Long-term chronosequence of forest succession in the upper Rio Negro of Colombia and Venezuela

Following slash-and-burn agriculture, number of species increased during the early stages of succession, with stands 20 to 40 years old having a species richness similar to that found in mature forests. Basal area varied from 11 m² ha^-1 in a 10-yr-old stand to 37 m² ha^-1 in a mature forest. Dry weights are given for leaves, twigs, branches, stems and roots in successional and mature tierra firme forests. The biomass for each component for 10-yr-old and mature forest stands, respectively, was 6-11 t ha^-1 for leaves, 11-23 t ha^-1 for twigs, 9-76 t ha^-1 for branches, 18-145 t ha^-1 for stems and 7-65 t ha^-1 for roots. Above-ground living biomass ranged from 44 t ha^-1 for 10-yr-old stands to 326 t ha^-1 for mature forests. Dead biomass varied from 1 t ha^-1 for 20-yr-old stands to 53 t ha^-1 for a mature forest. Above-ground living biomass increases linearly during the first 40 yr. No significant changes occur for the next 40 yr, because biomass accumulation is offset by death of long-lived successional species. About 190 yr was the estimated time taken by a previously-cultivated site to reach mature forest basal area and biomass values. -from Authors