Abstract

ALINARI, Julieta; CINGOLANI, Ana M; VON MULLER, Axel R  and  CABIDO, Marcelo. Tree size and microenvironment affect fire damage and survival in Chaco Serrano. Ecol. austral [online]. 2019, vol.29, n.2, pp.272-284. ISSN 1667-782X.

Wildfires differentially affect specimens of the same woody species, depending, among other factors, on tree size and microenvironment. This has implications for the structuring of forest landscapes, as forest recovery depends, in part, on the severity of fire on woody specimens. We aimed at analyzing how microenvironment and tree size affect fire damage and survival in two woody species common in the Chaco Serrano forest, along an altitudinal gradient in Córdoba Mountains (Argentina). We studied two wildfires that occurred in July and August 2007. We selected 163 espinillos (Vachellia caven) and 48 molles (Lithraea molleoides) located between 800 and 1700 m a. s. l. For each individual, we estimated pre-fire height and volume on the basis of the remaining woody tissues, and microenvironmental characteristics as plant cover, rock proportion under the crown, slope, aspect and insolation by interception. After three months we estimated the fire damage for each individual and three years later we evaluated survival. The espinillos with higher plant cover in their surroundings were more damaged, and this effect was more pronounced at lower altitudes. Additionally, individuals were more damaged in steep southern slopes than in northern slopes, while smaller individuals were more damaged than larger ones. Taller molles experienced less fire damage than shorter molles. The 94% of the espinillos and 92% of the molles survived the wildfire, with higher death probability for smaller individuals in the case of espinillo. We concluded the system becomes less susceptible to fire as succession proceeds, mainly because of the increasing size of woody individuals and the reduction of herbaceous cover.

Keywords : Altitude; Tree height; Mountain forest; Plant cover; Espinillo; Wildfires; Molle; Slope; Rockiness; Córdoba Mountains.

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