Effect of fire severity on regeneration success in the boreal forest of northwest Québec, Canada

Abstract

:Fire regimes in the boreal forest are dominated by crown fires that burn over large areas. However, these fires rarely burn forest stands entirely and with the same intensity throughout, resulting in a mosaic of vegetation burnt to varying degrees of severity. The objectives of this study were to: (1) assess regeneration of tree species six or seven years after fire in relation to crown fire severity in non-salvaged jack pine and black spruce stands, and (2) assess establishment preferences of seedlings on the different types of germination beds created by fire. Logistic regressions indicated that seed trees abundance influenced regeneration success. The relationship between fire severity at the crown level and regeneration success was not significant, although seedling recruitment appeared limited in areas where severity was light to moderate. Poisson regressions showed that seedlings preferentially establish on mineral soil, and that woody debris seem to be a good substrate for germination and survival. Seedlings establish more frequently and grow better where thickness of residual organic matter is lowest. Crown fire severity, combined with severity at ground level may therefore be a good indicator of regeneration success in coniferous stands.