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- Ostensvik, Tove, et al.
(author)
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Work exposure and complaints in a sample of French and Norwegian forest machine operators. A comparative field study within the ErgoWood programme.
- 2005
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Reports (other academic/artistic)abstract
- The aim of the present work is to evaluate muscle activity pattern, psychosocial working conditions and self-reported complaints of fatigue and pain in the neck, shoulders and forearms in two samples of forest machine operators driving harvesters in France and Norway. The EMG readings from four muscle groups were analysed in predetermined periods of sustained low level muscle activity (SULMA), ranging from 1.2-5 seconds up to > 20 minutes. The main result was the similarity between operators of the two different countries. Tendencies were found for higher static muscle activity and less muscular relaxation in all evaluated muscles in the French operators, but significant only for the right trapezius muscle. However, the level of muscular complaints was significantly higher among the Norwegian operators. The amount of both short and long SULMA was not significantly higher in the Norwegian group for the right side. This indicates that the amount of low-level muscle activity could be of higher importance than the gaps, or that the gaps are too short to have effect in reducing risk for discomfort or pain. The results indicate that the introduction of the SULMA concept may be of importance as a method for MSD risk assessment. Future work should concentrate on exploring the best linkage between SULMA and muscular complaints.
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| 2. |
- Dahlström, Niklas, et al.
(author)
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Long-term dynamics of large woody debris in a managed boreal forest stream.
- 2005
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In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 210:1-3, s. 363-373
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Journal article (peer-reviewed)abstract
- Little is known about how past forest management in Sweden influenced the quantity and quality of large woody debris (LWD) in streams. The present study provides information of the long-term dynamics of LWD in a reach of a boreal stream intersecting a managed forest. Dendrochronological methods were used to reconstruct mortality years of the pieces of LWD and the general history of fire and cuttings of the surrounding riparian forest. Today, spruce dominates among the living trees, whereas the LWD is dominated by birch in the forest and by pine in the stream. Fire frequency prior to active fire suppression was similar to values reported from boreal forests. Pine trees were more abundant in the riparian forest before selective logging operations and active fire suppression began in the 1800s. Many of the pieces of LWD found in the stream today died more than 200 years ago and derived from a cohort of pines that generated in the early 1600s. Pine LWD in stream channels is highly resistant to decomposition and can reside for more than 300 years. A substantial amount of the LWD found today in managed forest streams in boreal Sweden most likely derives from the time before extensive human influence and is likely to decrease further in the future. Management of riparian forests to ascertain future supply of long-lived LWD in streams should target to increase the proportion of pine trees.
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| 3. |
- Nordin, Annika, et al.
(author)
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Nitrogen deposition and the biodiversity of boreal forests : implications for the nitrogen critical load.
- 2005
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In: Ambio. - : Royal Swedish Academy of Science. - 0044-7447 .- 1654-7209. ; 34:1, s. 20-24
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Journal article (peer-reviewed)abstract
- The critical load concept is used to establish the deposition levels which ecosystems can tolerate without significant harmful effects. Here we summarize work within the Swedish research program Abatement Strategies for Transboundary Air Pollution (ASTA) assessing the critical load of N for boreal forests. Results from both field experiments in an area with low background N deposition in northern Sweden, and from a large-scale monitoring study, show that important vegetational changes start to take place when adding low N doses and that recovery of the vegetation after ceasing N input is a very slow process. The data presented indicate that changes in key ecosystem components occur even at a lower rate of N input than the present recommended empirical critical load for boreal forest understorey vegetation of 10-15 kg N ha-1 yr-1. Based on the data presented, we suggest that the critical load should be lowered to 6 kg N ha-1 yr-1.
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| 10. |
- Olofsson, Erika, et al.
(author)
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Decision support for identifying spruce forest stand edges with high probability of wind damage
- 2005
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In: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 207:1-2, s. 87-98
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Journal article (peer-reviewed)abstract
- In multiple-purpose forestry, windstorms affect both the ecological and economic values that forest stands represent. Silvicultural treatments and forest planning can reduce the probability of wind damage. A tool for the identification of spruce stands with a high probability of wind damage, aimed at helping forestry practitioners target such measures, is presented. Initial assessments of the annual probability of wind damage of exposed stand edges were made for a landscape of about 1200 ha in southern Sweden, using the WINDA system of models. In the calculations, each edge was classified as having either a high or a low annual probability of wind damage. Decision tree methodology using easily accessible variables was employed for identifying the edges classified as having a high probability of wind damage. Since in a multiple-use situation, the risk preferences of decision makers differ, one decision tree was constructed for each of three threshold probabilities of wind damage: 5, 10, and 20%. This corresponds to disturbance intervals of 20, 10, and 5 years or less in each case. The decision trees were found to correctly classify 64–71% of the high-probability stand edges, the misclassification rate for the low-probability stand edges being 12–26%. Alternative cost-matrices were used to take account of user-preferences regarding misclassification rates in the model output. Among the most important predictor variables used in the decision trees were stem taper, gap size in front of the stand edge, and the direction of wind exposure. In an evaluation landscape located 250 km from the parameterization landscape, the decision trees were found to correctly classify 44–50% and 0–83% of the high-probability stand edges with and without use of cost-matrices, respectively. For the evaluation landscape, a statistically significant difference between classifications produced by the decision tree approach and a set of randomly classified stand edges was obtained just for four of the decision trees. This result was explained in terms of the high degree of complexity of the underlying processes, limitations in the parameterization data set, and differences between the landscapes involved. Decision trees of the type described can thus provide help in practical forestry within and nearby the landscape used for constructing the decision trees. In general, the presented methodology appears to be suitable for developing management decision support tools.
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