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Articles containing the keyword 'limit value'.

Category: Research article

article id 984, category Research article
Christian Rottensteiner, Petros Tsioras, Heinz Neumayer, Karl Stampfer. (2013). Vibration and noise assessment of tractor-trailer and truck-mounted chippers. Silva Fennica vol. 47 no. 5 article id 984. https://doi.org/10.14214/sf.984
Highlights: Truck-mounted chippers were associated with higher vibration values, while tractor-trailer chippers had higher noise level; Chipping hardwood produced higher vibration magnitudes than softwood; Vibration and noise values in most cases did not exceed the exposure limit values set by the European Union.
During chipping, machine operators are exposed to whole-body vibration and noise bearing a risk to health. Vibration on the operator’s seat and noise inside the chipper cab was measured and analyzed. The factorial design considered two setup variants (tractor-trailer and truck-mounted) of two chipper models from different manufacturers during chipping of softwood and hardwood tree species. Furthermore, exposure to noise was measured during chipping of hardwood. Vibration and noise during chipping, driving between wood piles, and operational delays were measured separately. The results associated truck-mounted chippers with higher vibration values and tractor-trailer chippers with higher noise levels. The highest vibration levels were recorded while driving on the forest road from one log pile to another and the second highest during chipping. On the contrary, the lowest vibration levels were measured during operational delays with the chipper in idling condition. Chipping hardwood produced higher vibration magnitudes than softwood. Exposure to noise was significantly higher during chipping compared to driving and operational delays. Vibration and noise data were combined with time studies data, for the calculation of eight-hour energy equivalent total values, both for vibration and noise. In all cases, the exposure limit values set by the European Union were not exceeded, with the exception of truck-mounted chippers, which are likely to exceed the exposure action value for vibration.
  • Rottensteiner, University of Natural Resources and Life Sciences Vienna, Institute of Forest Engineering, Peter Jordan Straße 82, 1190 Wien, Austria ORCID ID:E-mail: christian.rottensteiner@boku.ac.at (email)
  • Tsioras, Aristotle University, P.O. Box 227, GR-541 24 Thessaloniki, Greece ORCID ID:E-mail: ptsioras@for.auth.gr
  • Neumayer, Specialist in Occupational Medicine, Wörndlestraße 10, 6020 Innsbruck, Austria ORCID ID:E-mail: heinz.neumayer@die-arbeitsmedizin.at
  • Stampfer, University of Natural Resources and Life Sciences Vienna, Institute of Forest Engineering, Peter Jordan Straße 82, 1190 Wien, Austria ORCID ID:E-mail: karl.stampfer@boku.ac.at

Category: Special section

article id 288, category Special section
Björn Berg, Per Gundersen, Cecilia Akselsson, Maj-Britt Johansson, Åke Nilsson, Lars Vesterdal. (2007). Carbon sequestration rates in Swedish forest soils – a comparison of three approaches. Silva Fennica vol. 41 no. 3 article id 288. https://doi.org/10.14214/sf.288

Carbon sequestration rates in forest soil can be estimated using the concept of calculable stable remains in decomposing litter. In a case study of Swedish forest land we estimated C-sequestration rates for the two dominant tree species in the forest floor on top of the mineral soil. Carbon sequestration rates were upscaled to the forested land of Sweden with 23 x 106 ha with Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (Karst.) L.). Two different theoretical approaches, based on limit-value for litter decomposition and N-balance for vegetation and SOM gave rates of the same magnitude. For the upscaling, using these methods, 17 000 grids of 5 x 5 km were used.

The ‘limit-value approach’ gave a sequestration of 4.8   106 tons of C, annually sequestered in the forest floor, with an average of 180 kg C ha–1 yr–1 and a range from 40 to 410 kg C ha–1 yr–1. The ‘N-balance approach’ gave an average value of c. 96 kg ha–1 yr–1 and a range from –60 to 360 kg ha–1 yr–1. A method based on direct measurements of changes in humus depth over 40 years, combined with C analyses gave an average rate that was not very different from the calculated rates, viz. c. 180 kg ha–1 yr–1 and a range from –20 to 730 kg ha–1 yr–1. These values agree with forest floor C sequestration rate based on e.g. sampling of chronsequences but differ from CO2 balance measurements.

The three approaches showed different patterns over the country and regions with high and low carbon sequestration rates that were not always directly related to climate.

  • Berg, Dept. of Forest Ecology, University of Helsinki, Finland (present address: Dipartimento Biologia Strutturale e Funzionale, Complesso Universitario, Monte S. Angelo, Napoli, Italy ORCID ID:E-mail: bjorn.berg@helsinki.fi (email)
  • Gundersen, Forest & Landscape Denmark, University of Copenhagen, Denmark ORCID ID:E-mail:
  • Akselsson, Swedish Environmental Research Institute, IVL, Gothenburg, Sweden ORCID ID:E-mail:
  • Johansson, Department of Forest Soils, SLU, Uppsala, Sweden ORCID ID:E-mail:
  • Nilsson, Department of Forest Soils, SLU, Uppsala, Sweden ORCID ID:E-mail:
  • Vesterdal, Forest & Landscape Denmark, University of Copenhagen, Denmark ORCID ID:E-mail:

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