Effect of Tree Form on the Productivity of a Cut-to-Length Harvester in a Hardwood Dominated Stand

It is commonly accepted that tree form has an impact on the productivity of single-grip harvesters. However, it remains unclear, which elements of tree form are significant and to what degree they impact harvesting productivity. This is of particular importance in hardwood dominated stands, where hardwood trees often exhibit complex and variable stem and crown architecture that can complicate and prolong the processing phase. With the development of specialized harvesting heads, hardwoods, which were mostly subject to motor-manual operations, are now increasingly being cut and processed with fully mechanized harvesting systems. The goal of this pilot project was to determine the effect of tree form on the productivity of mechanized cut-to-length harvesting. A time and motion study of a single-grip harvester, operating in a hardwood dominated stand, suggests that the presence of a fork or a large branch on the main stem can reduce machine harvesting productivity by 15 to 20%.