Length accuracy of logs from birch and aspen harvested in thinning operations
Abstract: Accurate log processing by harvesters during bucking is of great importance if round timber is to be fully exploited for maximum value recovery. Logs that exceed the target length can cause difficulties in further processing (e.g., in the pulp industry), while logs which are too short may not be of further use (e.g., boards for pallets). It can be difficult to achieve accurate log lengths due to irregular tree trunk shapes or errors in the measurement system in the harvester head. The objective of the research was to investigate how tree species and log diameter affect bucking length accuracy. The research was carried out in a premature broadleaved stand of birch and aspen in the third age class in the Zaporowo Forest District, northern Poland (54°24?47?N, 20°8?50?E). The thinning operation was carried out in early spring before the start of the growing season and after the snow cover had melted. Trees were cut using a UTC 150-6LS harvester, equipped with a CTL 40HW harvester head designed for hardwood. Pulp wood was harvested from the trees with an intended length of 2.50 m and a tolerance of ±0.05 m. The on-board harvester computer was set to a length tolerance of between 2.46 m and 2.54 m. More than 80% of the thicker birch and aspen logs (d1/2 > 14 cm) met the target length (2.50 ± 0.05 m), while only 70% and 50% of the thinner birch and aspen logs (d1/2 ≤ 14 cm) reached the target. For top logs, a different length tolerance should be applied compared to butt logs in order to achieve higher efficiency in length accuracy.
Length accuracy of logs from birch and aspen harvested in thinning operations
Abstract: Accurate log processing by harvesters during bucking is of great importance if round timber is to be fully exploited for maximum value recovery. Logs that exceed the target length can cause difficulties in further processing (e.g., in the pulp industry), while logs which are too short may not be of further use (e.g., boards for pallets). It can be difficult to achieve accurate log lengths due to irregular tree trunk shapes or errors in the measurement system in the harvester head. The objective of the research was to investigate how tree species and log diameter affect bucking length accuracy. The research was carried out in a premature broadleaved stand of birch and aspen in the third age class in the Zaporowo Forest District, northern Poland (54°24?47?N, 20°8?50?E). The thinning operation was carried out in early spring before the start of the growing season and after the snow cover had melted. Trees were cut using a UTC 150-6LS harvester, equipped with a CTL 40HW harvester head designed for hardwood. Pulp wood was harvested from the trees with an intended length of 2.50 m and a tolerance of ±0.05 m. The on-board harvester computer was set to a length tolerance of between 2.46 m and 2.54 m. More than 80% of the thicker birch and aspen logs (d1/2 > 14 cm) met the target length (2.50 ± 0.05 m), while only 70% and 50% of the thinner birch and aspen logs (d1/2 ≤ 14 cm) reached the target. For top logs, a different length tolerance should be applied compared to butt logs in order to achieve higher efficiency in length accuracy.
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- Bembenek M, Giefing DF, Karaszewski Z, Szczepańska-Álvarez A, Mederski PS (2013). Strip road impact on selected wood defects of Norway spruce (Picea abies (L.) H. Karst). Drewno 190: 63–76.
- Bembenek M, Mederski PS (2005). Ecological aspects of thinning operations with a harvester in a birch stand. Hum Nat Saf 11: 95–97.
- Cacot E, Bigot M, Cuchet E (2006). Developing full-mechanized harvesting systems for broadleaved trees: a challenge to face the reduction of the manual workforce and to sustain the supply of hardwood industries. In: Proceedings of 29th Council on Forest Engineering (COFE), 22 July–2 August 2006, Coeur d’Alene, ID, USA, p. 9.
- Glöde D (1999). Single- and double-grip harvesters – productive measurements in final cutting of shelterwood. J Forest Eng 2: 63–74.
- Karaszewski Z, Bembenek M, Mederski SP, Szczepańska-Álvarez A, Byczkowski R, Kozłowska A, Michnowicz K, Przytuła W, Giefing DF (2013a). Identifying beech round wood quality – distributions and the influence of defects on grading. Drewno 189: 39–54.
- Karaszewski Z, Giefing DF, Mederski SP, Bembenek M, Dobek A, Stergiadou A (2013b). Stand damage when harvesting timber using a tractor for extraction. For Res Pap 74: 27–34.
- Kraft G (1884). Beiträge zur Lehre von den Durchforstungen, Schlagstellungen und Lichtungshieben. Hannover, Germany: Klindworth’s Verlag (in German).
- Martin P, Lapeyre D, Douchet O, Restoy G, Guegand G (1996). Récolte mécanisée des taillis en bois ronds. Nangis, France: AFOCEL Fiche Information-Forêt (in French).
- Mederski PS (2006). A comparison of harvesting productivity and costs in thinning operations with and without midfield. Forest Ecol Manag 224: 286–296.
- Mederski PS (2013). The potential of harvester use for thinning operations in mixed birch-pine stands. Poznań, Poland: Wyd. UP w Poznaniu (in Polish).
- Mederski PS, Bembenek M, Erler J, Giefing DF (2011). Effects of an innovative thinning operation in a birch stand. Acta Sci Pol Silv Colendar Rat Ind Lignar 10: 29–38.
- Mederski PS, Bembenek M, Jakubowski M, Zinkevius R (2008a). Length accuracy of aspen logs harvested with CTL 40HW harvester head designed for broadleaved species. Hum Nat Saf 14: 241–243.
- Mederski PS, Bembenek M, Mendow N, Jakubowski M, Giefing DF (2008b). Pozyskiwanie buka harwesterem z głowicą do drzew liściastych CTL 40HW. In: Różański H, Jabłoński K, editors. Proceedings of Tendencje i problemy techniki leśnej w warunkach leśnictwa wielofunkcyjnego. Poznań, Poland: Wyd. Kat. Techn. Leśn. UP, pp. 56–62 (in Polish).
- Nieuwenhuis M, Dooley T (2006). The effect of calibration on the accuracy of harvester measurements. Int J Forest Eng 17: 25– 33.
- Różański H (1993). Wydajność i dokładność wyróbki drewna harwesterem wysięgnikowym Lokomo FMG 990/756. Przeg Techn Roln Leśn 10: 18–19 (in Polish).
- Sionneau J, Cuchet E (2001). Mechanisation of thinnings in hardwood, the French experience. In: Proceedings of the IUFRO meeting; Quebec, Canada, p. 8.
- Spinelli R, Magagnoti N, Nati C (2009). Options for the mechanised processing of hardwood trees in Mediterranean forests. Int J Forest Eng 20: 39–44.
- Spinelli R, Owende PMO, Ward SM (2002). Productivity and cost of CTL harvesting of Eucalyptus globulus stands using excavator- based harvesters. Forest Prod J 52: 67–77.
- Stempski W, Grodecki J, Wudarczyk M (2011). Impact of providing access to tree stands by means of a network of roads on the occurrence and size of tree shape defects. Forestry Letters 102: 93–101 (in Polish with abstract in English).
- Zinkevičius R, Steponavičius D, Vitunskas D, Činga G (2012). Comparison of harvester and motor-manual logging in intermediate cuttings of deciduous stands. Turk J Agric For 36: 591–600.