Vegetational patterns in burned and unburned areas investigated by using the detrended fluctuation analysis

Could the dynamics of vegetation covers be significantly influenced by fires? Is it possible to identify and quantify such effect? In order to detect fire-induced variability in vegetational dynamics, we performed a fluctuation analysis of time series of satellite SPOT-VEGETATION normalized difference of vegetation index (NDVI) data from 1998 to 2003 of two shrub-land test sites. We used the detrended fluctuation analysis (DFA), which permits the detection of persistent properties in nonstationary signal fluctuations. We analyzed two shrub-land sites, one in "healthy conditions" (fire-unaffected) and the other in "ill conditions" (fire-affected). Our results point out to the active role played by fires in increasing the persistence of the vegetation dynamics.