Logging residues consist of harvest

Logging residues consist of harvest losses, branches and stumps.
Logging residues are by-products of roundwood harvesting, that is,
they supply is connected to harvested volumes of roundwood. The
fraction of logging residues that can be removed from forests
depends on technical and environmental constraints such as
industrial roundwood harvesting methods, tree species, soil type,
etc. (Hakkila, 2004; EEA, 2007; Mantau et al., 2010). As this type of
data is not available at the global level, the share of logging residues
that can be recovered is commonly approximated by using recovery
ratios. Recovery ratios define the fraction of logging residues that
can be realistically harvested. The estimates of recovery ratios vary
in the range of 0.25–0.75 (Gan and Smith, 2006; Smeets and Faaij,
2007a; Titus et al., 2009; Offermann et al., 2011). Most studies use a
recovery ratio of 0.5, which is also used in this study.