Effect of fire on herbaceous "matorral" vegetation of Central Chile

This research aimed to determine the diversity and biomass of species in burned in the Jardin Botanico Nacional of Vina del Mar (JBN), region of Valparaiso, Chile (Lat. S 33 degrees 02' and Long. 71 degrees 35' O) from April to December 2012. Three sites were selected that were located on slopes with the same exposure: 1) site burned by fire in 2012, 2) site burned by fire in 2003, and 3) control site corresponding to an area without previous fires. Both shrub and herbaceous species were studied. The cover of shrubs, geophytes and therophytes was determined as well as the aboveground and belowground biomass of geophytes, with special attention paid to Oziroe arida. When O. arida was present, the diameter of its bulbs were studied. All information was processed by SAS software with ANOVA - analysis of 2 WAYS classification., The extensive geophyte coverage that exists in the site that was burned by fire in 2012 is due to the increased post-fire regeneration of this life-form. The biomass of geophytes is greater in the burned areas, especially during the first year after the fire (2012 site). On the site that burned in 2003, there was a higher percentage of therophyte coverage; there was no relationship found between the coverage of therophytes and the coverage of woody plants. It was determined that for each additional millimeter of diameter, there is an increase in age of 2.99 years for Oziroe arida bulbs, the most abundant geophyte in the site 1 (R-2 = 0.78); that is, the bulb diameter will be an indicator of the age of the bulbs. This study represents the first in the country to perform a quantitative analysis of the behavior of geophytes after fires (aboveground and belowground biomass), and it concluded that the action of fire favors the regeneration of geophytes through the generation of further overhead and underground biomass, which created conditions for increased reproduction.