Improving Hardwood Bucking Techniques In Cut-To-Length Harvesting Operations In Eastern Canada
One of the most complex working steps during hardwood harvesting operations is bucking. It is particularly demanding in trees with complex architecture and with diverse product specifications. Since bucking has a high potential of influencing value yield, astute bucking decisions are essential to reach an efficient use of the wood resource, while ensuring profitable harvesting. In softwood operations, the automatization of bucking can increase wood utilization and monetary value, whereas this is not possible yet in hardwoods.
A research initiative was undertaken to first characterize northern hardwoods of Acadian forests based on stand, site and tree attributes and understand which of those attributes influence volume recovery. In a second part, the focus was set on the increase of value recovery during harvesting operations.
To understand factors influencing product recovery in hardwoods, a characterization of Acadian forests in New Brunswick, Canada, was performed. The analysis was based on more than 250,000 trees inventoried between 2012 and 2021. Besides tree dimensions (DBH and height), results indicated the strong influence of site factors on product recovery.
In a second phase, the evaluation of actual bucking as compared to a bucking considered as optimal is mandatory. Therefore, a bucking optimizer, BuckR, based on dynamic programming was developed in R. Bucking was considered as optimal when reaching a maximum in monetary value generated at tree-level. Based on a taper model for each tree and the product specifications, all possible product permutations were calculated and finally the optimal cross-cutting sequence for each tree identified. Within the BuckR optimizer, tree taper was calculated based on diameter height combinations and the Canadian national taper model with parameters adjusted to the study trees.
The objective was, in a first step, to evaluate hardwood bucking when considering the main stem until the first branch. We expected larger differences between actual bucking and the optimized solution when product specifications are more intricate. Therefore, bucking of more than 300 sugar maple, red maple, yellow birch, and white birch trees harvested in Acadian forests of New Brunswick, Canada were investigated, and initial results will be presented.