Representative data in estimating the height of the mangrove forest canopy

Abstract

Introduction: The use of remote sensing in environmental studies has become increasingly promising, mainly due to its facilitating factor when dealing with inhospitable places. The study area is a small section of 4 acres located in the Guaratiba State Biological Reserve, which plays a very important role in preserving the remaining mangroves in the metropolitan region of Rio de Janeiro. This cutout was chosen due to accessibility criteria, given the need to enter the mangrove to collect data. Objective: The work sought to map this small area, characterizing the mangrove species and their heights, with the objective of relating the height data of the species obtained in the field with the 2019 LiDAR data, in order to understand whether these data , even after three years, are still significant. Results: The three species found in the area were Rhizophora Mangle (red mangrove), Avicennia schaueriana (black mangrove) and Laguncularia racemosa (white mangrove), which are the three predominant species in the surrounding area (ALMEIDA, 2010). Thus, when comparing the data obtained by the two surveys of canopy height, field and remote, 91 of the 106 points showed agreement in a global correlation of 85.85%. The classification was divided into heights E1, E2, E3, E4 to assist in the quick characterization in the field. In addition, the micro topography was compared in relation to the height of the trees, in which the presence of more developed individuals of Rhizophora and Laguncularia was identified in areas of lower altitude or more flooded, while those of Avicennia occur in the opposite process. Finally, it was possible to identify that even with the difference of three years, the height values obtained by LiDAR in the area are still representative, and that it is possible to estimate the canopy height of mangrove species using the 2019 LiDAR sensor currently.