"total fuel" (slightly) incorrectly written out (?)

[adrifoster]

So we have a 'sum fuel' written out here.

But in the current fire model we remove the "mineral portion" from the actual fuel attribute rather than an internal variable. This is fine scientifically (I'm pretty sure..) but it is a little misleading for writing out history variables.

My suggestion is that we leave the %non_trunk_loading attribute alone in this subroutine and instead calculate an internal variable and use that for the ROS calculations.

On the other hand, we can just specify in the history output that it is non-mineral fuel loading...