Demografia da regeneração natural de Swietenia macrophylla King (mogno) após exploração florestal de impacto reduzido na fazenda Seringal Novo Macapá na Amazônia ocidental brasileira.

Abstract

Swietenia macrophylla King (mahogany), is a climax species (light demanding), has great economic importance. His holding may affect the integrity of its people and as a result the Brazilian government established specific regulations for the management of forests with occurrence of mahogany. In this study we analyzed the dynamics of natural regeneration of S. macrophylla after opening the canopy by logging in sustainable forest management. The study area is located on the bank of the Purus River in New Farm Seringal Macapa, State of Amazonas. They selected fourteen trees S. macrophylla, four of which were explored and ten remained. Three plots of 10 x 200 m were installed in each of the 14 selected trees, following the direction of the dominant winds. The central portion of the tree starts at the base of 5m, the other two plots were established from the beginning of the central portion, one on each side, considering an angle of 45 ° between them. Each plot was divided into four sub-plots 50 x 10m, and each sub-plot was divided into smaller sub-portions 10 x 10m, to facilitate monitoring. These plots were counted all individuals mahogany seedlings of class (height <30.0 cm) and recorded and measured all the individuals of the species from seedlings class (30 cm <height and DBH <2.5 cm) up to 10cm DAP before the operation (2010) and after (2012 and 2014). The logging in the first instance adversely affected the natural regeneration of Swietenia macrophylla King, reducing its density and distribution. However, clearings made possible the restoration of the stock and frequency of regeneration, but only due to the trees of reproductive age who were left as door-seed. Thus, keeping adult trees of the species is more likely to recovery of regeneration after the activities of logging. Most natural mahogany regeneration occurred within 100m distance from the trees arrays. The implementation of government guidelines, DMC = 60 cm and leave 20% of the trees of commercial size as door-seed, seem to have had a positive effect on natural regeneration. However, four years of observations may be short to confirm these results and therefore a longer period of monitoring is advisable to corroborate the results of the investigation. Applying too, silvicultural treatments, enabling the supply of light to the development of species, as it was not found in individuals mahogany strata rods and saplings.