01964naa a2200205 a 450000100080000000500110000800800410001910000230006024500940008326000090017730000140018652012940020065000180149465000130151265000220152565000110154765000170155870000120157577301710158713278592002-11-22       1991    bl uuuu     u00u1 u    #d1 aSALDARRIAGA, J. G.  aRecovery of forest vegetation following slash-and-burn agriculture in the Upper Rio Negro  c1991  ap.303-312  aChanges in species composition, forest structure and biomass have been studied at 24 tropical forest sites along the Upper Rio Negro region of Colombia and Venezuela. Stands were selected from the tierra firme forests (non-flooded) to represent a chronosequence of succession following slash-and-burn agricultural practices. After abandonment, the number of species increases from early successional to mature forests. The speciescomposition of the mature forests depends on a small fraction of primary species that survive from early stages of succession and on the introduction of many primary species at later stages of succession. Small areas disturbed by slash-and-burn agriculture recover their original species composition, but the time required varies, dependingon the intensity and frequency of disturbance in the area. On a large scale, the forest is a mosaic of different aged patches and structural characteristics, with high variability among stands, depending on soils, micro-relief, species composition, and disturbance dynamics. Approximately 140-200 years is required for an abandoned farm to attain the biomass values comparable to those of a mature forest. Recovery is thus five to seven times longer in the Upper Rio Negro than in other tropical areas in South America.  aConservação  aEcologia  aFloresta Tropical  aManejo  aSilvicultura1 aUHL, C.  tIn: GOMEZ-POMPA, A.; WHITMORE, T.C.; HADLEY, M. Rain forest regeneration and management. Paris: UNESCO/Parthenon Publishing, 1991. (Man and the biophere seriesgv.6).