4. Eect of a required level of certainty
The uncertainty associated with the bene®ts of
either plantation silviculture or deforestation
avoidance is composed of two component uncer-
tainties: uncertainty regarding the carbon bene®t
per hectare and uncertainty regarding the number
of hectares of either plantation establishment or
avoided deforestation resulting from a given miti-
gation investment. Uncertainty in per-hectare
bene®ts can arise, for example, due to variation
in estimates of biomass of the original vegetation,
biomass of the replacement landscape, soil car-
bon changes, uncertainty in the baseline defores-
tation rate