**2. Scope and Methods**

This study reviews forest biomass that includes pulpwood, forest harvest residues (FHR), and sawmill residues. Terms like remaining slash or logging residues are considered FHR and are plant materials that remain on-site after conventional logging. Pulpwood is logs harvested for pulp and paper but is also suitable for bioenergy production, usually obtained through thinning practices. Sawmill residues for this study include offcuts, dust, and shavings. Other forms of forest biomass are small hardwood logs [48]; coarse woody debris (CWD) [49] and wood from mechanical fuel load reduction [50], which resemble either FHR or pulpwood. Studies on firewood for domestic use are not included in this study unless it is part of their recourse in combination with one of the previously described forest biomass types. Regrowth and short rotation trees have potential as biomass for energy generation, but there are many uncertainties with regard to their distribution and climatic tolerance [51–53] and are not discussed in this review.

Assessing the theoretical biomass potential for bioenergy generation requires measurement of above-ground biomass. Logs used for timber and paper industries are not included in this assessment. Attributes of the supply chain using forest biomass must be present to categorize studies at a harvesting, collection and transport (available biomass potential) and conversion (technological biomass potential) level. The economical biomass potential concerns cost related to the production and distribution of biomass energy with respect to alternative energy uses and the environmental biomass potential includes GHG emissions related to the conversion of forest biomass to bioenergy along the value chain.

Online research papers published in English language academic journals were obtained by searching electronic databases including Google Scholar, Scopus, and Web of Science. The keywords used in searches were: 'Australia' and 'forest' and a combination of 'energy', 'biomass', 'bioenergy', 'waste', 'residue', 'supply + chain', 'emission' and 'sustainable'. Review papers were included, but book chapters and reports were excluded. The literature search covered the period 2000 to 2020. For each paper, the following information was collected and analyzed:


Thirty-five original research journal articles were identified that assessed the use of forest biomass in Australia for bioenergy. The majority of these were published in the journals Biomass and Bioenergy (9), Forest Ecology and Management (6), and Australian Forestry (5). Most research (31 out of 35) considered the theoretical biomass potential and sixteen studies considered the available biomass potential. In ten research studies, the theoretical biomass potential was combined with the available biomass potential. Technological, economical and environmental biomass potential studies are far less frequent with studies including a technological or environmental biomass potential being the lowest in frequency (6 out of 35). Figure 1 depicts the classification of the studies on forest biomass potential based on occurring measures in the research to provide an overview.

**Figure 1.** Classification of the reviewed studies on forest biomass for bioenergy in Australia according to the included measures of forest biomass potential.
