Above-ground biomass accumulation and growth in a marginal nothofagus macrocarpa forest in Central Chile

Abstract

Nothofagus macrocarpa forests are situated in the northern limit of Nothofagus genus distribution in South America. Data related to their growth conditions are insufficient. Above-ground biomass accumulation and growth were evaluated in a secondary N. macrocarpa forest located in the northern limit of the species natural distribution. Nine plots were established, and 240 sprouts of different diameter classes were harvested. The age and volume of each sprout were determined, and tree growth in terms of diameter and height was also analyzed. Total aboveground biomass was measured in a subsample of 62 sprouts, according to the components: stem, branches and foliage. The forest had an uneven-aged coppice structure, the mean age being 39 years. Average diameter growth rate was 0.23cm/year, height growth rate was 32.3cm/year and the mean volume growth rate was 0.43m3·ha-1/year, which are lower than the values indicated for other species of the same genus. The accumulated above ground biomass reached 35.2ton·ha-1. The low values measured are explained by the marginal condition of the forest as well as its degradation status due to anthropogenic activity. This condition requires of setting measures that assure the survival and the recovery of this forest.