Silva Fennica vol. 59 no. 3 | 2025

Energy wood supply has faced significant challenges in Finland in recent years. While forest chip consumption has increased, the cessation of wood imports from Russia has added pressure on the use of domestic forest resources. This study examined the status of energy wood supply to heat-only and combined heat and power (CHP) plants from the perspective of energy wood suppliers. The survey-based study particularly focused on energy wood transport distances, the origin of delivered energy wood, and the proportion of various assortments. The operational environment, including wood fuel storage capacity and policy impacts, was also investigated. The results indicate that most energy wood consumed as forest chips was sourced less than 100 km from the consumer plant. However, these transport distances depended on annual forest chip consumption at the delivery point plant. Notably, energy wood was supplemented by roundwood that otherwise would have been suitable for processing in the forest industry; the proportion of that was 25–33% of all roundwood delivered.  The results of this study also highlighted the visible role of land-use change areas, especially for stump sourcing, while imported wood accounted for only a small fraction of the supply. In conclusion, to reduce the burning of industrial roundwood and to divert energy wood harvesting to young commercial forests, policy should place greater emphasis on the economic viability of harvesting small-diameter trees for energy production. Furthermore, uncertainty in the operational environment, caused by policy changes, should be mitigated.

• Niinistö, Natural Resources Institute Finland (Luke), Latokartanonkaari 9, FI-00790 Helsinki, Finland https://orcid.org/0009-0006-2645-0095 E-mail: tuomas.niinisto@luke.fi
• Anttila, Natural Resources Institute Finland (Luke), Latokartanonkaari 9, FI-00790 Helsinki, Finland https://orcid.org/0000-0002-6131-392X E-mail: perttu.anttila@luke.fi
• Kaseva, Natural Resources Institute Finland (Luke), Tietotie 4, FI-31600 Jokioinen, Finland https://orcid.org/0000-0002-8167-5434 E-mail: janne.kaseva@luke.fi
• Sikanen, Natural Resources Institute Finland (Luke), Yliopistokatu 6b, FI-80100 Joensuu, Finland https://orcid.org/0000-0001-6368-2879 E-mail: lauri.sikanen@luke.fi
• Kärhä, School of Forest Sciences, University of Eastern Finland, Yliopistokatu 7, FI-80101 Joensuu, Finland E-mail: kalle.karha@uef.fi
• Routa, Natural Resources Institute Finland (Luke), Latokartanonkaari 9, FI-00790 Helsinki, Finland https://orcid.org/0000-0001-7225-1798 E-mail: johanna.routa@luke.fi

Reliable forest inventory methods are important for informed management. The current study compared the quality of forest attribute models based on metrics from image matching point clouds, generated using various software packages, with those based on metrics from airborne laser scanning. The field- and remotely sensed data used in the analyses were collected as part of an operational forest management inventory in Norway. Results indicate that models based on point cloud data from airborne laser scanning (ALS) consistently produced smaller root mean square error values, demonstrating superior accuracy in capturing complex forest structures compared to models using image matching point clouds. While image matching offers advantages such as lower costs and broader area coverage, this data source primarily represents canopy surfaces, which complicate its use in inventories requiring detailed canopy information. Statistical analyses revealed no significant differences in model performance among various image matching software, but all being inferior to ALS. The study emphasizes the importance of selecting the appropriate source of remotely sensed data based on specific inventory needs.

• Bollandsås, Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Box 5003, 1430 Ås, Norway https://orcid.org/0000-0002-1231-7692 E-mail: ole.martin.bollandsas@nmbu.no
• Gobakken, Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Box 5003, 1430 Ås, Norway https://orcid.org/0000-0001-5534-049X E-mail: terje.gobakken@nmbu.no
• Næsset, Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Box 5003, 1430 Ås, Norway E-mail: erik.naesset@nmbu.no
• Roald, Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Box 5003, 1430 Ås, Norway E-mail: bjorn-eirik.roald@nmbu.no
• Ørka, Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Box 5003, 1430 Ås, Norway https://orcid.org/0000-0002-7492-8608 E-mail: hans-ole.orka@nmbu.no

Low tract size (ha) and harvested volume per hectare (m³ ha^–1) decrease the cost-efficiency of today’s conventional Nordic harvesting systems, which generally consists of a harvester and a forwarder. Low cost-efficiency is a problem because it reduces forest owners’ incentive to harvest wood and manage their forests. Today’s conventional harvesting system (two-machine system; TMS) was developed based on rotation forest management. As continuous cover forestry (CCF) grows in the Nordics, it is necessary to develop harvesting solutions that can operate cost-efficiently even when total removal (m³ per tract) is low. Single-machine systems (SMS) require only one machine to do all the harvesting activities; thus, SMS have only one machine-relocation cost per tract, instead of two per tract for TMS. SMS are generally categorized as either harwarders or dual machines, the difference being if the machine processes the logs directly onto the load space or not. In relation to TMS, the relative competitiveness of SMS increases with decreasing tract size, harvested volume per hectare, and/or average extraction distance. Because of site adaptation, CCF, and ever-expanding forest road networks, the trend in Nordic forestry over the last few decades has been that these three factors have been decreasing. CCF mainly entails thinning from above, which generally means the harvesting of large trees. SMS exist today, but almost exclusively as small-sized dual machines that cannot cut large trees. Thus, there is a pronounced need for commercially available SMS that can fell and process large trees.

• Ersson, SLU, School of Forest Management, SE-739 21 Skinnskatteberg, Sweden https://orcid.org/0000-0003-2442-7482 E-mail: back.tomas.ersson@slu.se
• Manner, Skogforsk, Uppsala Science Park, SE-751 83 Uppsala Sweden https://orcid.org/0000-0002-4982-3855 E-mail: jussi.manner@skogforsk.se
• Kärhä, School of Forest Sciences, University of Eastern Finland (UEF), P.O. Box 111, FI-80101 Joensuu, Finland E-mail: kalle.karha@uef.fi