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

Category: Research article

article id 10161, category Research article
Jussi Manner, Anders Mörk, Martin Englund. (2019). Comparing forwarder boom-control systems based on an automatically recorded follow-up dataset. Silva Fennica vol. 53 no. 2 article id 10161. https://doi.org/10.14214/sf.10161
Highlights: Boom-tip control saves time compared to the conventional system; This study introduced a field-study design enabling establishment of causal relationships during ordinary forwarding operations; Although the study design requires some extra arrangements, it efficiently combines the representativeness of conventional follow-up datasets with establishment of causal relationships that traditionally have been possible only through observational time studies or standardized experiments.

Crane work is the most time-consuming work element in forwarding. Hence, assist systems like boom-tip control are of interest. The first commercially available boom-tip control for forwarders was introduced in 2013. In this study we analysed whether replacing conventional boom control (CBC) with John Deere’s version of boom-tip control (named Intelligent Boom Control, IBC), increases crane-work productivity. We used data automatically gathered from 10 final-felling stands, covering typical logging conditions for southern, central and northern Sweden. Two John Deere 1510E and two John Deere 1910G forwarders were operated by seven experienced operators during the follow-up study, covering 1238 loads in total. A split-plot design was applied to isolate effects of the boom-control system being used (CBC, IBC). We found that using IBC for loading work (crane work and driving included) saved 5.2% of productive machine time compared to using CBC (p ≤ 0.05). The corresponding saving when using IBC for unloading work was 7.9% (p ≤ 0.05). Depending on geophysical factors, this corresponds to approximately 4% savings in productive machine time for forwarding as a whole, including pure transport (with and without load). Moreover, the study introduced in cut-to-length context a novel field-study design to collect a large follow-up dataset in the course of ordinary forwarding operations. We found the study design to be a cost-efficient way to combine the representativeness of conventional follow-up datasets with the ability to establish causal relationships. Establishment of causal relationships has traditionally been possible only through observational time studies or standardized experiments.

  • Manner, The Forestry Research Institute of Sweden (Skogforsk), Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID: http://orcid.org/0000-0002-4982-3855 E-mail: jussi.manner@skogforsk.se (email)
  • Mörk, The Forestry Research Institute of Sweden (Skogforsk), Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail: anders.mork@skogforsk.se
  • Englund, The Forestry Research Institute of Sweden (Skogforsk), Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail: martin.englund@skogforsk.se
article id 1019, category Research article
Michael Henke, Stephan Huckemann, Winfried Kurth, Branislav Sloboda. (2014). Reconstructing leaf growth based on non-destructive digitizing and low-parametric shape evolution for plant modelling over a growth cycle. Silva Fennica vol. 48 no. 2 article id 1019. https://doi.org/10.14214/sf.1019
Highlights: A complete pipeline for plant organ modelling (at the example of poplar leaves) is presented, from non-destructive data acquisition, over automated data extraction, to growth and shape modelling; Leaf contour models are compared; Resulting “organ” modules are ready for use in FSPMs.
A simple and efficient photometric methodology is presented, covering all steps from field data acquisition to binarization and allowing for leaf contour modelling. This method comprises the modelling of area and size (correlated and modelled with a Chapman-Richards growth function, using final length as one parameter), and four shape descriptors, from which the entire contour can be reconstructed rather well using a specific spline methodology. As an improvement of this contour modelling method, a set of parameterized polynomials was used. To model the temporal kinetics of the shape, geodesics in shape spaces were employed. Finally it is shown how this methodology is integrated into the 3D modelling platform GroIMP.
  • Henke, Department Ecoinformatics, Biometrics & Forest Growth, University of Göttingen, 37077 Göttingen, Germany ORCID ID:E-mail: mhenke@uni-goettingen.de (email)
  • Huckemann, Institute of Mathematical Stochastics, University of Göttingen, 37077 Göttingen, Germany ORCID ID:E-mail: huckeman@math.uni-goettingen.de
  • Kurth, Department Ecoinformatics, Biometrics & Forest Growth, University of Göttingen, 37077 Göttingen, Germany ORCID ID:E-mail: wk@informatik.uni-goettingen.de
  • Sloboda, Department Ecoinformatics, Biometrics & Forest Growth, University of Göttingen, 37077 Göttingen, Germany ORCID ID:E-mail: bslobod@web.de
article id 1030, category Research article
Jussi Manner, Tomas Nordfjell, Ola Lindroos. (2013). Effects of the number of assortments and log concentration on time consumption for forwarding. Silva Fennica vol. 47 no. 4 article id 1030. https://doi.org/10.14214/sf.1030
Highlights: We analysed the effects of total and forwarded log concentrations (m3 (100 m)–1) and the number of loaded assortments on forwarding; The combination of the number of loaded assortments and their abundance (i.e. forwarded log concentration) affected time consumption most; This knowledge enables improved efficiency by optimizing number and assortment proportions in the various loads required to forward a stand.
Forwarding has been carried out for 50 years, but much is still unknown about this work. Its complexity comes from both stand features and essential decision-making. Forwarding time consumption is influenced by e.g. log concentrations and number of assortments. Traditionally, focus has been on the total log concentration (TLC), referring to all logs at the harvesting site. However, we focused on forwarded log concentration (FLC), the load-specific log concentration which depends on the assortment distribution at harvesting site and the load-specific number of assortments. To evaluate the effects of TLC, number of assortments in a load and FLC on the loading and unloading times, a standardized field experiment was carried out. Pile and load sizes were constant, while TLC and FLC were manipulated by varying the pile distribution on the test path. For all work elements, the time consumption per m3 was significantly affected by the number of assortments that were loaded, but only the “driving while loading” work element was also significantly influenced by TLC. However, when untangling the intercorrelation between tested factors, it was found that the time consumption for driving while loading significantly decreased as a function of FLC and was unaffected by the number of assortments in a load. That FLC influences the forwarding time consumption highlights the need to study the effects of combining various assortment proportions in a load. Such knowledge will enable analysis of the most efficient number and assortment proportions to combine in the various loads required to forward a given stand.
  • Manner, Swedish University of Agricultural Sciences, Department of Forest Biomaterial and Technology, SE-901 83 Umeå, Sweden ORCID ID:E-mail: jussi.manner@slu.se (email)
  • Nordfjell, Swedish University of Agricultural Sciences, Department of Forest Biomaterial and Technology, SE-901 83 Umeå, Sweden ORCID ID:E-mail: tomas.nordfjell@slu.se
  • Lindroos, Swedish University of Agricultural Sciences, Department of Forest Biomaterial and Technology, SE-901 83 Umeå, Sweden ORCID ID:E-mail: ola.lindroos@slu.se

Category: Research note

article id 1717, category Research note
Jussi Manner, Olle Gelin, Anders Mörk, Martin Englund. (2017). Forwarder crane’s boom tip control system and beginner-level operators. Silva Fennica vol. 51 no. 2 article id 1717. https://doi.org/10.14214/sf.1717
Highlights: Boom tip control (BTC) allows the operator to control boom tip movements directly, instead of controlling each movement separately to achieve the desired boom tip movement; BTC eased boom control, so beginner-level operators using BTC achieved higher productivity than beginner-level operators using a conventional (reference) system; There were no significant differences in the slopes of learning curves between the systems.

The forwarder loads processed wood and transports it to a landing. Productivity of forwarding could be improved by increasing driving speed, but difficult forest terrain limits this. According to current literature, crane work is the most time-consuming work element of forwarding, so improving crane work productivity is essential for improving forwarding productivity. One way to do this is through automation of recurrent boom movement patterns, or alternatively automation can be used to ease crane work. When using conventional boom control (CBC), the operator manually controls each of the independent boom joint movements and combines them to achieve a desired boom tip movement, but boom tip control (BTC) allows the operator to control boom tip movements directly. The objective of the present study was to examine whether BTC facilitates crane work and affects the slopes of learning curves for beginner-level forwarder operators. The study was carried out using a standardised test routine to evaluate effects of two fixed factors, system (levels: CBC, BTC) and point of time (four levels), on five dependent variables. Four of the five dependent variables measured ease of boom control and the fifth measured crane work productivity. The results showed that there were no significant differences in the slopes of learning curves between the systems but the BTC did increase crane work productivity and made boom control easier.

  • Manner, The Forestry Research Institute of Sweden (Skogforsk), Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID: http://orcid.org/0000-0002-4982-3855 E-mail: jussi.manner@skogforsk.se (email)
  • Gelin, The Forestry Research Institute of Sweden (Skogforsk), Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail: olle.gelin@skogforsk.se
  • Mörk, The Forestry Research Institute of Sweden (Skogforsk), Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail: anders.mork@skogforsk.se
  • Englund, The Forestry Research Institute of Sweden (Skogforsk), Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail: martin.englund@skogforsk.se

Category: Article

article id 7158, category Article
Olavi Huuri. (1965). Männyn- ja kuusenkäpyjen varastoinnin vaikutus niistä saatavan siemenen itävyyteen. Acta Forestalia Fennica vol. 78 no. 5 article id 7158. https://doi.org/10.14214/aff.7158
English title: The effects of storage in cones on the viability of pine and spruce seeds.

Seed storing experiments with cones of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) were conducted in Oitti seed extracting plant in Southern Finland from February to December 1955. The pine cones were stores for 267 and the spruce coned for 304 days. In four of the storage methods the cones were packed in sacks and another four in wooden boxes. Sample of cones were taken once a month, seeds were extracted and the germinative capacity was tested. The remaining extracted seeds were placed in storage, and in January 1956 moved to cold seed cellar until 1962, when the viability of the seeds was tested.

According to the results, cleaned pine cones can be stores for at least nine months using almost all methods of storage which are commonly used at our seed traction plants, without hazarding the usability of the seeds. The seeds in spruce cones, however, seemed to be more sensitive to conditions during the storage. The germinative capacity of the spruce seeds began to decrease after the beginning of May. Later the seeds were infected with mould, which increased towards the end of the experiment.

Thus, preservation of the germinative capacity of the seeds of pine and spruce requires storage in different conditions. The results suggest that extraction of spruce seeds should be finished during the cold winter months. It seems that seed in the cones of pine and spruce endure storage in piles of paper or cloth sacks at least as well as in wooden boxes. Occasional warming of the storage, snow and foreign material among the cones and an over meter thick cone layer decreased the germinative capacity of spruce seeds during spring and summer. Spruce seeds that had been extracted immediately after collecting of the cones preserved their germinative capacity well during an eight years storage period.

The PDF includes a summary in English.

  • Huuri, ORCID ID:E-mail:
article id 7486, category Article
Paavo Yli-Vakkuri. (1959). Siemensiipien hankaajista ja niiden vaikutuksesta siemenen itävyyteen. Acta Forestalia Fennica vol. 68 no. 4 article id 7486. https://doi.org/10.14214/aff.7486
English title: On machines for abrading seed wings and their influence on the germinative capacity of the seed.

This paper deals with two machines designed for abrading seed wings, and their influence on the germinative capacity of seed of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.). Both machines are commonly used in Finland.

The results of the study indicate that the act of abrading may cause slight or even serious injuries to the seed. Slight injuries of about 3% are probably not easily avoided if mechanical abrading is resorted to. It must be noted, however, that even this reduction in germinative capacity causes significant yearly loss. If the reduction in germinative capacity is greater, which seems to be possible, it is advisable to test the mechanism of the machine and its method of abrading. As the clearance of the machines can affect the extent of injuries, all machines should be tested. If possible, a continual operation control should be arranged. It could, at the same time, to supply material for improving the abrading method and equipment.

The PDF includes a summary in English.

  • Yli-Vakkuri, ORCID ID:E-mail:
article id 7367, category Article
Esko Kangas. (1942). Karistuslämmön vaikutuksesta männyn siemenen karisemiseen ja itämiseen. Acta Forestalia Fennica vol. 50 no. 14 article id 7367. https://doi.org/10.14214/aff.7367
English title: Effect of seed extracting temperature on extraction and germination of Scots pine seeds.

Temperatures needed in extracting Scots pine (Pinus sylvestris L.) seeds is relatively high, however, there is little information on its effect on germination of the seeds. This survey aimed at studying how different temperatures affect both extraction result and germination of Scots pine seeds. Comparisons between different temperatures (20, 30, 40, 50, 60 and 70 ºC) were made from cones collected from same sample trees, three trees in total.

Temperatures 20 and 30 ºC resulted in incomplete opening of the cones, and gave thus smaller amount of seeds. Complete extraction requires at the least the temperature of 40 ºC. The result is slightly better in 50 ºC, but germination of the seeds is little lower. Temperatures 60 and 70 ºC improve the results, but in the cost of germination. The main reason for lower germination percentage was that the higher temperatures release more empty and defective seeds from the cones. Results of different sample trees were different due to, for instance, quality and size of cones. Higher temperatures accelerated the extraction. According to the study, perfect extraction in 40 ºC requires longer extraction time than when the temperature of 50 ºC is used. In practice, 50 ºC temperature or even little higher temperatures can be used when the extraction time is shorter. Decessive factors in choosing the temperature would be the humidity of cones and length of extraction time.

The PDF includes a summary in German.

  • Kangas, ORCID ID:E-mail:

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