Anthropogenic fire history and red oak forests in south-central Ontario

The regeneration and dominance of northern red oak (Quercus rubra L.) has b een associated with fire throughout eastern North America. Red oak in centr al Ontario grows near the northern edge of its distribution in mixed hardwo od-coniferous forests under mesic conditions where it competes with more sh ade-tolerant species. We hypothesized that the abundance of red oak in thes e stands was largely the result of anthropogenic burning and natural fires, which would favor the regeneration and recruitment of northern red oak ove r such shade-tolerant species as sugar maple (Acer saccharum Marsh.). Fire histories dating from the mid-1600s were constructed by dendrochronological methods from fire scars on stumps, trees, and natural remnants of red pine (Pinus resinosa Ait.), white pine (Pinus strobus L.), and red oak at six s ites in south-central Ontario. Fire histories of the sites are characterize d by abrupt changes in fire interval. As much or more variance in fire inte rval is found within sites as is found among sites. Differences in the mean fire interval among sites are related to the density and migration of hist oric aboriginal and European populations. The mean fire interval varied fro m more than 70 years to six years depending on site location and historic p eriod. The occurrence and abundance of red oak is linked to anthropogenic f ire regimes.