Speaker
Description
Harvesting operations in short-rotation eucalyptus plantations present increasing challenges, particularly when balancing diverse operational practices and performance expectations. Variability in field operations further complicates decision‑making, underscoring the need for models that capture realistic productivity dynamics. This study used a simulation-based approach to evaluate how the performance of two commonly used farm tractors modifications —differing in size class and equipped with different types of backhoe grapples—is influenced by payload characteristics and extraction distance in Thailand’s very short‑cycle eucalyptus plantations. Both tractors (T1 and T2) were monitored using GNSS, from which operational events and travel speeds were derived. Payload size was estimated through manual field measurements. Simulation experiments were then used to quantify how moving speed and payload size affect productivity across a range of extraction distances. Significant differences (α = 0.05) in travel speed and payload capacity between the two machines resulted in pronounced disparities in productivity as extraction distance increased. While the number of daily work cycles for both tractors remained similar up to an extraction distance of 100 m, differences emerged in daily production (m³), productivity (m³/h), and efficiency (h/m³), with the larger T1 consistently outperforming T2. At longer distances (e.g., 1000 m), the combined effect of reduced speed and smaller payloads tripled the unit extraction time for T2. These results have important implications for operational planning in Southeast Asian short‑rotation forestry. Because these tractors are often used interchangeably in local practice, keeping extraction distances below 50 m minimizes performance variability. At greater distances, T1 maintains notably higher production and a greater number of work cycles, emphasizing the importance of selecting an appropriately sized tractor based on site layout. These tractor modifications were introduced for the first time in international context and presented new sights for small-sized timber extraction performance.
| Keywords | performance; models; simulation; plantation |
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