As i wrote in the paragraph you quote, my assumption is that this models wooden items being burnt at the end of their useful lives. But hey, don't take my word

As i wrote in the paragraph you quote, my assumption is that this models wooden items being burnt at the end of their useful lives. But hey, don't take my word for it - in the paper, that bit references this: Penman J, Gytarsky M, Hiraishi T, Krug T. Good practice guidance for land use, land-use change and forestry. Intergovernmental Panel on Climate Change (IPCC), chapter 3, Appendix 3.A.1.3. UNEP; 2003. p. 268–70. Which you can read here: https://www.ipcc-nggip.iges.or.jp/public/gpglulucf/gpglulucf_contents.html https://www.ipcc-nggip.iges.or.jp/public/gpglulucf/gpglulucf... https://www.ipcc-nggip.iges.or.jp/public/gpglulucf/gpglulucf_files/Chp3/App_3a1_HWP.pdf https://www.ipcc-nggip.iges.or.jp/public/gpglulucf/gpglulucf... So dive into the gory details of harvested wood products, and the basis for their future methodological development to your heart's content!