Can unproductive sites function as refuges for Austrocedrus chilensis against fire?

LANDESMANN, J.; GOWDA, J.H.; KITZBERGER, T.

Concepción

Conferencia; IUFRO Landscape Ecology Conference; 2012

IUFRO

Fire is a disturbance that modulates forests dynamics all around the world. Sites with less biomass, less humidity and placed in higher positions in the landscape could have less probability of being burned and/or being affected by less severe fires. Furthermore, thicker trees could be more fire resistant. Austrocedrus chilensis forests of northwestern Patagonia have been in expansion after the suppression of the XX century fires. Our hypothesis is that there are sites in the landscape that, because of their biophysics characteristics are less affected by fire, allowing the survivorship of seeder trees and consequently forests regeneration and expansion. We found that Austrocedrus trees with fire scars where older and bigger in diameter than the rest of the trees. Some of the thicker ones had more number of fire scars, indicating the survival to many fires. What’s more, in eight of the nine study sites, we found female trees with fire scars. However, we did not find any pattern on the physical variables studied that could explain the survivorship of these individuals to fire. Our results show that individual trees which survived fire could have acted as seed sources originating the post-fire forests that dominate todays northwestern Patagonian landscapes. Still, we could not identify yet physical attributes which could explain the persistence of a higher frequency of these individuals in a site.