Frações da serapilheira no sítio das árvores gigantes no Parque Nacional Montanhas do Tumucumaque

Abstract

In recent decades, anthropogenic activities have caused changes in natural ecosystems, intensifying global climate change. Due to its vast extent and biodiversity, the Amazon plays an essential role in carbon sequestration and global climate balance, with litter being an important component in the relationship between soil and vegetation, nutrient cycling, and carbon storage. This study evaluated the composition and accumulation of litter in areas containing Dinizia excelsa (angelim-vermelho), a large emergent species with high wood density. The research was conducted in the Montanhas do Tumucumaque National Park, located in the state of Amapá, Brazil. Accumulated litter was collected in four plots using 625 cm² (25 × 25 cm) frames. The collected material was separated into five fractions (leaves, branches, bark, reproductive material, and miscellaneous), then oven-dried at 65 °C for 96 h and weighed to determine the biomass of each fraction. Dinizia excelsa, one of the largest trees in the Amazon, stands out for its large size and high wood density characteristics that may directly influence both the accumulation and quality of litter, prolonging carbon retention in the soil. Part of the study’s hypothesis is that this species contributes significantly to biomass stocks, surpassing other species within the same phytophysiognomy. The results showed a predominance of the leaf fraction (38.16%–43.95%), followed by branches (24.09%–28.64%) and bark (17.30%–25.56%), a pattern typical of humid tropical forests such as the one studied. The miscellaneous fraction ranged from 8.03% to 10.10%, while reproductive material showed the lowest contribution (1.79%–4.63%). Differences in the amount of accumulated litter among the studied plots may be related to microclimate and canopy structure, influenced by emergent individuals. The order of contribution of the fractions was: leaves > branches > bark > miscellaneous > reproductive material. It is concluded that Dinizia excelsa influences both the input and quality of accumulated litter, reinforcing its ecological importance in Amazonian forests and highlighting its essential role in organic matter input and nutrient cycling.