Riku Tarvainen, Kirsi Riekki, Heikki Ovaskainen, Asko Poikela, Kalle Kärhä, Jukka Malinen. (2025). Estimating stand variables in first-thinnings using harvester data. Silva Fennica vol. 59 no. 3 article id 25014. https://doi.org/10.14214/sf.25014

Keywords: forest inventory; diameter distribution; stand variables; harvester data; accurate GNSS positioning; harvesting quality; Reynold’s error index

Highlights: The idea was to identify the trees removed from the strip roads from the harvester data and use them as a sample of the initial growing stock of the first thinning stand; The goal was also to estimate the number of stems, basal area and diameter distribution of the growing stock after thinning; The sampling method based on identifying strip road trees is applicable to monitoring the density of the remaining growing stock at first thinning stands.

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First thinning is an important operation in forest management because it determines the further growth of the whole stand. Harvester operators open strip roads to the thinning stand and select which trees are removed and which are left to grow. Modern cut-to-length harvesters produce precise information about the dimensions and positions of the cut trees. The location of the harvester is already commonly recorded to harvester production (hpr) files, according to the StanForD 2010 standard, and recording the position of the harvester head is also becoming more common. The aim of this study was to develop a method to estimate the stem count and basal area of the remaining growing stock using this novel harvester data. Precision hpr data from Komatsu harvesters and reference field measurements were gathered from seven stands in western Finland in the summer of 2024. In the method used, the strip road trees were identified and used as samples representing the initial growing stock. The remaining growing stock was estimated using diameter distributions, and by subtracting the harvested trees from the initial growing stock. The results were evaluated using Reynold’s error index, in addition to a visual interpretation of the diameter distributions with respect to the reference data. We found that the method had the potential to determine the basal area and diameter distribution of the remaining growing stock. In the future, this method can be automated, which will allow automated reporting and quality management in first-thinning operations.

Tarvainen, Metsäteho Oy, Vernissakatu 1, FI-01300 Vantaa, Finland https://orcid.org/0009-0001-2336-3125 E-mail: riku.tarvainen@metsateho.fi
Riekki, Metsäteho Oy, Vernissakatu 1, FI-01300 Vantaa, Finland https://orcid.org/0009-0007-8366-3297 E-mail: kirsi.riekki@metsateho.fi
Ovaskainen, Metsäteho Oy, Vernissakatu 1, FI-01300 Vantaa, Finland https://orcid.org/0000-0001-5063-6662 E-mail: heikki.ovaskainen@metsateho.fi
Poikela, Metsäteho Oy, Vernissakatu 1, FI-01300 Vantaa, Finland E-mail: asko.poikela@metsateho.fi
Kärhä, University of Eastern Finland, School of Forest Sciences, Faculty of Science, Forestry and Technology, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: kalle.karha@uef.fi
Malinen, Metsäteho Oy, Vernissakatu 1, FI-01300 Vantaa, Finland https://orcid.org/0000-0002-5023-1056 E-mail: jukka.malinen@metsateho.fi

article id 144, category Research article

Markku Oikari, Kalle Kärhä, Teijo Palander, Heikki Pajuoja, Heikki Ovaskainen. (2010). Analyzing the views of wood harvesting professionals related to the approaches for increasing the cost-efficiency of wood harvesting from young stands. Silva Fennica vol. 44 no. 3 article id 144. https://doi.org/10.14214/sf.144

Keywords: cost-efficiency; energy wood; early thinnings; industrial roundwood; costs; gap analysis; opinion survey

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A lot of viable guidelines are currently available for more cost-effective harvesting of energy wood and industrial roundwood (i.e. pulpwood) from young stands. The study ranked the proposed potential approaches for increasing the cost-efficiency of small-diameter (d1.3 < 10 cm) energy wood and industrial roundwood harvesting from early thinnings. Research data, based on a total of 40 personal interviews, was collected in early 2008. The interviewees were divided into four wood harvesting professional groups: 1) Managers in wood procurement organizations, 2) Forest machine contractors, 3) Forest machine manufacturers and vendors, and 4) Wood harvesting researchers. In the opinion of the respondents, there is great potential to increase the cost-efficiency of wood harvesting through improving harvesting conditions (i.e. effective tending of seedling stands, delaying harvesting operations, and pre-clearance of dense undergrowth). The interviewees also underlined that harvesting methods can be rationalized, e.g. multiple-tree handling in industrial roundwood cuttings, crane scale measurement, integrated wood harvesting, and careful selection of stands for harvesting. The strong message given by the interviewees was that the education of forest machine operators must be made more effective in the future. There would be significant possibilities for cost savings in young stands, if methods and techniques with the most potential were utilized completely in wood harvesting.

Oikari, Karelwood, Kontiolahti, Finland E-mail: markku.oikari@karelwood.com
Kärhä, Metsäteho Oy, Helsinki, Finland E-mail: kk@nn.fi
Palander, University of Eastern Finland, Faculty of Science and Forestry, Joensuu, Finland E-mail: tp@nn.fi
Pajuoja, Metsäteho Oy, Helsinki, Finland E-mail: hp@nn.fi
Ovaskainen, University of Eastern Finland, Faculty of Science and Forestry, Joensuu, Finland E-mail: ho@nn.fi

article id 398, category Research article

Heikki Ovaskainen. (2005). Comparison of harvester work in forest and simulator environments. Silva Fennica vol. 39 no. 1 article id 398. https://doi.org/10.14214/sf.398

Keywords: time study; single-grip harvester; harvester simulator; working technique; PlusCan

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Harvester simulators offer a safe and cost-saving method for studying the basics of harvester controls and working technique. Therefore, harvester simulators are increasingly being used in the education of harvester operators. In this study, the objective was to compare harvester work in real and simulator environments, and to determine how a professional harvester operator’s working technique may have changed in the simulator environment. Specific features of the simulator that encumbered operators’ normal work are also presented; and the correspondence of the simulator to reality is evaluated. The work of six professional harvester operators was studied in thinning and in clear cutting stands in both environments: first in the real forest and thereafter on the simulator. The results indicate that the operators’ working technique on the simulator was mainly the same as in the real forest. This means that the same restrictions are valid on the simulator as in the forest. The basic principles of harvesting must be known so that high productivity and good quality can be obtained. However, certain simulator-specific features encumbered the work of harvester operators. Limited visibility to the side increased the need to reverse and the 3D-visualization caused failed catches. Improvements in software would remove some of the defects, e.g. failed felling and cheating in the felling phase. These results also indicate that simulators can be used for research purposes.

Ovaskainen, University of Joensuu, Faculty of Forestry, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: heikki.ovaskainen@joensuu.fi

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