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Articles by Juho Rantala

Category: Research article

article id 982, category Research article
Karri Uotila, Timo Saksa, Juho Rantala, Nuutti Kiljunen. (2014). Labour consumption models applied to motor-manual pre-commercial thinning in Finland. Silva Fennica vol. 48 no. 2 article id 982. https://doi.org/10.14214/sf.982
Highlights: When a young stand grows and gets older, the work time needed to make pre-commercial thinning increases. The stands of Norway spruce (Picea abies (L.) Karst.), Scots pine (Pinus sylvestris L.) and hardwoods (Betula spp.) required an additional 8.2%, 5.2%, and 3.3% work-time per year, respectively.
Labour models were developed to estimate the time required to Pre-Commercially Thin (PCT) with a clearing saw 4- to 20-year-old stands of the main commercial tree species in Finland. Labour (i.e., work-time consumption) was estimated from the density and stem diameter of the removal of 448 stands via an existing work productivity function. The removal based estimator attained was used as the basis for a priori mixed linear regression models. The main finding was that when a young stand grows and gets older, the work time needed to make a PCT increases. The stands of Norway spruce (Picea abies (L.) Karst.), Scots pine (Pinus sylvestris L.) and hardwoods (Betula spp.) required an additional 8.2%, 5.2%, and 3.3% work-time per year, respectively. Site fertility also played a role in that the most fertile site (mesic OMT) had an estimated labour requirement 114% higher than that for dryish VT. We also note that, per unit area, small stands require less labour than large ones and soil preparation method had a minor effect on the labour estimate. The stands which had previously gone through PCT were separately analysed. In those stands, the only significant variable concerning the labour estimate was age. The a priori models described here can help foresters to develop economic management programmes and issue quotes for forestry services.
  • Uotila, Finnish Forest Research Institute, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: karri.uotila@metla.fi (email)
  • Saksa, Finnish Forest Research Institute, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: timo.saksa@metla.fi
  • Rantala, Metsä Group, Lielahdenkatu 10, FI-33400 Tampere, Finland ORCID ID:E-mail: juho.rantala@metsagroup.com
  • Kiljunen, Metsähallitus, Asemakatu 7, FI-70107 Kuopio, Finland ORCID ID:E-mail: nuutti.kiljunen@metsa.fi
article id 919, category Research article
Karri Uotila, Juho Rantala, Timo Saksa. (2012). Estimating the need for early cleaning in Norway spruce plantations in Finland. Silva Fennica vol. 46 no. 5 article id 919. https://doi.org/10.14214/sf.919
Effective management of Norway spruce (Picea abies (L.) Karst.) plantations requires detailed information on stand development, which is costly to measure. However, estimating the need for early stand management from site attributes that persists stabile after ones measured, may provide an inexpensive alternative. This study compared hardwood competition in spruce plantations of varying ages and tested the usability of this information in estimating the need for early cleaning. The data included 197 spruce plantations (4–7 years old) inventoried in southern Finland in 2007. The level (Low, Substantial, High) of need for early cleaning was subjectively determined by contrasting location and size of competing hardwoods to a conifer crop tree. Then the stage of the need for early cleaning was modelled according to site and stand attributes. Nearly 60% of the conifer crop trees in the plantations were subjectively judged to require early cleaning (Substantial 37.2%, High 21.2%), but only 10 per cent of the evaluated area was cleaned. Need for cleaning was intense on peatlands or damp soils, whereas it was mild on unprepared soils or cleaned sites. Traditional site characteristics used in forest management planning can be useful for recognising the peripheral cases, where need for cleaning is probably high or low. However, on a typical mineral soil plantation (uncleaned, soil prepared) the model indicates the differences in the need for early cleaning weakly. The need for early cleaning was already high in 4-year-old plantations, why stand age did not have significant effect on development of the need. Thus, the timing of an operation can not be predicted with the model. Nonetheless, early cleaning very likely opens growth space of crop trees in a 4–7-year-old spruce plantation. Therefore, from an aspect of crop growth, an uncleaned Norway spruce plantation in this age group is quite consistently worth cleaning.
  • Uotila, Finnish Forest Research Institute, Suonenjoki Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: karri.uotila@metla.fi (email)
  • Rantala, Metsä Group, Tampere, Finland ORCID ID:E-mail: juho.rantala@metsagroup.com
  • Saksa, Finnish Forest Research Institute, Suonenjoki Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: timo.saksa@metla.fi
article id 912, category Research article
Heidi Hallongren, Juho Rantala. (2012). Commercialisation and international market potential of Finnish silvicultural machines. Silva Fennica vol. 46 no. 4 article id 912. https://doi.org/10.14214/sf.912
Recently, the need to mechanise silvicultural operations has increased in the Nordic countries. While several new machine concepts have been developed, the manufacture of silvicultural devices remains at the market introduction stage. Information is required in support of existing and forthcoming Finnish small-scale producers of silvicultural devices, who wish to commercialise and further market their innovations in domestic and export markets. The aim of this study was to identify the opportunities, challenges and market potential of business activities that develop in connection with device or machine production. Small-scale Finnish manufacturers of silvicultural devices, Finnish large-scale harvester manufacturers and international silvicultural experts participated in the study. The results show that participant groups have varying opinions of cooperation methods and export activities, as well as of the export markets with the best potential. According to international silvicultural experts, mechanised planting and pre-commercial thinning have the greatest potential worldwide. However, demand for mechanised pre-commercial thinning and planting has been mainly confined to the Nordic countries. For a foreign firm marketing a new silvicultural machine concept, the most important customers and cooperation partners are locally operating forest firms, machine contractors and research organisations. The results of the study provide a useful overview of the current state of silvicultural device manufacturing in Finland.
  • Hallongren, Finnish Forest Research Institute, Suonenjoki Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: heidi.hallongren@metla.fi (email)
  • Rantala, Metsä Group, Tampere, Finland ORCID ID:E-mail: juho.rantala@metsagroup.com
article id 125, category Research article
Juho Rantala, Tiina Laine. (2010). Productivity of the M-Planter tree-planting device in practice. Silva Fennica vol. 44 no. 5 article id 125. https://doi.org/10.14214/sf.125
Need to mechanise tree-planting work have recently increased for many reasons. The newest planting and soil scarification device performing work in Nordic forests is the Finnish M-Planter. This study aims to clarify M-Planter’s productivity in practice and show how various factors affect it. The follow-up data set covers 607 work shifts, of 13 operators with, in total, five M-Planters. The average productivity figures for the operators were 143 and 169 seedlings per effective working hour during the first and second planting season, respectively. Overall, the measured average productivity was 34.2% lower than that observed in an earlier work study of the M-Planter based on an experimental study design. On average, the operators learned to use the combination of the M-Planter and a base machine more efficiently while their experience in using it increased during the follow-up. Increasing number of stones and stumps as well as a thicker humus layer decreased productivity of the M-Planter. The study concludes that utilisation of the full productivity potential of the M-Planter requires not only good operators but also development of the whole planting service supply chain.
  • Rantala, Finnish Forest Research Institute, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: juho.rantala@metla.fi (email)
  • Laine, Finnish Forest Research Institute, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
article id 146, category Research article
Karri Uotila, Juho Rantala, Timo Saksa, Pertti Harstela. (2010). Effect of soil preparation method on economic result of Norway spruce regeneration chain. Silva Fennica vol. 44 no. 3 article id 146. https://doi.org/10.14214/sf.146
Economic result of forest regeneration chains, based either on spot mounding or on disc trenching and planting of Norway spruce (Picea abies [L.] Karst.) seedlings, were clarified and compared to each other. First, effects of soil preparation method on early development of Norway spruce stands were measured from field experiments. Second, the effects of soil preparation method on stand level management programs were modelled. The modelling was based on growth simulation and investment calculations. The soil preparation methods substantially affected early development of a stand. The density of the removed trees in early cleaning was 56% higher on the disc-trenched area compared to the spot-mounded area. The difference was especially high (120%), close by (< 25 cm) the remained spruce seedlings. There was also a difference between the methods in the growth of crop spruces; at biological age of 8 years, the mean height of spruce was 110 cm on the spot-mounded area and 68 cm on the disc-trenched area. The differences led to divergent management programs between the areas. The disc-trenched area needed three young stand management operations whereas two was enough at the spot-mounded area. Although disc trenching is a less expensive method than spot mounding, the total management costs were higher in disc trenching than in spot mounding. Furthermore, incomes from the first commercial thinning were higher when regeneration based on spot mounding. At the interest rate of 3%, the investment in spot mounding had 329 EUR ha–1 higher net present value than the investment in disc trenching.
  • Uotila, Finnish Forest Research Institute, Suonenjoki, Finland ORCID ID:E-mail: karri.uotila@metla.fi (email)
  • Rantala, Finnish Forest Research Institute, Suonenjoki, Finland ORCID ID:E-mail:
  • Saksa, Finnish Forest Research Institute, Suonenjoki, Finland ORCID ID:E-mail:
  • Harstela, Finnish Forest Research Institute, Suonenjoki, Finland ORCID ID:E-mail:
article id 186, category Research article
Juho Rantala, Pertti Harstela, Veli-Matti Saarinen, Leo Tervo. (2009). A techno-economic evaluation of Bracke and M-planter tree planting devices. Silva Fennica vol. 43 no. 4 article id 186. https://doi.org/10.14214/sf.186
Techno-economically reasonable mechanization of tree planting has proved to be a difficult task in the Nordic working conditions. Although planting machines and combinations of base machine and planting device have been developed since the 1970s, mechanized planting has not been cost-competitive to manual planting. The aim of this study was to find out work time distributions, productivities, costs and effects of different work difficulty factors on productivities and costs of the state-of-the-art Nordic planting devices, Swedish Bracke and Finnish M-Planter, and to compare the devices with each other. The theory of comparative time studies was the base for the experimental design of this study. In the average working conditions, productivity (E15) of M-Planter (236 seedlings/hour) was 36.0% higher than that of Bracke (174 seedlings/hour). Here, M-Planter performed planting work 23.4% cheaper than Bracke. However, the difference depended greatly on the working conditions; the more stones or stumps the smaller the difference, and the more slash the bigger the difference.
  • Rantala, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: juho.rantala@metla.fi (email)
  • Harstela, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
  • Saarinen, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
  • Tervo, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
article id 429, category Research article
Juho Rantala. (2004). Optimizing the supply chain strategy of a multi-unit Finnish nursery company. Silva Fennica vol. 38 no. 2 article id 429. https://doi.org/10.14214/sf.429
This paper introduces a capacitated mixed integer programming (CMIP) model for solving an integrated production-distribution system design problem (PDSDP) in the seedling supply chain management (SCM) of a multi-unit Finnish nursery company. The model was originally developed from a strategic perspective in which a company desires to evaluate the expansion or closure of its facilities. Nevertheless, the model is also used for solving operational and tactical level problems by applying applicable constraints. The data were collected from the company studied. The results proved that economies of scale could be exploited in seedling production more than the company does today; Compared to the company’s current supply chain strategy with 5 nursery units producing seedlings, when other supply chain strategies were applied the number of nursery units decreased by 2–4 units, and cost savings in the supply chain varied from 11.3% to 21.3%.
  • Rantala, Finnish Forest Research Institute, Suonenjoki Research Station, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: juho.rantala@metla.fi (email)
article id 515, category Research article
Juho Rantala, Kari Väätäinen, Nuutti Kiljunen, Pertti Harstela. (2003). Economic evaluation of container seedling packing and disinfection machinery. Silva Fennica vol. 37 no. 1 article id 515. https://doi.org/10.14214/sf.515
Productivity and costs of packing container seedlings were studied in a mechanised line for packing and disinfecting seedling trays. The hypothesis was that adequate cost-efficiency could be achieved when some common principles of mechanisation were applied. Results indicated that the unit costs are lower than those of manual packing, if these principles were applied and the annual number of packed seedlings exceeded 6 million. However, most of the nurseries in Finland are still too small to gain a real advantage from large-scale production.
  • Rantala, Finnish Forest Research Institute, Suonenjoki Research Station, FIN-77600 Suonenjoki, Finland ORCID ID:E-mail: juho.rantala@metla.fi (email)
  • Väätäinen, Finnish Forest Research Institute, Joensuu Research Centre, FIN-80101 Joensuu, Finland ORCID ID:E-mail:
  • Kiljunen, Finnish Forest Research Institute, Suonenjoki Research Station, FIN-77600 Suonenjoki, Finland ORCID ID:E-mail:
  • Harstela, Finnish Forest Research Institute, Suonenjoki Research Station, FIN-77600 Suonenjoki, Finland ORCID ID:E-mail:

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