Speaker
Description
The practice of poplar forest establishment, maintenance, and harvesting varies globally, potentially inducing significant effects on cost structures and environmental impacts. In Romania, for instance, a typical life cycle involves operations such as ground clearing, stump removal, soil milling, pit drilling, and manual planting, followed by several cultivation stages, thinning, and clear-felling. While mechanized pit drilling is not a new option, modern machinery has seen significant technical and operational improvements. In this study, we utilized an extensive GNSS-annotated dataset collected from two tractor classes during pit-drilling operations. Specific events - including entering a row, drilling a pit, moving between locations, re-entering maneuvers, and relocation - were documented at one-second intervals. These data were used to extract event durations and frequencies to compare the performance of the two tractors. Given the non-normal nature of the data, bootstrapping was employed to infer the mean values and compare differences at the event level. Our findings suggested significant performance differences between the tractors, which were subsequently treated as two distinct options for cost assessment. The cost assessment integrated detailed statistics on fixed, variable, and labor costs. Using performance metrics such as event duration and speed, we conducted a cost simulation driven by plot size (1 to 20 hectares), variable plot dimensions, and four common planting schemes (5 × 4, 4 × 4, 4 × 2, and 3 × 2 m), resulting in nearly 84,000 comparison datasets. We evaluated two unit cost metrics: cost per pit and cost per hectare. Performance strongly influenced outcomes; the larger tractor class yielded higher unit costs, likely due to increased maneuvering and inter-pit travel time. Within the same tractor class, unit costs increased non-linearly with plot width, reflecting the impact of frequent entry and exit maneuvers relative to shorter on-row operations. When analyzed against plot length, costs were largely clustered by plot size, with cost differences becoming most pronounced for plots up to 5 hectares. These results provide updated performance and cost figures for poplar establishment in Romania. Furthermore, they demonstrate that the current practice of clear-felling in plots up to 5 hectares represents an economically critical threshold, beyond which cost reductions become marginal. Internationally, our findings illustrate how plot geometry and planting schemes drive costs, supporting the selection of optimal tractor classes for specific site conditions.
| Keywords | Establishment; Drivers; Trends; Economics |
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