Johanna Routa

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.

In this book we summarize peer-reviewed scientific articles and research reports from Finland, Sweden, and Norway on continuous cover forestry (CCF), i.e. forestry without clearcutting This book originates from growing interest in CCF among various stakeholders, and aims to promote discussion, further research, and inform decision-makers The book targets those interested in boreal forests, forest management, and ecosystem services In this chapter we review the background to the use of CCF and the reasons that led to its prohibition and subsequent resurgence in the Nordic countries

This study evaluated the positioning accuracy of moving forest harvesters using global navigation satellite system (GNSS) signals under a forest canopy, and developed approaches for forecasting accuracy under a mature spruce canopy cover. Real-time kinematic positioning with a Trimble R12 receiver on top of a harvester achieved high positioning accuracy, with 86% of observations meeting a maximum precision of 8 mm. However, the presence of a canopy cover hampered the GNSS’s performance as there were fewer satellites available, leading to an increased number of inaccurate positions and larger values of the dilution of precision in geometry (GDOP), position (PDOP), vertical (VDOP) and horizontal directions (HDOP). The canopy cover estimated from the viewshed analysis of the digital surface model (DSM) was found to be a significant predictor of the dilution of precision and maximum deviation from the true position. These findings suggest that viewshed analysis provides more precise results than a mere canopy cover percentage for evaluating the impact of canopy cover on the GNSS’s positioning of a harvester, despite its computational demands. Developing intelligent algorithms for precise positioning under the canopy can facilitate autonomous harvesting and forwarding, allowing for the implementation of digitalization in forest operations.

Fuel consumption is one of the key parameters in mechanised forest operations, particularly on lower bearing capacity soils, as wheel chains or bogie tracks can have a strong effect on it. This study aims to analyse the fuel consumption of several individual wheeled cut-to-length forwarder set-ups with different types of bogie tracks on peatland using automatic recording of data bus information. Two types of forwarders, 8-wheeled and 10-wheeled, and three types of tracks were tested on peatland in Eastern Finland. A mixed-model approach is the basis to study the fuel consumption as a function of the soil bearing capacity, the number of passes of the machine on the same soil, the section (curve or straight) and other variables related to the machine performance and set-up, for a total of N=27,928 fuel observations on three machines in 33 plots (trail segments). The model results in an R2=0.78; the number of passes increases the fuel consumption significantly, while the soil bearing capacity did not affect the fuel consumption. There are, however, important differences between the machines performance, which are addressed in the model. By contributing to the knowledge on the connection between operational conditions and fuel consumption, the study can contribute to the aim towards a sustainable forest operation through minimizing negative environmental impacts and providing the necessary tools for further research efforts.

The comminution of fuelwood for efficient transportation and handling exposes the material to various biological and chemical decomposition processes. The stockpiling of fuel chips can result in significant dry matter losses (DML) and consequent release of CO₂ into the atmosphere. The decomposition processes could be controlled by managing the chip moisture content (MC). MC control by utilizing the self-heating of stockpiled stemwood chips together with wind-driven ventilation was tested in a practical storage experiment, using uncovered and plastic-covered piles as references. The data were analyzed with linear mixed models. The predicted DML was 2.4–3.8% during the monitoring period of 5.9 months, but no significant differences appeared between the storage treatments. The increase in the basic density of the chips decreased DML. On average 1.7–3.5% of the recoverable energy content of the chips was lost during the experiment. The predicted average decline in the MC was ca. 4–8 percentage points (p.p.). The MC of the chip samples stored under plastic tarp was 4–5 p.p. lower than those stored in the uncovered piles. Heat generation within the piles was modest due to the high quality of the chips, and the ventilation solution tested only marginally affected the drying process and the mitigation of DML.

The use of sustainably sourced biomass is an important tool for mitigating the effects of climate change; but biomass is far from being a homogeneous resource. The aim of this study was to examine the decision-making process of industrial end-users considering biomass procurement. An online, two-part survey generated responses from 27 experienced professionals, representing a portfolio of facilities varying in size, technology, and biomass types, across Australia, Canada, Finland, and Sweden. A PAPRIKA conjoint analysis approach was used to analyze the data so that the attributes that influenced procurement decisions could be weighted and ranked. The results provided an insight into end-users’ views on factors including facility location, size, and biomass storage, handling, and procurement for different wood-based industrial services. The most important decision-making attribute appeared to be the type of biomass assortment, at individual, national, and aggregated levels. Of seven sub-categories of biomass assortments, sawdust (35%) was the most preferred type followed by stem wood chips (20%) and energy wood (15%). We concluded that, from the end-user’s perspective, a pre-defined biomass assortment is the most important factor when deciding on feedstock procurement at a bioenergy facility. These results help us better understand end-users’ perceptions of biomass properties in relation to their conversion processes and supply preferences and can inform product development and the securement of new niches in alternative business environments by existing and future biohubs.

Minimising dry matter losses during storage of comminuted forest fuels is desirable from both an economic and a sustainability perspective. This study examined fuel quality and amount of recovered energy during the storage of forest wood chips stored at full industrial scale at three locations, and the effect of sieving and covering piles with a water-resistant, vapour-permeable fabric. Sieving wood chips before storage, that is, reducing the number of fines smaller than 8 mm, reduced the cumulative dry matter losses to <2%, while cumulative dry matter losses after storage for 4–6 months using current practices, that is, unsieved and uncovered, reached 10.6%. The combined effect of storage management led to a value loss of 11.5%, while both covering and sieving led to lower losses, with the combination of sieving and covering giving a 1.3% value increase, and thus, increased storability.