Estoque de carbono no solo, na serapilheira e na biomassa em povoamentos de Khaya
Nenhuma Miniatura disponível
Data
2025-03-25
Autores
Gomes, Gabriel Soares Lopes
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Federal do Espírito Santo
Resumo
African mahogany (genus Khaya) has emerged as a promising species for both carbon sequestration and high-value biomass production, especially due to its qualities as a hardwood used in the furniture, shipbuilding and civil construction. The aim of this study was to evaluate the dynamics of carbon and nutrients in soil, litter and aboveground biomass, comparing three African mahogany species (K. grandifoliola, K. ivorensis and K. senegalensis). The study was carried out in 9.5-year-old Khaya. stands in the Vale Natural Reserve (RNV), ES, established at a spacing of 5 m × 5 m, distributed in rectangular sample plots of 1,200 m2. Disturbed soil samples were collected for chemical analysis and undisturbed samples were collected for determination of soil density (SD) at depths of 0-5, 5-10, 10-20, 20-30 and 30-40 cm, with subsequent comparison to the native forest area. Sampling of litter was performed randomly, with the aid of a quadrangular template, collecting 30 samples per plot in a single period. Biomass assessment was carried out using the direct method, with the cut of 12 trees per species and fractionation into: stem wood, stem bark, branches and leaves. The nutrient stock of each tree fraction was obtained and the amount of nutrients exported in different harvest scenarios was estimated. The results indicated that there were no differences in soil carbon and nitrogen stocks among Khaya, but the values obtained were similar to those of the reference area. Biomass, concentration and carbon stocks of litter were not influenced by the species. K. ivorensis was approximately 70 % superior in terms of nitrogen stock in litter. The carbon stock in aboveground biomass for K. grandifoliola, K. ivorensis and K. senegalensis was 37.97, 33.66 and 33.86 Mg ha-1. Furthermore, the analysis of biomass production and nutrient dynamics in different harvest scenarios demonstrated that conservative management practices, such as selective removal of biomass, result in lower nutrient losses, contributing to soil conservation and plantation sustainability. In general, K. senegalensis exhibited the highest percentages of bark, while K. ivorensis stood out for the highest percentage of leaves. The biomass of stem wood and branches did not vary according to the species. The relative proportions of biomass show the following order of allocation: branches > stem wood > stem bark > leaves. The total amount of N, P, K and S were not influenced by the species, but the stocks of Ca and Mg were higher for K. grandifoliola, being 22.1 % higher for Ca than for K. senegalensis and 42.3 % higher for Mg than for K. ivorensis. These results provide a solid basis for the sustainable management of African mahogany, suggesting that, in addition to the environmental benefits, this species may be a viable economic alternative for the Brazilian forestry sector, with high potential for reducing GHG emissions and diversifying forest production.
Descrição
Palavras-chave
Mahogonny , Nutrição florestal , Ciclagem biogeoquímica , Exportação de nutrientes