Processing Small-Sized Trees at Landing by a Double-Grip Machine: A Case Study on Productivity, Cardiovascular Workload and Exposure to Noise

Abstract

To be characterized as sustainable, forest operations need to be studied and validated from many points of view, including their productivity, ergonomics and costs. In most of these areas, performance enhancement was found to be sustained by the development and use of mechanization, including that of landing operations done to process small-sized trees. For these, an affordable and sustainable alternative could be that of using double-grip processors. However, there is a lack of information characterizing their capability and performance, which was one of the main reasons for carrying on this study. Observational data were collected over four operational days for a HYPRO 775 double-grip processor to estimate the productivity, exposure to noise and cardio-vascular workload in processing small-sized trees at landing. Miniaturized dataloggers and video recording were used to document close to 28 h spent at the workplace and 15 h of operation, respectively. A time study was used to estimate the productive performance and the commonly used metrics were computed to evaluate the exposure to noise and cardio-vascular workload. A delay-free work cycle was framed around a processed tree and it took, on average, ca. 45 s. Based on 901 processed trees (average height of ca. 12 m and average breast height diameter of ca. 12 cm), the net productivity rate was estimated at ca. 65 trees per hour (ca. 224 logs of 2.4 m produced per hour). While the cardiovascular activity indicated light work, exposure to noise seems to be a concerning problem to be addressed in the future, given the figures found (A-weighted sound pressure level higher than 85 dB(A) and the sound pressure level normalized for a nominal day of 92.79 dB(A)). This becomes even more important as this study found a machine utilization rate of ca. 60%, therefore an extension of productive time could increase the exposure to noise. We conclude that double-grip processors represent a valuable technical alternative in processing small-sized trees at landing if supplementary precautions would be taken against exposure to noise. These may rest very well in the awareness and behavior of the operators as well as in wearing protective equipment.