Scale effects of vegetation and topography on burn severity under prevailing fire weather conditions in boreal forest landscapes of Northeastern China

Understanding the controlling factors of burn severity requires consideration of the scale at which these factors work. This investigation explored how well topography and vegetation factors can explain variation of burn severity in a boreal forest landscape of northern China under prevailing fire weather conditions. Eight grain sizes were examined that ranged from 30 to 2500 m. A burn severity map was derived from calculating the difference between pre- and post-fire Normalized Difference Vegetation Index of two Landsat Thematic Mapper images. Results indicate that (1) burn severity in the boreal forest landscape of northern China was mainly controlled by vegetation at grain sizes smaller than 500 m. At grain sizes larger than 1000 m, topography accounted for more variation in burn severity; (2) the relative importance of topography factors was stable with increasing grain sizes and generally ranked in order of aspect, slope, and elevation; (3) stand age appeared to be more important where canopy cover and understory cover substantially fluctuated with increasing grain sizes; and (4) the linear relationships between burn severity and specific factors of topography and vegetation decreased with increasing grain sizes. Our study can help managers to design fire management plans according to vegetation characteristics that are found important in controlling burn severity and prioritize management locations based on the relative importance of vegetation and topography.