Evaluating ground disturbance at elephant skid trails, logging roads and log landings under the Myanmar selection system

There has been growing interest in the practice of reduced-impact logging (RIL) to enhance various ecological services of selectively logged tropical forests. It is thus important to evaluate the effectiveness of different logging operations between RIL and conventional logging (CON). The Myanmar Selection System (MSS) has a long history and is well known for its use of elephants for skidding, which is considered one form of RIL. However, the difference in the impacts of logging operations between the MSS using elephants for skidding and machine-only-based operations commonly adopted in other countries is unknown. The present study evaluated ground disturbance along elephant skid trails, along logging roads and at log landings in four compartments logged under the MSS, comparing with reported values for CON and RIL in the other countries. The ground disturbance in the MSS compartments was, respectively, 2.1% and 0.4% in average for logging roads and log landings; it is not significantly different from that for CON and RIL (p > 0.05). In contrast, the disturbed area along elephant skid trails (0.9%) is much lower than that for CON (5.2%) and RIL (4.7%) (p < 0.05). A large difference in the width of skid trails was found between elephant skidding (1.0 m) and machinery (CON: 5.5 m, RIL: 4.6 m) (p < 0.0001). We conclude that elephant skidding can largely reduce ground disturbance due to much narrower width of the skid trails as compared with machine skidding, while MSS does not differ from the other countries in ground disturbance at logging roads and log landings.