From forest to shrubland: Structural responses to different fire histories in Prosopis flexuosa woodland from the Central Monte (Argentina)

Abstract

We estimate post-fire population trajectories, and to analyze the effect of fire recurrence on the post-fire recovery in seven different fire histories in the Central Monte. The structure of stems showed that unburned woodland and woodlands with the longest post-fire recovery time presented higher proportion of stems with basal diameter (BD)>5 cm. On sites with higher recurrence of fires, the stems with BD>5 cm almost disappeared. Tree height and crown diameter showed a significant decrease at sites recently burned, and this pattern was reinforced in areas with recurrent fires. Results suggest that the structure of woodland in the southeast of Mendoza Province (Argentina) is strongly controlled by the fire history. Fire generates a population dominated by individuals with numerous smaller-sized stems, which becomes more evident in environments where fire recurrence is higher. Structural changes induced by fire indicate that logging may not be possible in the area, needing development of techniques for post-fire management of the burned areas. An increase in fire frequency is to be expected in the area, and therefore a modification of the structure of the P. flexuosa population, leading to woodland conversion to shrubland and loss of capacity for natural recovery.