Forest bioenergy or forest carbon: A review

摘要

An article by Jon McKechnie et al entitled Forest Biomass or Forest Carbon purports to use an integrated life cycle assessment (LCA) and forest carbon analysis when examining the use of wood for electrical generation. Most publications assume that the CO_2 emitted is carbon neutral because plants will re-absorb the CO_2 through photosynthesis. However, the article challenges this hypothesis and states that incomplete LCAs are undertaken. The article demonstrates that it will take many years to recapture the CO_2 when the wood is used for bioenergy. But when analyzing the capture of CO_2, only regrowth is considered and not the tree growth of the whole forest. If in the example given, a full account is taken of the aboveground yield, it is shown that the annual increment from the management units is nearly double the potential removals for wood products, including bioenergy. Thus, rather than a decrease in forest capital there is an increase. Proper and full LCAs must be undertaken of the whole forest, rather than partial analysis: the latter results in erroneous accounting. It is very misleading and should not be used or cited. This same error has been made by a number of other quoted publications.