Avaliação dos tratamentos silviculturais para produção diversificada e de Platonia insignis Mart. (bacuri) das unidades experimentais de manejo de florestas secundarias no Nordeste Paraense

Abstract

The agricultural use of secondary forest areas by the traditional method of slash and burn results in environmental degradation, which makes necessary studies of alternative uses of these forests. A research project is being conducted in the Northeast of Pará in an attempt to find ways to exploit secondary forests and enable appropriate techniques for their management. Silvicultural experiments for diversified production (PD) and Platonia insignis Mart, (Bacuri) (BP) have been installed. The study is being carried out in approximately 20 year old stands in the community of Enfarrusca, Bragança - PA. As criteria for the selection of species for the treatments the following characteristics were adopted: minimum diameter of 5.0 in for PD and 10 cm for BP, at 1.30 m from the ground, complete stem without damage or rot, healthy crown and with good development. The silvicultural treatment consisted of eliminating competing individuals at the crown level of the selected tree using direct cutting (thin trees and vines) or girdling (used on trees that could cause damage to other species by falling). In the PD area 168 individuals were identified, of which 73 individuals in the control plots, without intervention (TO), distributed in 8 species and 95 individuals for treatment with intervention (TI), distributed in 14 species. In the area of BP were' identified138 individuals, where in the TO and TI plots there are 42 and 96 individuals of bacuri respectively. The fourth year of measurement showed that the mean diametric growth for PD in the intervention area was 0.12 cm compared to the untreated area; and the mean diameter growth for BP in the intervention area was 0.34 cm compared to the untreated area. The small difference between the TO and Tinas plots is probably due to the short period of time that was not enough for the treatment to take effect and/or the intense regeneration by regrowth of the eliminated species that possibly increased competition with the selected species.