FIRE EFFECT UPON THE REGENERATION OF Pinus oocarpa Schiede ex Schltdl.

Abstract

Wildfires currently affect the La Primavera forest (LP); tree species have therefore developed adaptations that allow them to resist, avoid or recover from them; one of these is Pinus oocarpa, a conifer of widespread distribution in this area and whose seedlings exhibit minimal height growth and a branchy state that prevents them from attaining the reproductive stage, which results in low survival. The present study evaluates the regeneration of this species after the 2005 fire in that urban forest. In 2010, permanent 100 m2 circular sites were established, the number of individuals per plot was recorded, and reproduction by seed or root and shoot age was calculated. Results indicate a density of 62.6 shoots per site. 83 % of the population was asexually reproduced, with an age of 2-9 years; the rest is the outcome of asexual reproduction, with 1 year maximum, and exhibits a branchy state. The affected area showed a positive response on the regeneration of P. oocarpa; this species has adapted to constant and frequent burning, by modifying its root structure as a strategy of resistance; however, it showed no progress in the growing stages. This phenomenon leads to the design of a prevention plan and subsequent restoration of a fire to ensure that individuals will reach a large enough size to survive, reproduce and reduce, where possible, reforestation, as this is sometimes rather unsuccessful and has high costs.