The Lac La Ronge area is characterized by its cycle of well-known fire intervals on the mainland scape. Unfortunately, there was a lack of data surrounding fire history and regime patterns on the islands. This is due to the fact that fires under 200 hectares are considered small, and as such are not entered into the federal and provincial databases.
One of our primary objectives was to compare avian diversity across islands as a function of time elapsed since fire, and as such we needed to reconstruct the fire history of the study islands using a mixture of Landsat imagery and dendrochronology across the series of candidate islands.
Pre-1984
In order to map fire regime history prior to 1984, dendrochronology was required. Of all islands in the archipelago, candidate islands were narrowed down to those who exhibited an even-aged forest structure. Eligible islands had a 30 meter x 30 meter permanent plot established, and rested a minimum 15 meters from the waters edge. Two tree cores were taken from each of a series of 25 trees situated closest to the centre of the plot. These cores were used to identify disturbance events by building a master chronology for their respective sites, and oldest recorded ages were used to approximate the time since fire.
Post-1984
For disturbance events after the 1984 threshold, Landsat imagery and data tracking for fire events was available. Obtained from Glovis, it was used to construct a composite image of the Lac La Ronge area using bands 3, 4, and 5 for Landsat 4 - 5. Further, bands 4, 5, and 6 were used for Landsat 8.