Progress Report on the Research Project Entitled Post-Fire Vegetation Monitoring of Two Recent Burns on Isle Royale National Park

Janke, Robert

During the summer of 1977, permenent vegetation plots were established at two burn sites on ISRO, Card Point and McGinty's Cove, so that successional changes could be monitored. At the Card Point Burn, the organic layer of the soil was burned down to mineral soil in some areas, while in other areas within the burn it was completely unburned. Vegetation plots were established in both types of soil condition so that the effects of the presence or absence of the upper soil organic layer on post-fire vegetation establishment could be compared. This report deals with the vegetation monitoring effort which occurred in the summer of 1990. For both burns white birch (Betula papyrifera) and quaking aspen (Populus tremuloides) have the highest seedling densities. At McGinty's cove, balsam fir (Abies balsamea) and white spruce (Picea glauca) also invaded the burn soon after the fire probably because this site is surrounded by a mature forest containing seed-bearing spruce and fir; Card Point is surrounded by shore or swamp. White birch, quaking aspen, big-tooth aspen (Populus grandiedentata) and white spruce all have considerably greater seedling densities on burned soil than on unburned soil. Balsam fir has greater seedling densities onthe unburned soil. Other measurements made included sapling densities from 3 meter circular plots, tree densities from 6 meter radius plots, and ground cover data from square quadrants on burned and unburned soil. Early plant invaders on burned and unburned soils are listed. After 15 years of change, the author found that the vegetation in both burns is still changing relatively rapidly, and that the post-fire succession that occurs on burned soil is very different from that on unburned soil. The author recommends monitoring these burns at about 5 year intervals in the future.