Fire records based on dendrochronological techniques for a coniferous forest in the southeastern region of Jalisco, Mexico

Abstract

Introduction: There is growing public awareness in Mexico concerning natural resources and, in particular, the threat they face due to the increase in the number of forest fires. Objective: To reconstruct the fire records of a 66-year period (1945-2011) and analyze its relationship with climate conditions in the southeastern part of Jalisco. Materials and methods: Pinus douglasiana Martínez samples were processed according to standard dendrochronological techniques. The statistical analysis and relationship of fires with climate were determined with the burnr library of the R program. Winter precipitation and PDSI (Palmer Drought Severity Index) and PDO (Pacific Drought Oscillation) indices were used as proxies for climate. Results and discussion: All scars (114) were in the zone of initial growth of earlywood; therefore, fires occurred during the spring (dry season). The mean fire frequency interval for the 100 % filter of scars was 5.1 years, for the 10 % filter it was 6.1 years, and for the 25 % filter, representing the most extensive fires, it was 6.4 years. Drought preconditions and dry conditions modulated by the PDO had significant influence on fire occurrence. Conclusions: Historical reconstruction shows that the fire regime is frequent, of low intensity and with no change over the last four decades. To maintain these characteristics, monitoring and forest fuel management actions are important.