Illustrating GHG emissions variations by geographic region and previous land-use

I found a graph created by Stanford University illustrating the variation in cultivation emissions from biofuels in different regions of the US, which is most likely to reflect on variations in soil organic carbon content and climate.

Curtright, 2011

Here is another graph, illustrating the importance of prior landuse and what biofuel it is replaced with (direct land-ue change).

Curtright, 2011

Please note that these are the immediate emissions from the direct land-use change; these emissions decrease with time. This means that while this graph does not show the overall long-term emissions from biofuels, it allows the comparison of GHG emissions from 1st generation biofuels (corn) and second generation biofuels (switchgrass), as well as showing the importance of direct land-use change.

The most surprising aspect shown in this graph is probably the relatively small short-tem emissions from forest conversion. It would perhaps be interesting to know what assumptions were used here i.e. it may be that the emissions from deforestation were attributed to the logging industry instead of to biofuels, producing such low emissions; or whether the wood from deforestation is assumed to be used as a biofuel (although this is not explicitly specified by Curtright, it seems that the latter is the assumption used).

*CRP crops are Conservation Reserve Program crops, which include vegetation beneficial for wildlife (FSA, 2011).