Conservation Ecology: Variability in fire frequency and forest composition in Canada's southeastern boreal forest: a challenge for sustainable forest management: Fig. 4

Fig. 4. Data from Lake Francis (Abitibi, Quebec, 48^o31'35"-78 ^o28'20"). (a) Distribution of charcoal influx (mm^{2 .}cm^{-2 .} yr^-1; thin line) and the low-frequency filter series computed with inverse Fourier transformation. (b) Charcoal index (mm^{2 .}cm^{-2 .} yr^-1); the high-frequency curve is obtained by detrending the raw data using the low-frequency filter. (c) Fire chronology is computed by applying a threshold of 1.25 on the high-frequency curve.