1. ASSESSMENT OF WORKERS PHYSICAL WORKLOAD IN SEMI-MECHANIZED SILVICULTURAL OPERATIONS IN MOUNTAINOUS REGIONS, IN BRAZIL 
LABERGO
Ergonomic Laboratory
Research Support Foundation of Minas Gerais State
National Council for Scientific and Technological Development
Id #899
Stanley SCHETTINO, M.S., Work Safety Engineer -
Luciano José MINETTE, M.S., D.S., Associate Professor -
Amaury Paulo de SOUZA, M.S., Ph.D., Full Professor -
Felipe Leitão da Cunha MARZANO, M.S., Work Safety Engineer -
Angelo Casali de MORAES, M.S., Work Safety Engineer -
Introduction 1.
In mountainous regions of Brazil most of the silvicultural operations can only be performed by manual or semi-mechanized methods, presenting a number of ergonomic problems. These may cause damage to the health and welfare of workers, especially due to: high physical workload, high noise and vibration levels, high forces exerted, inappropriate postures and repetitive movements.
Figure 1 - Eucalyptus plantation in mountainous area
Objective 2.
The objective of the study was to evaluate the operators physical workload, during semi-mechanized operations of digging hole and weeds cutting, in eucalyptus plantation areas in mountainous regions.
Methods 3.
The study was carried out in a forest company producing wood for a cellulose industry, in the State of Minas Gerais, Brazil. The company used wood from Eucalyptus plantation, 7 years old, with a yield production of 300 cubic meter per hectare of wood, located in a mountainous regions (Figures 1 and 2). The sampling was performed with 65 forestry workers who performed the activities.
The workers heart rate measurements were carried during the work day for both semi-mechanized operations of digging hole and plantation weeds cleaning (Figures 3 and 4, respectively). These data allowed to calculate the cardiovascular workload (CVW) using an methodology proposed by APUD (1989).
Figure 2 - Young plantations, harvested areas and conservation forests
Results 4.
The semi-mechanized digging hole activity required a high worker physical effort. The average cardiovascular workload was 50%, which was above 40%, the limit recommended by APUD (1989). The operator average heart rate throughout the workday (134 bpm) was greater than the recommended limit of 122 bpm. These results indicated ​​poor working conditions due to excessive use of force, awkward postures, machine vibration and noise, heated environment by the sun, soil compacted and with presence of roots. Despite of the forest worker had already acquired good physically fit, the activity was classified as heavy, with a strong tendency to extremely heavy.
To carry out the activity of semi-mechanized plantation weeds cleaning the workers average cardiovascular load was 35%. This value was below the recommended limit proposed by APUD (1989); even so the work was classified as moderately heavy, since the mean heart rate throughout the workday was 112 bpm.
Discussion 5.
The semi-mechanical digging hole operation required a new work process to fit the job to the workers capacity. These was done by establishing resting pauses, postural working training and by rearrangement of the production target. The semi-mechanized plantation weeds cleaning operation complied with the ergonomic requirements, but it was moderately heavy and needed attention from de company with respect to training and resting pauses. To avoid health damage, accidents, excessive work force, fatigue, absenteeism and incapacity it was recommend that the employer monitored the operations according to the results presented in this study.
Figure 3 - Semi-mechanized digging hole activity
Acknowledgements 6.
This research was partially funded by the CNPq - National Council for Scientific and Technological Development and FAPEMIG - Research Support Foundation of Minas Gerais State. The authors wish to thanks the support and technical assistance provided by the Ergonomic Laboratory Research group at the Forest Engineering Department of the Universidade Federal de Viçosa.
References 7.
Figure 4 - Semi-mechanized weeds cutting activity
APUD, E Guidelines on ergonomics study in forestry. Genebra: ILO.