Holocene palaeofires in Neotropics high mountains: The contribution of soil charcoal analysis.

The Holocene palaeofires in Southern America has been generally attributed to climate until the middle Holocene and to human activities for later periods. Soil charcoal analysis and extensive AMS dating were carried out on six soil profiles, between 3400 and 3900 m a.s.l. in the Guandera Biological Reserve (Western Cordillera Real, North Ecuador). AMS results showed an ordered stratification of charcoals allowing a fire history reconstruction over the last 11,700 cal BP. The reported fire occurrences fit well with Holocene global scale arid periods. The association between fires and climate signals suggested a marginal role of humans in the environmental history of the studied area. Here, the human inference started at ca 2500 cal BP, but became considerable only in the last millennium.