MORTALITY AND TREE RECRUITMENT IN A TEMPERATE PINE-OAK FOREST IN JALISCO STATE

Abstract

Forest dynamics and succession patterns involve certain processes including mortality and incorporation of individuals, the knowledge of which is the basis for forest protection and management actions. The mortality and tree recruitment rates in the natural reserve of Sierra de Quila, Jalisco, were assessed. Two measurements were carried out in 31 permanent monitoring sites: one in the year 2002, and another in the year 2010. These measurements included all the trees with a normal diameter of ≥ 7 cm, apart from the recruited trees. The registered mortality codes were: standing dead, felled, cut down and dead with no apparent traces. The mortality rates, the exponential recruitment rate and the average life span of the forest were estimated. The first sampling involved 918 individuals distributed in 17 species, and the second sampling included 897 individuals distributed in 16 species. An annual mortality rate of 1.75 % and an exponential mortality rate of 1.77 % were calculated. The annual recruitment rate was 1.08 %, and the exponential recruitment rate was 1.07 %. The estimated average life span of the forest varied between sites, but the overal average was 45.4 years. The differences between the samples, for both individuals and demographic rates, indicated an imbalance in the population dynamics of the forest.