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A Pilot Study to Develop Guidelines for Reducing Tree Planter Injuries
RS2003/04-DG10
Final Report Date: March 2006
| Principal Investigator: | Ernst Stjernberg (Forest Engineering Research Institute of Canada) | |
| Co-investigators: |
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For more information about this project, please contact Ernst Stjernberg.
Issue
Musculoskeletal injuries (MSIs) are common in tree planting, which exposes workers to risk factors such as repetitive movements, high physical workload, and less than optimal tool and equipment design. In order to address this problem effectively, a rigorous evaluation of these risk factors is needed, as well as an understanding of how they are affected by different tree planting techniques and equipment.
This was a pilot study to prepare for a larger study and the development of MSI prevention guidelines for tree planting. Researchers gathered baseline data and developed measurement techniques for studying tree planter postures, muscle exertions and issues with tools such as vibration and shock.
Key findings
- Awkward postures were observed when opening planting holes, taking seedlings out of the bag, and inserting seedlings into the soil.
- The fit of tools was not optimal. Shovels lengths varied greatly and bags of seedlings were heavier than recommended.
- An anti-vibration glove was found to be ineffective in protecting against the repeated shocks at the tree planter’s hand during use of planting tools such as shovels.
Objectives
- To analyze tree planting tasks that involve muscle stress.
- To compare the fit of tree planting equipment with ergonomic guidelines.
- To test measurement and evaluation techniques that can be used in a larger study of MSIs risk factors and prevention in tree planting.
- To collect baseline data for future research.
Method
The study was designed in three parts: a task analysis, assessment of forearm muscle activities during planting, and development of methods for evaluating shock and vibration during use of planting tools.
For the task analysis, 16 volunteers from a crew of tree planters were interviewed and their equipment was measured. Each participant was then videotaped for one hour while planting trees. Tree planters’ postures and movements were analyzed, and the effect of shovel style and length on postures was assessed.
The assessment of forearm muscle activities during planting was conducted using electromyography (EMG). For five tree planters, muscles were wired for EMG in each arm, and measurements were taken over a period of approximately 45 minutes. Results were recorded and analyzed.
To develop and test techniques for the evaluation of shocks and vibrations in a planting tool, a series of pilot studies was conducted. Researchers first developed a data collection and analysis system for assessing the shocks to the tree planter’s hand when a shovel is used. This system was then tested under simulated field conditions, involving two different types of shovels, and two different conditions – with and without anti-vibration gloves.
Results
- Awkward postures were observed when opening planting holes, taking seedlings out of the bag, and inserting seedlings into the soil as follows:
- 43 percent of shoulder abductions, 27 percent of shoulder flexions and 39 percent of trunk flexions during shoveling.
- 29 percent of wrist postures and 44 percent of shoulder abductions when taking seedlings out of the bag.
- The weight of full bags of seedlings range from 13 to 24 kilograms, which is heavier than the previously recommended range of 10 to 15 kilograms.
- Methods for measuring shock and vibration in tree planting tools were developed.
- An anti-vibration glove was found to be ineffective in reducing peak acceleration at the hand during use of planting tools.
Conclusions
The number of awkward postures in all joint positions observed in this study reinforces the need for guidelines to avoid or reduce them. The methods developed and tested in the study worked well and with some adjustments are suitable for the large scale study that is planned.
The pilot studies of vibration and shock showed the newly developed measurement and analysis techniques to be effective for assessing shocks occurring at the hand of tree planters, although further validation is needed. The pilot studies also found that an anti-vibration glove did not provide effective protection during use of tree planting tools.
Future directions
The field work for the main study was completed in 2005-2006 and the resulting guidelines to reduce tree planting injuries will be published by the Forest Engineering Research Institute of Canada (FERIC) in early 2007. The richly illustrated guidelines show how to plant safely while using ergonomically correct equipment. If followed, it is expected that tree planters will have fewer MSI injuries and be more productive, thus reducing costs.