Terrestrial Storage of Biomass (TSB) is a Negative Emission Technology for removing CO2 already in the atmosphere. Compared to other NETs, TSB is a natural, carbon- and energy-efficient, and low-cost option. Nature performs the work of removal by growing biomass via photosynthesis. The key to permanent carbon sequestration is to bury the biomass in pits designed to minimize decomposition. Decomposition of wood follows the same path as decomposition of municipal waste in landfills. A review of the chemistry of biomass formation and decomposition leads to key concepts for TSB burial pit design. Decomposition is inherently slow due to the cross-linking and dense packing of cellulose. Like catalytic reactions, decomposition attack can only occur at the surface. Methane formation from even asmall amount of decomposition has been raised as a concern due to its high global warming potential. This concern is shown to be unfounded due to a great difference in time constants for methane formation and its removal from the air by ozone oxidation. The small extent of woody biomass decomposition is spread over hundreds to thousands of years. However, methane has a short lifetime in air of only about 12 years. A model that couples the exceedingly slow rate of methane formation with the fast
removal by oxidation predicts that methane will peak at a very small fraction of the buried biomass carbon within about 10 years and then rapidly decay towards zero. The implication is that no additional equipment needs to be added to TSB to collect and burn
the methane as is done in municipal landfills.