Dinâmica das populações de duas espécies arbóreas de Burseraceae na Floresta na Nacional do Tapajós, Belterra, PA

Abstract

The rich biodiversity of the Amazon rainforest needs to be further studied to increase its scientific knowledge. There are still areas with few studies on botany, just as there are tree populations whose phytosociology, especially with regard to structure, is unknown. In the present study the dynamics of the populations of two species of Burseraceae (Protium altsonii Sandwith and Protium apiculatum Swart) were evaluated in a forest logged 36 years ago, compared to an unlogged area, both located in the Tapajós National Forest, municipality of Belterra, Pará, at the km 67 of BR 163, Santarém-Cuiabá Highway. We tried to answer the question: these two species, which are currently used for the production of timber and non-timber products, are ecologically sustainable for continuous production in the Tapajós National Forest? We used continuous forest inventory data from 18 permanent plots of 50m x 50m installed in 25 logged hectares and 18 plots in 30 unlogged hectares, thus a total sample of 9 ha (36 plots), of which 4.5 ha in the logged area and 4.5 ha in the unlogged one. Ali trees with DBH (diameter measured at 1.30 m above the soil) > 5.0 cm were inventoried. The structure of each area was characterized by determining the abundance, frequency, dominance and importance value index of the two species. The results of the research made it possible to conclude that: 1) populations of both species have structures capable of sustaining them in the area in a sustainable way, as long as there are no natural or high intensity anthropogenic changes, with no imminent risk of extinction; 2) the two species have stocks that could be harvested for the production of timber and non-timber products, however, timber production is currently not possible because the trees do not have the minimum cutting diameter allowed by the current legislation. The production of non-timber products may be the alternative of use for both species, considering that both have stock for this and that, like other species of the same genus, they have already been used on a commercial scale; and 3) we recommend to intensify studies on the technology of the timber of the two species in order to suggest changes in the Forestry Law in relation to the minimum cutting diameter, after technical proof of the feasibility of using the timber. We also recommend that studies on uses of these species in medicine, especially, be intensified.