Effect of two management systems on an open ombrophilous forest, Maranhão state, Brazil

Abstract

The objective of this study was to evaluate the floristic composition, diversity and structure of an Open Ombrophilous Forest, before and after harvesting, using the forest management systems in alternate strips (SAS) and the selective system (SS). The study was conducted at the Forest Management Unit of the MAGELA project, located in the municipality of Codó, state of Maranhão. The data were collected in six permanent plots of 50 m x 200 m located in the Annual Production Units (APU) 1 and 2, in which all trees with a diameter at 1.30 m from the ground (DBH) greater than or equal to 15 cm were measured, while trees with 5 cm < DBH <15 cm were measured in rectangular subplots of 5 m x 50 m. Data were collected on two occasions, namely: before (2001) and after (2004) the harvest. Species' richness and diversity recovered, and even increased, after the application of the SAS and SS systems, but there were changes in species composition, as many new species were registered, while others were extinct. The community structure was extremely affected by the systems, as there were major changes in the ranking of the most ecologically important species. In the short term, the volume of SAS, after exploration, was greater than that registered for the SS, indicating that, probably, the APU submitted to the SS will take longer to recover the harvested volume. © 2021 University of Sao Paolo. All rights reserved.