This study aimed to identify and quantify phenolic and resin acid extractive compounds in Scots pine stemwood and sawmill residues in four climatic regions of Finland to evaluate their most optimal sources for bio-based chemical biorefining and bioenergy products. The sample consisted of 140 trees from 28 stands, and sawdust lots from 11 log stands. NMR for the overall extractive analysis and HPLC for the quantitative estimation of phenolic and resin acid compounds were employed. Correlation analysis, multivariate factor analysis, principle component analysis and multiple linear regression modelling were applied for statistical analysis. HPLC identified 12 extractive compounds and NMR five more resin acids. Pinosylvin (PS), pinosylvin monomethyl ether (PSMME), and partly neolignans/lignans occurred in the largest concentrations. Wood type caused the most variation, heartwood having larger concentrations than sapwood (sawdust between them). Regional differences in the concentrations were smaller, but factor analysis distinguished the northern and the southern regions into their own groups. The results indicated higher concentrations of PS, PSMME, and vanillic acid in southern regions and those of, e.g., PSMME glycoside, lignan 2, and neolignan 1 in northern regions. The rather low concentrations of extractives in stemwood and sawdust imply value-added products, efficient sorting and/or large raw material volumes.

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Fuel wood pellets have the tendency of undergoing self-heating and off-gassing during storage and transportation. Self-heating can lead to spontaneous combustion and cause fires while toxic gasses such as carbon monoxide and some volatile organic compounds released due to off-gassing are a human health and environmental hazard. Previous research suggests that the self-heating and off-gassing of wood pellets are as a result of the oxidation of wood extractives. The aim of this study was to identify the extractives, i.e., fatty and resin acids that are responsible for the emissions of carbon monoxide, carbon dioxide and methane from wood pellets by testing the off-gassing tendencies of pellets produced from synthetic microcrystalline cellulose and different additive oils. The additive oils were intentionally selected to represent different types of wood extractives (mainly fatty and resin acids) and they included: tall oil, pine rosin, linseed oil and coconut oil. The highest mean concentrations of carbon monoxide, carbon dioxide and methane were recorded from cellulose pellets with added linseed oil. The concentrations of carbon monoxide and methane for the other four pellet types were negligible and there was no carbon dioxide emission. Pellets with added linseed oil had high off-gas emissions due to the high content of unsaturated fatty acids compared to other pellet types.

Climate change concerns have goaded countries toward seeking renewable energy options (bio-energy being one of them) to replace/supplant the conventional fossil-fuel alternatives (coal, oil and natural gas) commonly used now. Fuel pellets—at the confluence of the forestry, agriculture, waste management and bio-energy sectors—when produced from biomass residues, serve the dual purpose of ensuring energy security and environmental sustainability. By valorizing more and more organic wastes to bio-energy products, one could, to use the old adage, ‘kill two birds with one stone’. Social LCA is a method used to analyze a very wide range of social issues associated with the stakeholders in a value chain—workers, local community dwellers, society, global consumers, banks, investors, governments, researchers, international organizations and NGOs. In this analysis, the authors commence with a highly focused, niche literature review on the social dimension of sustainability in the African energy/bio-energy sector. The streamlined social footprint analysis inspired by the relatively lesser number of such studies for this sector in Africa is not a novel addition per se to the S-LCA knowledge base. The purpose of the application is to shed light on something in Zambia that must be understood better so as to bring about much-needed alterations in the direction of sustainable development. While the questions addressed to four different groups of stakeholders encompass a clutch of sustainable development goals, gender equality (SDG 5) and the need for greater interest on the part of governments and investors (SDG 9) to look at sustainable alternatives to the status quo stand out as concerns that need to be tided over. This paper and the streamlined social footprint analysis carried out are all the more relevant and timely when one considers some key changes that have happened in Zambia over the last five years—the implementation of the National Energy Policy in 2019 and the creation of the Ministry of Green Economy in 2021. These are verily harbingers of positive change auguring well for future developments in the bio-energy (and bio-pellets) sector, not just in Zambia but, by way of emulating and learning, in other countries on the continent.