Use este identificador para citar ou linkar para este item: https://repositorio.inpa.gov.br/handle/1/18953
Título: Forest structure and carbon dynamics in Amazonian tropical rain forests
Autor: Vieira, Simone Aparecida
Camargo, Plínio Barbosa de
Selhorst, Diogo
Silva, Roseana Pereira da
Hutyra, Lucy R.
Chambers, Jeffrey Quintin
Brown, Irving Foster
Higuchi, Niro
Santos, Joaquim dos
Wofsy, Steven C.
Trumbore, Susan Elizabeth
Martinelli, Luiz Antônio
Palavras-chave: Biomass
Carbon Cycle
Carbon Sequestration
Growth Rate
Rainforest
Stand Structure
Tropical Forest
South America
Data do documento: 2004
Revista: Oecologia
É parte de: Volume 140, Número 3, Pags. 468-479
Abstract: Living trees constitute one of the major stocks of carbon in tropical forests. A better understanding of variations in the dynamics and structure of tropical forests is necessary for predicting the potential for these ecosystems to lose or store carbon, and for understanding how they recover from disturbance. Amazonian tropical forests occur over a vast area that encompasses differences in topography, climate, and geologic substrate. We observed large differences in forest structure, biomass, and tree growth rates in permanent plots situated in the eastern (near Santarém, Pará), central (near Manaus, Amazonas) and southwestern (near Rio Branco, Acre) Amazon, which differed in dry season length, as well as other factors. Forests at the two sites experiencing longer dry seasons, near Rio Branco and Santarém, had lower stem frequencies (460 and 466 ha-1 respectively), less biodiversity (Shannon-Wiener diversity index), and smaller aboveground C stocks (140.6 and 122.1 Mg C ha-1) than the Manaus site (626 trees ha -1, 180.1 Mg C ha-1), which had less seasonal variation in rainfall. The forests experiencing longer dry seasons also stored a greater proportion of the total biomass in trees with >50 cm diameter (41-45 vs 30% in Manaus). Rates of annual addition of C to living trees calculated from monthly dendrometer band measurements were 1.9 (Manaus), 2.8 (Santarém), and 2.6 (Rio Branco) Mg C ha-1 year-1. At all sites, trees in the 10-30 cm diameter class accounted for the highest proportion of annual growth (38, 55 and 56% in Manaus, Rio Branco and Santarém, respectively). Growth showed marked seasonality, with largest stem diameter increment in the wet season and smallest in the dry season, though this may be confounded by seasonal variation in wood water content. Year-to-year variations in C allocated to stem growth ranged from nearly zero in Rio Branco, to 0.8 Mg C ha -1 year-1 in Manaus (40% of annual mean) and 0.9 Mg C ha-1 year-1 (33% of annual mean) in Santarém, though this variability showed no significant relation with precipitation among years. Initial estimates of the C balance of live wood including recruitment and mortality as well as growth suggests that live wood biomass is at near steady-state in Manaus, but accumulating at about 1.5 Mg C ha-1 at the other two sites. The causes of C imbalance in living wood pools in Santarém and Rio Branco sites are unknown, but may be related to previous disturbance at these sites. Based on size distribution and growth rate differences in the three sites, we predict that trees in the Manaus forest have greater mean age (∼240 years) than those of the other two forests (∼140 years). © Springer-Verlag 2004.
DOI: 10.1007/s00442-004-1598-z
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