Appendix A. Age structure of the chronosequence stands and a discussion on the determination of time since fire.
Stand name represents soil burn severity (HI = high, LO = low) and stand postfire age (asterisks = radiocarbon date used instead of tree-ring date). Total number of trees dated is given.
Most stands < 200 yrs old have a strong regeneration pulse that corresponds to the post-fire recruitment, except stands HI-128 and HI-174. In these stands, a small establishment peak is followed by a larger peak approximately 50 years later. We determined that the first peak corresponded to the postfire cohort because these trees had strong radial and height growth, while trees in the second peak were initially suppressed indicating shaded establishment conditions. The break-up of the postfire cohort occurs around 100150 years in black spruce forests (Lecomte et al. 2006), making the sampling and dating of the downed postfire cohort difficult in stands older than 150 years because of wood decomposition. This may account for the low quantity of trees dated in the first cohort in stands HI-128 and HI-174 (but see HI-184). In stands where all trees had suppressed growth and no establishment pulse, time since fire was determined using radiocarbon dating (see Methods and Tables 1 and 2).
Lecomte N., M. Simard, and Y. Bergeron. 2006. Effects of fire severity and initial tree composition on stand structural development in the coniferous boreal forest of northwestern Quebec, Canada. Ecoscience 13:152163.