Post-fire recovery occurs overwhelmingly by resprouting in the Chaco Serrano forest of Central Argentina

Abstract

In fire-prone landscapes, differences in post-fire regeneration by resprouting between species or sites could be far more important in explaining vegetation physiognomy and composition than seed regeneration. This is the first study exploring the relative contribution of tree resprouts and seeds to post-fire crown volume in the Chaco Serrano forest of South America. Additionally, we compare the resprouting response among species and quantify post-fire changes in tree composition among sites. We established 290 permanent plots distributed in three sites affected by wildfires in 2005. For all tree species in all plots we recorded survival of every individual 1 year after the fire; at the plot level, we recorded the above-ground tree volume before and 3 years after the fire. Resprouting from the base was the main resprouting type. Survival varied between species from 73% to 100% for native species and from 7% to 100% for non-natives. Before the fire, crown volume was similar in the three sites, and was completely lost after the fire in 92% of the plots. Three years after the fire, between 8% and 58% of crown volume was recovered. The ratio of crown recovery because of resprouts and seedlings was 1562:1. Tree composition exhibited few changes because of the high post-fire survival of most native species. We conclude that in the semiarid Chaco Serrano ecosystem tree species regenerate mainly by resprouting. This regeneration mode should be taken into account to better understand post-fire successional pathways of these forests, their management and the restoration of burnt forest areas. © 2013 Ecological Society of Australia.