Effects of Grass Fires on the Trajectory of Vegetation Dynamics in Abandoned Agricultural Lands: A 30-year Retrospective Based on Remote Sensing Data (A Study of an Area South of the Moscow Region)

Abstract

The authors propose that the spatial structure of woody vegetation on former arable lands can be used as a diagnostic feature that indicates the occurrence or absence of grass fires after land abandonment. Based on the analysis of a series of Landsat satellite images from 1985 to 2016 for an area of 256.5 km 2 located in Central European Russia, the authors have reconstructed the history of spring fire events. They found correlations between the frequency of fire events and the density and spatial structure of woody vegetation on abandoned arable lands. Without fires, areas with homogeneous woody vegetation are formed: individuals of pioneer tree species (Betula pendula, B. pubescens and Salix caprea) are evenly distributed and exist in high densities over the entire area. Affected by fires, trees become unevenly distributed over the area: pioneer trees grow in groups or as separate individuals depending on the intensity and frequency of grass fires. With frequent fires, the vegetation remains in a weedy stage for decades.