Analysis of postural strain of loggers during timber harvesting in a spruce stand

Konrad Sawastian, Witold Grzywiński, Rafał Turowski


Motor-manual felling is the most common way of timber harvesting in Poland. This method of working exposes chainsaw operators to high ergonomic risk factors. One of the most significant of these is forced working postures. Research was carried out on two loggers working in a felling-age spruce stand. Over two consecutive days, video documentation was made, which was then analyzed using a computerized version of the OWAS method – WinOWAS. Based on 874 observations (467 for logger 1 and 407 f or logger 2) the positions occurring were assigned respectively to 40 and 33 different codes. The codes most frequently recorded were 2121, 2131, 4131, 1171, 4121 and 1121. Positions in categories III and IV occupied 32.5% of the working shift in the case of logger 1,and 27.3% in the case of logger 2. Static strain for both loggers was found to be average. The loggers worked most of the time with their backs bent forward. This back position was most common during felling (79.7% for logger 1, 62.6% for logger 2). Working position showed more variation in the case of the legs. Acceptable positions, such as standing on straight legs, accounted for more than 40% of all leg positions.


timber harvesting, chainsaw operator, OWAS method, postural strain

Full Text:



EU-OSHA. 2007. Introduction to work-reletade musculoskeletal disorders. Factsheet 71. European Agency for Safety and Health at Work.

Fibiger W. 1976. Ochrona zdrowia pracowników leśnictwa. PZWL, Warszawa.

Forestry Leśnictwo 2014. (2014). GUS, Warszawa.

Giefing D.F. 1996. Badania procesów technologicznych pozyskiwania drewna. Zast. Ergon. 2-3: 143-147.

Grzywiński W. 2004. Energy load of workers employed at timber harvesting. Electron. J. Pol. Agric. Univ.,Ser. Forestry 7, 2.

Grzywiński W. 2010. Ergonomia i ochrona pracy w leśnictwie. Przewodnik do ćwiczeń. Wyd. UP,Poznań.

Grzywiński W. 2011. The effect of selected factors on the type of working postures of chainsaw operator during felling. Wyd. UP, Poznań.

Grzywiński W., Bujnowska J. 2009. OWAS method application to identifying postural hazard of fellers during timber harvesting in beech stands. W: Formec 2009: 42 International Symposium on Forestry Mechanization. Proc., Kostelec nad Cernymi lesy, 21-24 June, 2009. CULS, Prague, 166-172.

Grzywiński W., Łukaszuk T. 2008. Obciążenie pracą fizyczną w procesie pozyskania drewna. [W:] Paluch R., Jach K., Kuliński M., Michalski R. (red).

Grzywiński W., Sawa L., Nowik A., Nowicki G. 2013.Structure of work accidents in the Regional Directorate of the State Forests in Szczecinek in the years 1990-2009. Sylwan 157 (6): 403-414.

Obciążenia układu ruchu. Przyczyny i skutki. Ofic. Wyd. PWr. Wrocław, 163-173.

Grzywiński W., Tomczak A., Jelonek T., Kupczyk G.,Pazdrowski W. 2005. Effect of working postures Turing tree felling using the chainsaw on the degree of work arduousness and safety. Zesz. Nauk. AR Krak. 419, Ses. Nauk. 91: 319-325.

Hagen K. B. 1990. Biomechanical analysis of spinal load In motor-manual cutting. J. For. Eng. 2 (1): 39-41.

Harstela P. 1990. Work postures and strain of workers in Nordic forest work: A selective review. Int. J. Ind. Ergon. 5 (3): 219-226.

Hagen K. B., Magnus P., Vetlesen K. 1998. Neckshoulder and low-back disorders In the forestry industry: Relationship to work tasks and perceived psychosocial job stress. Ergonomics 41 (10): 1510-1518.

Hignett S., Mcatamney L. 2000. Rapid Entire Body Assessment (REBA). Appl. Ergon. 31 (2): 201-205.

Hildebrandt V. H., Bongers P. M., Van Dijk F. J. H.,Kemper H. C. G., Dul J. 2002. The influence of climatic factors on non-specific back and neckshoulder disease. Ergonomics 41 (1): 32-48.

Jabłoński K. 1996. Analiza wypadkowości w leśnictwie w latach 1990-1994. Zast. Ergon. 2/3: 131-138.

Jaworski J. 2008. Laboratorium Ergonomii. Przewodnik do ćwiczeń. Wyd. UWM, Olsztyn.

Karhu O., Kansi P., Kuorinka I. 1977. Correcting working postures in industry: A practical method for analysis. Appl. Ergon. 8 (4): 199-201.

Leszczyński K. 2006. Wielowymiarowa analiza zagrożeń operatorów pilarek spalinowych. Acta Agr. Silv.,Silvestris 44: 67-77.

Leszczyński K., Jałowska M. 2011. Similarity of the workstations involved in sanitation felling. Sylwan 155 (7): 437-445.

Makowiec-Dąbrowska T. (1999). Fizjologia pracy [W], J. A. Indulski (red.). Higiena pracy. IMP, Łódź, 71-152.

Mcatamney L., Corlett E.N. 1993. RULA: A survey method for the investigations of work-related upper limb disorders. Appl. Ergon. 24 (2): 91-99.

Opis taksacyjny [2007-2016] 2007. Nadleśnictwo Karnieszewice.

Ostrowski G. 2009. Analiza obciążenia fizycznego drwala podczas pozyskania drewna w rębnym drzewostanie bukowym. Master’s thesis, Katedra Użytkowania Lasu, AR Poznań.

Paluch R. 2005. Postawa ciała i przestrzeń pracy. Zast. Ergon. 1-3: 215-225.

Sowa J.M. 1995. Badania nad określeniem modeli funkcji stanu zagrożeń od drgań pilarek spalinowych w procesie pozyskania drewna. Wyd. AR, Kraków.

Sowa J.M. 1998. Analiza zagrożeń wibracyjnych operatorów pilarek spalinowych. Zast. Ergon. 2:189-196.

Stefański B. 2009. Analiza obciążenia fizycznego drwala podczas pozyskania drewna w rębnym drzewostanie sosnowym. Master’s thesis, Katedra Użytkowania Lasu, AR Poznań.

Stempski W. 2008. Worker’s physical load when harvesting logs on clear cuts. Acta Sci. Pol., Silv. Colendar. Rat. Ind. Lignar. 7 (3): 37-45.

Stempski W. 2009. Effect of labour organization on the level of energy expenditure and static loads of a worker in intermediate cutting. Acta Sci. Pol., Silv.Colendar. Rat. Ind. Lignar. 8 (2): 53-60.

Tomczak A., Jelonek T., Grzywiński W. 2012. Pozyskiwanie drewna pilarką. Techniczne, ergonomiczne i organizacyjne aspekty pracy drwala.Ofic. Wyd. G&P, Poznań.

WinOWAS. A computerized system for the analysis of work postures. 1996. © Tampere University of Technology, Occupational Safety Engineering, Tampere, Finland.

Zanuttini R., Cielo P., Poncino D. 2005. Il metodo OWAS. Prime applicazioni nella valutazione del rischio di patologie muscolo-scheletriche nel settore forestale in Italia. Forest@ 2 (2): 242-255.

Ziemann D. 2011. Analiza obciążenia fizycznego drwala podczas pozyskania drewna w rębnym drzewostanie świerkowym. Master’s thesis, Katedra Użytkowania Lasu, UP Poznań.

Forestry Letters  eISSN 2450-4920

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we'll assume that you are happy to receive all cookies from this website. If you would like to change your preferences you may do so by following the instructions here