| I used two chronosequences to study the structural development of jack pine (Pinus banksiana) stands in northern lower Michigan following either clearcut harvesting and replanting or stand-replacing wildfire. The chronosequences were used to quantify (1) aboveground biomass, (2) stem density, (3) snag density and volume, (4) coarse woody debris volume, and (5) forest floor mass, and within-stand patchiness. Total aboveground biomass and stem density in the harvest sites closely resembled that of the wildfire-regenerated sites across all stand ages. In contrast, within-stand patchiness of live stem density was much higher in the wildfire sites for the first 20 years of stand development. Harvest sites possessed very little dead wood at young ages, but snag volume and CWD gradually increased. Young wildfire sites contained the largest amounts of dead wood; those levels declined dramatically in the first 20 years. Both chronosequence recovery patterns merged by 40 years post-disturbance where they began a steady increase in total dead wood. Forest floor mass was very high in young harvest stands compared to young wildfire stands, but by approximately 10 years there is no longer a discernible difference. The differences between the chronosequences were driven mainly by recovery in the youngest (<20 yrs) sites, after which many of the attributes were very similar. This has important implications for management that is intended to replicate natural recovery across stand development, and not just at stand maturity. |
