Dynamic landunits carbon and nitrogen conservation: Determine value contributed by special landunits

(From NCAR Teamwork site, 2016-02-02)

An example of the problem is: Let's say we have a grid cell that was 100% glacier. The glacier retreats, creating a new natural vegetated column. What should the carbon and nitrogen states be in this new column? A number of discussions have suggested that we start with near-zero values. But do we need at least a little bit of initial carbon and nitrogen to give things a kick-start?

I see that some patch-level seedc & seedn is added to new PFTs (currently in dynConsBiogeochemMod). Is this sufficient, or do we need some additional column-level (soil) carbon / nitrogen? For one thing, I'm guessing that the patch-level seedc / seedn doesn't do anything for the bare ground PFT; so if the only PFT in the new vegetated column is bare ground, do we need to add any seed C/N?