Here we present details of the approaches we used to quantify the different
forcing agents associated with the Donnelly Flats fire, which burned during 11-18 June
1999 in interior Alaska (63°, 55′ N; 145°, 44′ W) as a result of human ignition. As
described in the main text, we developed radiative forcing estimates for the first year
immediately after fire and over a period of 80 years after fire (including the first year).
The longer interval represented the amount of time required for the vegetation to recover
to a pre-fire state that was defined by our control stand. This fire was so small that it had
a minor effect on the global radiation budget. Nevertheless, working out the contribution
of the various forcing agents and their combined effect for a single fire is a necessary step
towards assessing the impact of a changing boreal fire regime on climate at regional or
continental scales.