Historia de incendios en un bosque de pino de la sierra de Manantlán, Jalisco, México

Sierra de Manantlán Biosphere Reserve (RBSM) in Jalisco is the most important reserve in western Mexico, where fres are one of the main forest disturbances. In order to reconstruct historical fre regimes, partial sections of Pinus douglasiana with fre scars were collected. Using dendrochronological techniques, the exact dating of 293 scars from 51 trees allowed the reconstruction of fre frequency for the period 1867-2010. We reconstructed mean fre interval of 5.5 years (MFI: all scars) and 3.6 years for the Weibull mean probability interval (WMPI). The MFI (≥ 25% scarred) was 8.9 years and WMPI was 6.9 years. The seasonal patterns of fre occurrence showed that most fres (68.3%) were formed in middle earlywood, 30% in early earlywood and 1.7% in late earlywood. Considering the phenology of the species, it was determined that 98.3% of fres occurred in spring and 1.7% at the beginning of summer. The fres were recorded in dry years, but the relationship was not statistically significant. A strong relationship between droughts and widespread fres was observed. Likewise, it was determined that climate variability was strongly related to ENSO; fres reconstructed from 1956 to 2010 correspond with both El Niño and La Niña events.