O Manejo florestal como meio de conservação de espécies: uma proposta de manejo da espécie Acapu (Vouacapoua americana Aubl.)

Abstract

The species Vouacapoua americana Aublet (acapu or acapuzeiro), has great wood importance and, ecologically, stands out in the composition of the forests where it occurs. In the Brazilian Amazon, the species is being heavily explored without taking into account the knowledge of its ecological, structural, dynamic, silvicultural, use, economic variables, among others. The aim of this study was to contribute to the establishment of sustainable management of V. americana. The distribution zone of the V. americana populations occur in the Eastern Amazon. Dendrometric, dendrological and tree location data were obtained from Pre-Harvest Forest Inventories (IFPC) and their Continuous Forest Inventories (IFC). Information on the diametric, basal, volumetric and hypsometric structure of the species was obtained from each studied population. To evaluate the spatial distribution pattern, Ripley's K(h) function was used. To identify the ecological group of the V. americana species, two groups were considered: pioneer and non-pioneer (later successional state)For the dynamics, three stages were considered, regeneration (total height ≤30cm to DBH<2.5cm), shrub stratum (2.5cm ≤ DBH <10cm) and arboreal stratum (DBH≥10cm), and the Natural Regeneration rate (TR) was calculated. %), Ingress/recruitment (I%) and Mortality (M%). Based on the structural and dynamic characteristics, guidelines for the sustainable management of V. americana were defined. A total of 36,609 trees with a diameter varying between 10 cm and 127.32 cm were registered. Density between 6.31 trees/ha and 25.55 trees/ha. Diametric distribution showed decrease from the smallest to the largest diameter classes and when adjusted presented a distribution curve resembling a "reverse-J", a behavior reported in other studies with the species and in primary forests without disturbance anthropogenic, indicating this type of diametric distribution as a structural characteristic of the species. The basal area ranged between 0.5063m²/ha and 3.4521m²/ha, this variation was mainly influenced by the density of the species than by the DAP presented. The commercial height ranged from 2.00 m to 25.00 m, with median heights from 10 to 16 m predominating, values similar to these were observed in other studies with the species. The volume ranged from 1.6645m³/ha to 32.169m³/ha, the highest concentrations were observed in diameter classes between 40 and 80cm. V. americana was characterized in the successional group of non pionner species, having as the spatial arrangement of the trees the aggregated or grouped pattern, which was influenced by the dispersal syndrome of the species. The dynamics in the levels of seedlings, canes and trees showed variation in ingress and mortality rates, and in the arboreal population the number of trees did not vary much between measurements, indicating adaptation of the species to shading conditions in the forest. The tree population presented a diameter growth ranging from 0.22 to 0.29 cm/year, being considered low, however, in accordance with other studies for the species. The characteristics of structure, dynamics, ecology, phenology and use of V. americana provided the definition of guidelines for the sustainable management of the species: pre- exploratory forest inventory must be carried out for all trees with at least DBH ≥ 30cm; the period of exploitation of the wood product must be the months of the Amazonian summer in the region where the species occurs, before the phenophase of flowering, fruiting and seed dissemination; the minimum cut diameter (DMC) 40.00cm and the maximum cut diameter (DMxC) up to 80.00 cm; exploration intensity should be based on the adjusted diametric distribution and the observed diametric distribution; the cutting cycle must be defined by the ratio between the class interval of the diameter distribution and its growth in diameter; the selection of trees to be logged must be contained in the diameter classes of the logging interval, between the DMC and DMxC, and the density of this selection must not exceed the logging intensity; and silvicultural treatments should be based on population dynamics studies of the species.