Forest plantations can substantially contribute to carbon sequestration and greenhouse gases (GHG) mitigation at the country and global scale. Forest fires (specially when combined with droughts) may significantly reduce such carbon sequestration capability. IPCC has global scale estimates for such losses, but they can vary widely depending on crops, climate, topography and management, among others. IPCC defines a factor for biomass loss as a consequence of forest fires, expressed as a fraction of total biomass. This methodology implies using aggregated data and the default emission factor, being only recommended for countries where wildfires are not a key category. In Chile, and over the last decade, there are between 5,000 to 8,000 wildfires annually (average 6,398 for the period 2011-2020), burning an average of 122,328 hectares each year. Countries may progress in the refinement of such factors depending on the availability and reliability of local values. This paper aims at estimating C_f values for the main forest plantation species in Chile: Pinus radiata, Eucalyptus nitens, and Eucalyptus globulus, across different age-classes and forest fire severities. To this aim we assessed the biomass loss after forest fires for a stratified sample of forest plots for the season 2018-2019. We fitted a model to predict the amount of biomass loss during fires, and in this way, predict the emissions associated to wildfires. The model employs very simple predictive variables, age and species, because statistics for burnt areas in plantations are only provided by age-classes and species, without details about productivity or management.