Bioenergy production from stump harvesting in Finland
Stump harvesting in Finland has been fluctuating a lot in Finland regarding the economic situation in the society. Traditionally stumps were used for tar burning. Finnish forest industry became interested in the underground fiber stock in the 1960s’ and stumps were used as raw material for sulphate pulp production (Hakkila 1977). The costs of the harvesting made it however unprofitable and the usage of the stumps decreased (Laitila 2010).
During the last great economic depression, the by-products of the forest industry did not cover the demand for the renewable energy resources. Therefore, and also to fulfill the requirement of the EU, energy production from the harvested stumps were started. The stump harvest was justified with the additional income to forest owners, too (Koistinen et. al 2016). Also, the tilling costs of the ground are reduced due to stump harvesting (Koistinen et. al 2016). The first company which started stump harvesting was UPM, one of the largest forest companies in Finland.
Stumps were considered as good raw material for the energy production for several years. However, using stumps for energy has decreased a lot recently. According to Natural Resources Institute Finland (2018), the energy generation from stumps fell by nearly one third and was about 0,5 m^3 in 2017. There are several reasons for the decrease. One of the most important issue with stumps is impurities on the stumps, like mineral soil and rocks, which cause problems on the power plants (Laitila 2010). Also, there are sufficiently enough raw material provided by forest industry at the moment and there is no need for extra forest energy (Yle Uutiset 2017).
NGOs are against the idea of the stump harvest because of its negative environmental consequences. Indeed, some invertebrates may suffer from the stump harvest, ground flora changes, and soil disturbance can be seen after a decade after the stump harvest (Andersson 2012, Kaarakka et al. 2018). However, it has been researched that stump harvests reduce the impacts of the root-rot-fungi and that the natural regeneration of the forest is better when stumps are removed (Persson 2013, Saksa 2013). There is no significant effect on the nutrient balance in stump harvest (Perssion et al. 2017), but some of the solid matter may leach in consequence of the stump harvest (Keto-Tokoi 2018). Therefore, stump harvest is only recommended on the nutritious lands where there are no steep slopes and soil is not vulnerable for erosion (Koistinen et. al 2016).
In 2013, NGOs, especially WWF Finland, were against the stump harvesting, and there was a lot of public discussion around the topic. WWF prompted to leave off the stump harvest in Finnish forests because of its serious harms to the forest ecology (WWF Finland 2013). At the same time, the government was willing to support the bioenergy production in order to reach the EU-targets and the forest owners were in the need for extra income.
Nowadays, the conflict, or public discussion, around the topic is rather non-existing. In 2018, WWF only wanted some restrictions on the stump harvest (Keto-Tokoi 2018). This may be due to the reduced amount of the stump harvest in general but also the new research results which indicates that stump harvest does not significantly harm the environment when done according to the guidelines.
Keywords: stump harvest, forest management, researchers, bioenergy companies, government, NGOs, forest owners
Andersson, J. 2012. Long- and short-term effects of stump harvesting on saproxylic beetles and ground flora. Swedish University of Agricultural Sciences.
Hakkila, P. 1977. Kantopuu metsäteollisuuden raaka-aineena. Folia Forestalia 292. 39s.
Kaarakka, L. M., Vaittinen, J., Marjanen, M., Hellsten, S., Kukkola, M., Saarsalmi, A., Palviainen, M. M. & Helmisaari, H-S. M. 2018. Stump harvesting in Picea abies stands: soil surface disturbance and biomass distribution of the harvested stumps and roots. Forest Ecology and Management: 425: 27-34.
Keto-Tokoi, P. 2018. WWF Suomen raportteja 37: Tutkimustietoon perustuvia suosituksia vastuullisen metsänhoidon kehittämiseksi. 136 s.
Koistinen, A., Luiro, J-P. & Vanhatalo, K. (toim.) 2016. Metsänhoidon suositukset energiapuun korjuuseen, työopas. Tapion julkaisuja.
Laitila, J. 2010. Kantojen korjuun tuottavuus. Metlan työraportteja 150. 29 s.
Natural Resources Institute Finland. 2018. Wood in energy generation 2017. Cited: [11.2.2019] Available: https://stat.luke.fi/en/wood-energy-generation-2017_en
Persson, T. 2013. Environmental consequences of tree-stump harvesting. Forest Ecology and Management. 290: 1-4.
Persson, T. 2017. Stump harvesting for bioenergy – methods and environmental effects, Scandinavian Journal of Forest Research, 32:3, 201- 203.
Saksa, T. 2013. Regeneration after stump harvesting in southern Finland. Forest Ecology and Management. 290: 79-82.
Toivanen, T., Markkanen, A., Kotiaho, J. S. & Halme, P. 2012. The effect of forest fuel harvesting on the fungal diversity of clear-cuts. Biomass & Bioenergy 39: 84–93.
WWF Finland. 2013. Kannonnosto ei kuulu kestävään metsätalouteen. [Cited: 13.2.2019] Available: https://wwf.fi/wwf-suomi/viestinta/uutiset-ja-tiedotteet/Kannonnosto-ei-kuulu-kestavaan-metsatalouteen-1935.a
YLE Uutiset. Hakkuista ei revitä enää kaikkea irti – kiistelty kantojen käyttö energiapuuksi romahti. Cited: [11.2.2019] Available: https://yle.fi/uutiset/3-9638544
YLE Uutiset. Kantojen poltosta kiistaa. [Cited: 13.2.2019] Available https://yle.fi/uutiset/3-5683974