I came across this report from Arup last night: https://www.istructe.org/IStructE/media/Public/Resources/ARUP-Embodied-carbon-timber_1.pdf
Within it makes a claim that managed forests increase carbon sequestration over natural forests, and makes reference to another Arup report “Rethinking Timber Buildings”, 2019 (available here). Wherein I can find one reference to a paper that asserts that modelling finds that a managed forest sequesters more carbon than a natural one - Greenhouse Gas Balance of Native Forests in New South Wales, Australia. This paper, upon which the whole house of cards seems to rest, was produced by the NSW Department of Primary Industries (i.e., the logging department), and when you look at the forecasts it becomes immediately clear that their estimation of maximum carbon in a forest is wildly underestimated at around 130 tCO2/ha.
More recent (and dare I say more rigorous) data is available from this summary by Keith, Lackey and Lindenmayer wherein the lowest value for above ground biomass in NSW forests is 182 tC/ha, and 252 tC/ha when you include the below ground biomass. In some NSW forests the values are as high as 447 tC/ha above ground and 615 tC/ha total. Converting to tCO2/ha yields a minimum above ground value of ~670 tCO2/ha.
Below I have included the summary box from the report - obviously there are some methodological flaws, and it is difficult to reconcile what the true impact is, but I’m curious what the implications are when the evidence does not really support the underlying premise. @raphael.sperry and @frances.yang I’m especially curious to hear your thoughts.