Quality, productivity and costs of spot mounding after slash and stump removal

Abstract

In Nordic countries, the harvesting of slash and stumps from regeneration areas for energy purposes has rapidly increased, and will increase further in the future. This development has unknown technoeconomic effects on soil scarification. This study investigated three spot mounding methods and factors affecting their quality, productivity and costs in regeneration areas after slash and stump removal. The methods were integrated stump lifting and spot mounding (INTE), separate excavator-based spot mounding (BLADE), and separate spot mounding by a continuously working mounding unit (CONT). The average quality of work was worst in INTE, while CONT was the most sensitive to stoniness. Average work times per spot mound were 4.1 and 3.1 times higher in INTE and BLADE, respectively, than in CONT. Altogether, the cost–quality ratio of CONT was better than that of the other methods, except in very small areas.

Keywords:

• Bioenergy
• forest chips
• forest regeneration
• logging residues
• soil scarification
• stump lifting

Acknowledgements

The authors thank UPM Forest for financial support and especially aid in arranging machine units and regeneration areas needed in field experiments. We also acknowledge two anonymous referees and Dr Juha Lappi for their valuable comments.