:
article id 162, category Research article
Ruut Rabinowitsch-Jokinen, Ilkka Vanha-Majamaa. (2010). Immediate effects of logging, mounding and removal of logging residues and stumps on coarse woody debris in managed boreal Norway spruce stands. Silva Fennica vol. 44 no. 1 article id 162. https://doi.org/10.14214/sf.162
Wood fuel production has increased remarkably, but its environmental effects within the forest ecosystem have not yet been studied much. We investigated the immediate effects of two series of forest management treatments, which produce timber and forest chips, on the volume and decay classes of coarse woody debris (CWD). One of the treatment series included logging and residue harvesting (LRH) and mounding (M), while the other series included LRH and mounding combined with stump harvesting (MSH). We hypothesized that, i) LRH reduces CWD, excluding stumps; ii) the more intense the soil preparation treatment is, M vs. MSH, the more CWD is destroyed; iii) both LRH and soil preparation treatments (M and MSH) reduce the occurence of snags, highly decayed CWD and deciduous CWD in particular. Ten sample plots in mature managed Norway spruce (Picea abies (L.) H. Karst.) dominated forests were located in Southern Finland. The total volume of CWD on the sample plots was measured three times: before and after LRH, and after M or MSH. LRH significantly decreased the volume of snags and the combined volume of snags and logs. MSH significantly decreased the total volume of CWD, while M had no significant effect on the volume of CWD. The middle and highly decayed CWD were destroyed most easily in the treatments.
  • Rabinowitsch-Jokinen, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301, Vantaa, Finland ORCID ID:E-mail:
  • Vanha-Majamaa, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301, Vantaa, Finland ORCID ID:E-mail: ilkka.vanha-majamaa@metla.fi (email)

Category: Research note

article id 60, category Research note
Dominik Röser, Blas Mola-Yudego, Robert Prinz, Beatrice Emer, Lauri Sikanen. (2012). Chipping operations and efficiency in different operational environments. Silva Fennica vol. 46 no. 2 article id 60. https://doi.org/10.14214/sf.60
This research analyses the productivity of energy wood chipping operations at several sites in Austria and Finland. The aim of the work is to examine the differences in productivity and the effects of the operational environment for the chipping of bioenergy at the roadside. Furthermore, the study quantifies the effects of different variables such as forest energy assortments, tree species, sieve size and machines on the overall productivity of chipping. The results revealed that there are significant differences in the chipping productivity in Austria and Finland which are largely based on the use of different sieve sizes. Furthermore, the different operational environments in both countries, as well as the characteristics of the raw material also seem to have an effect on productivity. In order to improve the chipping productivity, particularly in Central European conditions, all relevant stakeholders need to work jointly to find solutions that will allow a greater variation of chip size. Furthermore, in the future more consideration has to be given to the close interlinkage between the chipper, crane and grapple. As a result, investments costs can be optimized and operational costs and stress on the machines reduced.
  • Röser, Finnish Forest Research Institute, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: dominik.roser@metla.fi (email)
  • Mola-Yudego, University of Eastern Finland, School of Forest Sciences, Joensuu, Finland ORCID ID:E-mail:
  • Prinz, Finnish Forest Research Institute, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Emer, University of Padova, Department of Land, Agriculture and Forest Systems, Legnaro (PD), Italy ORCID ID:E-mail:
  • Sikanen, University of Eastern Finland, School of Forest Sciences, Joensuu, Finland ORCID ID:E-mail:
article id 148, category Research note
Ola Lindroos, Magnus Matisons, Petter Johansson, Tomas Nordfjell. (2010). Productivity of a prototype truck-mounted logging residue bundler and a road-side bundling system. Silva Fennica vol. 44 no. 3 article id 148. https://doi.org/10.14214/sf.148
When recovering logging residues (LR) for bioenergy its density should be increased before road transport, otherwise a low proportion of the trucks’ load capacity will be used. One way this can be currently done is to compress LR into bundles that are forwarded to roadside landing. A less well-developed alternative is to forward loose LR and bundle it at landing. In the presented study, a prototype specifically developed for road-side bundling was found to produce larger, heavier bundles than bundling machinery intended for in-field use (mean length, diameter and raw bulk density 4.7 m, 0.8 m and 285 kg m–3, respectively, with 299–445 kg oven dry matter per bundle). The machine was also at least 30% more productive than previously described in-field bundling systems, producing 14–19 bundles per productive work hour (PWh), equivalent to 5.2–7.8 oven-dry tonnes PWh–1. Bundles were estimated to use 67–86% of an LR truck’s 30 tonnes load capacity, similar to proportions used when transporting loose LR. However, a continuous feeding and compressing process would probably almost double productivity, while longer bundles would enable full use of truck load capacity. With such improvements bundling at road-side could provide a viable alternative to current LR-recovering systems.
  • Lindroos, Department of Forest Resource Management, Swedish University of Agricultural Sciences, Umeå, Sweden ORCID ID:E-mail: ola.lindroos@srh.slu.se (email)
  • Matisons, Department of Forest Resource Management, Swedish University of Agricultural Sciences, Umeå, Sweden ORCID ID:E-mail:
  • Johansson, Sveaskog Förvaltnings AB, Vindeln, Sweden ORCID ID:E-mail:
  • Nordfjell, Department of Forest Resource Management, Swedish University of Agricultural Sciences, Umeå, Sweden ORCID ID:E-mail:
article id 311, category Research note
Dan Bergström, Urban Bergsten, Tomas Nordfjell, Tomas Lundmark. (2007). Simulation of geometric thinning systems and their time requirements for young forests. Silva Fennica vol. 41 no. 1 article id 311. https://doi.org/10.14214/sf.311
In Fennoscandia, large areas that have not been subjected to pre-commercial thinning (PCT), and thus support dense stands, are becoming suitable for harvesting biomass. However, efficient systems for harvesting biomass from young stands have not yet been developed. In order to optimise biomass harvesting it is here hypothesized that the handling unit should not be a single tree but a corridor area, i.e., all trees in a specific area should be harvested in the same crane movement cycle. Three types of corridor harvesting approaches (using accumulating felling heads for geometric harvesting in two different patterns) were compared in terms of time required to fell a corridor of standardised size. Corridors are defined as strips of harvested areas between conventional strip-roads. Harvests were simulated in two types of stands, first thinning (FT) and delayed PCT stands, in which the spatial positions of the trees had been mapped. The differences in simulated time consumption per corridor were minor when the only variable changed was the corridor pattern. However, there were ca. 2-fold and 3-fold differences in simulated time consumption per corridor between the harvesting approaches for the FT stand and the PCT-stand, respectively. Furthermore, area handling (felling head accumulating all trees corridor-wise, with no restrictions on the accumulated number of trees except for a certain load limit) was found to give up to 2.4-fold increases in productivity compared to a single-tree (reference) approach for the FT stand. In conclusion, the simulation results clearly show the benefits of applying area-harvesting systems in young, dense stands.
  • Bergström, SLU, Dept. of Forest Resource Management, SE-901 83 Umeå, Sweden ORCID ID:E-mail:
  • Bergsten, SLU, Dept. of Forest Ecology and Management, SE-901 83 Umeå, Sweden ORCID ID:E-mail:
  • Nordfjell, SLU, Dept. of Forest Resource Management, SE-901 83 Umeå, Sweden ORCID ID:E-mail:
  • Lundmark, SLU, Vindeln Experimental Forests, Svartberget Field Station, SE-922 91 Vindeln, Sweden ORCID ID:E-mail:

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