Differences in land ownership, fire management objectives and source data matter: A reply to Hanson and Odion (2014)

Abstract

We respond to Hanson and Odion (2014), who claim in this journal (vol. 23, no. 1, pp. 1-8) that their reanalysis of fire severity patterns in and around the Sierra Nevada refutes earlier work showing increases in fire severity in certain forest types over the last 3 decades. Hanson and Odion base their reanalysis on a highly inaccurate, very coarse-scale, and geographically misregistered vegetation map. Also, in contrast to the previous work, which was restricted to wildfires on Forest Service lands in forest types differentiated by their fire regimes, Hanson and Odion combine all types of fires on lands of all jurisdictions and stratify by very broad, unorthodox vegetation types that conjoin very different fire regimes. As such, their work does not constitute a test of the previous work. We present analyses that demonstrate sources of error associated with Hanson and Odion's data and the analyses they perform, and explore how that error might confound their results. Fundamental and compounded problems in Hanson and Odion (2014) cast strong doubt on their conclusions.