Climatic influence on fire regime (1700 to 2008) in the Nazas watershed, Durango, Mexico

Background Fire scars are the primary source of physical evidence used to date past fires around the world, and to estimate parameters of historical fire regimes and fire-climate relationships. Despite an increase in studies about historical fire regimes and the relationship between fire and climate, these studies are still limited for Mexican forests. Our goal was to characterize the historical fire regime in two sites with different elevations, to assess changes in fire frequency, and to determine the relationship between fire regimes and climate patterns in a conifer-dominated forest in the Upper Nazas watershed of the Sierra Madre Occidental, Mexico. We were able to cross-date 50 fire-scarred samples of Pinus arizonica Engelm., P. strobiformis Engelm., P. teocote Schlecht. & Cham., P. durangensis Martinez, and Pseudotsuga menziesii (Mirb.) Franco and identify a total of 596 fire scars.