Background:The characterization of surface and canopy fuel loadings in fire-prone pine ecosystems is critical for understanding fire behavior and anticipating the most harmful ecological effects of fire.Nevertheless,the joint consideration of both overstory and understory strata in burn severity assessments is often dismissed.The aim of this work was to assess the role of total,overstory and understory pre-fire aboveground biomass(AGB),estimated by means of airborne Light Detection and Ranging(LiDAR)and Landsat data,as drivers of burn severity in a megafire occurred in a pine ecosystem dominated by Pinus pinaster Ait.in the western Mediterranean Basin.Results:Total and overstory AGB were more accurately estimated(R2 equal to 0.72 and 0.68,respectively)from LiDAR and spectral data than understory AGB(R2=0.26).Density and height percentile LiDAR metrics for several strata were found to be important predictors of AGB.Burn severity responded markedly and non-linearly to total(R2=0.60)and overstory(R2=0.53)AGB,whereas the relationship with understory AGB was weaker(R2=0.21).Nevertheless,the overstory plus understory AGB contribution led to the highest ability to predict burn severity(RMSE=122.46 in dNBR scale),instead of the joint consideration as total AGB(RMSE=158.41).Conclusions:This study novelty evaluated the potential of pre-fire AGB,as a vegetation biophysical property derived from LiDAR,spectral and field plot inventory data,for predicting burn severity,separating the contri-bution of the fuel loads in the understory and overstory strata in Pinus pinaster stands.The evidenced relationships between burn severity and pre-fire AGB distribution in Pinus pinaster stands would allow the implementation of threshold criteria to support decision making in fuel treatments designed to minimize crown fire hazard.

José Manuel Fernández-Guisuraga;Susana Suárez-Seoane;Paulo M.Fernandes;Víctor Fernández-García;Alfonso Fernández-Manso;Carmen Quintano;Leonor Calvo

Area of Ecology,Department of Biodiversity and Environmental Management,Faculty of Biological and Environmental Sciences,University of León,24071,León,Spain;Centro de Investiga??o e de Tecnologias Agroambientais e Biológicas,Universidade de Trás-os-Montes e Alto Douro,5000-801,Vila Real,Portugal;Department of Organisms and Systems Biology(Ecology Unit)and Research Unit of Biodiversity(IMIB;UO-CSIC-PA),University of Oviedo,Oviedo,Mieres,Spain;Agrarian Science and Engineering Department,School of Agricultural and Forestry Engineering University of León,24400,Ponferrada,Spain;Electronic Technology Department,School of Industrial Engineering,University of Valladolid,47011,Valladolid,Spain;Sustainable Forest Management Research Institute,University of Valladolid-Spanish National Institute for Agriculture and Food Research and Technology(INIA),34004, Palencia,Spain

森林生态系统（英文版）

[1]José Manuel Fernández-Guisuraga;Susana Suárez-Seoane;Paulo M.Fernandes;Víctor Fernández-García;Alfonso Fernández-Manso;Carmen Quintano;Leonor Calvo-.Pre-fire aboveground biomass,estimated from LiDAR,spectral and field inventory data,as a major driver of burn severity in maritime pine(Pinus pinaster)ecosystems)[J].森林生态系统（英文版）,2022(02):234-246

pinaster,overstory,dismissed,megafire

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