The productivity of mechanical logging has increased substantially from the early 1990s. The productivity of thinning has increased more than that of regeneration felling.
This is indicated in a study of the Natural Resources Institute Finland (Luke), based on mechanical harvesting data collected between 2014 and 2017. The study identified, for example, harvesting conditions, the structure of machine operating hours, the productivity of logging and fuel consumption.
Collecting logging residues reduces productivity
Adapting working methods to collect logging residues afterwards reduced productivity in terms of effective time by roughly ten per cent in spruce-dominated clear cutting areas. Average productivity in terms of utilised time was 10.2 cubic metres per hour at thinning sites and 22.1 cubic metres per hour at regeneration felling sites. In addition to the actual logging process, utilised time includes any interruptions at the worksite, and effective time includes machine’s downtimes of at most 30 seconds.
The average stem volume was smaller in Northern Finland than in other regions, particularly in terms of regeneration felling. At regeneration felling sites, the average stem volume has increased since the early 1990s when the previous public follow-up study was conducted (Kuitto et al. 1994). Thinning sites consist of significantly smaller trees than in the 1990s when thinning was mostly carried out manually. When measured by the average stem volumes at the time (thinning 183 dm3, regeneration felling 309 dm3), productivity in terms of utlised time has increased by 70 per cent at thinning sites and by 60 per cent at regeneration felling sites.
The productivity of large harvesters mainly designed for regeneration felling only exceeded the productivity of smaller machines when the stem size was more than 300 dm3.
“The results of logging productivity and fuel consumption indicate that harvesters have partly been over-sized considering the size of trees. However, allocating correct machines to their ideal conditions requires sufficiently large reserve of sites”, says Paula Jylhä, senior scientist at Luke.
The study was funded by the Finnish Forest Research Institute and Luke. It was completed in the FOBIA project, coordinated by Luke and mainly funded by the EU’s Northern Periphery and Arctic Programme. The goal of the project is to improve the business skills of forest machine entrepreneurs through training.
Further information (in Finnish):
Jylhä, P., Jounela, P., Koistinen, M. & Korpunen, H. 2019. Koneellinen hakkuu: Seurantatutkimus. (Mechanical logging: a follow-up study) Natural resources and bioeconomy studies 11/2019. Natural Resources Institute Finland. Helsinki. 53 p. Available at: https://jukuri.luke.fi/bitstream/handle/10024/543864/luke-luobio_11_2019_v2.pdf?sequence=7&isAllowed=y
