Response of Six Boreal Tree Species to Stand Replacing Fire and Clearcutting

Emulation of natural disturbance processes and their effects is important to maintain the structure and composition of managed forests. To examine whether logging and fire have different effects on natural regeneration, we studied the recruitment of six common boreal tree species (Populus tremuloides, Betula papyrifera, Pinus banksiana, Picea mariana, Picea glauca, and Abies balsamea) after fire and clearcutting in northern Ontario. Regeneration densities of all studied species, except P. glauca and A. balsamea, were positively related to their respective pre-disturbance basal area. Post-disturbance regeneration densities of P. tremuloides and P. banksiana did not differ between disturbance types, whereas those of B. papyrifera were higher after fire, and those of P. mariana and A. balsamea were higher after clearcutting. Among tree species, the composition of P. tremuloides increased by approximately 35% after both disturbance types, that of B. papyrifera increased by 22% after fire and 11% after clearcutting, whereas those of P. banksiana, P. mariana, P. glauca, and A. balsamea decreased to various extents. Compared with fire, clearcutting significantly increased the post-disturbance presence of A. balsamea, which is attributed to surviving advance regeneration after logging. The natural regeneration process after fire appears to be emulated by clearcutting for P. tremuloides, P. banksiana, P. mariana, and P. glauca, but the increase in B. papyrifera after clearcutting is less pronounced than after fire, whereas the reduction of A. balsamea after clearcutting is less severe than after fire.