Avaliação e Monitoramento da Regeneração Natural de Florestas Secundárias no Município de Bragança, Pará

Abstract

In Pará, the Bragantine region was one of the first areas to be massively colonized and to suffer from the process of vegetation removal, where 90% of the primary forest was transformed into secondary forest with various stages of development. Research on the dynamics of natural regeneration is essential for the development and correct application of forest management plans and silvicultural treatments. This work is being developed with the objective of contributing to the knowledge of floristic composition and dynamics of natural regeneration of secondary forests in the Municipality of Bragança-PA (Brazil). Subplots of 5mx5m and 1x5 meters were allocated to monitor natural regeneration. For the 40 year old forest, 1999 individuals belonging to 107 species and 37 botanical families were sampled. For the 50 year old forest, 1895 individuals were sampled, distributed among 135 species and 45 botanical families. The behavior of the dynamics of natural regeneration was evaluated by the entry rate (1%), mortality rate (M%) and natural regeneration rate (TR%). The results show that the youngest secondary forest (capoeira) (40 years) showed a TR% of 4.93, 1% of 23.73 and M% of 18.22. The 50-year-old forest showed during observations a TR% of -7, 33.1% of 16.28 and M% 26.55. The high mortality rate found in this forest compared to the 40 year old forest is probably due to small and recent disturbances (falling trees and branches) that are affecting the establishment and emergence of new individuals of natural regeneration.