LEAF-AREA INDEX AND ABOVEGROUND BIOMASS OF TERRA-FIRME RAIN-FOREST AND ADJACENT CLEARINGS IN AMAZONIA

1. Leaf area index (L*) and above-ground biomass were determined by destructive sampling for a 400-m2 area of terra firme amazonian rain forest and for an adjacent clearing. 2. While L* in the forest varied considerably with height through the canopy for four separately sampled 100-m2 subplots, the cumulative L* was similar with a mean value of 5.7 +/- 0.5. 3. The total above-ground dry biomass of the forest was 265 +/- 95 t ha-1, while the leaf dry biomass was 6.3 +/- 0.5 t ha-1. 4. The specific leaf area (SLA, cm2 g-1) was determined, and found to vary linearly with canopy depth rising from 65 cm2 g-1 at the canopy top, to 114 cm2 g-1 at 5 m above the forest floor. The average for the four subplots was 90 cm2 g-1. 5. The leaf area index of grass in the clearing (blade only) averaged 0.8 +/- 0.4, and total green area index (blade+stem) averaged 1.2 +/- 0.6. Total above-ground dry biomass (blade, stem) was 2.3 +/- 0.6 t ha-1, while including dead plant material gave a total dry biomass of 5.6 +/- 2.1 t ha-1. Specific leaf area of the grass was 79 cm2 g-1. 6. The results clearly demonstrate the profound change in leaf area and biomass which accompany amazonian deforestation.