This chapter gives an overview of the key technologies to produce biochar. First, an introduction will be given to the different thermochemical conversion techniques of dry biomass (including pyrolysis) which result in char as one of the product fractions. A second part of this chapter is devoted to the discussion on how the biochar physicochemical properties result from the type of biomass feedstock used, as well as from the prevailing process conditions applied during thermochemical conversion – as some of these physicochemical properties in biochar have a major impact on the functionality and stability of biochar in soil. A major challenge for the successful deployment of biochar systems is to render its production economically profitable. Hence, this chapter concludes with an economic assessment of biochar. This last part of the chapter also emphasizes the potential increase in value creation in the biochar production process by identifying potential economic uses of co-products, including bio-oil and producer gas.

Forests are important for providing wood for products and energy, and the demand for wood is expected to increase over the next decades. The potential woody biomass supply was estimated for the period 2000–2020 for stem wood as well as residues, taking into account economic, environmental and technical restrictions. Constraints reducing the availability of forest biomass were defined and quantified for three mobilisation scenarios and five wood price scenarios in order to estimate the realisable potentials. The theoretical biomass potential was estimated from Austrian forest inventory data and applying the PROGNAUS forest growth simulator. It lies between 32.7 and 38.4 million m3 equivalents yr-1 over bark for the period 2000–2020. The realisable potential in Austria was estimated in a range between 23.9 and 31.1 million m3 equivalents yr-1 over bark for the period 2000–2020. These potentials represent 73–84% of the theoretical potential. Nutrient sustainability in the context of whole-tree harvesting appeared to be an important constraint when considering how much biomass is realisable from forests. The attitude of private forest owners towards increased harvest of forest biomass is also of major importance for the realisable potential, given the small-scale structure of forest ownership in Austria.

Biochar is currently one of the dominant topics in soil research, despite the fact that it is not a new discovery. It has the potential to address some of the most pressing questions humanity is currently facing, that is climate change, food security, energy security and environmental pollution. However, a soil system is very complex and together with the multitude of biochar production settings and nearly infinite number of potential feedstock resources it becomes evident that there is no single solution for these challenges available. This is specifically an issue when addressing the potential of biochar for climate change mitigation via reduction of greenhouse gases (GHG). Systems approaches are needed, covering the entire supply chain and backed up with life cycle assessments to ensure a positive impact by using biochar as a tool for environmental management.

This chapter provides a summary and brief introduction of the subsequent chapters of this book, with a focus on biochar for climate change mitigation, including an economic assessment of GHG abatement costs. The FOREBIOM project will be briefly introduced and results on biochar erosion after amendment of a forest floor are presented.

Coppice forests, originating from vegetative propagation (stump stools or root suckers), are an important component of forest ecosystems worldwide. Even though their economic importance has been reduced in Europe, especially since the Second World War, they still serve as important sources of raw materials (mostly firewood) for local communities. In addition, coppice forests could be considered as ‘hotspots of biodiversity’, having high habitat, historical and genetic resource values while being relatively resistant to environmental impacts such as droughts.

In this context, our chapter emphasizes the main characteristics of silvicultural coppice systems (e.g. simple coppice, short-rotation coppice, high coppice, coppice selection and coppice with standards), their ecology, history and current significance in Europe.

The two case studies on carbon stocks of coppice with reserves and coppice with standards in Austria are important arguments for considering coppice forests as a sustainable source of sawlogs for highly valuable wood products and of biomass (energy wood) that can be used for firewood as well as in pyrolysis processes.

Biochar systems are designed to meet four related primary objectives: improve soils, manage waste, generate renewable energy, and mitigate climate change. Supply chain models provide a holistic framework for examining biochar systems with an emphasis on product life cycle and end use. Drawing on concepts in supply chain management and engineering, this chapter presents biochar as a manufactured product with a wide range of feedstocks, production technologies, and end use options. Supply chain segments are discussed in detail using diverse examples from agriculture, forestry and other sectors that cut across different scales of production and socioeconomic environments. Particular attention is focused on the environmental impacts of different production and logistics functions, and the relationship between supply chain management and life cycle assessment. The connections between biochar supply chains and those of various co-products, substitute products, and final products are examined from economic and environmental perspectives. For individuals, organizations, and broad associations connected by biochar supply and demand, achieving biochar’s potential benefits efficiently will hinge on understanding, organizing, and managing information, resources and materials across the supply chain, moving biochar from a nascent to an established industry.

Biochar as a boon for soil fertility in the tropics still has to show that it is able to provide the same benefits to soils in temperate regions. Here an Austrian study with the objective to analyze the extent of benefits that biochar application offers to agricultural soils in Europe beyond its role as a carbon sequestration strategy is presented. Based on hypothesis testing, several potential benefits of biochar were examined in a series of lab analyses, greenhouse and field experiments. Three hypotheses could be confirmed: biochar can protect groundwater by reducing the nitrate migration in seepage water; biochar can mitigate atmospheric greenhouse gas accumulation by reducing soil N2O emissions; and biochar can improve soil physical properties by increasing water storage capacity. One hypothesis was only partly confirmed: biochar supports the thriving of soil microorganisms only in specific soil and climate settings. Two hypotheses were refuted: biochar does not generally provide nutrients to plants except when produced from specific feedstocks or by combining it with mineral or organic fertilizers; the cost-effectiveness of biochar application is not given under current production costs if the existing benefits of biochar are not transferable to financial value.