Increasing the risk of severe wildfires in San Dimas, Durango, Mexico caused by fire suppression in the last 60 years

Abstract

To sustainably manage forests, it is important to understand the historical fire regimes including the severity, frequency, seasonal timing of fires as well as the relationship between climate and fire in order to develop management plans that mimic and/or complements the natural disturbance pattern. The objectives of this study were to reconstruct the natural fire regime within a Pinus lumholtzii site in order to understand the fire regimes within this forest type as well as adjacent high timber value mixed-pine forests where historical fire regimes are not available due to past timber harvesting activities. Using 36 fire-scarred trees, we reconstructed the historical fire regimes in San Dimas, Durango, México for the last 238 years. We found a pattern of frequent fires but an absence of fire since 1962, with most fires (98%) being recorded in the spring season. The lack of fire for over six decades within these historically frequent fire forests could result in high fuel accumulation. Such conditions in combination with increasing temperatures and aridity in the region could increase the risk of high severity wildfires that could jeopardize the sustainability of these forests and the human communities that these forests support.