Determining burn severity and its impact on post fire regeneration in the Nothofagus forests of Tierra del Fuego, Argentina.

MATTHEW JOSEPH RUGGIRELLO; GIMENA NOEMÍ BUSTAMANTE; PETE FULÉ; ROSINA SOLER

Conferencia; Conference: 8th International Wildland Fire Conference; 2023

AGIF

In Tierra del Fuego, southern Argentina, recent wildfires in Nothofagus (southern beech) forests have produced post-fire conditions commonly associated with high burn severities (high mortality and deep ground-layer consumption). Still, burn severity has not been systematically categorized for fires in the region. In two recent wildfires (2008, 2019), we established 80 burned and 16 unburned (control) plots in N. pumilio and N. antarctica forests in which we visually estimated burn severity, measured live tree basal area, estimated bare-soil abundance, and tallied seedlings (≤30cm). Visual estimations classified 71% of post-fire plots as having burned at high severity (>90% overstory mortality, >50% bare-mineral soil) and 29% at low severity (≤90% but >0% overstory mortality, ≤50% bare-mineral soil but >0%). Average live basal area increased from 0 m2ha-1 in high-severity burn plots, to 5 m2ha-1 in low-severity plots, and 41 m2ha-1 in controls. Bare-soil dominated microsites represented 29% of all microsties in high-severity plots, 18% in low-severity plots, and 1% in controls. Seedling density was negatively correlated with both visual estimates of burn severity (r=-0.43, p