Assessing the Guidelines for Pre-Harvest Clearing Operations of Understory in First Thinnings: Preliminary Results from Stora Enso in Finland
Abstract
The objective of this study was to analyze forest industry professionals’ opinions of the utility of pre-clearance work prior to the first-thinning operations. A total of 153 interviews were conducted with three groups of professionals (forest machine entrepreneurs, harvester operators and logging officers) with a response rate of 80%. In general, the respondents agreed that the occurrence of understory would hinder the cutting work if the softwood tree understory density exceeded 1,152 trees/ha and a height of 1.42 m. The corresponding values for broadleaved trees were 1,669 trees/ha and a height of 1.86 m. The respondents stated that trees eligible for logging should be pre-cleared within a circular area with a mean radius of 1.24 m, and the stump height of cleared trees should not exceed 10.8 cm. In intermediate areas (i.e., outside of the circular areas) understory trees exceeding a height of 1.96 m should be pre-cleared. Pre-harvest clearing should be conducted, on average, 9.2 months prior to the logging operation. The results indicated significant differences between the opinions of the respondents concerning the understory density, the height that would hinder cutting and the most convenient pre-harvest clearing method. As a result of this research, pre-clearance guidelines, based on the best-practice knowledge of the professionals, was launched at Stora Enso company in Finland. Because the study results were based on subjective knowledge, they should be validated by long-term empirical data collection and continuing analysis of the effect of understory trees on the efficiency of a forest machine operator.
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References
- Äijälä, O., Koistinen, A., Sved, J., Vanhatalo, K., Väisänen, P. (Eds.), 2019. Metsänhoidon suositukset (Recommendations of good silviculture). Tapion julkaisuja. 252 p.
- Bergström, D., Di Fulvio, F., Nuutinen, Y., 2016. Effect of Forest Structure on Operational Efficiency of a Bundle-Harvester System in Early Thinnings. Croatian Journal of Forest Engineering, 37(1):37-49.
- Dehlén, J., 2010. Mindre studie av en ny gallringsmetod i stamtät förstagallring av gran i södra Sverige (A brief study of a new thinning method in dense first-thinning of spruce in southern Sweden). Sveriges lantbruksuniversitet, Skogshushållning, Examens-arbete 12. 49 p.
- Eriksson, A., Lindberg, A., 2010. Förröjning i förstagallring - vad kostar det och följer utförarna instruktionerna (Cleaning understorey trees in first thinning - what is the cost and do the contractors follow their directive)? Sveriges lantbruksuniversitet, Skogshushållning, Examensarbete 18. 45 p.
- Finnish Forest Centre. 2019. Korjuujäljen tarkastusten tulokset vuodelta 2018 (Harvesting quality in thinning stands in Finland, 2018). https://www.metsakeskus.fi/sites/default/files/tiedote-liite-korjuujalki-tarkastukset.pdf (Accessed: 21 September 2019).
- Frank, N., 2006. Underröjning i förstagallring (Cleaning of understorey trees before thinning). Sveriges lantbruksuniversitet, Institutionen för skogens produkter och marknader, Examensarbeten 64. 9 p.
- Haavikko, H., Kärhä, K., Hourula, M., Palander, T., 2019. Attitudes of Small and Medium-Sized Enterprises towards Energy Efficiency in Wood Procurement: A Case Study of Stora Enso in Finland. Croatian Journal of Forest Engineering, 40(1):107-123.
- Hakkuukonetyömaan ennakkoraivaus (Pre-clearance of mechanized harvesting site). 2001. Metsätehon opas. 7 p.
- Heikkinen, A., 2012. Ennakkoraivaustarpeiden määrittä-minen ensiharvennuskohteilla Metsähallituksen Kuh-mon metsätiimissä (Determining of pre-clearing needs at first thinning sites in Metsähallitus forestry team of Kuhmo). Bachelor’s Thesis. North Karelia University of Applied Sciences. 45 p.
- Hjelmqvist, R., 2016. Jämförelse av produktivitet och kostnader för drivningsarbetet vid två olika förröjningsnivåer i första gallring av konfliktbestånd (Comparison of productivity and costs for harvesting and forwarding at two different preclearance levels in first thinning of conflict stands). Sveriges lantbruks-universitet, Institutionen för Skogens Biomaterial och Teknologi, Arbetsrapport 17. 37 p.
